浅谈 MVP in Android

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一、概述

对于MVP（Model View Presenter），大多数人都能说出一二：“MVC的演化版本”，“让Model和View完全解耦”等等。本篇博文仅是为了做下记录，提出一些自己的看法，和帮助大家如何针对一个Activity页面去编写针对MVP风格的代码。

对于MVP，我的内心有一个问题：

为何这个模式出来后，就能被广大的Android的程序员接受呢？

问了些程序员，他们对于MVP的普遍的认识是：“代码很清晰，不过增加了很多类”。我在第一次看到MVP的时候，看了一个demo，看完以后觉得非常nice（但是回过头来，自己想个例子写，就头疼写不出来，当然这在后文会说）。nice的原因还是因为，这个模式的确让代码的清晰度有了很大的提升。

那么，提升一般都是对比出来的，回顾下，没有应用MVP的代码结构。很多人说明显是MVC么：

View：对应于布局文件
Model：业务逻辑和实体模型
Controllor：对应于Activity

看起来的确像那么回事，但是细细的想想这个View对应于布局文件，其实能做的事情特别少，实际上关于该布局文件中的数据绑定的操作，事件处理的代码都在Activity中，造成了Activity既像View又像Controller（当然了Data-Binder的出现，可能会让View更像View吧）。这可能也就是为何，在该文中有一句这样的话：

Most of the modern Android applications just use View-Model architecture，everything is connected with Activity.

而当将架构改为MVP以后，Presenter的出现，将Actvity视为View层，Presenter负责完成View层与Model层的交互。现在是这样的：

View 对应于Activity，负责View的绘制以及与用户交互
Model 依然是业务逻辑和实体模型
Presenter 负责完成View于Model间的交互

ok，先简单了解下，文中会有例子到时候可以直观的感受下。

小总结下，也就是说，之所以让人觉得耳目一新，是因为这次的跳跃是从并不标准的MVC到MVP的一个转变，减少了Activity的职责，简化了Activity中的代码，将复杂的逻辑代码提取到了Presenter中进行处理。与之对应的好处就是，耦合度更低，更方便的进行测试。借用两张图（出自:该文），代表上述的转变：

转变为：

二、MVP 与 MVC 区别

ok，上面说了一堆理论，下面我们还是需要看一看MVC与MVP的一个区别，请看下图（来自：本文）:

其实最明显的区别就是，MVC中是允许Model和View进行交互的，而MVP中很明显，Model与View之间的交互由Presenter完成。还有一点就是Presenter与View之间的交互是通过接口的（代码中会体现)。

还有一堆概念性的东西，以及优点就略了，有兴趣自行百度。下面还是通过一些简单的需求来展示如何编写MVP的demo。

效果图：

看到这样的效果，先看下完工后的项目结构：

ok，接下来开始一步一步的编写思路。

（一）Model

首先实体类User不用考虑这个肯定有，其次从效果图可以看到至少有一个业务方法login()，这两点没什么难度，我们首先完成：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.zhy.blogcodes.mvp.bean;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Created by zhy on 15/6/18. */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">User</span>{</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> String username ;    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> String password ;    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> String <span class="hljs-title" style="box-sizing: border-box;">getUsername</span>()    {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> username;    }    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setUsername</span>(String username)    {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.username = username;    }    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> String <span class="hljs-title" style="box-sizing: border-box;">getPassword</span>()    {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> password;    }    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setPassword</span>(String password)    {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.password = password;    }}</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">4</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">5</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">6</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">7</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">8</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">9</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">10</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">11</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">12</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">13</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">14</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">15</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">16</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">17</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">18</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">19</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">20</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">21</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">22</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">23</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">24</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">25</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">26</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">27</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">28</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">29</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">30</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">31</span></li></ul>

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.zhy.blogcodes.mvp.biz;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Created by zhy on 15/6/19. */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">interface</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">IUserBiz</span>{</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">login</span>(String username, String password, OnLoginListener loginListener);}</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">4</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">5</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">6</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">7</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">8</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">9</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">10</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">11</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">12</span></li></ul>

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.zhy.blogcodes.mvp.biz;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.bean.User;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Created by zhy on 15/6/19. */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">UserBiz</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">IUserBiz</span>{</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">login</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String username, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String password, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> OnLoginListener loginListener)    {        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//模拟子线程耗时操作</span>        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Thread()        {            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>()            {                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>                {                    Thread.sleep(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2000</span>);                } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (InterruptedException e)                {                    e.printStackTrace();                }                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//模拟登录成功</span>                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"zhy"</span>.equals(username) && <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"123"</span>.equals(password))                {                    User user = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> User();                    user.setUsername(username);                    user.setPassword(password);                    loginListener.loginSuccess(user);                } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>                {                    loginListener.loginFailed();                }            }        }.start();    }}</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">4</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">5</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">6</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">7</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">8</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">9</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">10</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">11</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">12</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">13</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">14</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">15</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">16</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">17</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">18</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">19</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">20</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">21</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">22</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">23</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">24</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">25</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">26</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">27</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">28</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">29</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">30</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">31</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">32</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">33</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">34</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">35</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">36</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">37</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">38</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">39</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">40</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">41</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">42</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">43</span></li></ul>

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.zhy.blogcodes.mvp.biz;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.bean.User;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Created by zhy on 15/6/19. */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">interface</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">OnLoginListener</span>{</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> loginSuccess(User user);    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> loginFailed();}</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">4</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">5</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">6</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">7</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">8</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">9</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">10</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">11</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">12</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">13</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">14</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">15</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">16</span></li></ul>

实体类不用说，至于业务类，我们抽取了一个接口，一个实现类这也很常见~~login方法，一般肯定是连接服务器的，是个耗时操作，所以我们开辟了子线程，Thread.sleep(2000)模拟了耗时，由于是耗时操作，所以我们通过一个回调接口来通知登录的状态。

其实这里还是比较好写的，因为和传统写法没区别。

(二) View

上面我们说过，Presenter与View交互是通过接口。所以我们这里需要定义一个ILoginView，难点就在于应该有哪些方法，我们看一眼效果图：

可以看到我们有两个按钮，一个是login，一个是clear；

login说明了要有用户名、密码，那么对应两个方法：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;">    String getUserName();    String getPassword();</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">4</span></li></ul>

再者login是个耗时操作，我们需要给用户一个友好的提示，一般就是操作ProgressBar，所以再两个：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;">    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> showLoading();    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> hideLoading();</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li></ul>

login当然存在登录成功与失败的处理，我们主要看成功我们是跳转Activity，而失败可能是去给个提醒：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;">    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> toMainActivity(User user);    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> showFailedError();</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li></ul>

ok，login这个方法我们分析完了~~还剩个clear那就简单了：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;">    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> clearUserName();    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> clearPassword();</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li></ul>

综上，接口完整为：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.zhy.blogcodes.mvp.view;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.bean.User;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Created by zhy on 15/6/19. */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">interface</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">IUserLoginView</span>{</span>    String getUserName();    String getPassword();    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> clearUserName();    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> clearPassword();    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> showLoading();    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> hideLoading();    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> toMainActivity(User user);    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> showFailedError();}</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">4</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">5</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">6</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">7</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">8</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">9</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">10</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">11</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">12</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">13</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">14</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">15</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">16</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">17</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">18</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">19</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">20</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">21</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">22</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">23</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">24</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">25</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">26</span></li></ul>

有了接口，实现就太好写了~~~

总结下，对于View的接口，去观察功能上的操作，然后考虑：

该操作需要什么？（getUserName, getPassword）
该操作的结果，对应的反馈？(toMainActivity, showFailedError)
该操作过程中对应的友好的交互？(showLoading, hideLoading)

下面贴一下我们的View的实现类，哈，其实就是Activity，文章开始就说过，MVP中的View其实就是Activity。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.zhy.blogcodes.mvp;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.os.Bundle;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.support.v7.app.ActionBarActivity;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.view.View;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.widget.Button;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.widget.EditText;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.widget.ProgressBar;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.widget.Toast;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.R;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.bean.User;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.presenter.UserLoginPresenter;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.view.IUserLoginView;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">UserLoginActivity</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ActionBarActivity</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">IUserLoginView</span>{</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> EditText mEtUsername, mEtPassword;    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Button mBtnLogin, mBtnClear;    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> ProgressBar mPbLoading;    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> UserLoginPresenter mUserLoginPresenter = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> UserLoginPresenter(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>);    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">protected</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onCreate</span>(Bundle savedInstanceState)    {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.onCreate(savedInstanceState);        setContentView(R.layout.activity_user_login);        initViews();    }    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">initViews</span>()    {        mEtUsername = (EditText) findViewById(R.id.id_et_username);        mEtPassword = (EditText) findViewById(R.id.id_et_password);        mBtnClear = (Button) findViewById(R.id.id_btn_clear);        mBtnLogin = (Button) findViewById(R.id.id_btn_login);        mPbLoading = (ProgressBar) findViewById(R.id.id_pb_loading);        mBtnLogin.setOnClickListener(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> View.OnClickListener()        {            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onClick</span>(View v)            {                mUserLoginPresenter.login();            }        });        mBtnClear.setOnClickListener(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> View.OnClickListener()        {            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onClick</span>(View v)            {                mUserLoginPresenter.clear();            }        });    }    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> String <span class="hljs-title" style="box-sizing: border-box;">getUserName</span>()    {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> mEtUsername.getText().toString();    }    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> String <span class="hljs-title" style="box-sizing: border-box;">getPassword</span>()    {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> mEtPassword.getText().toString();    }    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">clearUserName</span>()    {        mEtUsername.setText(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>);    }    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">clearPassword</span>()    {        mEtPassword.setText(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>);    }    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">showLoading</span>()    {        mPbLoading.setVisibility(View.VISIBLE);    }    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">hideLoading</span>()    {        mPbLoading.setVisibility(View.GONE);    }    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">toMainActivity</span>(User user)    {        Toast.makeText(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>, user.getUsername() +                <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">" login success , to MainActivity"</span>, Toast.LENGTH_SHORT).show();    }    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">showFailedError</span>()    {        Toast.makeText(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>,                <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"login failed"</span>, Toast.LENGTH_SHORT).show();    }}</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">4</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">5</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">6</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">7</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">8</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">9</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">10</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">11</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">12</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">13</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">14</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">15</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">16</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">17</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">18</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">19</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">20</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">21</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">22</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">23</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">24</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">25</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">26</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">27</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">28</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">29</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">30</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">31</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">32</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">33</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">34</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">35</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">36</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">37</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">38</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">39</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">40</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">41</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">42</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">43</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">44</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">45</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">46</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">47</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">48</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">49</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">50</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">51</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">52</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">53</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">54</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">55</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">56</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">57</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">58</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">59</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">60</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">61</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">62</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">63</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">64</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">65</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">66</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">67</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">68</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">69</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">70</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">71</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">72</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">73</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">74</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">75</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">76</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">77</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">78</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">79</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">80</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">81</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">82</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">83</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">84</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">85</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">86</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">87</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">88</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">89</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">90</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">91</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">92</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">93</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">94</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">95</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">96</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">97</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">98</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">99</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">100</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">101</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">102</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">103</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">104</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">105</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">106</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">107</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">108</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">109</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">110</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">111</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">112</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">113</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">114</span></li></ul>

对于在Activity中实现我们上述定义的接口，是一件很容易的事，毕竟接口引导我们去完成。

最后看我们的Presenter。

（三）Presenter

Presenter是用作Model和View之间交互的桥梁，那么应该有什么方法呢？

其实也是主要看该功能有什么操作，比如本例，两个操作:login和clear。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span style="font-size:18px;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.zhy.blogcodes.mvp.presenter;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.os.Handler;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.bean.User;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.biz.IUserBiz;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.biz.OnLoginListener;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.biz.UserBiz;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.zhy.blogcodes.mvp.view.IUserLoginView;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Created by zhy on 15/6/19. */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">UserLoginPresenter</span>{</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> IUserBiz userBiz;    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> IUserLoginView userLoginView;    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Handler mHandler = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Handler();    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">UserLoginPresenter</span>(IUserLoginView userLoginView)    {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.userLoginView = userLoginView;        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.userBiz = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> UserBiz();    }    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">login</span>()    {        userLoginView.showLoading();        userBiz.login(userLoginView.getUserName(), userLoginView.getPassword(), <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> OnLoginListener()        {            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">loginSuccess</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> User user)            {                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//需要在UI线程执行</span>                mHandler.post(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Runnable()                {                    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>()                    {                        userLoginView.toMainActivity(user);                        userLoginView.hideLoading();                    }                });            }            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">loginFailed</span>()            {                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//需要在UI线程执行</span>                mHandler.post(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Runnable()                {                    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>()                    {                        userLoginView.showFailedError();                        userLoginView.hideLoading();                    }                });            }        });    }    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">clear</span>()    {        userLoginView.clearUserName();        userLoginView.clearPassword();    }}</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">1</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">2</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">3</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">4</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">5</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">6</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">7</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">8</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">9</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">10</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">11</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">12</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">13</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">14</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">15</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">16</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">17</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">18</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">19</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">20</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">21</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">22</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">23</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">24</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">25</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">26</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">27</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">28</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">29</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">30</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">31</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">32</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">33</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">34</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">35</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">36</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">37</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">38</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">39</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">40</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">41</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">42</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">43</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">44</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">45</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">46</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">47</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">48</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">49</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">50</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">51</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">52</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">53</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">54</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">55</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">56</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">57</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">58</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">59</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">60</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">61</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">62</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">63</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">64</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">65</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">66</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">67</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">68</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">69</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">70</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">71</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">72</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">73</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">74</span></li><li style="box-sizing: border-box; padding: 0px 5px;"><span style="font-size:18px;">75</span></li></ul>

注意上述代码，我们的presenter完成二者的交互，那么肯定需要二者的实现类。大致就是从View中获取需要的参数，交给Model去执行业务方法，执行的过程中需要的反馈，以及结果，再让View进行做对应的显示。

ok，拿到一个例子经过上述的分解基本就能完成。以上纯属个人见解，欢迎讨论和吐槽~ have a nice day ~。

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