OSC首发：android中的左右滑屏实现By ViewPager

先看效果，就是左右滑屏的效果

具体实现详解

android compatibility package, revision 3在7月份发布后，其中有个ViewPager引起了我的注意

官方的描述：

请参考：http://developer.android.com/sdk/compatibility-library.html#Notes

ViewPager的下载与安装

首先通过SDK Manager更新最新版android compatibility package, revision 3

更新后，在eclipse中工程上点击右键，选择android tools -> add compatibility library即可完成安装

实际上就是一个jar包，手工导到工程中也可

jar包所在位置是\android-sdk\extras\android\compatibility\v4\android-support-v4.jar

至此准备环境已经ok

下边还是通过代码进行说话吧

准备布局文件

viewpager_layout.xml

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1<?xmlversion="1.0"encoding="utf-8"?>

2<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

3android:layout_width="fill_parent"

4android:layout_height="fill_parent"android:orientation="vertical">

5<!-- 此处需要给出全路径 -->

6<android.support.v4.view.ViewPager

7android:id="@+id/viewpagerLayout"android:layout_height="fill_parent"android:layout_width="fill_parent"/>

8</LinearLayout>

layout1.xml

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1<?xmlversion="1.0"encoding="utf-8"?>

2<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

3android:layout_width="fill_parent"

4android:layout_height="fill_parent"android:orientation="vertical">

5<TextViewandroid:textAppearance="?android:attr/textAppearanceLarge"android:layout_height="wrap_content"android:id="@+id/textView1"android:layout_width="fill_parent"android:text="第一页"></TextView>

6<EditTextandroid:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/editText1">

7<requestFocus></requestFocus>

8</EditText>

9</LinearLayout>

layout2.xml

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1<?xmlversion="1.0"encoding="utf-8"?>

2<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

3android:layout_width="fill_parent"

4android:layout_height="fill_parent"android:orientation="vertical">

5<TextViewandroid:textAppearance="?android:attr/textAppearanceLarge"android:layout_height="wrap_content"android:id="@+id/textView1"android:layout_width="fill_parent"android:text="第二页"></TextView>

6<EditTextandroid:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/editText1">

7<requestFocus></requestFocus>

8</EditText>

9</LinearLayout>

layout3.xml

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1<?xmlversion="1.0"encoding="utf-8"?>

2<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

3android:layout_width="fill_parent"

4android:layout_height="fill_parent"android:orientation="vertical">

5<TextViewandroid:textAppearance="?android:attr/textAppearanceLarge"android:layout_height="wrap_content"android:id="@+id/textView1"android:layout_width="fill_parent"android:text="第三页"></TextView>

6<EditTextandroid:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/editText1">

7<requestFocus></requestFocus>

8</EditText>

9</LinearLayout>

主程序

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001package a.b;

002

003import java.util.ArrayList;

004import java.util.List;

005

006import android.app.Activity;

007import android.os.Bundle;

008import android.os.Parcelable;

009import android.support.v4.view.PagerAdapter;

010import android.support.v4.view.ViewPager;

011import android.support.v4.view.ViewPager.OnPageChangeListener;

012import android.util.Log;

013import android.view.LayoutInflater;

014import android.view.View;

015import android.widget.EditText;

016

017public class TestViewPager extendsActivity {

018privateViewPager myViewPager;

019

020privateMyPagerAdapter myAdapter;

021

022privateLayoutInflater mInflater;

023privateList<View> mListViews;

024privateView layout1 = null;

025privateView layout2 = null;

026privateView layout3 = null;

027

028@Override

029protectedvoid onCreate(Bundle savedInstanceState) {

030super.onCreate(savedInstanceState);

031setContentView(R.layout.viewpager_layout);

032myAdapter =new MyPagerAdapter();

033myViewPager = (ViewPager) findViewById(R.id.viewpagerLayout);

034myViewPager.setAdapter(myAdapter);

035

036mListViews =new ArrayList<View>();

037mInflater = getLayoutInflater();

038layout1 = mInflater.inflate(R.layout.layout1,null);

039layout2 = mInflater.inflate(R.layout.layout2,null);

040layout3 = mInflater.inflate(R.layout.layout3,null);

041

042mListViews.add(layout1);

043mListViews.add(layout2);

044mListViews.add(layout3);

045

046//初始化当前显示的view

047myViewPager.setCurrentItem(1);

048

049//初始化第二个view的信息

050EditText v2EditText = (EditText)layout2.findViewById(R.id.editText1);

051v2EditText.setText("动态设置第二个view的值");

052

053myViewPager.setOnPageChangeListener(newOnPageChangeListener() {

054

055@Override

056publicvoid onPageSelected(intarg0) {

057Log.d("k","onPageSelected - " + arg0);

058//activity从1到2滑动，2被加载后掉用此方法

059View v = mListViews.get(arg0);

060EditText editText = (EditText)v.findViewById(R.id.editText1);

061editText.setText("动态设置#"+arg0+"edittext控件的值");

062}

063

064@Override

065publicvoid onPageScrolled(intarg0, float arg1, int arg2) {

066Log.d("k","onPageScrolled - " + arg0);

067//从1到2滑动，在1滑动前调用

068}

069

070@Override

071publicvoid onPageScrollStateChanged(intarg0) {

072Log.d("k","onPageScrollStateChanged - " + arg0);

073//状态有三个0空闲，1是增在滑行中，2目标加载完毕

074/**

075* Indicates that the pager is in an idle, settled state. The current page

076* is fully in view and no animation is in progress.

077*/

078//public static final int SCROLL_STATE_IDLE = 0;

079/**

080* Indicates that the pager is currently being dragged by the user.

081*/

082//public static final int SCROLL_STATE_DRAGGING = 1;

083/**

084* Indicates that the pager is in the process of settling to a final position.

085*/

086//public static final int SCROLL_STATE_SETTLING = 2;

087

088}

089});

090

091}

092

093privateclass MyPagerAdapter extends PagerAdapter{

094

095@Override

096publicvoid destroyItem(View arg0,int arg1, Object arg2) {

097Log.d("k","destroyItem");

098((ViewPager) arg0).removeView(mListViews.get(arg1));

099}

100

101@Override

102publicvoid finishUpdate(View arg0) {

103Log.d("k","finishUpdate");

104}

105

106@Override

107publicint getCount() {

108Log.d("k","getCount");

109returnmListViews.size();

110}

111

112@Override

113publicObject instantiateItem(View arg0, intarg1) {

114Log.d("k","instantiateItem");

115((ViewPager) arg0).addView(mListViews.get(arg1),0);

116returnmListViews.get(arg1);

117}

118

119@Override

120publicboolean isViewFromObject(View arg0, Object arg1) {

121Log.d("k","isViewFromObject");

122returnarg0==(arg1);

123}

124

125@Override

126publicvoid restoreState(Parcelable arg0, ClassLoader arg1) {

127Log.d("k","restoreState");

128}

129

130@Override

131publicParcelable saveState() {

132Log.d("k","saveState");

133returnnull;

134}

135

136@Override

137publicvoid startUpdate(View arg0) {

138Log.d("k","startUpdate");

139}

140

141}

142

143}

在实机上测试后，非常流畅，这也就是说官方版的左右滑屏控件已经实现

目前，关于viewpager的文章非常少，本文是通过阅读viewpager源代码分析出的写法

当然此文章仅是抛砖引玉，而且属于框架式程序，目的就是让读者了解API的基本用法

希望这篇原创文章对大家有帮助

欢迎感兴趣的朋友一起讨论

共同学习，共同进步

另外，ViewPager的注释上有这么一段话，大体意思是该控件目前属于早期实现，后续会有修改

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01/**

02* Layout manager that allows the user to flip left and right

03* through pages of data. You supply an implementation of a

04* {@link PagerAdapter} to generate the pages that the view shows.

05*

06* <p>Note this class is currently under early design and

07* development. The API will likely change in later updates of

08* the compatibility library, requiring changes to the source code

09* of apps when they are compiled against the newer version.</p>

10*/