2016移动开发校赛之Android实践

来源：互联网发布：面膜纸知乎编辑：程序博客网时间：2024/04/29 14:51

　　学校组织的《移动互联网应用软件开发》技能竞赛，所有参赛命题均基于 Android 4.2 版本实现，比赛推荐使用的开发环境为：ADT， JDK 1.6， Android SDK 4.1
　　经过了四天的培训我们小组选择在计算器应用
计算器能够实现：

1. 数学四则运算
2. 实现开方元算
　3. 实现求倒数运算
　4. 实现百分比运算
　　　　　5. 实现删除一位数字的功能
　　　　　6. 实现删除所有数据的功能
　　　　　7. 实现临时存储数据的功能

　　目前我可以完成全部功能，虽然是扩展老师的基础程序，但还是很有成就感的。
　　我们先进行了对Java的培训，多线程、匿名内部类、接口及其子类异常的捕获，然后使用两本书《Android移动应用开发项目教程》和《Android编程权威指南》来开展对Android的学习。给我的感觉是，开发Android应用程序和普通的Java应用程序没有太大区别，最后运行的时候才Android虚拟机上运行就好。
　　开发Android项目的时候虽然老师给我们推荐谷歌推出了新的Android开发环境Android Studio，但是我们用的是带插件的Eclipse，安装好JDK配置好ADT集成开发环境之后就开始了。升级Android SDK也很重要，直接升级的话需要连接Google服务器的，所以是需要翻墙的，为了避免这种情况，也可以到高校自己的网站去升级。就不废话了，上代码。
　　MainActivity.java

package com.wangjingliang.calc;import java.util.*;import com.shiyifei.calc.R;import android.os.Bundle;import android.app.Activity;import android.util.Log;import android.view.Menu;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class MainActivity extends Activity {    EditText result;    // 保存当前输入框内容    String current = "0";    // 保存之前输入的内容    String prev = "";    // 保存输入状态，是刚刚输入了一个数字，还是输入了一个运算、控制符号    int status = 0; // 0 刚刚输入了数字， 1刚刚输入了运算符号    // 保存刚刚输入的运算符号    String com = "";    //保存存储器中的数值    String num = "";    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        // 拿到输入框对象        result = (EditText) findViewById(R.id.editText1);        // 让输入框一开始显示0        update();    }    // 此处的方法是和在布局中给按钮们设定的onclick属性对应的    // 点完那些按钮后，执行该方法    public void click(View v) {        // 现获取按钮上的内容        String btn_text = ((Button) v).getText().toString();        // 通过getId可以获取被点的按钮的id，和我们设定的id比照        switch (v.getId()) {        case R.id.b0:        case R.id.b1:        case R.id.b2:        case R.id.b3:        case R.id.b4:        case R.id.b5:        case R.id.b6:        case R.id.b7:        case R.id.b8:        case R.id.b9:            // 检测上一次输入的是什么，如果是数字，就连接显示，如果是运算符，清空输入框，            // 开始新的数字的显示            if (status == 0) {                // 检测当前输入框中是否仅有0，如果仅有零，就将当前内容替换为输入的数字                // 如果不是仅有0，则将当前按下的数字，连接到当前内容的最后                if (onlyZero())                    current = btn_text;                else                    current += btn_text;                // 把当前状态置为0，表示刚刚输入的是数字                status = 0;            } else if (status == 1) {                current = btn_text;            }            break;        // 如果按下了加号        case R.id.b_add:        case R.id.b_sub:        case R.id.b_multi:        case R.id.b_div:        case R.id.b_sqrt:        case R.id.b_rev:        case R.id.b_per:            // 把当前状态置为1，表示刚刚输入的是符号            status = 1;            // 把当前输入框的内容，作为之前输入的内容保存在prev中            prev = current;            // 保存当前运算符号            com = btn_text;            break;        case R.id.b_equal:            compute();            break;        case R.id.b_c:            clearAll();            break;        case R.id.b_ce:            clearPart();            break;        case R.id.b_back:            clearSingle();            break;        case R.id.b_dot:            addDot();            break;        case R.id.b_sign:            addSign();            break;        case R.id.b_ms:            Store();            break;        case R.id.b_mr:            Out();            break;        case R.id.b_mp:            addStore();            break;        case R.id.b_mc:            clearIn();            break;        }        // 更新输入框的当前内容        update();    }    /**     * 按下等号后调用的方法，计算     *      * @return 返回计算结果     */    private double compute() {        double old = Double.parseDouble(prev);        double cur = Double.parseDouble(current);        Log.d("------获取的按钮文字-------", com);        double result = 0;        if (com.equals("+")) {            result = old + cur;        } else if (com.equals("-")) {            result = old - cur;        } else if (com.equals("*")) {            result = old * cur;        } else if (com.equals("/")) {            // 除数为0检测            if (cur == 0) {                warning();            } else {                result = old / cur;            }        } else if (com.equals("sqt")) {            result = Math.sqrt(old);        } else if (com.equals("1/x")) {            result = 1 / old;        } else if (com.equals("%")) {            cur = (old*cur) / 100;        } else if (com.equals(""))            // 计算得到结果后，立刻更新输入框            prev = current;        current = result + "";        update();        return result;    }    /**     * 清理之前和当前的数据     */    private void clearAll() {        prev = "";        current = "";        com = "";        status = 0;    }    private void clearPart() {        current = "";    }    private void clearSingle() {        if (current.length() > 1) {            current = current.substring(0, current.length() - 1);        } else {            current = "0";        }        result.setText(current);    }    private void Store() {        num = current ;    }    private void addStore() {        double cur = Double.parseDouble(current);        double n = Double.parseDouble(num);        n += cur;        num = String.valueOf(n);    }    private void Out() {        current = num ;    }    private void clearIn() {        num = "";    }    private void addDot() {        if (current.indexOf(".") != -1) {            current = "";        } else {            current = current + ".";        }    }    private void addSign() {        if (current.indexOf("-") != -1) {            current = current.replace('-', ' ');        } else {            current = "-" + current;        }    }    // 更新输入框内容    public void update() {        result.setText(current);    }    public void warning() {        Toast.makeText(MainActivity.this, "除数不能为零", 0).show();    }    /**     * 检测当前输入的内容是否仅仅是0     *      * @return 如果只有零，返回true，否则false     */    public boolean onlyZero() {        return current.length() == 1 && current.equals("0");    }}

BuildConfig.java

/** Automatically generated file. DO NOT MODIFY */package com.shiyifei.calc;public final class BuildConfig {    public final static boolean DEBUG = true;}

R.java

/* AUTO-GENERATED FILE.  DO NOT MODIFY. * * This class was automatically generated by the * aapt tool from the resource data it found.  It * should not be modified by hand. */package com.shiyifei.calc;public final class R {    public static final class attr {    }    public static final class dimen {        /**  Default screen margins, per the Android Design guidelines.          Customize dimensions originally defined in res/values/dimens.xml (such as         screen margins) for sw720dp devices (e.g. 10" tablets) in landscape here.         */        public static final int activity_horizontal_margin=0x7f040000;        public static final int activity_vertical_margin=0x7f040001;    }    public static final class drawable {        public static final int ic_launcher=0x7f020000;        public static final int ic_launcher_calc=0x7f020001;    }    public static final class id {        public static final int LinearLayout1=0x7f080000;        public static final int action_settings=0x7f080023;        public static final int b0=0x7f08001e;        public static final int b1=0x7f080017;        public static final int b2=0x7f080018;        public static final int b3=0x7f080019;        public static final int b4=0x7f080010;        public static final int b5=0x7f080011;        public static final int b6=0x7f080012;        public static final int b7=0x7f080009;        public static final int b8=0x7f08000a;        public static final int b9=0x7f08000b;        public static final int b_add=0x7f080021;        public static final int b_back=0x7f080004;        public static final int b_c=0x7f080006;        public static final int b_ce=0x7f080005;        public static final int b_div=0x7f08000c;        public static final int b_dot=0x7f080020;        public static final int b_equal=0x7f080022;        public static final int b_mc=0x7f080008;        public static final int b_mp=0x7f08001d;        public static final int b_mr=0x7f08000f;        public static final int b_ms=0x7f080016;        public static final int b_multi=0x7f080013;        public static final int b_per=0x7f080014;        public static final int b_rev=0x7f08001b;        public static final int b_sign=0x7f08001f;        public static final int b_sqrt=0x7f08000d;        public static final int b_sub=0x7f08001a;        public static final int editText1=0x7f080001;        public static final int r1=0x7f080002;        public static final int r2=0x7f080007;        public static final int r3=0x7f08000e;        public static final int r4=0x7f080015;        public static final int r5=0x7f08001c;        public static final int textView1=0x7f080003;    }    public static final class layout {        public static final int activity_main=0x7f030000;    }    public static final class menu {        public static final int main=0x7f070000;    }    public static final class string {        public static final int action_settings=0x7f050001;        public static final int app_name=0x7f050000;        public static final int hello_world=0x7f050002;    }    public static final class style {        /**         Base application theme, dependent on API level. This theme is replaced        by AppBaseTheme from res/values-vXX/styles.xml on newer devices.            Theme customizations available in newer API levels can go in            res/values-vXX/styles.xml, while customizations related to            backward-compatibility can go here.        Base application theme for API 11+. This theme completely replaces        AppBaseTheme from res/values/styles.xml on API 11+ devices. API 11 theme customizations can go here.         Base application theme for API 14+. This theme completely replaces        AppBaseTheme from BOTH res/values/styles.xml and        res/values-v11/styles.xml on API 14+ devices. API 14 theme customizations can go here.          */        public static final int AppBaseTheme=0x7f060000;        /**  Application theme.  All customizations that are NOT specific to a particular API-level can go here.          */        public static final int AppTheme=0x7f060001;    }}

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