2016移动开发校赛之Android实践

　　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
　　目前我可以完成前6项的功能，后面不知道Android有没有提供特别的集合，我还没有完全实现其功能，希望看到的大神可以指教。
　　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 = "";

    List<String> list = new ArrayList();

    @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:
            Out();
            compute();
            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 = 100 / cur;
            result = old / cur;
        } 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() {
        List<String> list = new ArrayList();
        list.add(current);
    }

    private void Out() {
        Iterator it = list.iterator();  
        while(it.hasNext()) {  
            result.setText(it.next() + " ");  
        }  
    }

    private void clearIn() {
        List<String> list = new ArrayList();
    }

    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;
    }
}