2016移動開發校賽之Android實踐

　　學校組織的《移動互聯網應用軟件開發》技能競賽，所有參賽命題均基於 Android 4.2 版本實現，比賽推薦使用的開發環境為：ADT， JDK 1.6， Android SDK 4.1
　　經過了四天的培訓我們小組選擇在計算器應用
計算器能夠實現：
1. 數學四則運算
2. 實現開方元算
3. 實現求倒數運算
4. 實現百分比運算
5. 實現刪除一位數字的功能
6. 實現刪除所有數據的功能
7. 實現臨時存儲數據的功能
　　目前我可以完成前4項的功能，後面不知道Android有沒有提供特別的集合，我還沒有完全實現功能，希望看到的大神可以指教。
　　我們先進行了對Java的培訓，多線程、匿名內部類、接口及其子類異常的捕獲，然後使用兩本書《Android移動應用開發項目教程》和《Android編程權威指南》來開展對Android的學習。給我的感覺是，開發Android應用程序和普通的Java應用程序沒有太大區別，最後運行的時候才Android虛擬機上運行就好。
　　開發Android項目的時候雖然老師給我們推薦谷歌推出了新的Android開發環境Android Studio，但是我們用的是帶插件的Eclipse，安裝好JDK配置好ADT集成開發環境之後就開始了。升級Android SDK也很重要，直接升級的話需要連接Google服務器的，所以是需要翻牆的，為了避免這種情況，也可以到高校自己的網站去升級。就不廢話了，上代碼。
　　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;

    // 保存當前輸入框內容
    String current = "0";
    // 保存之前輸入的內容
    String prev = "";
    // 保存輸入狀態，是剛剛輸入了一個數字，還是輸入了一個運算、控制符號
    int status = 0; // 0 剛剛輸入了數字， 1剛剛輸入了運算符號
    // 保存剛剛輸入的運算符號
    String com = "";

    List list = new ArrayList();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // 拿到輸入框對象
        result = (EditText) findViewById(R.id.editText1);

        // 讓輸入框一開始顯示0
        update();
    }

    // 此處的方法是和在布局中給按鈕們設定的onclick屬性對應的
    // 點完那些按鈕後，執行該方法
    public void click(View v) {

        // 現獲取按鈕上的內容
        String btn_text = ((Button) v).getText().toString();

        // 通過getId可以獲取被點的按鈕的id，和我們設定的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:
            // 檢測上一次輸入的是什麼，如果是數字，就連接顯示，如果是運算符，清空輸入框，
            // 開始新的數字的顯示
            if (status == 0) {
                // 檢測當前輸入框中是否僅有0，如果僅有零，就將當前內容替換為輸入的數字
                // 如果不是僅有0，則將當前按下的數字，連接到當前內容的最後
                if (onlyZero())
                    current = btn_text;
                else
                    current += btn_text;
                // 把當前狀態置為0，表示剛剛輸入的是數字
                status = 0;
            } else if (status == 1) {
                current = btn_text;
            }
            break;

        // 如果按下了加號
        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:
            // 把當前狀態置為1，表示剛剛輸入的是符號
            status = 1;
            // 把當前輸入框的內容，作為之前輸入的內容保存在prev中
            prev = current;
            // 保存當前運算符號
            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;
        }

        // 更新輸入框的當前內容
        update();

    }

    /**
     * 按下等號後調用的方法，計算
     * 
     * @return 返回計算結果
     */
    private double compute() {
        double old = Double.parseDouble(prev);
        double cur = Double.parseDouble(current);

        Log.d("------獲取的按鈕文字-------", 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("/")) {
            // 除數為0檢測
            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(""))
            // 計算得到結果後，立刻更新輸入框
            prev = current;

        current = result + "";
        update();
        return result;
    }

    /**
     * 清理之前和當前的數據
     */
    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 list = new ArrayList();
        list.add(current);
    }

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

    private void clearIn() {
        List 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 ;
        }
    }

    // 更新輸入框內容
    public void update() {
        result.setText(current);
    }

    public void warning() {
        Toast.makeText(MainActivity.this, "除數不能為零", 0).show();   
    }

    /**
     * 檢測當前輸入的內容是否僅僅是0
     * 
     * @return 如果只有零，返回true，否則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;
    }
}