监听返回键并退出所有Activity示例

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http://blog.csdn.net/u010142437/article/details/12244551

主题 Activity

下面给出3个简单的Activity，并在它们之间跳转，如果想点击某个Activity的返回键时就退出所有Activity，就只需监听该Activity的返回键即可。所有Activity都存放在一个集合里面，退出应用时，只需遍历该集合并逐一finish掉。代码如下：

MyAppalication：存放所有activity，提供添加activity和退出所有activity的方法

package com.home.exitapp;import java.util.ArrayList;import android.app.Activity;import android.app.Application;public class MyAppalication extends Application {  // 存放activity的集合  private ArrayList<Activity> list = new ArrayList<Activity>();  private static MyAppalication instance;  public MyAppalication() {  }  /**   * 利用单例模式获取MyAppalication实例   *    * @return   */  public static MyAppalication getInstance() {    if (null == instance) {      instance = new MyAppalication();    }    return instance;  }  /**   * 添加activity到list集合   *    * @param activity   */  public void addActivity(Activity activity) {    list.add(activity);  }  /**   * 退出集合所有的activity   */  public void exit() {    try {      for (Activity activity : list) {        activity.finish();      }    } catch (Exception e) {      e.printStackTrace();    } finally {      System.exit(0);    }  }  @Override  public void onLowMemory() {    super.onLowMemory();    System.gc();  }}

BaseActivity：抽象出添加activity的方法

package com.home.exitapp;import android.app.Activity;import android.os.Bundle;public class BaseActivity extends Activity {  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    MyAppalication.getInstance().addActivity(BaseActivity.this);  }}

MyActivity1：

package com.home.exitapp;import android.app.AlertDialog;import android.content.DialogInterface;import android.content.Intent;import android.os.Bundle;import android.view.KeyEvent;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class MyActivity1 extends BaseActivity {  private Button btn_1_2;  private Button btn_1_3;  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.main1);    // MyAppalication.getInstance().addActivity(MyActivity1.this);    btn_1_2 = (Button) findViewById(R.id.main1_btn_1_2);    btn_1_3 = (Button) findViewById(R.id.main1_btn_1_3);    btn_1_2.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        Intent intent = new Intent(MyActivity1.this, MyActivity2.class);        startActivity(intent);      }    });    btn_1_3.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        Intent intent = new Intent(MyActivity1.this, MyActivity3.class);        startActivity(intent);      }    });  }  @Override  public boolean onKeyDown(int keyCode, KeyEvent event) {    if (event.getKeyCode() == KeyEvent.KEYCODE_BACK) {      // return true;//返回真表示返回键被屏蔽掉      creatDialog();// 创建弹出的Dialog    }    return super.onKeyDown(keyCode, event);  }  /**   * 弹出提示退出对话框   */  private void creatDialog() {    new AlertDialog.Builder(this)        .setMessage("确定退出app?")        .setPositiveButton("YES",            new DialogInterface.OnClickListener() {              @Override              public void onClick(DialogInterface dialog,                  int which) {                MyAppalication.getInstance().exit();              }            })        .setNegativeButton("NO", new DialogInterface.OnClickListener() {          @Override          public void onClick(DialogInterface dialog, int which) {            dialog.dismiss();          }        }).show();  }}

MyActivity2：

package com.home.exitapp;import android.app.AlertDialog;import android.content.DialogInterface;import android.content.Intent;import android.os.Bundle;import android.view.KeyEvent;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class MyActivity2 extends BaseActivity {  private Button btn_2_1;  private Button btn_2_3;  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.main2);    btn_2_1 = (Button) findViewById(R.id.main2_btn_2_1);    btn_2_3 = (Button) findViewById(R.id.main2_btn_2_3);    btn_2_1.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        Intent intent = new Intent(MyActivity2.this, MyActivity1.class);        startActivity(intent);      }    });    btn_2_3.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        Intent intent = new Intent(MyActivity2.this, MyActivity3.class);        startActivity(intent);      }    });  }  @Override  public boolean onKeyDown(int keyCode, KeyEvent event) {    if (event.getKeyCode() == KeyEvent.KEYCODE_BACK) {      // return true;//返回真表示返回键被屏蔽掉      creatDialog();// 创建弹出的Dialog    }    return super.onKeyDown(keyCode, event);  }  /**   * 弹出提示退出对话框   */  private void creatDialog() {    new AlertDialog.Builder(this)        .setMessage("确定退出app?")        .setPositiveButton("YES",            new DialogInterface.OnClickListener() {              @Override              public void onClick(DialogInterface dialog,                  int which) {                MyAppalication.getInstance().exit();              }            })        .setNegativeButton("NO", new DialogInterface.OnClickListener() {          @Override          public void onClick(DialogInterface dialog, int which) {            dialog.dismiss();          }        }).show();  }}

MyActivity3：

package com.home.exitapp;import android.app.AlertDialog;import android.content.DialogInterface;import android.content.Intent;import android.os.Bundle;import android.view.KeyEvent;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class MyActivity3 extends BaseActivity {  private Button btn_3_2;  private Button btn_3_1;  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.main3);    btn_3_2 = (Button) findViewById(R.id.main3_btn_3_2);    btn_3_1 = (Button) findViewById(R.id.main3_btn_3_1);    btn_3_2.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        Intent intent = new Intent(MyActivity3.this, MyActivity2.class);        startActivity(intent);      }    });    btn_3_1.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        Intent intent = new Intent(MyActivity3.this, MyActivity1.class);        startActivity(intent);      }    });  }  @Override  public boolean onKeyDown(int keyCode, KeyEvent event) {    if (event.getKeyCode() == KeyEvent.KEYCODE_BACK) {      // return true;//返回真表示返回键被屏蔽掉      creatDialog();// 创建弹出的Dialog    }    return super.onKeyDown(keyCode, event);  }  /**   * 弹出提示退出对话框   */  private void creatDialog() {    new AlertDialog.Builder(this)        .setMessage("确定退出app?")        .setPositiveButton("YES",            new DialogInterface.OnClickListener() {              @Override              public void onClick(DialogInterface dialog,                  int which) {                MyAppalication.getInstance().exit();              }            })        .setNegativeButton("NO", new DialogInterface.OnClickListener() {          @Override          public void onClick(DialogInterface dialog, int which) {            dialog.dismiss();          }        }).show();  }}

main1.xml：

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="I am the first activity"        android:textSize="25sp" />    <Button        android:id="@+id/main1_btn_1_2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="跳到2" />    <Button        android:id="@+id/main1_btn_1_3"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="跳到3" /></LinearLayout>

main2.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#f000f0"    android:orientation="vertical" >    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="I am the second activity"        android:textSize="25sp" />    <Button        android:id="@+id/main2_btn_2_1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="跳到1" />    <Button        android:id="@+id/main2_btn_2_3"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="跳到3" /></LinearLayout>

main3.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#00f0ff"    android:orientation="vertical" >    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="I am the third activity"        android:textSize="25sp" />    <Button        android:id="@+id/main3_btn_3_2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="跳到2" />    <Button        android:id="@+id/main3_btn_3_1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="跳到1" /></LinearLayout>

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