监听返回键并退出所有Activity示例

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);}}@Overridepublic 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 {@Overrideprotected 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;@Overridepublic 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() {@Overridepublic void onClick(View v) {Intent intent = new Intent(MyActivity1.this, MyActivity2.class);startActivity(intent);}});btn_1_3.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Intent intent = new Intent(MyActivity1.this, MyActivity3.class);startActivity(intent);}});}@Overridepublic 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() {@Overridepublic void onClick(DialogInterface dialog,int which) {MyAppalication.getInstance().exit();}}).setNegativeButton("NO", new DialogInterface.OnClickListener() {@Overridepublic 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;@Overridepublic 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() {@Overridepublic void onClick(View v) {Intent intent = new Intent(MyActivity2.this, MyActivity1.class);startActivity(intent);}});btn_2_3.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Intent intent = new Intent(MyActivity2.this, MyActivity3.class);startActivity(intent);}});}@Overridepublic 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() {@Overridepublic void onClick(DialogInterface dialog,int which) {MyAppalication.getInstance().exit();}}).setNegativeButton("NO", new DialogInterface.OnClickListener() {@Overridepublic 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;@Overridepublic 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() {@Overridepublic void onClick(View v) {Intent intent = new Intent(MyActivity3.this, MyActivity2.class);startActivity(intent);}});btn_3_1.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Intent intent = new Intent(MyActivity3.this, MyActivity1.class);startActivity(intent);}});}@Overridepublic 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() {@Overridepublic void onClick(DialogInterface dialog,int which) {MyAppalication.getInstance().exit();}}).setNegativeButton("NO", new DialogInterface.OnClickListener() {@Overridepublic 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>