Android中如何实现一键退出

在Application中

package com.example.application;

import java.util.LinkedList;
import java.util.List;

import android.app.Activity;
import android.app.Application;

public class ExitApplication extends Application {
private List<Activity> activityList = new LinkedList<Activity>();
private static ExitApplication instance;

private ExitApplication() {
}

// 单例模式获取唯一的exitapplication
public static ExitApplication getInstance() {
if (null == instance) {
instance = new ExitApplication();
}
return instance;
}

// 添加activity到容器中<pre name="code" class="java">@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ExitApplication.getInstance().addActivity(this);

public void addActivity(Activity activity) {activityList.add(activity);}// 遍历所有的Activiy并finishpublic void exit() {for (Activity activity : activityList) {activity.finish();}System.exit(0);}}

在Activity中

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

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
AlertDialog.Builder builder = new Builder(this);
builder.setTitle("提示");
builder.setMessage("确定要退出吗？");
builder.setPositiveButton("退出", new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
// 一键退出
ExitApplication.getInstance().exit();
}
});
builder.setNegativeButton("再看看", new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
builder.show();
return super.onKeyDown(keyCode, event);
}