Android完全退出应用程序

转载请标明出处：http://blog.csdn.net/wu_wxc/article/details/52434568
本文出自【吴孝城的CSDN博客】

在Android的Activity中，当有多个Activity多次跳转后，点击返回或退出按钮会发现它会出现循环，会将刚刚打开的Activity，打开了多少次，一次次返回回去，当回到最开始的Activity后才会回到桌面

想要应用程序完全退出，
可定义一个栈，利用单列模式管理Activity，写一个ExitApplication类。
在每个Activity的onCreate()方法中调用ExitApplication.getInstance().addActivity(this);方法，将该Activity添加到ExitApplication实例中，
在要退出的地方调用ExitApplication.getInstance().exit();方法，从而将整个应用程序完全退出。

下面是一个列子，有两个Activity，再写一个ExitApplication类。布局代码就不贴了
先写ExitApplication类
ExitApplication.java

package cn.wuxiaocheng.myapp;

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

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

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

private ExitApplication() {

    }

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

// 将Activity添加到容器中
public void addActivity(Activity activity) {
        activityList.add(activity);
    }

// 当要退出Activity时，遍历所有Activity 并finish
public void exit() {
for (Activity activity : activityList) {
            activity.finish();
        }
        System.exit(0);
    }
}

MainActivity.java

package cn.wuxiaocheng.myapp;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

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

//将该Activity添加到ExitApplication实例中，
        ExitApplication.getInstance().addActivity(this);
    }

// Button按钮,跳转到其他Activity
public void click(View v) {
        Intent intent = new Intent(MainActivity.this, Test.class);
        startActivity(intent);
    }

// 物理返回键，双击退出
private long exitTime = 0;

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN) {
if ((System.currentTimeMillis() - exitTime) > 2000) {
                Toast.makeText(MainActivity.this, "再按一次退出程序", Toast.LENGTH_SHORT).show();
                exitTime = System.currentTimeMillis();
            } else {
                ExitApplication.getInstance().exit();
            }
return true;
        }
return super.onKeyDown(keyCode, event);
    }


// 退出按钮
public void back(View v) {
// 结束所有Activity
        ExitApplication.getInstance().exit();
    }
}

Test.java

package cn.wuxiaocheng.myapp;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.View;


public class Test extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
        setContentView(R.layout.test);
    }

// Button按钮,跳转到其他Activity
public void onc(View v) {
        Intent intent = new Intent(Test.this, MainActivity.class);
        startActivity(intent);
        Test.this.finish();
    }

}