android 完全退出应用程序

转载自：http://www.yoyong.com/archives/199，十分感谢

android 完全退出应用程序

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Posted on June
16, 2011 by Charlie Posted
in android and
tagged android
退出应用程序, 单例模式管理Activity.

android退出应用程序会调用android.os.Process.killProcess(android.os.Process.myPid())或是System.exit(0)，这只是针对第一个Activity(也就是入口的Activity)时生效。如果有A,B,C三个Activity,而想在B或C中Activity退出，调用上面的方法，往往会销毁当前的Activity返回上一个Activity。当然也可以逐个返回上一个Activity，直到跳转到入口的Activity，最后退出应用程序。但这样比较麻烦，而且逐个返回的体验并不友好。

网上比较流行的方法是定义栈，写一个ExitApplication类，利用单例模式管理Activity，在每个在Activity的onCreate()方法中调用ExitApplication.getInstance().addActivity(this)方法,在退出时调用ExitApplication.getInstance().exit()方法，就可以完全退出应用程序了。

ExitApplication类

代码如下：



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import java.util.LinkedList;

import java.util.List;



import android.app.Activity;

import android.app.Application;



public class ExitApplication extends Application {



private List activityList = new LinkedList();

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;



}

//添加Activity到容器中

public void addActivity(Activity activity)

{

activityList.add(activity);

}

//遍历所有Activity并finish



public void exit()

{



for(Activity activity:activityList)

{

activity.finish();

}



System.exit(0);



}

}

下面的三个类IndexActivity, BActivity,CActivity是简单的例子，分别是IndexActivity–>BActivity–>CActivity的跳转顺序。在每个Activity类中onCreate()方法中调用ExitApplication.getInstance().addActivity(Activity activity)方法。在任何一个Activity界面退出应用程序时，只要调用ExitApplication.getInstance().exit()方法，就可以在任何一个Activity中完全退出应用程序。

IndexActivity 类源代码：

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import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;



public class IndexActivity extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);



Button next=(Button)findViewById(R.id.next_to_b);

next.setOnClickListener(nextClick);



Button exit=(Button)findViewById(R.id.exit_main);

exit.setOnClickListener(exitClick);

ExitApplication.getInstance().addActivity(this);



}



OnClickListener nextClick=new OnClickListener() {



@Override

public void onClick(View v) {

// TODO Auto-generated method stub



Intent intent=new Intent(IndexActivity.this,BActivity.class);

startActivity(intent);



}

};



OnClickListener exitClick=new OnClickListener() {



@Override

public void onClick(View v) {

// TODO Auto-generated method stub

ExitApplication.getInstance().exit();

}

};

}

BActivity 类源代码：

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import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;



public class BActivity extends Activity {



@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);



setContentView(R.layout.b);

Button next_to_c=(Button)findViewById(R.id.next_to_c);

next_to_c.setOnClickListener(next_to_cClick);



Button exit_b=(Button)findViewById(R.id.exit_b);

exit_b.setOnClickListener(exitClick);

ExitApplication.getInstance().addActivity(this);



}



OnClickListener next_to_cClick=new OnClickListener() {



@Override

public void onClick(View v) {

// TODO Auto-generated method stub



Intent intent=new Intent(BActivity.this,CActivity.class);

startActivity(intent);



}

};



OnClickListener exitClick=new OnClickListener() {



@Override

public void onClick(View v) {

// TODO Auto-generated method stub

ExitApplication.getInstance().exit();

}

};

}

CActivity 类源代码：

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import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;



public class CActivity extends Activity{



@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);



setContentView(R.layout.c);



Button exit_c=(Button)findViewById(R.id.exit_c);

exit_c.setOnClickListener(exitClick);

ExitApplication.getInstance().addActivity(this);



}



OnClickListener exitClick=new OnClickListener() {



@Override

public void onClick(View v) {

// TODO Auto-generated method stub

ExitApplication.getInstance().exit();

//如果只是调用以下其中的一个方法，并不会完全退出应用

//android.os.Process.killProcess(android.os.Process.myPid());

//System.exit(0);

}

};



}