[置顶] android页面管理器。可以实现完整退出android软件

package com.by2n.application;

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

import android.app.Activity;

public class Application extends android.app.Application {

@Override
public void onLowMemory() {
// TODO Auto-generated method stub
super.onLowMemory();
System.gc();
}

private List<Activity> mList = new LinkedList<Activity>();
private static Application instance;

public synchronized static Application getInstance(){
if(null == instance){
instance = new Application();
}
return instance;
}

public void addActivity(Activity activity){
mList.add(activity);
}

public void exit(){
try{
for(Activity a:mList){
if(a != null){
a.finish();
}
}
}catch(Exception e){
e.printStackTrace();
}finally{
System.exit(0);
}
}
}