Android开发_通过ExitManager关闭所有activity

package cn.com.util;import java.util.LinkedList;import java.util.List;import android.app.Activity;import android.app.Application;public class ExitManager extends Application{private List<Activity> activityList=new LinkedList<Activity>();   private static ExitManager instance;      private ExitManager(){      }   public static ExitManager getInstance(){   if (instance==null) {instance=new ExitManager();}   return instance;   }   public void addActivity(Activity activity){   activityList.add(activity);   }   public void exit(){   for(Activity activity:activityList){     if(!activity.isFinishing()){      activity.finish();     }   }   int id=android.os.Process.myPid();   if(id!=0){   android.os.Process.killProcess(id);   }   }}