管理Activity

 开源中国摘取的代码，这个可以管理activity

package net.oschina.app;

import java.util.Stack;

import android.app.Activity;
import android.app.ActivityManager;
import android.content.Context;

/**
* 应用程序Activity管理类：用于Activity管理和应用程序退出
* @author liux (http://my.oschina.net/liux)
* @version 1.0
* @created 2012-3-21
*/
public class AppManager {

    private static Stack<Activity> activityStack;
    private static AppManager instance;

    private AppManager(){}
    /**
     * 单一实例
     */
    public static AppManager getAppManager(){
        if (instance== null ){
            instance= new AppManager();
        }
        return instance;
    }
    /**
     * 添加Activity到堆栈
     */
    public void addActivity(Activity activity){
        if (activityStack== null ){
            activityStack= new Stack<Activity>();
        }
        activityStack.add(activity);
    }
    /**
     * 获取当前Activity（堆栈中最后一个压入的）
     */
    public Activity currentActivity(){
        Activity activity=activityStack.lastElement();
        return activity;
    }
    /**
     * 结束当前Activity（堆栈中最后一个压入的）
     */
    public void finishActivity(){
        Activity activity=activityStack.lastElement();
        if (activity!= null ){
            activity.finish();
            activity= null ;
        }
    }
    /**
     * 结束指定的Activity
     */
    public void finishActivity(Activity activity){
        if (activity!= null ){
            activityStack.remove(activity);
            activity.finish();
            activity= null ;
        }
    }
    /**
     * 结束指定类名的Activity
     */
    public void finishActivity(Class<?> cls){
        for (Activity activity : activityStack) {
            if (activity.getClass().equals(cls) ){
                finishActivity(activity);
            }
        }
    }
    /**
     * 结束所有Activity
     */
    public void finishAllActivity(){
        for ( int i = 0 , size = activityStack.size(); i < size; i++){
            if ( null != activityStack.get(i)){
                activityStack.get(i).finish();
            }
        }
        activityStack.clear();
    }
    /**
     * 退出应用程序
     */
    public void AppExit(Context context) {
        try {
            finishAllActivity();
            ActivityManager activityMgr= (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
            activityMgr.restartPackage(context.getPackageName());
            System.exit( 0 );
        } catch (Exception e) {    }
    }
}