android activity的管理類的實現

一個全聚德activity manager類

public class AppManager {
    private static Stack<Activity> activityStack;
    private static AppManager instance;

    public AppManager() {
    }

    /**
     * 單一實例
     */
    public static AppManager getAppManager() {
    if(instance==null) {
        instance=new AppManager();
       }
        return  instance;
       }
    /**
     * 添加activity到堆棧
     */
    public void addActivity(Activity activity){

        if(activityStack==null){
            activityStack=new Stack<Activity>();

        }
        activityStack.add(activity);
    }
    /**
     * 獲取當前的activity（堆棧中最後一個押入的）
     */
    public Activity currentActivity(){
        Activity activity=activityStack.lastElement();
     return  activity;
    }
    /**
     * 結束指定的activity
     */
    public void finishActivity(Activity activity){
        if(activity!=null&&!activity.isFinishing()){
            activityStack.remove(activity);
            activity.finish();
            activity=null;
        }
    }
    /**
     * 結束指定類名的activity
     */
    public void finishActivity(Class<?> cls){
        for(Activity activity:activityStack){
            if(activity.getClass().equals(cls)){
                finishActivity(activity);
                break;
            }
        }
    }

    /**
     * 結束所有的activity
     */
    public void finishAllActivity(){
        for(int i=0,size=activityStack.size();i<size;i++){
            if(null!=activityStack.get(i)){
                finishActivity(activityStack.get(i));
                break;
            }

        }
        activityStack.clear();
    }

    /**
     * 獲取指定的Activity
     *
     */
    public static Activity getActivity(Class<?> cls) {
        if (activityStack != null)
            for (Activity activity : activityStack) {
                if (activity.getClass().equals(cls)) {
                    return activity;
                }
            }
        return null;
    }

    /**
     * 退出應用程序
     */
    public void AppExit(Context context){
        finishAllActivity();
        //殺死應用進程
        android.os.Process.killProcess(Process.myPid());
        System.exit(0);

    }
}