通過ActivityManager我們可以獲得系統里正在執行的activities，包括程序(Process)等、應用程式/包、服務(Service)、任務(Task)資訊。

1、判斷應用App是否活動

/**
 * 判斷應用是否已經啟動
 * @param context 一個context
 * @param packageName 要判斷應用的包名
 * @return boolean
 */
private boolean isAppAlive(Context context, String packageName){
   ActivityManager activityManager =
           (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);
   List<ActivityManager.RunningAppProcessInfo> processInfos
           = activityManager.getRunningAppProcesses();
   for
 
(int i = 0; i < processInfos.size(); i++){
       if(processInfos.get(i).processName.equals(packageName)){
           Log.i("NotificationLaunch",
                   String.format("the %s is running, isAppAlive return true", packageName));
           return true;
       }
   }
   Log.i("NotificationLaunch"
 
,
           String.format("the %s is not running, isAppAlive return false", packageName));
   return false;
}

2、判斷Activity是否活動

/**
 * 判斷MainActivity是否活動
 * @param context 一個context
 * @param activityName 要判斷Activity
 * @return boolean
*/
private boolean isMainActivityAlive(Context context, String activityName){
   ActivityManager am = (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);
   List<ActivityManager.RunningTaskInfo> list = am.getRunningTasks(100
 
);
   for (ActivityManager.RunningTaskInfo info : list) {
       // 注意這裡的 topActivity 包含 packageName和className，可以打印出來看看
       if (info.topActivity.toString().equals(activityName) || info.baseActivity.toString().equals(activityName)) {
           Log.i(TAG,info.topActivity.getPackageName() + " info.baseActivity.getPackageName()="+info.baseActivity.getPackageName());
           return true;
       }
   }
   return false;
}

3、Activity是否顯示在前臺

/**
 * 檢測某Activity是否在當前Task的棧頂
 */
private boolean isTopActivity(String activityName){
    ActivityManager manager = (ActivityManager) mContext.getSystemService(ACTIVITY_SERVICE);
    List<ActivityManager.RunningTaskInfo> runningTaskInfos = manager.getRunningTasks(1);
    String cmpNameTemp = null;
    if(runningTaskInfos != null){
        cmpNameTemp = runningTaskInfos.get(0).topActivity.toString();
    }
    if(cmpNameTemp == null){
        return false;
    }
    return cmpNameTemp.equals(activityName);
}

4、Service是否在執行

/**  
 * 用來判斷服務是否執行.  
 * @param context  
 * @param className 判斷的服務名字  
 * @return true 在執行 false 不在執行  
 */  
public static boolean isServiceRunning(Context mContext,String className) {   
    boolean isRunning = false;   
    ActivityManager activityManager = (ActivityManager)   
                                 mContext.getSystemService(Context.ACTIVITY_SERVICE);    
    //此處只在前30箇中查詢，大家根據需要調整                             
    List<ActivityManager.RunningServiceInfo> serviceList = activityManager.getRunningServices(30);   
    if (!(serviceList.size()>0)) {   
        return false;   
    }   
    for (int i=0; i<serviceList.size(); i++) {   
        if (serviceList.get(i).service.getClassName().equals(className) == true) {   
            isRunning = true;   
            break;   
        }   
    }   
    return isRunning;   
}   

參考資料