在android 5.0以上，如何判斷當前應用是在前台還是后台

今天在做項目時遇到這個問題，本來很簡單的，但是在Android 5.1 的系統上運行卻出錯了，在網上查找答案后發現原來是在android 5.0 之后getRunningTask（）方法被廢棄，失效了。在網上查到的解決方法如下，已驗證有效：

 

private boolean isAppIsInBackground(Context context) {
       boolean isInBackground = true;
       ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
       if (Build.VERSION.SDK_INT > Build.VERSION_CODES.KITKAT_WATCH) {
           List<ActivityManager.RunningAppProcessInfo> runningProcesses = am.getRunningAppProcesses();
           for (ActivityManager.RunningAppProcessInfo processInfo : runningProcesses) {
               //前台程序
               if (processInfo.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
                   for (String activeProcess : processInfo.pkgList) {
                       if (activeProcess.equals(context.getPackageName())) {
                           isInBackground = false;
                       }
                   }
               }
           }
       } else {
           List<ActivityManager.RunningTaskInfo> taskInfo = am.getRunningTasks(1);
           ComponentName componentInfo = taskInfo.get(0).topActivity;
           if (componentInfo.getPackageName().equals(context.getPackageName())) {
               isInBackground = false;
           }
       }

       return isInBackground;
   }