判断当前App处于前台还是后台状态

public static boolean isApplicationBackground( final Context context) {
    ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    List<ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks( 1 );

    if (!tasks.isEmpty()) {
      ComponentName topActivity = tasks.get( 0 ).topActivity;
      if (!topActivity.getPackageName().equals(context.getPackageName())) {
        return true ;
      }
    }
    return false ;
   }

需要添加权限

<uses-permission android:name= "android.permission.GET_TASKS" />