android 前後臺的判斷

/**
 * 判斷當前應用程序(如Activity、包名)處於前臺還是後臺 (可見/不可見)
 * return false 在前臺
 * return true 在後臺
 */
private boolean isAppToBackground(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;
}