Android 判断app是否在前台运行

<!-- 前台还是后台 -->
<uses-permission android:name="android.permission.GET_TASKS" />

private boolean isForeground(Context context) {
        ActivityManager am = (ActivityManager) context
                .getSystemService(Context.ACTIVITY_SERVICE);
        ComponentName cn = am.getRunningTasks(1).get(0).topActivity;
        String currentPackageName = cn.getPackageName();
        if (!TextUtils.isEmpty(currentPackageName)
                && currentPackageName.equals(context.getPackageName())) {
            Log.i("yy", "处于前台");
            return true;
        }
        Log.i("yy", "处于后台");
        return false;
    }