Android ขอคำสั่งวิธีการปิดตัวบอกเวลาข้างบนหน่อยครับ แนะนำที

requestWindowFeature(Window.FEATURE_NO_TITLE);

//Remove notification bar
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

<activity android:name=".MainActivity"
          android:label="@string/app_name"
          android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen">

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.lesterxu.testapp2">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.NoActionBar">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

<style name="AppTheme.NoActionBar">
     <item name="windowActionBar">false</item>
     <item name="windowNoTitle">true</item>
 </style>