如何删除显示应用程序名称的空间

@Override
public void onCreate(Bundle savedInstanceState) {
    requestWindowFeature(Window.FEATURE_NO_TITLE);       
    super.onCreate(savedInstanceState);
}

<activity android:name=".YourClassName"
   android:theme="@android:style/Theme.NoTitleBar">
</activity>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/Theme.AppCompat.Light.NoActionBar" >

<style name="MyTheme" parent="@android:style/Theme.NoTitleBar">
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowBackground">@drawable/xyz</item>
</style>