在style.xml中定义：

<style name="FullScreenTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="android:windowFullscreen">true</item>
    </style>

使用：

<activity android:name=".ui.SplashActivity" android:screenOrientation="portrait"
                  android:theme="@style/FullScreenTheme"