使用Android Studio(当前版本是2.2.2)很容易添加一个全屏活动。

请看步骤:

右键单击你的java主包，选择“新建”，选择“活动”，然后点击“全屏活动”。

自定义活动(“活动名称”，“布局名称”等)，点击“完成”。

完成了!

现在你有一个全屏的活动很容易(查看java类和活动布局，以了解事情是如何工作的)!

 protected void onCreate(Bundle savedInstanceState) {
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    super.onCreate(savedInstanceState);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_splash_screen);
    getSupportActionBar().hide();

}

在AndroidManifest.xml文件:

<activity
    android:name=".Launch"
    android:label="@string/app_name"
    android:theme="@android:style/Theme.NoTitleBar.Fullscreen" > <!-- This line is important -->

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

或者在Java代码中:

protected void onCreate(Bundle savedInstanceState){
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
}

根据安卓开发者培训

你应该做到以下几点:

科特林：

private fun hideSystemBars() {
  val windowInsetsController =
      ViewCompat.getWindowInsetsController(window.decorView) ?: return
  // Configure the behavior of the hidden system bars
  windowInsetsController.systemBarsBehavior =
      WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
  // Hide both the status bar and the navigation bar
  windowInsetsController.hide(WindowInsetsCompat.Type.systemBars())
}

Java:

private void hideSystemBars() {
  WindowInsetsControllerCompat windowInsetsController =
      ViewCompat.getWindowInsetsController(getWindow().getDecorView());
  if (windowInsetsController == null) {
    return;
  }
  // Configure the behavior of the hidden system bars
  windowInsetsController.setSystemBarsBehavior(
      WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
  );
  // Hide both the status bar and the navigation bar
  windowInsetsController.hide(WindowInsetsCompat.Type.systemBars());
}

通过缺口或切口区域显示内容。这可以从文档中得到帮助:

LAYOUT_IN_DISPLAY_CUTOUT_MODE_SHORT_EDGES -在纵向和横向模式下将内容呈现到剪切区域。

对我来说最重要的是activity样式中的这一行:

// Important to draw through the cutouts
<item name="android:windowLayoutInDisplayCutoutMode">shortEdges</item> 

对我来说，我想以沉浸式模式展示图像。当我点击它时，我希望系统UI(状态和导航栏)显示出来。

以下是我的解决方案:

在Activity中，一些显示/隐藏系统UI的方法(状态条/导航条)

private fun hideSystemUI() {
    sysUIHidden = true
    window.decorView.systemUiVisibility = (
            View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
            or View.SYSTEM_UI_FLAG_LAYOUT_STABLE 
            // Hide the nav bar and status bar
            or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // Hide nav bar
            or View.SYSTEM_UI_FLAG_FULLSCREEN // Hide status bar
            )
}


private fun showSystemUI() {
    sysUIHidden = false
    window.decorView.systemUiVisibility = (
            View.SYSTEM_UI_FLAG_LAYOUT_STABLE
            // Set the content to appear under the system bars so that the
            // content doesn't resize when the system bars hide and show.
            or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION // layout Behind nav bar
            or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN // layout Behind status bar
            )
}

2-确保在你的xml布局的根视图中

android:fitsSystemWindows="false"

3-全屏活动的风格将给状态/导航栏显示时一个半透明的背景:

<style name="FullscreenTheme" parent="AppTheme">
    <item name="android:actionBarStyle">@style/FullscreenActionBarStyle</item>
    <item name="android:windowActionBarOverlay">true</item>
    <item name="android:windowBackground">@null</item>
    <item name="metaButtonBarStyle">?android:attr/buttonBarStyle</item>
    <item name="metaButtonBarButtonStyle">?android:attr/buttonBarButtonStyle</item>
    <item name="android:statusBarColor">#50000000</item>
    <item name="android:navigationBarColor">#50000000</item>
    // Important to draw behind cutouts
    <item name="android:windowLayoutInDisplayCutoutMode">shortEdges</item> 
</style>

<style name="FullscreenActionBarStyle" parent="Widget.AppCompat.ActionBar">
    <item name="android:background">@color/sysTransparent</item>
</style>

import androidx.core.view.WindowInsetsCompat.Type

fun Activity.fullscreen() {
    with(WindowInsetsControllerCompat(window, window.decorView)) {
        systemBarsBehavior = WindowInsetsControllerCompat.BEHAVIOR_SHOW_BARS_BY_SWIPE
        hide(Type.systemBars())
    }
}

fun Activity.exitFullscreen() {
    WindowInsetsControllerCompat(window, window.decorView).show(Type.systemBars())
}