这对我很管用。

if (Build.VERSION.SDK_INT < 16) {
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
    } else {
        View decorView = getWindow().getDecorView();
        int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
        decorView.setSystemUiVisibility(uiOptions);
    }

充分沉浸:

private void askForFullScreen()
    {
        getActivity().getWindow().getDecorView().setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                        | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar
                        | View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar
                        | View.SYSTEM_UI_FLAG_IMMERSIVE);
    }

脱离完全沉浸模式:

 private void moveOutOfFullScreen() {
        getActivity().getWindow().getDecorView().setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
    }

只需将此代码粘贴到onCreate()方法中

requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);

用kotlin是这样做的:

class LoginActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_login)
        window.decorView.systemUiVisibility =
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE or
                View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN or
                View.SYSTEM_UI_FLAG_FULLSCREEN

    }
}

身临其境的模式

沉浸式模式适用于用户需要与屏幕进行大量交互的应用程序。例如游戏、浏览图库中的图像或阅读分页内容(如书籍或演示文稿中的幻灯片)。为此，只需添加这几行:

View.SYSTEM_UI_FLAG_HIDE_NAVIGATION or
View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION

粘性身临其境

在常规的沉浸式模式下，每当用户从边缘滑动时，系统都会负责显示系统条——你的应用程序甚至不会意识到这个手势发生了。因此，如果用户可能真的需要从屏幕边缘滑动作为主要应用体验的一部分——比如在玩一款需要大量滑动的游戏或使用绘图应用时——你应该启用“粘性”沉浸模式。

View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY

有关更多信息:启用全屏模式

如果你使用键盘，有时会发生状态栏显示时，键盘显示。在这种情况下，我通常将此添加到我的style xml

styles.xml

<style name="FullScreen" parent="AppTheme">
    <item name="android:windowFullscreen">true</item>
</style>

还有这一行到我的载货单上

<activity
        android:name=".ui.login.LoginActivity"
        android:label="@string/title_activity_login"
        android:theme="@style/FullScreen">

从mozilla找到解决方案，他们在这里做了一个扩展库

如果链接中断，这里是代码

/**
 * Retrieves a {@link WindowInsetsControllerCompat} for the top-level window decor view.
 */
fun Window.getWindowInsetsController(): WindowInsetsControllerCompat {
    return WindowInsetsControllerCompat(this, this.decorView)
}


/**
 * Attempts to call immersive mode using the View to hide the status bar and navigation buttons.
 * @param onWindowFocusChangeListener optional callback to ensure immersive mode is stable
 * Note that the callback reference should be kept by the caller and be used for [exitImmersiveModeIfNeeded] call.
 */
fun Activity.enterToImmersiveMode(
    onWindowFocusChangeListener: ViewTreeObserver.OnWindowFocusChangeListener? = null
) {
    window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
    window.getWindowInsetsController().apply {
        hide(WindowInsetsCompat.Type.systemBars())
        systemBarsBehavior = WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
    }

    // We need to make sure system bars do not become permanently visible after interactions with content
    // see https://github.com/mozilla-mobile/fenix/issues/20240
    onWindowFocusChangeListener?.let {
        window.decorView.viewTreeObserver?.addOnWindowFocusChangeListener(it)
    }
}

/**
 * Attempts to come out from immersive mode using the View.
 * @param onWindowFocusChangeListener optional callback to ensure immersive mode is stable
 * Note that the callback reference should be kept by the caller and be the same used for [enterToImmersiveMode] call.
 */
@Suppress("DEPRECATION")
fun Activity.exitImmersiveModeIfNeeded(
    onWindowFocusChangeListener: ViewTreeObserver.OnWindowFocusChangeListener? = null
) {
    if (WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON and window.attributes.flags == 0) {
        // We left immersive mode already.
        return
    }
    onWindowFocusChangeListener?.let {
        window.decorView.viewTreeObserver?.removeOnWindowFocusChangeListener(it)
    }
    window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
    window.getWindowInsetsController().apply {
        show(WindowInsetsCompat.Type.systemBars())
    }
}

在onCreate()中的setContentView之后使用这个方法，并通过getWindow()传递Window对象。

    public void makeActivityFullScreen(Window window){
    View decorView = window.getDecorView();
    //        int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
       window.getAttributes().layoutInDisplayCutoutMode = WindowManager.LayoutParams.LAYOUT_IN_DISPLAY_CUTOUT_MODE_SHORT_EDGES;
    }
    decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE
            | View.SYSTEM_UI_FLAG_FULLSCREEN
            | View.SYSTEM_UI_FLAG_LAYOUT_STABLE
            | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
            | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
            | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
    );
}

此代码也将适用于缺口屏幕。要检查缺口全屏，你需要安卓P，但如果你有一个缺口显示手机，然后去设置->显示设置->应用程序显示比例->选择你的应用程序->有两个安全的选项是显示和全屏，请选择全屏并运行应用程序，你可以看到缺口的全屏也没有安卓派