I hope It helps you.

Previously, when implementing edge-to-edge navigation or immersive mode, one of the first steps to take was to use the systemUiVisibility flags in order to request the app to be laid out fullscreen, This new Android release deprecates this field and in order to layout the app fullscreen you have to use a new method on the Window class: setDecorFitsSystemWindows passing false as an argument like below.

window.setDecorFitsSystemWindows(false)

WindowInsetsController class which allows you to do things that previously were controlled via systemUiVisibility flags, like hiding or showing the status bar or navigation bar(hide and show methods, respectively)

For example, you can easily show and hide the keyboard as shown below:

// You have to wait for the view to be attached to the
// window (otherwise, windowInsetController will be null)
view.doOnLayout {
    view.windowInsetsController?.show(WindowInsets.Type.ime())
    // You can also access it from Window
    window.insetsController?.show(WindowInsets.Type.ime())
}

WindowCompat.setDecorFitsSystemWindows(window, false)

Watch this tutorial from official Android Developers channel.

As of version 1.5.0-alpha02, androidx.core has WindowCompat.setDecorFitsSystemWindows()

To enable edge-to-edge:

WindowCompat.setDecorFitsSystemWindows(window, false)

TL;DR snippet

Wrapping in if-else structure needed to avoid java.lang.NoSuchMethodError: No virtual method setDecorFitsSystemWindows exception on older SDK versions.

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
    window.setDecorFitsSystemWindows(false)
} else {
    window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_FULLSCREEN
}

Links with full information about insets and fullscreen modes in Android 11

https://blog.stylingandroid.com/android11-windowinsets-part1/

https://www.youtube.com/watch?v=acC7SR1EXsI

Also you may want to have a translucent status bar and you can do it simply through setting a style to your app's theme as follows:

<style name="App.MyTheme" parent="Theme.MaterialComponents.DayNight.NoActionBar">
    <item name="android:windowLightStatusBar">true</item>
</style>

A lint message can be displayed (depending on you curren min api level): android:windowLightStatusBar requires API level 23 (current min is 21), so you need to override this theme in v23 styles

For compatibility, use WindowCompat and WindowInsetsControllerCompat. You'll need to upgrade your gradle dependency for androidx.core to at least 1.6.0-alpha03 so that there will be support for setSystemBarsBehavior on SDK < 30.

private fun hideSystemUI() {
    WindowCompat.setDecorFitsSystemWindows(window, false)
    WindowInsetsControllerCompat(window, mainContainer).let { controller ->
        controller.hide(WindowInsetsCompat.Type.systemBars())
        controller.systemBarsBehavior = WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
    }
}

private fun showSystemUI() {
    WindowCompat.setDecorFitsSystemWindows(window, true)
    WindowInsetsControllerCompat(window, mainContainer).show(WindowInsetsCompat.Type.systemBars())
}

You can find out more information about WindowInsets by watching this YouTube video

For devices with notches at the top of the display, you can add the following to your v27 theme.xml file make the UI appear either side of the notch:

<item name="android:windowLayoutInDisplayCutoutMode">shortEdges</item>

You can read more at this link: Display Cutout

If somebody search for Java version.

For Activity:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
    getWindow().setDecorFitsSystemWindows(false);

    if (getWindow().getInsetsController() != null) {
        getWindow().getInsetsController().hide(WindowInsets.Type.statusBars() | WindowInsets.Type.navigationBars());
        getWindow().getInsetsController().setSystemBarsBehavior(WindowInsetsController.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE);
    }
} else {
    getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
}

for FragmentDialog and AlertDialog:

if (getDialog() != null && getDialog().getWindow() != null) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
        getDialog().getWindow().setDecorFitsSystemWindows(false);
    } else {
        if (getActivity() != null) {
            getDialog().getWindow().getDecorView().setSystemUiVisibility(getActivity().getWindow().getDecorView().getSystemUiVisibility());
        }
    }
}

According to Chris Banes @ Android Developers official youtube channel use following code

class MainActivity : AppCompatActivity() {
    private lateinit var binding: ActivityMainBinding
    private lateinit var view: View

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        view = binding.root
        setContentView(view)
    }

    override fun onWindowFocusChanged(hasFocus: Boolean) {
        super.onWindowFocusChanged(hasFocus)
        if (hasFocus) hideSystemUI()
    }

    private fun hideSystemUI() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
             // Tell the window that we want to handle/fit any system windows
             WindowCompat.setDecorFitsSystemWindows(window, false)

             val controller = view.windowInsetsController

             // Hide the keyboard (IME)
             controller?.hide(WindowInsets.Type.ime())

             // Sticky Immersive is now ...
             controller?.systemBarsBehavior = BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE

             // When we want to hide the system bars
             controller?.hide(WindowInsets.Type.systemBars())

             /*val flag = WindowInsets.Type.statusBars()
             WindowInsets.Type.navigationBars()
             WindowInsets.Type.captionBar()
             window?.insetsController?.hide(flag)*/
        } else {
            //noinspection
            @Suppress("DEPRECATION")
            // For "lean back" mode, remove SYSTEM_UI_FLAG_IMMERSIVE.
            window.decorView.systemUiVisibility = (View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
                // 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_STABLE
                or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                // Hide the nav bar and status bar
                or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                or View.SYSTEM_UI_FLAG_FULLSCREEN)
        }
    }
}

Here is Sample Link User interface sample

For Java users (thanks to @James):

//hide system UI
Window window = activity.getWindow();
View decorView = activity.getWindow().getDecorView();

WindowCompat.setDecorFitsSystemWindows(window, false);
WindowInsetsControllerCompat controllerCompat = new WindowInsetsControllerCompat(window, decorView);
controllerCompat.hide(WindowInsetsCompat.Type.systemBars() | WindowInsetsCompat.Type.navigationBars());
controllerCompat.setSystemBarsBehavior(WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE);

(Edit) Use BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE to only show sytemBars temporarily when when swiping, BEHAVIOR_SHOW_BARS_BY_SWIPE will show them permanently after swiping.

Source : https://developer.android.com/reference/android/view/WindowInsetsController#BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE

2022 Offical Solution with Kotlin Code:

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())

Source: https://developer.android.com/training/system-ui/immersive#kotlin

For anyone looking to do this in Xamarin Forms and C#, I have added this code in the MainActivity class in the MainActivity.cs file:

    private void SetWindowLayout()
    {
        if (Window != null) {
            if (Build.VERSION.SdkInt >= BuildVersionCodes.R) {
                IWindowInsetsController wicController = Window.InsetsController;


                Window.SetDecorFitsSystemWindows(false);
                Window.SetFlags(WindowManagerFlags.Fullscreen, WindowManagerFlags.Fullscreen);

                if (wicController != null) {
                    wicController.Hide(WindowInsets.Type.Ime           ());
                    wicController.Hide(WindowInsets.Type.NavigationBars());
                }
            }
            else {
                #pragma warning disable CS0618

                Window.SetFlags(WindowManagerFlags.Fullscreen, WindowManagerFlags.Fullscreen);

                Window.DecorView.SystemUiVisibility = (StatusBarVisibility) (SystemUiFlags.Fullscreen           |
                                                                       SystemUiFlags.HideNavigation       |
                                                                       SystemUiFlags.Immersive            |
                                                                       SystemUiFlags.ImmersiveSticky      |
                                                                       SystemUiFlags.LayoutHideNavigation |
                                                                       SystemUiFlags.LayoutStable         |
                                                                       SystemUiFlags.LowProfile);
                #pragma warning restore CS0618
            }
        }
    }

Then, in the OnCreate overridden method make a call to SetWindowLayout()

Then, override the OnWindowFocusChanged() method:

    public override void OnWindowFocusChanged(
        Boolean bHasFocus)
    {
        base.OnWindowFocusChanged(bHasFocus);

        if (bHasFocus)
            SetWindowLayout();
    }

I hope this helps everyone in Visual Studio.

Loz.

JAVA

 private void showSystemUI() {
            WindowCompat.setDecorFitsSystemWindows(getWindow(), true);
            new WindowInsetsControllerCompat(getWindow(), yourRootView).show(WindowInsetsCompat.Type.systemBars());
        }

        private void hideSystemUI() {
            WindowCompat.setDecorFitsSystemWindows(getWindow(), false);
            WindowInsetsControllerCompat controller = new WindowInsetsControllerCompat(getWindow(), yourRootView);
            controller.hide(WindowInsetsCompat.Type.systemBars());
            controller.setSystemBarsBehavior(WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE);
        }

use this : window.setDecorFitsSystemWindows(false)

Make sure that you have android build gradle setup that has minsdk of 30

In the Styles file add two items:

<item name="windowActionBar">false</item>
<item name="windowNoTitle">true</item>

And in activity file before setContentView(R.layout.activity_main) this following lines :

try {
   actionBar!!.hide();
} catch (e:Exception){
        
}

Here is a straight forward solution that works for all android version and hides the status bar

 WindowInsetsControllerCompat(window,  window.decorView).hide(WindowInsetsCompat.Type.systemBars())

It works well on emulators but sometimes on a real device if the keyboard pops up the status bar is shown again. If you don't really need to hide/show the status bar programmatically then just add window full screen as an item to the theme you will use for that screen. For example you can create a style in theme.xml

 <style name="HideStatusBar" parent="Theme.MaterialComponents.DayNight.NoActionBar">
<!-- Primary brand color. -->
<item name="colorPrimary">@color/purple_500</item>
<item name="colorPrimaryVariant">@color/purple_700</item>
<item name="colorOnPrimary">@color/white</item>
    <!-- hides status bar-->
    <item name="android:windowFullscreen">true</item>
</style>

and in the AndroidManifest.xml you add a style to that activity section

 <activity
        android:name=".MainActivity"
        android:screenOrientation="portrait"
   <!-- The style-->
        android:theme="@style/NoactionBar"
        android:exported="true" />

This also works for all version

If you are using Jetpack Compose, use this method in setContent:

@Composable
fun HideSystemUi()
{
    val systemUiController = rememberSystemUiController()

    SideEffect {
        systemUiController.isSystemBarsVisible = false
    }
}

Do not forget to add this to your app's build.gradle file (adjust the version if necessary):

implementation "com.google.accompanist:accompanist-systemuicontroller:0.17.0"

The documentation can be found here, although you might want to have a look at the sources.