How to make an activity full screen in android studio?

There are several ways to do so, Some of them is given below:

i: Add this method to the activity.java file and call it.

private void fullScreenUI() {
    //Full Screen App
View decorView = getWindow().getDecorView();
    
    int uiOptions;

    uiOptions = (SYSTEM_UI_FLAG_IMMERSIVE
   // Set the content to appear under the system bars so that the
   // content doesn't resize when the system bars hide and show.
                    | SYSTEM_UI_FLAG_LAYOUT_STABLE
                    | SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                    | SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
   // Hide the nav bar and status bar
                    | SYSTEM_UI_FLAG_HIDE_NAVIGATION
                    | SYSTEM_UI_FLAG_FULLSCREEN);

    decorView.setSystemUiVisibility(uiOptions);

}

Just Call this Function in any Activity and You are good to go. 👌👌

ii: Second ways are just adding this item in style.xml

<item name="android:windowFullscreen">true</item>