Viewing Image Or Content In Full Screen

[gorkijatt]

"I need some help. I don't know where to ask questions regarding this. The thing is, I want to view an image in full screen by hiding the navigation and status bars. I used
WindowCompat.setDecorFitsSystemWindows(window, false)
which started showing content behind the status bar.
When I add the flags to hide the status and navigation bars, the content automatically takes margin from the top. I've tried everything available on the internet, but no luck. I can't figure out where I am going wrong. I've been trying this for at least 4 days, and I still haven't had any luck."

class MainActivity : ComponentActivity() {
    @OptIn(ExperimentalMaterial3WindowSizeClassApi::class)
    override fun onCreate(savedInstanceState: Bundle?) {
        
        //showing the content behind status bar
        WindowCompat.setDecorFitsSystemWindows(window, false)

        super.onCreate(savedInstanceState)
        setContent {
            MyApplicationTheme {
                
                //hiding the status and nav bar
                val systemUiController = rememberSystemUiController()
                systemUiController.isStatusBarVisible = false // Status bar
                systemUiController.isNavigationBarVisible = false // Navigation bar
                systemUiController.isSystemBarsVisible = false // Status & Navigation bars
                systemUiController.navigationBarDarkContentEnabled = true

                // A surface container using the 'background' color from the theme
                Box(
                    modifier = Modifier
                        .fillMaxSize()
                        .background(Color.White)
                        .padding(0.dp),
                ) {
                    Greeting("Android")
                }
            }
        }
    }
}

what i achieved is the top status bar is hided but the box is not filling the size.. i am using pixel 7 on android 14 here