Ho to get s8 useable screen android?

Question

I am noob in android. My problem about useable height of 18:9 devices. When I try to get useable screen in these aspect-ratio my application is woking fine all android devices but when ı compile in Samsung Galaxy s8 it is not working. I am trying to get useable screen of devices. I have already tried method which in these links

https://stackoverflow.com/questions/43628047/how-to-support-189-aspect-ratio-in-android-apps

https://android-developers.googleblog.com/2017/03/update-your-app-to-take-advantage-of.html

And I use dynamically

DisplayMetrics metrics = this.getResources().getDisplayMetrics(); width = metrics.widthPixels; height = metrics.heightPixels ;

And I tried

private int getSoftButtonsBarHeight() {
        // getRealMetrics is only available with API 17 and +
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
            DisplayMetrics metrics = new DisplayMetrics();
            getWindowManager().getDefaultDisplay().getMetrics(metrics);
            int usableHeight = metrics.heightPixels;
            getWindowManager().getDefaultDisplay().getRealMetrics(metrics);
            int realHeight = metrics.heightPixels;
            if (realHeight > usableHeight)
                return realHeight - usableHeight;
            else
                return 0;
        }
        return 0;
    }

And when I try to set params MATCH_PARENT height it is working good. But I need to find useable height pixel to desing my other views proportionally .

Actually these code DisplayMetrics metrics = this.getResources().getDisplayMetrics(); height = metrics.heightPixels ; working in my Activity but when I try to use it in another window which I extend from FramaLayout and add to activity it is not working.

Here is my code block

public class StudentLoginActivity extends Activity {  ...
    FrameLayout.LayoutParams containerParams = new ScrollView.LayoutParams(width, height-sb);
    container = new FrameLayout(this);
    container.setLayoutParams(containerParams);
    container.setBackgroundColor(Color.rgb(248,248,248));
    loginStudentView = new StudentLoginView(this);
    container.addView(loginStudentView); ...

}

   public class StudentLoginView extends FrameLayout { ...
    FrameLayout.LayoutParams cp = new FrameLayout.LayoutParams(width, height);
    setLayoutParams(cp); ...

}

But this problem related with android navigationBar height because when I show navigation bar there is no problem but if I hide navigationBar it is not resize application still working that there is a navigation bar on screen (but I hide the navigationBar).

My problem is very similar this link

android Navigation Bar hiding and persantage of usable screen overlap

Answer 1

You can get the useable height (even on Galaxy S8 with or without shown NavBar) with the decorview:

    //Get the correct screen size even if the device has a hideable navigation bar (e.g. the Samsung Galaxy S8)
    View decorView = getWindow().getDecorView(); //if you use this in a fragment, use getActivity before getWindow()
    Rect r = new Rect();
    decorView.getWindowVisibleDisplayFrame(r);
    int screenHeight = r.bottom; // =2220 on S8 with hidden NavBar and =2076 with enabled NavBar
    int screenWidth = r.right; // =1080 on S8