NULL Window Insets

Question

I am trying to get the DisplayCutout and getting a

java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.DisplayCutout android.view.WindowInsets.getDisplayCutout()' on a null object reference

Here is my code:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
   DisplayCutout displayCutout;
   displayCutout = getWindow().getDecorView().getRootWindowInsets().getDisplayCutout();
   //Logger.e(TAG, "MARGIN " + displayCutout.getSafeInsetTop());
}

Answer 1

getRootWindowInsets returns null if and only if the view is detached. Make sure you're calling it from the correct context.

Answer 2

you should put your code on

@Override
public void onAttachedToWindow() {
    super.onAttachedToWindow();
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
      DisplayCutout displayCutout;
      displayCutout = 
      getWindow().getDecorView().getRootWindowInsets().getDisplayCutout();
     //Logger.e(TAG, "MARGIN " + displayCutout.getSafeInsetTop());
    }
}

Answer 3

I had to use a combination of OnApplyWindowInsetsListener and get DisplayCutout from DecorView:

public class MyActivity extends AppCompatActivity implements androidx.core.view.OnApplyWindowInsetsListener {

    private Rect insets = new Rect();

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        //...
        ViewCompat.setOnApplyWindowInsetsListener(getWindow().getDecorView(), this);
    }

    @Override
    public WindowInsetsCompat onApplyWindowInsets(View v, WindowInsetsCompat insets) {
        DisplayCutoutCompat cutoutCompat = insets.getDisplayCutout();
        if (cutoutCompat != null) {
            this.insets.set(cutoutCompat.getSafeInsetLeft(), cutoutCompat.getSafeInsetTop(), cutoutCompat.getSafeInsetRight(), cutoutCompat.getSafeInsetBottom());
        } else {
            this.insets.set(insets.getSystemWindowInsetLeft(), insets.getSystemWindowInsetTop(), insets.getSystemWindowInsetRight(), insets.getSystemWindowInsetBottom());
        }

        //cutoutCompat is null at this point... So get it the other way.
        if (getWindow().getDecorView() != null && Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
            WindowInsets rootWindowInsets = getWindow().getDecorView().getRootWindowInsets();
            if (rootWindowInsets != null) {
                DisplayCutout displayCutout = rootWindowInsets.getDisplayCutout();
                if (displayCutout != null) {
                    this.insets.set(displayCutout.getSafeInsetLeft(), displayCutout.getSafeInsetTop(), displayCutout.getSafeInsetRight(), displayCutout.getSafeInsetBottom());
                }
            }
        }

        return insets;
    }
}

Answer 4

public static boolean hasNotchInScreenOfAndroidP(View context) {
    final boolean[] ret = {false};
    final View view=context;
    if (Build.VERSION.SDK_INT >= 28) {
        if (context==null){
        }else {
            context.post(new Runnable() {
                @Override
                public void run() {
                    WindowInsets windowInsets=view.getRootWindowInsets();
                    if (windowInsets==null){
                    }else {
                        DisplayCutout displayCutout = view.getRootWindowInsets().getDisplayCutout();
                        if (displayCutout == null ) {
                            ret[0] = false;
                        } else {
                            List<Rect> rects = displayCutout.getBoundingRects();
                            if (rects == null || rects.size() == 0) {
                                ret[0] = false;
                            } else {
                                ret[0] = true;
                            }
                        }
                    }
                }
            });

        }

    }
    return ret[0];
}

ComUtil.getStateBarHeightOfSeparationFromTheTop(this, getWindow().getDecorView());