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());
}

Callery

I experience the same problem, the best workaround I could find so far is to delay calling this method, for example doing it in a button click event. – Zeidman

Answer 1

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

Salsala

I'm calling it in onResume() and setContentView is called in onCreate() so there should be no issue with the activity being attached. – Callery

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());
    }
}

Barrera

but there is a bug #65621459 – Monosyllabic

App crashes on Android 7. It is still null – Impetus

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;
    }
}

Tbar

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());

Brassware

Answer 5

try below code. I was able to get status bar height with View.OnAttachStateChangeListener. In my case, I have attached listener to ScrollView(mDetailScrollView), change it to any view that you want to attach the listener.

    ...
    mDetailScrollView.addOnAttachStateChangeListener(new View.OnAttachStateChangeListener() {
        @Override
        public void onViewAttachedToWindow(View v) {                
            DisplayCutout displayCutout = getDisplayCutout();
            if (displayCutout != null) {
                // your code...
            }
        }

        @Override
        public void onViewDetachedFromWindow(View v) {
        }
    });
    ...

    private DisplayCutout getDisplayCutout() {
        if (activity != null) {
            WindowInsets windowInsets = getWindow().getDecorView().getRootWindowInsets();
            if (windowInsets != null) {
                return windowInsets.getDisplayCutout();
            }
        }

        return null;
    }

Mytilene

Answer 6

you can get DisplayCutout in handler

    val cutoutHandler = HandlerThread("cutout-thread")
    cutoutHandler.start()
    var handler = object : Handler(cutoutHandler.looper) {
        override fun handleMessage(msg: Message?) {
            super.handleMessage(msg)
            runOnUiThread {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) { // 9.0原生
                    val windowInsets = window.decorView.rootWindowInsets
                    val displayCutout = windowInsets.displayCutout
                }
                cutoutHandler.quit()
            }
        }
    }
    Thread {
        handler.sendEmptyMessage(0)
    }.start()

Syllabogram

Answer 7

This was occurring for me when running an emulator. It looks like even if you have an emulator with a default skin that has a display cutout, it still may not register it as a display cutout device.

You can work around this by enabling the "Simulate a display with a cutout" in the developer options:
https://developer.android.com/guide/topics/display-cutout/#test_how_your_content_renders

Septime