Fragment - removeGlobalOnLayoutListener IllegalStateException

Question

I\'m trying to get the height and width of an ImageView in a Fragment with the following ViewTreeObserver:

import andr         


        

Answer 1

Better try to check if a getViewTreeObserver is alive. I think the following code will work. Based on https://stackoverflow.com/a/15301092/2914140, https://stackoverflow.com/a/26193736/2914140 and some others.

** Update **

After reading Remove listener from ViewTreeObserver, https://stackoverflow.com/a/40013262/2914140 I rewrote a bit.

public static void captureGlobalLayout(@NonNull final View view,
                                       @NonNull final ViewTreeObserver.OnGlobalLayoutListener listener) {
    ViewTreeObserver vto = view.getViewTreeObserver();
    if (vto.isAlive()) {
        vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
                    @Override
                    public void onGlobalLayout() {
                        ViewTreeObserver vto = view.getViewTreeObserver();
                        if (vto.isAlive()) {
                            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                                vto.removeOnGlobalLayoutListener(this);
                            } else {
                                //noinspection deprecation
                                vto.removeGlobalOnLayoutListener(this);
                            }
                            listener.onGlobalLayout();
                        }
                    }
                });
    } else {
        view.post(new Runnable() {
            @Override
            public void run() {
                listener.onGlobalLayout();
            }
        });

    }
}

** Old answer **

Strange but even if view.getViewTreeObserver().isAlive() is true, then next call to view.getViewTreeObserver() may again produce the same exception. So, I surrounded a code with try-catch. Possibly you may skip all this and retain only view.post(...) block.

if (view.getViewTreeObserver().isAlive()) {
    try {
        view.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                if (view.getViewTreeObserver().isAlive()) {
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                        view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                    } else {
                        view.getViewTreeObserver().removeGlobalOnLayoutListener(this);
                    }
                }
                yourCode();
            }
        });
    } catch (IllegalStateException e) {
        e.printStackTrace();
        // The same as below branch.
        getActivity().runOnUiThread(new Runnable() {
            @Override
            public void run() {
                view.post(new Runnable() {
                    @Override
                    public void run() {
                        yourCode();
                    }
                });
            }
        });
    }
} else {
    getActivity().runOnUiThread(new Runnable() {
        @Override
        public void run() {
            // Try to wait until the view is ready.
            view.post(new Runnable() {
                @Override
                public void run() {
                    yourCode();
                }
            });
        }
    });
}

Probably view.post(...) is enough, but I called it from background thread, so if you do the same, better should invoke it from runOnUiThread(new Runnable() ....