A small layout to observe measure calls to know when the layout dimentions are fixed.

MeasureCallbackLayout.java

public class MeasureCallbackLayout extends FrameLayout {
    private final List<MeasureCallback> listeners = new ArrayList<>();
    private int width = -1;
    private int height = -1;

    public MeasureCallbackLayout(Context context) {
        super(context);
    }

    public MeasureCallbackLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MeasureCallbackLayout(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @SuppressLint("NewApi")
    public MeasureCallbackLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    public boolean addMeasureListener(MeasureCallback callback) {
        return listeners.add(callback);
    }

    public boolean removeMeasureListener(MeasureCallback callback) {
        return listeners.remove(callback);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if((MeasureSpec.getMode(widthMeasureSpec) == MeasureSpec.EXACTLY || MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.EXACTLY) &&
            MeasureSpec.getSize(widthMeasureSpec) != width && MeasureSpec.getSize(heightMeasureSpec) != height) {
            width = MeasureSpec.getSize(widthMeasureSpec);
            height = MeasureSpec.getSize(heightMeasureSpec);
            for (int i = listeners.size() - 1; i >= 0; i--) {
                listeners.get(i).onMeasured();
            }
        }
    }

    public interface MeasureCallback {
        void onMeasured();
    }
}