Android - Align view center to bottom of other view

Question

A picture tells more than a lengthy speech :

I want to align vertically the center of the red part with the middle of the black part. I have no constraint of contai

Answer 1

Finally, I use a more programmatic way to solve this problem, because the size of Views are not fixed.

Here the solution :

The layout :

The code :

            red.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
                @Override
                public void onGlobalLayout() {
                    red.getViewTreeObserver().removeOnGlobalLayoutListener(this);

                    LayoutParams params = new LayoutParams(
                            LayoutParams.MATCH_PARENT,      
                            LayoutParams.WRAP_CONTENT
                            );
                    params.setMargins(0, 0, 0, red.getHeight()/2);
                    black.setLayoutParams(params);
                }
            });

Thanks for your help ! It helps me found this !