View coordinates inside fragment are always null

Question

I need to get coordinates of some view inside my layout. I've try to do like (inside onCreateView)

TextView[] tv = new TextView[3]
tv[0] = (TextView) view.findViewById(R.id.content0);
tv[1] = (TextView) view.findViewById(R.id.content1);
tv[2] = (TextView) view.findViewById(R.id.content2);
RectF[] positions = new RectF[3];

for (int i = 0; i < tv.length; i++) {
    int top = tv[i].getTop();
    int left = tv[i].getLeft();
    int width = tv[i].getWidth();
    int height = tv[i].getHeight();
    positions[i] = new RectF(left, top, left + width, top + height);

}

But if i try to print positions array into Logcat, i obtain always 0,0,0,0. What's wrong?

the information you are looking for are available at runtime but only when the views are drawn. — Blackbelt, Feb 13 '14 at 14:03

score 1 · Answer 1 · answered Feb 13 '14 at 15:07

As blackbelt mentions, you have to wait for the layout of the views to get the dimension. Use a ViewTreeObserver.

    getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            for (int i = 0; i < tv.length; i++) {
                int top = tv[i].getTop();
                int left = tv[i].getLeft();
                int width = tv[i].getWidth();
                int height = tv[i].getHeight();
                positions[i] = new RectF(left, top, left + width, top + height);

            }
            getViewTreeObserver().removeOnGlobalLayoutListener(this);

        }
    });

View coordinates inside fragment are always null

1 Answers1