如何找到位置或在textview中找到任何单词的矩形并将按钮放在那上面？

I am working on a story app.Where We need to provide quizes. Now I am having a story and there are some blanks or hidden words over that story. Whenever I click over that hidden word,I will get the 4 options to answer that. I tried by placing button over the words,But that would be only when I am using some static position. I just want to know how can I get the frame of that word,which I need to hide ,so that I can place some button over that and can hide this.I am working on a story app.Where We need to pr