How To Set Text Of Text View When Button Is Clicked

I am trying to set the Text of a Text View when a button is clicked.

I have been struggling, because the variable will increment, but If i put the code in to set the text, it crashes the app ?

Here is my code when it crashes:

Quote:

package com.example.test;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;

[Code].....

however if I comment out the line

Quote:

score.setText(points);

, the app doesnt crash, but it doesnt do anything then.