Question

I’m a learner in Android. If button is clicked I want to displayString[]={"Rubin","Android","Steve"} in textview.

I’m getting null pointer exception on onClick

Code:

    TextView tv;
Button b1;
    String question[]={"Rubin","Android","Steve"};


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.ques);
    tv = (TextView) findViewById(R.id.button1);
    b1 = (Button) findViewById(R.id.startExam);
    b1.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            // TODO Auto-generated method stub
            tv.setText(question[0]);
        }
    });
}

Answer 1

here is the error

tv = (TextView) findViewById(R.id.button1);

In TextView you are assigning command Button’s id. Please check your ques.xml and see what Id you have assigned for TextView. Assign that id in Activity and your problem is solved.