Null pointer exception in for loop with random numbers

Question

For some reason my code gives one random number but crashes after the second due to a null pointer exception. Does anybody know how I can fix this?

public void shownumbers() {
    Timer MyTimer = new Timer();
        MyTimer.scheduleAtFixedRate(new TimerTask() {
            @Override
            public void run() {
                Random r = new Random();
                TextView viewbox = (TextView) findViewById(R.id.textView);
                viewbox.setText(Integer.toString(r.nextInt(10)));
            }
        }, 100, 500);

@EdGeorge not really a duplicate because context here is quite relevant. — px06, Sep 03 '16 at 22:23
In short, at some point you are ending up with `null.member` where `member` is field or method. But `null` doesn't have any members. You need to check your log to and debut what exactly is your `null`. — Pshemo, Sep 03 '16 at 22:26
The issue is probably that you are calling `setText` on the wrong thread. Use `runOnUiThread` to ensure you are doing it on the UI Thread — Ed Holloway-George, Sep 03 '16 at 22:34

score 0 · Answer 1 · answered Sep 03 '16 at 22:26

0

The function findViewById(int) returns null if R.id.textView is not found. You can check the stack trace of your NullPointerException and find the exact line where it fails.

answered Sep 03 '16 at 22:26

Larry B.

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Null pointer exception in for loop with random numbers

1 Answers1