Android App Crashing after calling method in a thread?

Question

Currently in my Android Game there is a simple thread that runs, decreasing a horizontal progressbar by 1 every X milliseconds. I'm trying to implement a method so when the progressbar hits 0, a TextView changes to "Game Over". The app crashes whenever this function is called in this way. I have also initialized the variable correctly so the method should have no trouble seeing this TextView.

    public class MyThread extends Thread{
        @Override
        public void run(){
            while (counter > 0 && keepRunning){
                counter = counter - 1;
                android.os.SystemClock.sleep(calculateSleepTick());
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        progressTest.setProgress(counter);
                    }
                });
            }
            isGameOver();
        }
    }

    public void isGameOver(){
        scoreText.setText("Game Over");
    }

If there is a crash then there is a corresponding Logcat entry - please share this as well — Bö macht Blau, Jun 28 '18 at 19:27
Try using a handler - https://stackoverflow.com/a/13840315/2308683 — OneCricketeer, Jun 28 '18 at 19:40
You cannot update UI components other than UI thread. To update UI you need to post the data into UI/main thread. — Sumit T, Jun 28 '18 at 19:40

score 2 · Answer 1 · answered Jun 28 '18 at 19:32

2

Your isGameOver function sets the text of a UI element. You can't call functions of UI elements on a thread other than main. It needs to be posted to the UI thread to do that.

answered Jun 28 '18 at 19:32

Gabe Sechan

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That makes sense. What can I google or research so I can fix this? – Chris Jun 28 '18 at 19:33
1

Your code already shows how to do it- you post to a UI thread handler to set the progress level. – Gabe Sechan Jun 28 '18 at 19:36

score 1 · Accepted Answer · answered Jun 28 '18 at 19:33

1

You cannot update UI in non UI threads. Call isGameOver() this way.

runOnUiThread(new Runnable() { @Override public void run() { isGameOver(); } });

answered Jun 28 '18 at 19:33

Mean Coder

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Ah thanks man. Where would I implement this. Do I have to create a new object or? – Chris Jun 28 '18 at 19:39
https://www.intertech.com/Blog/android-non-ui-to-ui-thread-communications-part-1-of-5/ – Mean Coder Jun 28 '18 at 20:26

Android App Crashing after calling method in a thread?

2 Answers2