Thread :Can't create handler inside thread that has not called Looper.prepare()

[Sahar Cohen]

I'm a beginner, and I'm trying to create a 2D game and I have issue that I don't understand and don't know how to solve.

I have an issue with a thread and the error I get is

Can't create handler inside thread that has not called Looper.prepare()

I saw some question anout this issue, but I couldn't figure out the way to solve it.

This is the code

package com.example.spaceshiprunnerv01;

import android.graphics.Canvas;
import android.os.Looper;
import android.view.SurfaceHolder;


public class MainThread extends Thread {
    private static final int MAX_FPS = 30;
    private double avrageFPS;
    private final SurfaceHolder surfaceHolder;
    private GamePanel gamePanel;
    private boolean running;
    public static Canvas canvas;

    public void setRunning(boolean running) {
        this.running = running;
    }

    public MainThread(SurfaceHolder surfaceHolder, GamePanel gamePanel) {
        super();
        this.surfaceHolder = surfaceHolder;
        this.gamePanel = gamePanel;
    }


    @Override
    public void run() {
        long startTime;
        long timeMillis = 1000 / MAX_FPS;
        long waitTime;
        int frameCount = 0;
        long totalTime = 0;
        long targetTime = 1000 / MAX_FPS;
        while (running) {
            startTime = System.nanoTime();
            canvas = null;
            try {
                canvas = this.surfaceHolder.lockCanvas();
                synchronized (surfaceHolder) {
                    this.gamePanel.update();
                    this.gamePanel.draw(canvas);
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (canvas != null) {
                    try {
                        surfaceHolder.unlockCanvasAndPost(canvas);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }
            timeMillis = (System.nanoTime() - startTime) / 1000000;
            waitTime = targetTime - timeMillis;
            try {
                if (waitTime > 0) {
                    this.sleep(waitTime);

                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            totalTime += System.nanoTime() - startTime;
            frameCount++;
            if (frameCount == MAX_FPS) {
                avrageFPS = 1000 / ((totalTime / frameCount / 1000000));
                frameCount = 0;
                totalTime = 0;
                System.out.println(avrageFPS);
            }


        }


    }
}

[Paul Clapham]

Hi Sahar, welcome to the Ranch!

If I was the one who got that message "Can't create handler inside thread that has not called Looper.prepare()" then my first idea would be to have my thread call Looper.prepare(). Probably near the beginning, because "prepare" sounds like the sort of thing which should be done at the beginning. I'd suggest trying that.

[Sahar Cohen]

Paul Clapham wrote:Hi Sahar, welcome to the Ranch!

If I was the one who got that message "Can't create handler inside thread that has not called Looper.prepare()" then my first idea would be to have my thread call Looper.prepare(). Probably near the beginning, because "prepare" sounds like the sort of thing which should be done at the beginning. I'd suggest trying that.

Hi Paul, Thanks for your response.
I tried at first to put Looper.prepare (): before while but it did not help
I think I need to use Thread and Handler with getMainLooper but I do not have any idea how to combine them together
You have an idea?

[Paul Clapham]

Sahar Cohen wrote:You have an idea?

No, sorry, "did not help" doesn't spark any bright ideas in my head.

[Knute Snortum]

Sahar Cohen,

If you TellTheDetails (that's link) of what happened when you tried to put Looper.prepare() before the while loop, you may get a better response.

I've moved this to the Android forum.