Question

A thread:

    public class DrawThread extends Thread {
    private RMapCanvas canvas;
    final Handler myHandler = new Handler();
    final ArrayList<RGroupMapLayer> layers;

    public DrawThread(RMapCanvas aCanvas, ArrayList<RGroupMapLayer> arrayOfLayers)
    {
        canvas = aCanvas;
        layers = arrayOfLayers;
    }

    public void run() {
        activity.RaiseNotification(activity.getApplicationContext().getResources().getString(R.string.loading).toString());
        for (RGroupMapLayer l : layers)
             {
                 l.validateAndRepairView(false, canvas.renderer, canvas.mapView);
                 l.render(canvas.renderer, canvas.mapView, canvas.mapEvent, 5000000, 5000000);
                 if (settings.getPositionFeature() != null)
                 {
                     RPointFeatureStyle positionStyle = new RPointFeatureStyle(RPointFeatureStyle.SIMPLE_POINT_STYLE_GPS);
                     positionStyle.render(settings.getPositionFeature(), renderer, mapView);
                 }
                 myHandler.post(new Runnable() {
                     @Override
                     public void run() {
                         canvas.RenderComplete(); 
                     }});
             }
     activity.statusMessage.cancel();
    }

    public synchronized void requestStop() {
        activity.statusMessage.cancel();
        this.interrupt();
    }
}

Calling the requestStop that interrupts a thread is not enough. The thread just keeps running. Can some one please update the code to show me the correct way of stopping this thread? And by the way … the RenderComplete() methods updates the UI (witch is a problem in my case, because “old” threads keep updating the UI even if new one is starter and the old one interrupted).

Thanx in advance.

Answer 1

In general interrupting or stoping threads by yourself is not recommended. Your thread should have a flag inside the run method. When the flag is true – the thread is running, when the flag is false – thread is also running, but now it doesn’t do anything. The system will stop this thread when needed. Here’s how it should look:

    public void run() {
        while (flag) {
        //do your work
        }
    }

And to “stop” the thread just use flag = false;

Hope this helps.