Listener method (interface in Service) in my Activity doesn't want to display a simple message

问题

Good day to you all. I'm experiencing quite an issue right now with my simple Android application.

The 2 main elements I have are a bound Service and a main Activity. I want the Activity to display (through TextViews) the fact that the Service found something. To do so, I declare a Listener interface within the Service, handle a list of listeners registered to him and notify the listeners with a specific method.

MyService

    void notifyNewElement(){
        for (Listener listener : listeners) {
            listener.handleNewElement(this);
        }
    }

    public interface Listener {
        void handleNewElement(MyService sender);
    }

    private List<Listener> listeners = new ArrayList<Listener>();

    public void addListener(Listener listener) {
        this.listeners.add(listener);
    }

    public void removeListener(Listener listener) {
        this.listeners.remove(listener);
    }

MainActivity

    buttonStart.setOnClickListener(
                new View.OnClickListener()
                {
                    public void onClick(View view)
                    {
                        registerListener();
                    }
                });
    buttonStop.setOnClickListener(
                new View.OnClickListener()
                {
                    public void onClick(View view)
                    {
                        unresgisterListener();
                    }
                });

    void registerListener(){
        tService.addListener(this);
    }

    void unresgisterListener(){
        tService.removeListener(this);
    }

    public void handleNewElement(MyService sender) {
        Log.d("NEW_ELEM","new element found");
        message_box.setText("new element found");
    }

I ofcourse recovered the TextViews and such in the Activity, I don't have to show the code here as I know everything's fine on that side. As you can see in the last method, the Log.d() works fine, the method is really triggered. But when I want to update the TextView, the Activity can't do it PLUS the service stops doing his calculations. As funny as it could be, if I unregister the listener and register it again (through the 2 buttons you can see in the Activity), the Service calculations don't get stopped anymore when triggering handleNewElement, yet the TextView is still not updated (it just doesn't block anymore).

I used exactly the same setup in another application and it worked like a charm :/

If you guys have any idea of what could be the cause of all that trouble, it'd be wonderful for you to share it !

Thanks in advance.

回答1:

public void handleNewElement(MyService sender) {
    Log.d("NEW_ELEM","new element found");
    runOnUiThread(new Runnable(){
        public void run(){
            message_box.setText("new element found");
        }
    });
}

来源：https://stackoverflow.com/questions/13306221/listener-method-interface-in-service-in-my-activity-doesnt-want-to-display-a

标签

android

service

interface

listener