Question

how do I post messages to the main UI looper from a thread?
I’m working on a stand-alone helper class, which should display a window.

A bad solution would be to pass a View via the construct, and then use View.post(),
but I’m looking for a better solution.

I thought this would work, but I get the common “no on ui thread” exception.

public class Example {

    private Context context;

    public Example(Context context) {
        this.context = context;
    }

    public void build() {

    }

    public void show() {
        Handler handler = new Handler(Looper.getMainLooper());
        handler.post(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(context, "test", Toast.LENGTH_LONG);
            }
        }); 
    }

}

Answer 1

Simply pass the context and make use of the runonUiThread method, like this,

((Activity)contextObj).runOnUiThread(new Runnable() {

                public void run() {
                     Toast.makeText(context, "test", Toast.LENGTH_LONG).show();

                }
            });