How to post toast from non ui Widget thread

Question

I am trying to post a toast after calling a function from a non UI thread in a widget. I\'ve read multiple ways of doing this (post/new handler/broadcast) but most methods s

Answer 1

You can create your own version of runOnUiThread(). This is what I use when I need to run something in the UI thread from outside an Activity:

public final class ThreadPool {
    private static Handler sUiThreadHandler;

    private ThreadPool() {
    }

    /**
     * Run the {@code Runnable} on the UI main thread.
     *
     * @param runnable the runnable
     */
    public static void runOnUiThread(Runnable runnable) {
        if (sUiThreadHandler == null) {
            sUiThreadHandler = new Handler(Looper.getMainLooper());
        }
        sUiThreadHandler.post(runnable);
    }

    // Other, unrelated methods...
}

Then, you can simply call ThreadPool.runOnUiThread(runnable).

You can find more information on how this works in this post series: Android: Looper, Handler, HandlerThread. Part I

Answer 2

• You should use asyncTask for do the things in background instead of using Thread().
• And if you just want a simple toast remove Thread() and toast the message.
• If you still need to use thread and want to display message.You can toast message using below:

if(Looper.myLooper() == null) {

    Looper.getMainLooper();

}

Looper.prepare();

new Handler().post(new Runnable() {

    @Override
    public void run() {

        Toast.makeText(LargeAppWidget.this.context, "Sample Text", Toast.LENGTH_SHORT).show();

    }
});

Looper.loop();

It is not recommended to use looper.