IntentService won't show Toast

The accepted answer is not correct.

Here is how you can show toast from onHandleIntent():

Create a DisplayToast class:

public class DisplayToast implements Runnable {    private final Context mContext;    String mText;    public DisplayToast(Context mContext, String text){        this.mContext = mContext;        mText = text;    }    public void run(){        Toast.makeText(mContext, mText, Toast.LENGTH_SHORT).show();    }}

Instantiate a Handler in your service's constructor and call the post method with a DisplayToast object inside.

public class MyService extends IntentService {Handler mHandler;public MyService(){    super("MyService");    mHandler = new Handler();}@Overrideprotected void onHandleIntent(Intent intent) {    mHandler.post(new DisplayToast(this, "Hello World!"));}}

You should start the Toast on the main thread:

new Handler(Looper.getMainLooper()).post(new Runnable() {        @Override        public void run() {            Toast.makeText(getApplicationContext(), message, Toast.LENGTH_LONG).show();        }});

This is because otherwise the thread of the IntentService quits before the toast can be send out, causing a IllegalStateException:

java.lang.IllegalStateException: Handler (android.os.Handler) {12345678} sending message to a Handler on a dead thread

onHandleIntent() is called from a background thread (that is what IntentService is all about), so you shouldn't do UI from there.