Android Service to show toast

Question

This code is supposed to use a service to show a toast message. There are no errors, but it doesn't show the toast.

main activity

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Intent i= new Intent(this, BackgroundMusic.class);
    this.startService(i); 

}



}

service (its called Background Music but for now it is supposed to show a toast message)

public class BackgroundMusic extends IntentService {

 public BackgroundMusic() {
      super("BackgroundMusic");
  }



 @Override
  protected void onHandleIntent(Intent intent) {
      // Normally we would do some work here, like download a file.
      // For our sample, we just sleep for 5 seconds.
     Context context = getApplicationContext();
     CharSequence text = "Hello toast!";
     int duration = Toast.LENGTH_SHORT;

     Toast toast = Toast.makeText(context, text, duration);
     toast.show();
 }



}

manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.starwars"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="18" />

<application
    android:allowBackup="true"
    android:debuggable="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
     <service android:name=".BackgroundMusic" />
    <activity
        android:name="com.example.starwars.MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:label="@string/app_name" android:name="BackgroundMusic"/>
</application>

</manifest>

Answer 1

See this part of the docs

(An IntentService has a few limitations:

It can't interact directly with your user interface. To put its results in the UI, you have to send them to an Activity.

You need to put it on the main Thread. See the answer here by rony of a way to do that.

and from the full documentation on IntentService

handles each Intent in turn using a worker thread