How do I set the icon for the Android app?

If you want to change the icon of the app depending on the size of the device, go to the 'res/drawable' in the project folder and

Make icons tailored to each star size

Go to the Android manifest file

<application android:icon="@drawable/icon_name" android:label="@string/app_name" >
.... 
</application> 

Please put the icon name in android:icon= as shown.