ImageButton is a great addition in Android. However, it can generate a warning which can luckily easy to overcome.
Description Resource Path Location Type: [Accessibility] Missing contentDescription attribute on image menu.xml /project/res/layout line 22 Android Lint Problem.
To fix this add the following line in the xml at the ImageButton
android:contentDescription="@string/desc"Resolved this warning by setting attribute contentDescription as the warning says and the problem is solved.