Not sure if this can help:
If you use ImageButton without a background, and you set the value to Padding, your button will have a large area with clicks.
<ImageButton android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/img_close" android:id="@+id/btnClose" android:padding="25dip" android:background="#0000"></ImageButton>
Xavi gil
source share