[android] ImageButton in Android

You can also set background is transparent. So the button looks like fit your icon.

 <ImageButton
    android:id="@+id/Button01"
    android:scaleType="fitcenter" 
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:cropToPadding="false"
    android:paddingLeft="10dp"
    android:background="@android:color/transparent"
    android:src="@drawable/eye" />