How to set ImageButton pressed state background in Android Studio

How to set ImageButton pressed state background in Android Studio

activity_main.xml

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rl"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="10dp"
    tools:context=".MainActivity"
    android:background="#f6f5f9"
    >
    <!-- ImageButton with default click effect/pressed state -->
    <ImageButton
        android:id="@+id/ib"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/transparent_image_button"
        />
    <!--
        ImageButton with custom pressed state.
        ImageButton selector.
        ImageButton click effect.
        A transparent png image used for ImageButton.
    -->
    <ImageButton
        android:id="@+id/ib2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/transparent_image_button"
        android:layout_toRightOf="@id/ib"
        android:background="@drawable/imageview_selector"
        android:padding="5dp"
        />
</RelativeLayout>

res/drawable/imageview_selector.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- disabled state-->
    <item
        android:state_enabled="false"
        android:drawable="@android:color/holo_red_light"
        />
    <!-- pressed state / clicked state -->
    <item
        android:state_pressed="true"
        android:state_enabled="true"
        android:drawable="@android:color/holo_red_dark"
        />
    <!-- focused state -->
    <item
        android:state_focused="true"
        android:state_enabled="true"
        android:drawable="@android:color/holo_orange_dark"
        />
    <!-- enabled state / default state-->
    <item
        android:state_enabled="true"
        android:drawable="@android:color/holo_blue_light"
        />
</selector>