How to set state_selected in ripple drawable

To add to @Sohaib 's answer:

@Alanv is right that the OP didn't need a mask. But if one of your selector states is transparent and you need a mask it goes here:

<?xml version="1.0" encoding="utf-8"?>
<ripple
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:color="@color/ripple_color">

    <!-- mask here... -->
    <item android:id="@android:id/mask">
        <color android:color="@color/black"/> <!-- any color will do -->
    </item>

    <item>
        <selector>
            <!-- ... NOT here. -->
            <item android:state_selected="true">
                <color android:color="@color/blue"/>
            </item>

            <item android:state_activated="true">
                <color android:color="@color/red"/>
            </item>

            <item>
                <color android:color="@color/transparent"/>
            </item>
        </selector>
    </item>
</ripple>

I initially had the mask inside my selector and :boom:

Found the answer, just in case someone else having the same problem

<?xml version="1.0" encoding="utf-8"?>
<ripple
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:color="#DDDDDD"
    >


    <item>
        <selector>
            <item android:state_selected="true">
                <color android:color="#EEEEEE" />
            </item>

            <item android:state_activated="true">
                <color android:color="#EEEEEE" />
            </item>

            <item>
                <color android:color="#FFFFFF" />
            </item>
        </selector>
    </item>


</ripple>

Combining the above answer with other answers from:

What should be the color of the Ripple, colorPrimary or colorAccent? (Material Design)

Gives a nice ripple effect which also works for when the item is in a selected state.

<ripple xmlns:android="http://schemas.android.com/apk/res/android"
    android:color="?attr/colorControlHighlight">
<!-- Ripple mask - applied to all selector states -->
<item android:id="@android:id/mask">
    <color android:color="#42ffffff" />
</item>
<!-- Selected state of item -->
<item>
    <selector>
        <item android:state_selected="true">
            <color android:color="?attr/colorAccent" />
        </item>
    </selector>
</item>
</ripple>

This goes in your drawable-v21 folder, for other platforms you can just create a selector which uses the accent color:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@color/accent" android:state_selected="true"/>
    <item android:drawable="@color/accent" android:state_pressed="true"/>
</selector>