Ripple effect on shape drawable

More simple solution - to use this drawable-xml as value of property "android:background" of the Button:

drawable/bkg_ripple.xml:

<?xml version="1.0" encoding="utf-8"?>
<ripple xmlns:android="http://schemas.android.com/apk/res/android"
    android:color="?attr/colorControlHighlight">
    <item android:drawable="?attr/colorPrimary"/>
    <item android:id="@android:id/mask">
        <shape android:shape="rectangle">
            <solid android:color="#000000" />
        </shape>
    </item>
</ripple>

button.xml:

<Button
    android:id="@+id/mybutton"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    ...
    android:background="@drawable/bkg_ripple"
/>

My advice would be not to use <ripple tag. I have 2 reasons: it is not that easy to do exactly what you want and you have to 2 different .xml files for every background. I don't like to have drawable-v21 folder.

My solution is to wrap your Button with FrameLayout and use android:foreground attribute. This way you can have whatever background you want and you can keep the ripple effect.

<FrameLayout
    android:id="@+id/login_button"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="20dp"
    android:layout_weight="1"
    android:paddingTop="10dp"
    android:paddingBottom="10dp"
    android:foreground="?attr/selectableItemBackground">

    <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@drawable/background_button"/>
</FrameLayout>

Notice that I moved all the attributes and the id to FrameLayout. You should set onClickListener to FrameLayout instead of the Button.

Btw, ?attr/selectableItemBackground is great. Use it as much as possible. It replaces blue Holo color with gray for old devices from Android 4.0 to 4.3.

Try this.

ripple_effect.xml

<ripple xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:color="#2797e0"
tools:targetApi="lollipop">
<item android:id="@android:id/mask">
    <shape android:shape="rectangle">
        <solid android:color="#2797e0" />
    </shape>
</item>

button.xml

 <Button
                android:id="@+id/login_button"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="20dp"
                android:layout_weight="1"
                android:paddingTop="10dp"
                android:paddingBottom="10dp"
                android:background="@drawable/ripple_effect"/>

build.gradle

   compile 'com.android.support:appcompat-v7:23.1.1'