Material effect on button with background color

When you use android:background, you are replacing much of the styling and look and feel of a button with a blank color.

Update: As of the version 23.0.0 release of AppCompat, there is a new Widget.AppCompat.Button.Colored style which uses your theme's colorButtonNormal for the disabled color and colorAccent for the enabled color.

This allows you apply it to your button directly via

<Button
  ...
  style="@style/Widget.AppCompat.Button.Colored" />

If you need a custom colorButtonNormal or colorAccent, you can use a ThemeOverlay as explained in this pro-tip and android:theme on the button.

Previous Answer

You can use a drawable in your v21 directory for your background such as:

<?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"/>
</ripple>

This will ensure your background color is ?attr/colorPrimary and has the default ripple animation using the default ?attr/colorControlHighlight (which you can also set in your theme if you'd like).

Note: you'll have to create a custom selector for less than v21:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@color/primaryPressed" android:state_pressed="true"/>
    <item android:drawable="@color/primaryFocused" android:state_focused="true"/>
    <item android:drawable="@color/primary"/>
</selector>

Assuming you have some colors you'd like for the default, pressed, and focused state. Personally, I took a screenshot of a ripple midway through being selected and pulled the primary/focused state out of that.

There is another simple solution to provide custom background for "Flat" buttons while keeping their "Material" effects.

1. Place your button in ViewGroup with desired background set there
2. set selectableItemBackground from current theme as background for your button (API >=11)

i.e. :

<FrameLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@color/blue">
    <Button
        style="?android:attr/buttonStyleSmall"
        android:background="?android:attr/selectableItemBackground"
        android:textColor="@android:color/white"
        android:textAllCaps="true"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Button1"
        />
</FrameLayout>

Can be used for Flat buttons, it works on API >=11, and you will get ripple effect on >=21 devices, keeping regular buttons on pre-21 till AppCompat is updated to support ripple there as well.

You can also use selectableItemBackgroundBorderless for >=21 buttons only.