res/drawable/ic_keyboard_spacebar_pressed.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright 2014 Google Inc. All Rights Reserved. -->
<!--
This mess is all to draw a rectangle in the right place on the screen.
Here's what's going on:
    - Keyboard uses the intrinsic size of the drawable to work out where the drawable should be
      centered in the key.
    - Inset uses the intrinsic size of its inner drawable. This effectively scales the drawable
      down to add padding, and doesn't make the drawable bigger.
    - LayerList uses the maximum intrinsic size of its items as its intrinsic size.
    - So, we use a LayerList with a blank shape that assumes the size of the keyboard key.
    - We then add an inset with insetTop + insetBottom + inner shape = size of key.
-->
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
    <item>
        <shape>
            <size
                android:height="@dimen/keyboard_key_height"
                android:width="@dimen/keyboard_key_spacebar_width" />
            <solid android:color="@color/ime_background_letters" />
        </shape>
    </item>
    <item>
        <inset
            android:insetTop="@dimen/keyboard_spacebar_pressed_margin"
            android:insetBottom="@dimen/keyboard_spacebar_pressed_margin"
            android:insetLeft="@dimen/keyboard_key_spacebar_visual_horizontal_padding"
            android:insetRight="@dimen/keyboard_key_spacebar_visual_horizontal_padding" >
            <shape
                android:shape="rectangle">
                <size
                    android:height="@dimen/keyboard_spacebar_height"
                    android:width="@dimen/keyboard_key_spacebar_visual_width" />
                <corners
                    android:radius="@dimen/keyboard_spacebar_rounding" />
                <solid
                    android:color="@color/ime_foreground_spacebar_pressed" />
            </shape>
        </inset>
    </item>
</layer-list>