Color state list resource

A ColorStateList is an object you can define in XML and apply as a color that actually changes colors depending on the state of the View object it is applied to. For example, a Button widget can exist in one of several states: pressed, focused, or neither. Using a color state list, you can provide a different color for each state.

You describe the state list in an XML file. Each color is defined in an <item> element inside a single <selector> element. Each <item> uses various attributes to describe the state in which it is used.

During each state change, the state list is traversed top to bottom, and the first item that matches the current state is used. The selection is isn't based on the "best" match, but rather the first item that meets the minimum criteria of the state.

Note: If you want to provide a static color resource, use a simple color value.

file location:

res/color/filename.xml
The filename is used as the resource ID.

compiled resource datatype:

Resource pointer to a ColorStateList

resource reference:

In Java: R.color.filename
In XML: @[package:]color/filename

syntax:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
    <item
        android:color="hex_color"
        android:lStar="floating_point_value"
        android:state_pressed=["true" | "false"]
        android:state_focused=["true" | "false"]
        android:state_selected=["true" | "false"]
        android:state_checkable=["true" | "false"]
        android:state_checked=["true" | "false"]
        android:state_enabled=["true" | "false"]
        android:state_window_focused=["true" | "false"] />
</selector>

elements:

<selector>

Required. This is the root element. Contains one or more <item> elements.

Attributes:

xmlns:android: String. Required. Defines the XML namespace, which is "http://schemas.android.com/apk/res/android".

<item>

Defines a color to use during certain states, as described by its attributes. It is a child of a <selector> element.

Attributes:

android:color

Hexadeximal color. Required. The color is specified with an RGB value and optional alpha channel.

The value always begins with a pound (#) character, followed by the Alpha-Red-Green-Blue information in one of the following formats:

#RGB
#ARGB
#RRGGBB
#AARRGGBB

android:lStar

Floating point. Optional. This attribute modifies the base color's perceptual luminance. It takes either a floating-point value between 0 and 100 or a theme attribute that resolves as such. The item's overall color is calculated by converting the base color to an accessibility friendly color space and setting its L* to the value specified on the lStar attribute.

Example: android:lStar="50"

android:state_pressed

Boolean. "true" if this item is used when the object is tapped, such as when a button is touched or clicked. It's "false" if this item is used in the default, non-tapped state.

android:state_focused

Boolean. "true" if this item is used when the object is focused, such as when a button is highlighted using the trackball or D-pad. It's "false" if this item is used in the default, non-focused state.

android:state_selected

Boolean. "true" if this item is used when the object is selected, such as when a tab is opened. It's "false" if this item it used when the object isn't selected.

android:state_checkable

Boolean. "true" if this item is used when the object is checkable. It's "false" if this item is used when the object isn't checkable. Only useful if the object can transition between a checkable and non-checkable widget.

android:state_checked

Boolean. "true" if this item is used when the object is checked. It's "false" if it is used when the object is deselected.

android:state_enabled

Boolean. "true" if this item is used when the object is enabled, capable of receiving touch or click events. It's "false" if it is used when the object is disabled.

android:state_window_focused

Boolean. "true" if this item is used when the application window has focus, meaning the application is in the foreground. It's "false" if this item is used when the application window doesn't have focus, such as if the notification shade is pulled down or a dialog appears.

Note: The first item in the state list that matches the current state of the object is applied. So, if the first item in the list contains none of the preceding state attributes, then it applies every time. For this reason, place your default value last, as shown in the following example.

example:

XML file saved at res/color/button_text.xml:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true"
          android:color="#ffff0000"/> <!-- pressed -->
    <item android:state_focused="true"
          android:color="#ff0000ff"/> <!-- focused -->
    <item android:color="#ff000000"/> <!-- default -->
</selector>

The following layout XML applies the color list to a View:

<Button
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/button_text"
    android:textColor="@color/button_text" />

see also:

Animation

Drawable