A ColorStateList is an XML-definable resource that acts as a dynamic color, changing based on the state of the Android View it’s applied to. For example, a button widget can be pressed, focused, or idle, and a color state list lets you assign distinct colors to each state.

These state-based colors are defined inside a single <selector> root elemant in an XML file. Each color uses an <item> tag, with attributes describing the conditions for its application. The system checks these items top-to-bottom whenever the view’s state changes, selecting the first item that meets all minimum matching state requirements (not the best overall match).

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File Location & Resource Details

• Storage Path: res/color/filename.xml (filename becomes the resource ID)
• Compiled Type: Resource pointer to a ColorStateList instance
• Resource References:
  • Java/Kotlin: R.color.filename
  • XML: @[package:]color/filename

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XML Syntax

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:color="hex_color"
        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>

Key Elements

• <selector>: Root element. Contains one or more <item> tags.
  • Mandatory Attribute: xmlns:android (must be http://schemas.android.com/apk/res/android)
• <item>: State-based color definition (child of <selector>).
  • Mandatory Attribute: android:color (hexadecimal color value starting with #, formats include RGB, ARGB, RRGGBB, AARRGGBB)
  • Optional State Attributes:
    • state_pressed: Applies when the view is pressed (e.g., button tapped)
    • state_focused: Applies when the view is focused (e.g., button highlighted via trackball)
    • state_selected: Applies when the view is selected (e.g., active tab)
    • state_checkable: Applies when the view can be checked/unchecked
    • state_checked: Applies when the view is checked (e.g., checked checkbox)
    • state_enabled: Applies when the view can receive input
    • state_window_focused: Applies when the app window has focus (foreground state)

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Example

1. Create the Color State List File: Save as res/color/btn_text_color.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 state (red) -->
       <item android:state_focused="true" android:color="#ff0000ff" /> <!-- Focused state (blue) -->
       <item android:color="#ff000000" /> <!-- Default state (black) -->
   </selector>
   

2. Apply to a View: Use @color/btn_text_color in your layout

   <Button
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:text="Click Me"
       android:textColor="@color/btn_text_color" />