Color State List Resource

Color State List Resource

@(Android)

Color State List Resource
概述

语法

示例

API Guides

A ColorStateList is an object you can define in XML that you can apply as a color, but will actually change colors, depending on the state of the View object to which it is applied. For example, a Button widget can exist in one of several different states (pressed, focused, or neither) and, using a color state list, you can provide a different color during each state.

You can 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 should be used.

During each state change, the state list is traversed top to bottom and the first item that matches the current state will be used—the selection is not based on the “best match,” but simply the first item that meets the minimum criteria of the state.

ColorStateList 是在 XML 中顶一顶 color 对象，但它会根据 View 对象的状态改变颜色。比如，Button 可以存在不同的状态（pressed, focused, or neither），使用color state list 就可以让 Button 在不同状态下显示不同的颜色。

在状态变化期间，从上到下遍历 state list ，使用和当前状态匹配的第一个 item ，该选择并非基于“best match”，而仅仅是一个满足该状态的最低标准的第一个 item。

概述

FILE LOCATION:

res/color/filename.xml

The filename will be 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

语法

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>

<selector>

Required. This must be the root element. Contains one or more

<item>

elements.

<item>

Defines a color to use during certain states, as described by its attributes. Must be a child of a

<selector>

element.

android:color

：颜色

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

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

#RGB

、

#ARGB

、

#RRGGBB

、

#AARRGGBB

android:state_pressed

：是否按下

android:state_focused

： 是否获得焦点

android:state_selected

： 是否被选中

android:state_checkable

： 是否能被勾选

android:state_checked

： 是否被勾选

android:state_enabled

： 是否可用

android:state_window_focused

： 是否在前台

示例

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>

This layout XML will apply 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" />