研究下 android.R.attr.textAppearanceSmall

/frameworks/base/core/res/res/values

1. themes.xml 找到:

<item name="textAppearanceSmall">@android:style/TextAppearance.Small</item>

2. styles.xml 找到

    <style name="TextAppearance.Small">
        <item name="android:textSize">14sp</item>
        <item name="android:textColor">?textColorSecondary</item>
    </style>

3. themes.xml 找到

<item name="textColorSecondary">@android:color/secondary_text_light</item>

4. 程序中就可以直接引用 android.R.color.secondary_text_light 这个值，而这个是在

/frameworks/base/core/res/res/color 下定义好复杂啊

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_window_focused="false" android:state_enabled="false" android:color="@android:color/dim_foreground_light_disabled"/>
    <item android:state_window_focused="false" android:color="@android:color/dim_foreground_light"/>
    <!-- Since there is only one selector (for both light and dark), the light's selected state shouldn't be inversed like the dark's. -->
    <item android:state_pressed="true" android:state_enabled="false" android:color="@android:color/dim_foreground_light_disabled"/>
    <item android:state_selected="true" android:state_enabled="false" android:color="@android:color/dim_foreground_light_disabled"/>
    <item android:state_pressed="true" android:color="@android:color/dim_foreground_light"/>
    <item android:state_selected="true" android:color="@android:color/dim_foreground_light"/>
    <item android:state_activated="true" android:color="@android:color/bright_foreground_light"/>
    <item android:state_enabled="false" android:color="@android:color/dim_foreground_light_disabled"/>
    <item android:color="@android:color/dim_foreground_light"/> <!-- not selected -->
</selector>

即，android.R.attr.textAppearanceSmall定义了一个文本的大小和一个文本的颜色。