是否支持API 26的文本颜色行为库? [英] Support library for text color behaviour of API 26?
问题描述
API 26引入了基于?colorForeground
的?textColorPrimary
的高级颜色计算.它使用状态primaryContentAlpha
和disabledAlpha
.
API 26 introduces an advanced color calculation for ?textColorPrimary
based on ?colorForeground
. It makes use of states, primaryContentAlpha
and disabledAlpha
.
sdk/platforms/android-26/data/res/color/text_color_primary.xml
:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_enabled="false"
android:alpha="?attr/disabledAlpha"
android:color="?attr/colorForeground"/>
<item android:alpha="?attr/primaryContentAlpha"
android:color="?attr/colorForeground"/>
</selector>
在API 23上,由于我没有弄清楚,它又变成了白色文本.
On API 23 it falls back to white text by means I failed to figure out.
我是否可以使用一个支持库来获取旧设备的API 26的颜色计算?
Is there a support library I could apply to get the color calculation of API 26 for older devices?
推荐答案
@ eugen-pechanec暗示缺少属性primaryContentAlpha
和scondaryContentAlpha
,恕我直言,低于API26.我们应该称其为bug还是缺失后端口?不知道.
@eugen-pechanec is hinting that the attributes primaryContentAlpha
and scondaryContentAlpha
are missing, IMHO below API 26. Should we call this a bug or a missing back port? Don't know.
结果是您不能使用设置?attr/colorForeground
作为默认设置来自动创建所有前景色.基本上,您有两种选择,要么不使用它来进行手动后退端口.
The consequence is that you can't use the setting ?attr/colorForeground
as a default to automatically create all foreground colours out of the box. You basically have two options, either not to use it to to do a manual back port.
您可以直接设置属性android:textColorPrimary
和android:textColorSecondary
,而不是从?attr/colorForeground
生成颜色.在大多数情况下,这将是最佳选择.
Instead of generating the colours from ?attr/colorForeground
you set the attributes android:textColorPrimary
and android:textColorSecondary
directly. This will be the best choice in most cases.
如果计划使用许多不同的主题,则希望启用该功能以将所有文本颜色设置为默认值.然后,您必须在根主题中实现API 26的行为.
If you plan to use a lot of different themes, you want to enable the feature to set defaults for all text colours in a central place. Then you have to implement the behaviour of API 26 in your root theme.
root theme
:
<!-- workaround to port back API 26+ behaviour -->
<!-- below 26 these two attributes are missing in the android namespace -->
<item name="primaryContentAlpha">1.0</item>
<item name="secondaryContentAlpha">.85</item>
<!-- works below 26 -->
<item name="android:disabledAlpha">.4</item>
<!-- use my own files to connect my custom attributes -->
<item name="android:textColorPrimary">@color/text_color_primary</item>
<item name="android:textColorSecondary">@color/text_color_secondary</item>
app/src/main/res/color/text_color_primary.xml
:
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_enabled="false" android:alpha="?android:disabledAlpha" android:color="?android:attr/colorForeground" />
<item android:alpha="?attr/primaryContentAlpha" android:color="?android:attr/colorForeground" />
</selector>
app/src/main/res/color/text_color_secondary.xml
:
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_enabled="false" android:alpha="?android:disabledAlpha" android:color="?android:colorForeground"/>
<item android:alpha="?secondaryContentAlpha" android:color="?android:colorForeground"/>
</selector>
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