android themes – defining colours in custom themes-ThrowExceptions

Exception or error:

I am sure there is a simple answer to that yet I just cant find it so I throw it into stackoverflow … 😉

I will just put it into an example. I have an android app where the user can choose the theme in the preferences – dark or light theme. Depending on the chosen theme I have to adjust 20 colors in my app. So I have the hope that I can define colours in the theme and then use the names of this so defined colours in the my TextViews etc. Yet so far I cant figure out how to do that and can’t find any solution here and there. I really dont want to define an extra dark and light style for each of these 20 colours yet so far that seems the only solution I can find.

Big thanks for any hint

martin:

UPDATE:

In pseudo syntax is that is what I am looking for. Is it possible?

<style name="AppTheme.MyDark" parent="android:Theme">
  -?-> titleColor = "#ffffff"
  -?-> introColor = "#ffaaaa"  
</style>

<style name="AppTheme.MyLight" parent="android:Theme.Light">
  -?-> titleColor = "#000000"
  -?-> introColor = "#004444"  
</style>


<TextView
        android:id="@+id/quoteTitle"
        android:textColor=@titleColor
        ...
</TextView>

<TextView
        android:id="@+id/quoteIntro"
        android:textColor=@introColor
        ...
</TextView>
How to solve:

I found a solution which seems to work. First you need to define the custom color fields in attr.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

<attr name="titleColor" format="reference|color" />
<attr name="introColor" format="reference|color" />

</resources>

Next you define your themes

<style name="AppTheme.MyDark" parent="android:Theme">
   <item name="titleColor">#FFFFFF</item>
   <item name="introColor">#FFFFFF</item>
</style>


<style name="AppTheme.MyLight" parent="android:Theme">
   <item name="titleColor">#000000</item>
   <item name="introColor">#004444</item>
</style>

and finally in your layout

<TextView
    android:id="@+id/quoteTitle"
    android:textColor="?titleColor"
    ...
</TextView>

<TextView
    android:id="@+id/quoteIntro"
    android:textColor="?introColor"
    ...
</TextView>

i found the solution mainly here

There seems to be no explanation in the official android documentation about using attributes. Best resource I found is here

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