CODEWITHSUNDEEP
javaandroidxmlandroid-layout
Soel Vodka
Soel Vodka

Reputation: 43

The question mark looks new to me

This 

<TextView
xmlns:android=”http://schemas.android.com/apk/res/android”
android:id=”@+id/separator”
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:gravity=”center”
style=”?android:attr/listSeparatorTextViewStyle” />

or this

   <item name="android:textColor">?textColorSecondary</item>

Sometimes I see the question mark in the xml node's content like that, and I don't know what it is for, no documentation right ?

Upvotes: 4

Views: 231

Answers (1)

full.stack.ex
full.stack.ex

Reputation: 1747

The ? references a resource in the current theme, it's decribed in Developer's Guide Accessing Resources:

A style attribute resource allows you to reference the value of an attribute in the currently-applied theme. Referencing a style attribute allows you to customize the look of UI elements by styling them to match standard variations supplied by the current theme, instead of supplying a hard-coded value. Referencing a style attribute essentially says, "use the style that is defined by this attribute, in the current theme."

To reference a style attribute, the name syntax is almost identical to the normal resource format, but instead of the at-symbol (@), use a question-mark (?), and the resource type portion is optional. For instance:

?[<package_name>:][<resource_type>/]<resource_name>

Upvotes: 3

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