Xamarin android custom view get custom attribute always returns default value

Question

I am making custom view in xamarin android. I have separate class library project for this custom view.

my attributes file in Resources/Values/attrs.xml looks like this:

<?xml version="1.0" encoding="utf-8" ?>
<resources>
  <declare-styleable name="ImageIconView">
    <attr name="imageIcon" format="integer" />
    <attr name="text" format="string" />
    <attr name="alignment" format="enum">
      <enum name="left" value="0"/>
      <enum name="center" value="1"/>
      <enum name="right" value="2"/>
    </attr>
  </declare-styleable>
</resources>

my custom view file for debugging looks like this:

I add the referece to this project and add this view in my xaml file for startup activity like this:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:my="http://schemas.android.com/apk/lib/mycomponents"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
  <mycomponents.views.ImageIconView
    android:layout_width="match_parent"
    android:layout_height="150dp" 
    my:text="text from xml!!!"
    my:imageIcon="50"
    my:alignment="center"
    />

</LinearLayout>

no compile or runtime erros. This custom view is shown on my base project-s startup activity. Even in debugging it goes to the setValuesFromXml method in my custom view file. But any kind of attempt to get int, string or enum value from IAttribueSet return default value. But still I get no any errors or exceptions.

How shall I get my custom attribute value from xml file?

Try to replace `xmlns:my="http://schemas.android.com/apk/lib/mycomponents"` with `xmlns:my="http://schemas.android.com/apk/res-auto"` — Kirill, Jun 15 '17 at 07:45
@g4s8 thanks!!! it works!! but I dont understand why. I misspell namespace? and res-auto automatically detects correct namespace? — mister_giga, Jun 15 '17 at 08:20
I've answered here: https://stackoverflow.com/a/44562475/1723695 — Kirill, Jun 15 '17 at 08:29
One question, are you inflating any layout from the view? If so, how are you doing it? — Software Dev, Apr 12 '19 at 06:08

Kirill · Accepted Answer · 2017-06-15T08:37:49.060

1

You should use xmlns:my="http://schemas.android.com/apk/res-auto" instead of xmlns:my="http://schemas.android.com/apk/lib/mycomponents". res-auto namespace automatically detects all attributes declared in you application including all library attributes. E.g. appcompat attributes are also accessible via res-auto namespace.

You may find it helpful: https://stackoverflow.com/a/26692768/1723695

edited Jun 15 '17 at 08:37

answered Jun 15 '17 at 08:27

Kirill

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Thank you very much – mister_giga Jun 15 '17 at 08:43
Any ideas on how i can inflate a layout from a view? – Software Dev Apr 12 '19 at 06:08

Xamarin android custom view get custom attribute always returns default value

1 Answers1