Does Android studio layout editor shows custom view properties?

Question

I have a compound view which consists of two Buttons and one Text view. I want to edit properties of these child views in the Android Studio Layout Editor but I can't. It only shows basic properties but no properties of my custom view.

Does the Android Studio Layout Editor only shows limited number of properties set by default? Is it possible to edit properties of my custom view from there, without manually editing the XML files?

Thanks in advance!!

Answer 1

As described in http://developer.android.com/training/custom-views/create-view.html#customattr you have to add a new ressource (res/values/attrs.xml).

<resources>
   <declare-styleable name="PieChart">
       <attr name="showText" format="boolean" />
       <attr name="labelPosition" format="enum">
           <enum name="left" value="0"/>
           <enum name="right" value="1"/>
       </attr>
   </declare-styleable>
</resources>

Within your View you have to reference this new ressource

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:custom="http://schemas.android.com/apk/res/com.example.customviews">
     <com.example.customviews.charting.PieChart
         custom:showText="true"
         custom:labelPosition="left" />
</LinearLayout>

Now you should see the properties in the editor.

Answer 2

If you customize a View with custom attributes, you need to use your own namespace to set your custom attributes.

First , set namespace in the root view of your layout like this:

xmlns:sidespinner="http://schemas.android.com/apk/res-auto"

Since custom attribute names are declared in your res/values/attrs.xml of your current project or library project, namespace sidespinner will tell aapt to obtain attributes from your current project or library project.

Second , set custom attributes in your custom View like this:

<your-custom-view
     sidespinner:boolean-attr="true"
     sidespinner:integer-attr="5"
     sidespinner:enum-attr="none"//your enum values
     sidespinner:dimen-attr="10dp" />

I hope you are clear about this. If you want to know how to customize attributes, refer to @SteffenTimm's answer.

Answer 3

change

xmlns:sidespinner="http://schemas.android.com/tools"

to

xmlns:sidespinner="http://schemas.android.com/apk/res-auto"

android studio will show custom attributes of your custom view.

be sure you defined custom attributes in res/values/attrs.xml