Android Custom Control namespace issue

Question

I've been working on a Custom Control for Android and although I tried to do what's suggested here there seems to be something I'm doing wrong.

Here's my code to see if anyone can spot the problem:

MyComponent.java

public MyComponent(Context context, AttributeSet attrs) 
{
  super(context);
  TypedArray arr = context.obtainStyledAttributes(attrs, R.styleable.MyComponent); 
  CharSequence myId = arr.getString(R.styleable.MyComponent_identifier); 

  if (myId != null) 
  {   
    this.setIdentifier(myId.toString()); 
  }

  Integer cds = arr.getInteger(R.styleable.MyComponent_cd_number, 0);

  if(cds != null)
  {
    this.setCds(cds);
  }

  arr.recycle();
 }

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>   
   <declare-styleable name="MyComponent">     
    <attr name="cd_number" format="integer" />   
    <attr name="identifier" format="string" />
   </declare-styleable> 
</resources>

main.xml

<TableLayout 
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:bgl="http://schemas.android.com/apk/res/my.test.package.components"
  android:id="@+id/table"
  android:layout_width="match_parent"
  android:layout_height="match_parent">

  ...

  <my.test.package.MyComponent 
     android:id="@+id/hand"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_span="2"
        bgl:cd_number="4"
        bgl:identifier="plr"/>

   ...

  </TableLayout>

When I put this I get the following errors:

error: No resource identifier found for attribute 'cd_number' in package 'my.test.package' error: No resource identifier found for attribute 'identifier' in package 'my.test.package'

If I change my namespace to something like:

xmlns:bgl="http://schemas.mywhatever.com/apk/res/my.test.package"

...the errors go way and the thing runs but myId is null and cds is 0 (the default value!) back on the MyComponent.java constructor.

I'd say it's some very basic mistake but I not being able to spot it and since there's not much documentation on this I decided to ask here.

Thanks in advance!

Diesel Heart · Accepted Answer · 2012-05-07T07:20:27.170

Ok. I got it solved!

On the original post I had:

xmlns:bgl="http://schemas.android.com/apk/res/my.test.package

...but in my source I had:

xmlns:bgl="http://schemas.android.com/apk/res/my.test.package.components

...because I thought one should put the URI to the components package.

THIS IS WRONG!

On the xmlns it should be the application name as is declared on the Manifest!

When I removed the "components" part of the xmlns it "matched" the application name in the Manifest and the errors went away and when I ran the thing in debug I could actually see the values I was passing to the parameters in the XML!

Hope this helps someone else! :-)

UPDATE

Later on I had the need to move the control into a library and faced the problem again. It seems that when you put the component in a library and use it on a client app you must declare the xmlns as below:

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

If you do so (and have the library declared as an Android dependency) Eclipse (or is it Android?) will search the dependencies for the appropriate attribute bindings.

Great job researching and providing the answer. the res-auto fix is exactly what I needed. — AlanKley, Apr 15 '13 at 16:16

score 0 · Answer 2 · answered Mar 17 '12 at 00:31

0

I had a problem similar to this, turned out it was calling a different constructor

Try with the constructor that takes in the defStyle parameter

public MyComponent(Context context, AttributeSet attrs, int defStyle)

answered Mar 17 '12 at 00:31

triggs

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Thanks, triggs. Unfortunately my problem seems to be another. I defined the ctor you suggested and if I don't change the namespace the errors persist. If I change the xmlns it will behave the same: the new ctor is never called and myId is null and cds is 0 as it were before. Anymore ideas? Anyone? – Diesel Heart Mar 17 '12 at 09:18

Android Custom Control namespace issue

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