android - Using Activities from Library projects

Question

I have a Library project set up and a project which depends on this library project - Everything compiles fine and I've had the Dependent project running fine however;

I'm have an intermittent problem however while using an Activity from the Library project.

My Library project can be "unchecked" as a library project and the "picker" Activity can be run in isolation. Running the Library project in it's own right works fine with no problems.

When I use the Library project (and the "picker" Activity) from the dependent project it gives me either NullPointerExceptions (or historically DexOp) errors saying that the "picker" Activity can't find it's resources.

Can anybody tell me if they have experienced this before?

EDIT

Manually copying the layout.xml used by the Library project activity to the dependent project makes the project open the "picker" Activity correctly. Is this required?! Surely not? This further makes me wonder if there is a problem with merging/referencing the integer id's from R.java in the Library project.

EDIT

I'm not sure if this is of any consequence, but one of my Library projects is a wrapper around a set of custom views used in different front end projects.

These custom views each have an Activity so that they can be tested in isolation.

One of these view's has custom attributes, which while running in isolation work very well. However, it doesn't seem like the dependent project correctly pull's in the attributes and keep's them in their original namespace, causing the imported layout's to throw compilation errors:

[2012-05-16 12:07:28 - Project] D:optworkspaceCustomGlowList
eslayoutmain.xml:14: error: No resource identifier found for attribute 'listId' in package 'com.company.library.glowlist'
[2012-05-16 12:07:28 - Project] D:optworkspaceCustomGlowList
eslayoutmain.xml:14: error: No resource identifier found for attribute 'type' in package 'com.company.library.glowlist

EDIT

DexOp errors were solved by removing a duplicate file name which was present in the Dependent project. Not sure if the file name was the problem or the contents of the file.

EDIT

I've been unable to find a solution to this problem as of yet (although @yorkw's answer certainly helps with the xml attributes! Thanks).

I have managed to make this problem intermittent however:

I have gone through each of the library projects and ensured they all had their own namespace (ie, com.company.library.component1, com.company.library.component2 etc). After a couple of clean's (each project ordered with the correct precedence) this problem resolves itself, however does eventually come back when switching around library/not a library to test components.

Answer 1

Cause:

Issue 9656: Library projects don't support custom XML attributes for custom classes

Solution:

Upgrade to latest SDK & ADT version (fixed was released since r17) and use http://schemas.android.com/apk/res-auto as custom attributes' namespace URI, see Revisions for ADT 17.0.0:

Added support for custom views with custom attributes in libraries. Layouts using custom attributes must use the namespace URI http://schemas.android.com/apk/res-auto instead of the URI that includes the app package name. This URI is replaced with the app specific one at build time.

Related Topic:

Help with a custom View attributes inside a Android Library Project