I am developing first time Android Library Project that have external dependences of different libraries like retrofit and ormlite-android. The problem i am facing right now is when i use my Android Library Project .aar file inside other project the class not found exception occur when run the code. Please can any one guide me how to fix such issues. Do i have to add external libraries reference inside my dependent app ?
I have problems with accessing resources in my android library. I have created library project with some resources (com.library) and then I imported module into application project (com.app). So I have Android Studio project with library and application.
When I want to access some library resource (com.library.R.string.label) I get error during compilation
package com.library.R does not exist
When I want to run some library method from application which contains/uses R.string.label I get
java.lang.NoClassDefFoundError: com.library.R$string
I added library to application gradle file using
compile project(':Library')
and from IDE perspective looks everything fine and R.java is created with references to resources. I want same usage as I'm using for example android.R.string.cancel or similar libraries in my application project.Where I'm doing mistake? Thank you for help.
PS: In the future I want to have my library project as aar package.
As soon as you add a library to your project all resources will be "copied" to the R-file of your app. So if you want to access a string from your library you don't do something like getString(com.library.R.string.some_string) you simply call getString(R.string.some_string) instead.
In terms of the library method: Would you mind sharing some code with us? Currently I can't imagine what's going wrong.
Problem was in wrong package name in gradle configuration files (after renaming).
I'm new to android development. I wanted to implement Navigation Drawer feature in my application, which requires android.support.v4.jar file to be included in my project. I'm using Android Studio to develop my application so I included the compile "com.android.support:support-v4:18.0.+" in my build.gradle file as mentioned in https://developer.android.com/tools/support-library/setup.html. My project is working fine, I was able to successfully include my library. I did adding library without resources.
What I couldn't figure out is the difference between adding library without resources and adding library with resources. Does adding library with resources mean including some sample project?
Thanks
For Android Studio projects using Gradle (which is what your project is), there isn't an important distinction between libraries with resources and without resources. The Gradle build system's support for Android is more advanced than anything available to Eclipse and can support libraries with and without resources the same way (you just add the compile statement to your dependencies as you have; you can also do it more easily via the Project Structure dialog).
In Eclipse, if you want to include a library with resources, you have to add it as a project (similar to an Android Studio module) to ensure the resources get included directly; there you can't include resourceful libraries as simple jar files.
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:\opt\workspace\CustomGlowList\res\layout\main.xml:14: error: No resource identifier found for attribute 'listId' in package 'com.company.library.glowlist'
[2012-05-16 12:07:28 - Project] D:\opt\workspace\CustomGlowList\res\layout\main.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.
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
not sure how you use the android library , but i've done this thing a lot of times without any problems , so please have a reading of the next things regarding using android libraries:
in order for an android project to use an android library project , you can either edit the "project.properties" and add the path to the library project there , or , much easier, right click the project (that uses the library project) , choose "android" category , and choose there "add" and choose the library project.
in order to make the android project to always open the android library project , also choose "java build path"->"projects" and choose the library project.
on the "project.properties" , try to set the target to the same target for both projects , and to the newest one that you have (latest now is 15) ,even if you can't test the app on this android version .
source files and all resources files (in the res folder) are ok to be used on the library projects.
assets folders cannot be used inside the library project . only on the android project that actually runs , the assets folder can be used . same thing goes to the proguard file .
the manifest of the library projects almost doesn't need to have almost anything . see this post for more information: https://stackoverflow.com/a/10445630/878126 . if there are activities on the library project that you wish to be able to access via the project that use it , don't forget to include them in the manifest of the android project (no need to write them in the manifest of the android library) .
remember to run lint before you export the app . it gives you plenty of warnings , but the most important warning is when you use too-new functions that cannot run on the range of APIs that you target . this is important for libraries since it's easy to get lost if there are multiple sources .
if you wish to extend activities on the android library , you need some kind of a method to go between them . the only way i know of is to extend the application and let it be the manager of how to create an intent for each of the activities . i think you can do other tricks , but they are all probably similar to this one.
if you have the same resource (any resource on the "res" folder) on both the android library and the android project, the one on the android project will replace the other one . this has advantages and disadvantages . remember that you can't have different file extensions for the same resource .
The problem was being caused by the R files from each of the Library projects not correctly being built and referenced. The resource files are built and referenced directly from the calling project.
Each of the Libraries need to have unique package as defined in the AndroidManifest.xml. This leads to each of it's resources being compiled in that unique namespace within the calling project alongside the Library jar which contains the class files.
The problem becomes intermittent when switching between a library and a runnable project because a clean and build needs to take place to regenerate these files as it isn't done automagically when unclicking the Use as library checkbox, where as the jar (and java classes) don't require as much coaxing for them to be correctly referenced as the library projects references them when acting as a Library.
This can lead to intermittent and also varying errors including missing references, DexOp and NullPointerExceptions depending on to what degree the R.java files have been mangled or partially built and what conflicts are taking places between packages.
I have same issue like, I have one library project and it has some activity.
When I was calling library project's Activity from my Main project, layout files resources were not getting loaded properly for the libray project's activity and giving "nullpointer exception" or "class could not be loaded", etc.
Solution: I have noticed that same layout file name is getting used in my Library project and Main project. I have just renamed those activity and it is solved.
May be this will help you.
I had similar issue when referencing Library project inside the Android App project. I deleted the R.java file from Library project so it generated again and App picked up the generated file. You should see the generated R.java file under your app project->gen->library_namespace_R.java.
I'm trying to create an android component that can be easily added to android projects as a jar library.
For this, I had to create new xml attributes in "res/values/attr.xml" that I add to my graphic xml element using the path:
xmlns:app="http://schemas.android.com/apk/res/com.component.mypackage"
Then I import this project as a jar library into another project.
To create my graphic components in the new project, I must change the path below:
xmlns:app="http://schemas.android.com/apk/res/com.mylibrary"
But the path is incorrect: the custom attributes are not found.
I managed to integrate the R file in the library jar and I could access it from my xml to declare a custom component like this:
<PreferenceScreen
xmlns:android = "http://schemas.android.com/apk/res/android"
xmlns:app = "http://schemas.android.com/apk/res/com.myLibraryPackage">
<com.myLibraryPackage.mySelfComponent
android:title="Name"
android:key="name"
app:hintText="Input your name"
android:dialogTitle="Your name "
app:validator="com.myLibraryPackage.myValidatorClass" />
What is strange is that if I put my file attr.xml in resources of my project, it works, which means it find com.myLibraryPackage.mySelfComponent. In that case, why it can't find also com.myLibraryPackage ?
(I also tried replacing
xmlns:app="http://schemas.android.com/apk/res/com.myLibraryPackage"
by
xmlns:app="http://schemas.android.com/apk/res/com.myApplicationPackage"
but it still doesn't work)
I would have preferred to use a jar to facilitate its integration in a project !
Has anyone encountered a problem like this who could help me?
Thank you.
I'm trying to create an android
component that can be easily added to
android projects as a jar library.
If you want reuse code and resources, it won't be possible to do it with a jar file. You'll need to convert your library to a library project.
Then I import this project as a jar
library into another project. To
create my graphic components in the
new project, I must change the path
below:
If you're using a library project, you'd still reference the custom attribute as if it were contained in the application (since android will merge all the resources together when the application is compiled):
xmlns:app="http://schemas.android.com/apk/res/com.component.mypackage"