I have made an android project in eclipse. This project has a library project:
the library project (marked with "is library") has included a jar file.
this library project does a lot of stuff with the use of the jar file.
in code everything is fine.
The problem is that the reference to the jar file doesn't exist anymore when it is compiled and installed to my phone.
When i add the jarfile also to my base project. Then the program works.
However, i don't believe that this is the right solution.
So what does i do wrong?
You should add a libs folder to your project
Then, add the jar to the folder and right click on the .jar file and go to Build Path, and select Add To Path or Build To Path. This way the library will be a part of your project. This should help.
The library jar you used in your Android Library Project must be manually added to the dependent application project's build path, not the Android library project build path itself, check out API here
Related
I'm very confused about adding external .jar files to my project.
I downloaded https://github.com/chrisbanes/Android-PullToRefresh library project.
After importing it to Eclipse, I cleaned & built it.
After that, in the bin/ folder of the library project, there is a .jar file.
Next I copied this .jar file to the /libs directory of my project from which I want to reference it.
As far as I understood, from now on there is no need to keep the library project in my workspace, because i added the .jar file to my project.
Picture of the projects tree:
https://www.dropbox.com/s/7w4tzis8v1vv4aj/jarProblem.png
When I'm running the referencing project with the library project open : no issues.
As soon as i close the library project: NullPointerException <- seems not to find the library.
I already tried every possible combination of build path configuration but I can't get my main project to be built with the pulltorefresh project closed.
I thought it was the sense of a .jar file to distribute a library without having to attach the source files.
It should work the same as the android-support-v4.jar ... for which i don't have the source code either.
What am I missing here ? Thank you.
There's a difference between a jar file and a library project.
Jar files can contain only code, no android resources. These just need to be placed in your libs folder and linked in.
Library projects can contain Android resources. They need to be compiled as Android libraries in Eclipse, and kept around as their own project. You then tell your main project that it references this one. Its necessary to keep the library project around because it needs to build the /gen files from it for your resources to be right. It also needs to be able to grab the contents of its assets folder.
Given that this library has a res folder, its an Android library project and can not be used as a simple jar.
I want to use a svg-android library to work with *.svg files in Android. For the same, I've installed the apache ant, created a folder in workspace called: SVGAndroid and then added
android.library.reference.1=C:\Android\workspace\SVGAndroid
to project.properties file.
There were no documentation for functions in ReadMe, so I'm wondering if the installation correct or not, how to reinstall an external lib in the second case and where are the examples of using svg-android?
For your including of the project, just include the project into your workspace and in your respective application under the properties of that project just add a dependency on a library that references svgandroid. Make SURE to include the files and ensure that the compile class files are present in the final output of the apk. This typically means that you add the project to your build path/order.
Another approach is to just take the entire project and compile it into a jar file and then include that jar in your libs folder and add that dependency on the jar file of that respective project to your core application.
Useful links
How can I use external JARs in an Android project?
I would rather suggest to not add the path to the project manually, but from Project Properties -> Android and you will have a list with all the library projects in the workspace from which you can choose the desired project.
Also I suggest adding in project.properties the following line:
manifestmerger.enabled=true
in order to have all the AndroidManifest.xml files of the referenced library projects merged into the main project's manifest.
If you want to include a library file in to your project follow the below steps;
Download a jar file and save it in any folder.
open your project.
Right click--> Build path--> Add External Archives---> Add your external jar file to your project
I'm trying to use an external jar file in my Android project, I follwed this step for including it:
I put the jar file in libs.
I configured the build path and now I can see the jar file in the Referenced Libraries section of the project.
I use the import to bring the class that I need inside the program.
But I always get NoClassDefFoundError. This jar already works with a classic java program.
Make sure that the jar is being built with the app. In eclipse,
right click on project --> build path --> configure build path.
Make sure the library is checked in the Order and Export tab.
Since Android SDK 17 there is not even necessary to manually add the jar files to buildpath, because they are added automatically, as stated here. Then I would suggest to:
remove the library from buildpath
clean the project
make sure the jar file is located in a folder called libs (not lib) located in the root folder of your project
refresh the project
run the project
The solution found was recompile the library with the version 6 of java and using the jar fail obtained
I am working on an app which uses Commonslang.jar libraries. I was trying to setup it on a new system with newly installed Eclipse.The project is not showing any error But when I run the project it force closes with NoClassDefFoundError at each point where I use Commonslang lib.
I dont know how to fix this problem.Please help?
I think there are "lib" folder in your project directory so just change it "libs" instead of "lib" and clean project and check it..
> Note: No need to build path for any third party library
You need to create libs folder in your project and copy that jar file there. Then in eclipse, right-click on that jar file (which is in libs folder) select Build Path and then select Add to Build Path.
Remember: if you are using a jar file in your Android Library Project, and associating that library project with your regular UI
project, it won't be enough. You must need to include that jar file
(as described above) in both of your projects (Android Library and UI
project) to make it work.
Have you added the jar to the Java Build Path?
Go to the Properties for the Project and select Java Build Path -> Libraries tab then add the external jar there.
I am trying to use phonegap inside an android library project. The library project compiles just fine but when i try to start an activity that extends DroidGap, i get this error
01-02 10:12:17.575: W/dalvikvm(316): Unable to resolve superclass of Lcom/***/***.
I think this is because the phonegap.jar file is not included in the compiled jar file of the android library project. I have tried using ant to build but it doesn't seem to work.
Edit: I am building a android library that can be used in other android projects. I am using the standard android library project but activities in this lib project that extended DroidGap class in phonegap.jar are crashing with the above error.
I´m afraid that is not possible yet. The result jar file will contain all classes and resources defined in the android library project, but will not include external jar files added to the build path. You will have to add those to your final Android Projects using that library. You can also find similar questions in SO like this one
create one folder 'lib' in your project. put your .jar file in lib folder. select your .jar file right clicked on ,select buid path --->'add to build'. will add your .jar file. now you can use this .jar file classes.
I would suggest not making the 'lib' folder manually.
Instead:
Right click Project --> Properties --
Select Java Build Path
Make sure Libraries is the tab selected at the top
Click Add External JARs
Then find your JAR...
Basically, the same way you may have added the PhoneGap.jar
The ADT (Android Development Tool Eclipse plug-in) has built-in support for the creation and reference of library projects. See the example in section 5 of this tutorial.
Try changing the name of the folder to libs instead of lib.
have you added required permission in manifest file..
see the below links
http://docs.phonegap.com/en/1.4.0/guide_getting-started_android_index.md.html