I am trying to reference a pure java-Project in my Android-Project -> The Java-Project has a whole bunch of classes I need to use. Oh, and as the first response pointed out: I am using eclipse, yes :)
Only Problem is: I Always get Could not find class 'XXX', referenced from method com.example.helloworld.MainActivity.onCreate. I seem to have missed SOME step or error...?
What I already did:
The Project is added as Project into the Java Build Path (logically nessecary)
It is marked in "Order and Export" in the Java Build Path and pushed to the top (this solved the problem for someone else here when dealing with Jar-files)
Ir is marked in "Project References" on Project settings.
I added the folder where the relevant class is under "Libraries" in build Path... I am not sure if that should be nessecary.
The Java-Project I reference has a whole load of Jars, but if that is the reason, should I not get a different errormessage?
I had the same issue and after some hours of frustration and search I have finally found the answer here:
Android, class not found from imported jar file
Basically, the issue was that the referenced pure-java project or the generated jar was built with Java 1.7, and Android projects are set to use 1.6.
Two ways to do this.
Jar that java project and copy the jar to the libs folder of your Android project.
Add the project as a dependent project to your Android project
Both work wonderfully.
But mind you, this pure-java project must add android.jar and not things like rt.jar :). Else you will get Dalvik exceptions.
Edit :
Dont forget to refresh and Project - Clean your android project.
Two things to check (you mentioned you are using Eclipse):
If your android project needs to use the pure-java project's JARs, check that those JARs are being exported in the build path options of the pure-java project. This is in the build path of the pure-java project you are trying to include, not the build path of the android project that is trying to include it. Under "Order and Export" tab for the pure-java project, note the comment "Exported entries are contributed to dependent projects". In this case, your android project is the dependent project and your pure-java project needs to do the contributing.
Make sure the pure-java project is actually opened in the IDE in addition to your android project. Probably trivial but sometimes overlooked.
If answer does not suffice, you may wish to mention if the missing classes are in .java source files, or if they are only found in JARs in the build path of the pure-java project
Edit: To further track down the issue, please confirm the following to make sure I understood your question:
The pure-java project does successfully build in the IDE
The 'class not found' error is one you are getting when you try and -build- your android project and not when you try and -run- it.
CLASSPATH (aka build path) can be nasty to untangle. If including the project is not working (assuming it does build), you could try building a JAR of your pure-java project and copying (and including) that and all the other JARs into your android project.
The android SDK does certainly complicate the build environment. One way to find out whether the problem is (A) your android project setup) OR (B) the way the pure-java project is packaged) is to create a different pure java project and try including the first one, preferably using the -exact- same line of code that gives you the build error in the android project, if possible.
Related
I'll try to explain as much as possible as this is more of a structural problem than code problem, ok, so i have project in which i am using android-support-library-v4, now in the same project i have now added three new libraries, these libraries also include android-support-library-v4, as they are part of their own code framework,
Now the problem is this is causing a jar mismatch in my project because i now have three same android-support-library-v4 in my project.
I tried the solution of removing the android-support-library-v4 jar file from my main project but this does not resolve the jar mismatch from the other libraries i have used in the project, and i cannot delete the android-support-library-v4 jars from the libraries as they would not work without them meaning they will stop functioning...
Simple solution for this problem , What i usually do is , steps are.
Just copy any android-support-library-v4 from any lib project
Then copy and replace this to all other libs projects.
This will remove your mismatch problem
I will suggest you to use Android Studio as Google official IDE.
I have been successfully using android-support-v7-appcompat library for last few months in my app to support action bar in older devices. Recently I have downloaded the Android 4.4(kitkat) updates with system image and SDK platform from the SDK Manager. I also added targetSdkVersion to "19" in manifest file. But my project was showing error as 'android-support-v7-appcompat jar mismatch. Fix your dependaecies.' Then I added the jar from /extras/android/support/.... to the project as an external jar using build path menu > add external jar. Now there is no error in the project and android-support-v7-appcompat.jar & android-support0v4.jar file is showing twice under 'Referenced Libraries' folder and also once under 'libs' folder. The project is not showing error and running, but crashing in different activities.
Previously I imported the android-support-v7-appcombat library as an external project in the workplace. I can see error in that project. Please suggest what should I do now. Also, android-support-v7-appcompat.jar umder Android Dependencies in Java Build Path showing error.
The error I see is:
Found 2 versions of android-support-v7-appcompat.jar in the dependency list,
but not all the versions are identical (check is based on SHA-1 only at this time).
All versions of the libraries must be the same at this time.
Versions found are:
Path: C:\<project hierarchy>\libs\android-support-v7-appcompat.jar
Path: C:\Users\....\sdk\extras\android\support\v7\appcompat\libs\android-support-v7-appcompat.jar
Jar mismatch! Fix your dependencies
After getting idea from different forum, I removed all the android-support-v7-appcompat libraries from different places, and imported android-v7 support library again in the project. Still it's showing error. Should I also delete android-support-v4 libraries from buildpath and libs/private librariry/referenced library folders?
This error occurs when there are multiple and different instances of the same library are found in the same project, or libraries used by it. A very simple way to resolve this is use the common lib at both the places. To do so:
Just copy your C:\Users....\AppData\Local\Android\android-studio\sdk\extras\android\support\v7\appcompat\libs\android-support-v7-appcompat.jar
and paste it in your libs folder, replace the old one with this. Clean the project, and it shall compile now..
Edit 1:
Basically the idea is if you are using the same libraries, it shall be the common jar, or the same jar.
In your case if you are using the appv7 as an external project, please go to libs folder of your project copy android-support-v4.jar, and paste into the libs of android-support-v7-appcompat project.
Also, make sure if there are other external jars or support libraries used by you, they shall be the similar jars in all the projects you are using.
I hope it helps!
I had exactly the same problem after installing all the updates mentioned in the question. I am sure there are different ways to solve this problem. Here is the way I used:
Previously, when an activity was created, the following project was automatically generated by the wizard:
androi-support-v7-appcompat and this project was added to the build path.
After all the updates, the following equivalent is generated when an activity is created:
appcompat_v7 with the jars of the same names.
I deleted androi-support-v7-appcompat and made sure the projects use appcompat_v7 to replace androi-support-v7-appcompat in their build paths. This made hundreds of errors generated by the duplicates go away.
I am glad that i finally found the answer. I was encountering the same problem again and again and i was like fed up.
Here is the answer to your question.
whenever you get such an error just don't touch anything other than libs folder. Just go directly into the libs folder and right away delete the android-support-v4.jar. and clean build your project. You will be relieved to get rid of errors.
Hope its useful to you.
Keep coding..
I have actually figured out the solution by trying different options suggested from different forum. I had manually change the android-support-v7-appcompat project's(which was added as an external project) project.properties file and had to set 'target=android-19'.
I installed a bunch of updates via Android SDK Manager this morning including Android SDK Tools 22.0.1. This has seemed to be disastrous so far. One disaster is handling libraries. Here is the scenario:
I have a project projFoo that uses a library project libFoo. libFoo uses a dozen or so libraries or projects. In other words, libFoo has the following in its Java Build Path:
projA, projB, projC,...
lib1.jar, lib2.jar, lib3.jar ...
I used to need only adding libFoo to the build path of projFoo, and everything was working fine until I installed the updates.
After the updates, I have been adding projA, projB, lib1.jar one by one to projFoo's build path even though projFoo does not use them directly. Without doing this, java.lang.NoClassDefFoundError would occur when I run the app.
I have cleaned all projects and restarted Eclipse many times. I also checked those referenced projects and libraries in Order and Export of libFoo, but adding those references still seems to be necessary. Is this the right way to handle this?
In the order and export tab of Java Build Path make sure Android private Libraries and Android Dependencies are checked.
Any libraries in .jar format should just go in the libs folder of your project. There's no need to add them to the build path.
Any libraries that are a project can just be added to the Java Build Path Projects tab, or if it is an android project, you can add it to the Library section under the Android pane.
I am currently working on an android application that needs to use some shared classes which are also used on some serverside.
So on the one hand I have this standard java project inside eclipse where I have some POJOs, infercaes and so on. And on the other hand I have an android application project with an activity that should use those POJOs.
My first try to get the android project to know the java project was simply adding it as a "required project" in the build-path properties inside eclipse. That resulted into:
java.lang.NoClassDefFoundError: my.package.Pojo
I googled it and tried a lot, but still the question stands:
How do I set everything up properly, so that my ADT v21.1 android project will still know my java project, even at runtime?
Some things I already tried that did not seem to change anything:
after adding the "required project" I also set the dependency to be exported under eclipse "Order and Export" dialog
I tried building the java project as a jar-file and adding it as a jar-dependency to the android project
I created a android library project as 'glue': I added the java project as a dependency to the library project and the library project as a 'android dependency' to the android project
I checked that all projects where inside the filesystem in the same parent folder (read, that the underlying ant task might have some troubles otherwise)
I googled for a loooong time
Would really be nice if someone could help. Maybe I'm just missing some tiny little thind?
Bluddy
The Problem is that I build the java project using Java 7 which seems to by not supported by android. 'Phix' pointed that out in his very helpful posting (he was also andwering himself):
https://stackoverflow.com/a/13304441/1145459
(answer by Bluddymarri, I just posted it here to help him get it closed)
I'm using Eclipse to learn to develop Android applications in Java. I haven't used Eclipse before.
The project I'm trying to use (supplied by OReilly as part of 'Android Application Development') is MJAndroid. When attempting to run the project, the Run fails, and the Problems tab mentions com.java.Object can't be found, and Eclipse asks me to check the build path. Clicking
Properties -> Java Build Path -> Libraries, the message 'Unable to get system library for the project' is displayed.
On a working project, Properties -> Java Build Path -> Libraries has an entry for Android 1.1, which if I click Edit, has the classpath container path of com.android.ide.eclipse.adt.ANDROID_FRAMEWORK.
It seems a simple matter of adding the correct container path to my non-working project. However Eclipse seems determined to make this as difficult as possible. No matter what I chose to add - jars, externals jars, variables, libraries, class folders, external class folders, nothing seems to take the form of 'com.android.ide.eclipse.adt.ANDROID_FRAMEWORK' that the 'Android 1.1' entry on the working app has.
How can I add this namespace to my project so it resembles the working one?
I'm quite sure it's a problem with Eclipse's somewhat odd user interface. Frankly there' nothing I'd prefer more than a file to modify and set such information - my background is in Python, and the whole eclipse environment seems an unnecessary burden.
I had faced the same issue when I imported a sample code downloaded from the internet. I am using android sdk 1.5 with 0.9 ADT plugins. Here is a simpler way to fix the andoid library reference issues
Right click on the project which has
issues and select properties
Select the appropriate Android build
(1.1, 1.5 or 1.5 with google api) and
say ok
Again right click on the project and
select "Android Tools > Fix Project
Properties"
Fix the imports once (if required)
Refresh the project and you should be
ready to go without any manual
editing
I faced this same problem after importing a project through GIT. The problem was that I didn't have the same target android platform installed, and the build path somehow got corrupted.
The first obvious thing i did was changing the target sdk in the project.properties, but even after cleaning up the project and Android Tools > Fix Project Properties, it didn't help and I was still getting the build error.
My solution after wasting close to 1 hour trying to figure this out?
RESTART ECLIPSE
Everything worked fine after that. Eclipse is pretty fickle. Only through years of experience you'll then understand her well. :)
Had the same problem and it turns out the Android SDK Location was not set which was a really simple fix. Go to Window->Preferences, click on 'Android' on the left hand menu, fill in the location of the Android SDK (e.g. C:\Program Files\Android\android-sdk) and click OK. Everything worked fine for me after that.
Found the answer in this set up guide: http://developer.motorola.com/docstools/library/Installing-Android-Dev-Environment/
Sometimes Eclipse can get a bit funny (technical term) with classpath container resolution.
You have a working project in your workspace, so you can rule out plugin installation issues. You could try opening the .classpath file (hidden by default, select the triangle in the top-right of the Package Explorer view, select Filters... and uncheck .* resources) and manually adding the container declaration.
`<classpathentry kind="con" path="com.android.ide.eclipse.adt.ANDROID_FRAMEWORK"/>`
You may then have to close the project and open it again (right-click->Close Project) before Eclipse recognises the change.
You may also find that there is an Android builder and/or nature. If you compare the .project files for the working and non-working versions you may see entries for Android builders/natures. Copying the relevant entries may resolve the issue.
sometimes, eclipse can help you.
In Android projects, click right button on the project-> Android Tools -> Fix Project Properties.
It's usefull in class path errors!!
Luck!
I would verify you have the correct version of Java installed as well as the Android SDK. I would recommend installing/reinstalling the ADT plugin in your eclipse, makes it alot easier to create the android project.
http://developer.android.com/sdk/1.5_r2/installing.html
Also. I guess the path of the Android SDK must be setup correctly. This happened when I was overloaded with projects and I decided to create a new workspace copying some existing stuff into it.
Seems that the new workspace requires you to setup these details too once again
Is that setup properly?