Develop Reference

Errors when importing someone else's projects - Android/Eclipse

I have been using Eclipse for about 6 months now, and I noticed that I rarely can import someone else's project into Eclipse. I get so many errors in many files. For example, I tried to import a friend's project that I know works just fine, but I get a lot of "R" errors, like Eclipse can't recognize "R" as a field, and then other weird ones like ActionBarActivity is not recognized or an entire imports like android.support.v4.app.Fragment that visually are in the library but are not being recognized by Eclipse as being there, and I check them and they are definitely marked "Is library" and added properly to the project. Anyone know why this is or how to fix? It's frustrating because to learn, sometimes you need to see someone else's app run first, then look at their code, but you can't. Thanks in advance.
My usual way of importing a project is to do File -> Import -> General -> Existing Projects into Workspace. Also, I have tried cleaning the project, but it doesn't work.

try this File -> Import -> Android -> Existing Android Code into WorkSpace ->then browse-> select your project->make sure the checkBox"copy the project into workSpace" is marked

Check your Build Path. In the Android Section, try using some other API level click on Apply and after your project finishes with the building workspace, again revert back to the original API and click on OK.
Also check for any Build Path errors.

So thanks to the help of everyone of this post, and others on another post, the problem was finally fixed and took several steps.
Turns out that the ActionBarActivity error had a quick fix (hover over it, you get quick fix options) of importing the appcompat_v7 library. I never chose that before, because I thought it was already installed, hence the conflict with android-support-v4.jar (meaning there were doubles of that library), but I chose to import it anyway and that error went away.
But I discovered that android-support-v4.jar was actually a component of appcompat_v7, so that was causing the "Jar mismatch!" error in the console. So I deleted android-support-v4.jar from the libs folder, and the jar mismatch went away.
Lastly, my layout files were all not being recognized, even though I knew the variable names were all correct. So the error was from when I tried to refresh my imports in the very beginning of the problem (using shift+command+O), thinking it was an import problem (which it was), but at that time, refreshing did nothing. BUT... Eclipse took away import com.laurengariepy.android.gridimagesearch.R; and replaced it with android.R;, which is what was causing all the layout errors. So once I put that com.laurengariepy.android.gridimagesearch.R; back, then all errors went away.
So the take-away to this story, is be careful with Eclipse version 22.6. The auto-import of the appcompat_v7 library will cause a lot of trouble when you try to import other people's projects, because they were likely not created in an IDE with appcompat_v7 already there.

Android Studio issue with R file

I was using Android studio now for a long time and it was fine. Recently, not sure what happened, but when I click on debug and have it perform make it complains about the R file and it seems like it doesn't generate it.
The only way it works is if I click on Build > Rebuild Project...problem is that it takes a long time for that to go through.
Is there anything I am missing? I updated the Android SDK tools, etc. as per some of the other suggestions?

Yes this is a known issue in the newest version of android studio. Google has suggested a temporary workaround until they can track down the problem and fix in next release. Turn off external builds in preferences > compiler. It might help.
Source: cannot resolve R into variable after Android studio update and R.java not updated after update to 0.1.6 .
Hope this helps.

Solution for android studio Users :
Goto : Menu tab - > Build - > Rebuild Project
after rebuild Project.R.Java file will be solve automatically ..

I was having the same problem, but it looks like a new update came out today. It seems to have solved the problem.

Try to import android.R, for every class you need R (of the package)
and then compile, it makes different error from before.
And remove all ('import android.R') , and rebuild it.
This trick is not for solving problem in proper way,
but makes the tool refresh.

And remove all "import android.R" , and rebuild it and import them again its working for me

Android studio suddenly cannot resolve symbol R

I was having a project open in Android studio. It was generated by the wizard and working fine.
I did some small changes to activity_main.xml and when I changed back to MainActivity.java i get the error in several places that it cannot resolve R. I might have done something to cause this. But I´m not sure what since it appered when I edited the xml.
Does anyone know what might be the solution to this?
I can find the R.java in r/release/packege/com/ and it looks fine.

Most of the time it is due to a bad XML file. XML files can be layout files, value files, or the Manifest file. Please check your xml files and try to rebuild the project. Sometimes cleaning the project and rebuilding it also works.

In addition, make sure you do not have a drawable with an invalid name. I had a drawable with a numeric filename and that didn't sit well with Android so it failed to compile R.java.

Downgrade Your Gradle Plugin Version
No amount of cleaning, rebuilding and restarting would do the trick for me.
The only thing that did the trick was downgrade our Gradle version from 3.4.0-alpha02 to 3.2.1.
So, instead of:
dependencies {
classpath 'com.android.tools.build:gradle:3.4.0-alpha02'
}
We used:
dependencies {
classpath 'com.android.tools.build:gradle:3.2.1'
}
After making that change and then doing a Gradle sync, everything worked.
Not sure if it's related to the alpha release or to that version or if changing your Gradle version at all just forces a refresh that otherwise cannot be done with the other commands, but there ya go.

Make sure in your AndroidManifest.xml the package name is correct. That fixed the problem for me when my R.whatever was marked red!

Try to clean the project by doing the following:
If you are using Windows, open CMD, cd to your project directory and run gradlew clean.

I just had this problem and the reason was that after editing the layout android studio automatically added an import to the source files:
import android.R
Of course the main R class has not all the symbols in your layouts, which made everything a red mess.
Removing that line solved for me.
EDIT:
Seems like eclipse had the same problem early on.

I sometimes get this after updating Android Studio. Not always straight away but after a while (perhaps after a restart of the program).
Here is what has worked for me: Tools - Android - Sync project with Gradle files.
For some reason just clicking the "Sync now" link that shows up after changing the build.gradle file has not done any change for me. Even though the messages says approximately the same thing.

I had the same problem because in my strings.xml I forgot to escape a apostrophe. Use " \' " never " ' " in xml file!

I had that same problem crop up, too (most recently while I was at lunch--came back and WTF?). And since this was a simple Hello, World program, there wasn't many places these errors could hide. The XML files looked fine--I hadn't even touched the manifest. A clean did nothing.
So I commented out a section of my layout.xml to try to narrow down the problem. Sure enough, the errors went away.
And then I simply UNcommented out exactly what I had commented...and everything was hunky-dory. Strange! Perhaps there was some lingering issues that needed to be touched in order to cause a rebuild of the layout file. You'd think basic stuff like that wouldn't happen these days, but they do.
One more thing! It's possible that something may happen to Java as well. It's very hard to know the status of the Java run-time environment; just easier to start again. So here's one more thing to try: restart your computer, restart Android Studio, AND THEN Invalidate Caches and Restart. Yep, the whole-hog.

When all else fails restarting android sometimes helps. During the start files are loaded afresh and this enables detection of the R

This problem occurs when you rename the package name.
After renaming the package name, you must change the older package
name to a newer one.
For me it solved the problem once I changed that.
After that, you might get errors in xml files, that you have to change
the package name there also.
That's it.

I just had the R problem and after a few hours found that the problem was my regional spelling as used in one of my xml files. The problem word was behaviour, which is spelled behavior by Americans.
I am Australian and we are taught ye olde English way of spelling certain words and so I looked past it a number of times before the penny dropped.
Its a small thing, but it can easily sneak up and bite you on the nether regions and is hard to spot and can waste a lot of time.

In my case I had just added some new image files to the drawable folder and accidentally put a GIF in there with my PNGs. I had not incorporated them into the project at all yet. I removed the GIF and then did a clean and rebuild. That fixed it for me.

I had this exact problem when importing a Udacity Example Program. The Message Pane in Android Studio said the error was failing to load a .PNG in a sub-directory deep in the Project Files.
Turns out the PNG with all of the sub-directory path names was greater than the name length limit defined by Windows 7 (260 characters). I gave the Project a shorter name - to free up some space - and then Android Studio happily compiled.

After you tried make project, clean project, rebuild project but still doesn't work.
Try restart Android studio

Error when importing com.google, com.android.internal.Telephony, etc

I've downloaded the android source code for CallLog, Contacts, Dialing from here.
But now, when I try to import this package on Eclipse, imports like:
com.google,
com.android.internal.Telephony,
com.android.internal.R,
com.google.android.collect,
android.provider.ContactsContract.Intents.UI,
android.provider.ContactsContract.SearchSnippetColumns,
android.provider.ContactsContract.ProviderStatus,
android.provider.ContactsContract.ContactCounts,
android.content.IContentService,
android.provider.ContactsContract.Intents.UI
And many other imports, show errors saying it cannot be resolved.
So my question is, why it shows this errors? Why I cant implement it without this errors? I use the Google APIs, I've created the project from an existing source code, but I dont know why this happens.

If you're sure that you have set up the Android SDK correctly, you should try to 'clean' your Eclipse project.
This usually solves import related errors in Eclipse for me.

Try right clicking the solution / project in the project explorer and choose "fix" near the bottom.

Conversion to Dalvik format failed with error 1 with javax/net/SocketFactory.class

Encounter this problem when trying to Build Project getting such output in console:
[2010-07-19 23:29:23 - myProject]
trouble processing "javax/net/SocketFactory.class":
[2010-07-19 23:29:23 - myProject]
Attempt to include a core VM class in something other than a core library.
It is likely that you have attempted to include the core library from a desktop
virtual machine into an application, which will most assuredly not work. If
you really intend to build a core library -- which is only appropriate as
part of creating a full virtual machine binary, as opposed to compiling an
application -- then use the "--core-library" option to suppress this error
message. If you go ahead and use "--core-library" but are in fact building
an application, then please be aware that your build will still fail at some
point; you will simply be denied the pleasure of reading this helpful error
message.
[2010-07-19 23:29:23 - myProject] 1 error; aborting
[2010-07-19 23:29:23 - myProject] Conversion to Dalvik format failed with error 1
I was looking for my project to use the package javax, not found, clean all also does not help. what I am doing wrong?
Update
Sorry guys, but I could not find good fix for that, I want to emphasize the fact, that i dont use SocketFactory class in my project at all! source code was not changed before this problem, and that's why i think that problem in eclipse or adt or something else, BUT if i use ant(generated by sdk) to build this project there is no problem!!!
I solve this problem by removing Eclipse, Android SDK, Eclipse workspace, and just reinstall them, after this all works fine for now.
Hope this will help someone.

I had the same problem..
This worked for me
project-->properties->java build path->libraries-> remove all including android jars
now go the project browser, right click on the project you are working on,
then android tools---> fix project properties...
do a clean and then build...

I solved the problem (at least for me).
Here's what I did:
Go to Project » Properties » Java Build Path » Libraries
Remove all except the "Android X.Y" click OK.
Go to Project » Clean » Clean projects selected below » select your project and click OK.
That did the trick for me.
Hope it works for you as well
Update: well actually I might have to retract my opinion.. the actions removed the error messages but now I am missing certain classes and methods... arggghhhh

I just restarted Eclipse, and the error didn't appear anymore!

I had the same problem,and solved it as follows:
First clean all jars; (This problem must because your some jars)
Delete the project;
Reimport project;
Make sure your sdk is right, and project select one sdk version;
(This is my issue to solve the problem) Right click your project, and select "build-path", next select "add Librarys", and add your private jars;
clean-build, the problem has fixed;

I just had the same problem and I tried all of the solutions listed here with no success (I was starting to get annoyed). Then I removed the project from the workspace and then imported it again, and there were no problems!

This happened to me this way,
I have a quite an old project which I had to start working again today. I use 'Universal Image Downloader' library for basically every project where I have to deal with lots of images. So in this old project I had the source files of 'Universal Image Downloader' included to it's 'src' path. Back then I was a newbie and slowly I started developing my own library which could handle every day simple Android development tasks very easily. Obviously I included the 'Universal Image Downloader' to this.
After dusting off the old project today the first thing I did was to reference my library to speed up the development process but as I was trying to debug I ran into the "Conversion to Dalvik format failed with error 1" over and over again. First I thought it was the support library but even after clearing all libraries and adding only mine and doing a quick 'Fix project properties' I still got it. After trying various solutions I noticed this in the console "java.lang.IllegalArgumentException: already added: Lcom/nostra13/universalimageloader/cache/disc/BaseDiscCache;"
It was as simple as that... I'm trying to compile a class which has already been compiled.
Solution : I just simply removed all the class files I got from 'Universal Image Downloader' library from the 'src' directory. Since my library references "Universal Image Downloader" library the old project started working just fine.

Hit same problem shown on your log when trying to run an example project which was imported into eclipse.
Additional Info: in eclipse's Problems View I see the following error:
"The project cannot be built until build path errors are resolved"
In my case the imported project find the libraries just right(by just right I mean I can see the external path to each of the android libs in this case 2 libs, android.jar and maps.jar). So no shuffling of libs in my case, but might be your problem.
I followed Spock's suggestion of cleaning the project which I had to clean multiple times until it somehow resolve its issues. After, issue was solved I had to specify an AVD for the project to run and soon after was up and running on the emulator. Also, note that my eclipse is set up to Build Automatically.
In my case I'm not missing any class files or anything after the clean as the build is properly generating them.
Regards!

I was getting the same error. My problem was that i had an android device hooked up to debug with. As soon as I unplugged it I was able to export.

The answer I found was checking the source and library build path in the project's properties. Most likely there will be a duplicate as in something being referenced in both the source and library tabs. So delete the extra in the source tab and then clean the project and you should be good to go.

Either:
javax.net.SocketLibrary is in your source code, or
javax.net.SocketLibrary is included in a JAR file in your project

Under certain conditions it gets its knickers in a twist and the best fix I've found is to remove referenced jars, clean, add them back in and then compile again.
I believe the error can be caused by including the same classes twice.
This error will also occur (and you won't be able to get rid of it by cleaning) when using classes that are not part of the Android environment.

To summarise the information in the link bimbim.in provided (well my understanding when I glanced over it)
The Android Davik VM tries to compile the jars but finds some stuff that it can't compile to .dex files
so
Just create a "lib" directory in the root of the project (where the src, bin res directories are) and add them to the build path. Project Properties... Java Build Path... Libraries.. Add JARs..

I could resolve this issue by creating a new project, looks like the some project settings were creating this issue and could not really find the root cause for that. But, dumping the existing source code onto the new project resovled this issue. If anyone has found the root cause for this problem pls do let me know.

I had the same problem and solved it as follows:
- Go to Project/Properties/Java Build Path/Libraries and remove all JARs except Android
- Do a project clean
- Add the JARs again as External JARs (first time I added them internally, so that might be the problem)
After that the error was gone.

I solved the problem by updating available packages in the Android SDK et AVD manager. No need to remove Eclipse.

Whenever the Project is having the ambitious data. This problem is caused. May be android can't able to find which one choose.

From what I understand, this same cryptic error could be caused from a wide variety of reasons. I've got "Conversion to Dalvik format failed with error 1" error too. In my case the problem was that for some reason Project -> Properties -> Java Compiler was not set to "Enable project specific settings" with proper Java 1.5 settings, but was left to defaults instead (1.6 in my case). Debug, build and test on devices/emulators worked fine, but export always failed with the above error message.
If unsure about the proper settings, create the same project on some alternative location and just copy all needed files from the old project into the new one. This fixed the issue for me.
The next problem with the same error message came from using proguard. Updating to the latest version by replacing the one that came with android sdk, fixed that.
Hope this helps

My problem was having a jar file in my src folder. Removing jars from the build path works, but only if you don't need the jar in question. For people who need the jar in question, make sure that your jar file is not in the project folder (maybe just src subtree, but I would keep it separate to test). Put it on your desktop or something and try the "Add external jar.." option. Be sure to remove the jar from the project filesystem before adding another external. Having both is what causes the problem.

I have done it as the instruction of the first answer and it works.(Linux)
I think the problem may caused by SDK or ADT updates.
I do have to clear all the lib in Java Building path and then use android tools to fix the project. After cleaning and rebuild, it works as before.