Although I know this question has been asked a million times, I have tried going through many of the stackoverflow questions and none of the answers have worked.
I have an old version of my project that I know worked and built correctly, which I added back into my eclipse workspace. When I clean and build the project, I am given with errors with the R cannot be resolved..
What I've tried:
- Building/Cleaning project
- Was going to clear the gen folder, BUT R.java didn't even exist in there
- Checking through my XML files to ensure there's no errors
- Restarting Eclipse
Extra note:
- My ADT plugin and Android SDK was the LAST version directly after Google released it's updates to merge everything over to Android Studio.
I just solved this problem for myself. I was using the Eclipse Android SDK on Windows 7. The problem was that the Eclipse program did not have permission to create the R file. To fix it I went to "User Account Control" settings in the Windows Control panel and lowered the slider to a lower security level. After rebooting the computer and cleaning the application in Eclipse Android SDK there were no more errors.
I've experienced the same problem a week ago. After installing the beta version of android studio I was unable to run android projects in eclipse. Uninstalling android studio fixed all the "R cannot be resolved to.." errors.
After trying everything I tried one last thing.. which was to update all of my plugins and libraries for Android. This actually solved the issue. I'm sure not that many people will probably have my specific issue since it will eventually go away, but it is a different problem I have not found and a different solution I have also not found...
I faced Simmilar problem, i cleaned project, Restarted Eclipse, and many other things like remove errors from problems,
but it was DUE TO: an Image Name in Drawable it contained Capital Latter i did Re factor -->Rename and Problem solved..
Related
This question already has answers here:
"R cannot be resolved to a variable"? [duplicate]
(30 answers)
Closed 9 years ago.
I am getting this classic error in Eclipse IDE. I am bored of Eclipse's bugs. They driving me mad.
I almost tried everything which suggested as solution (by Googling). None of them worked.
My project was working normally but not code changes.
I see that my code changes does not acting on my app (on AVD) then I cleaned my project (under Project > Clean...). R.java file was gone and res folder was empty.
Now I am getting that error: R cannot be resolved to a variable.
What should I do?
And also I tried to delete project and create again with Android Project from Existing Code I've backed-up before. It already gives same error after cleaning.
Any ideas would be appreciated.
I assume you have updated ADT with version 22 and R.java file is not getting generated.
If this is the case, then here is the solution:
Hope you know Android studio has gradle building tool. Same as in eclipse they have given new component in the Tools folder called Android SDK Build-tools that needs to be installed. Open the Android SDK Manager, select the newly added build tools, install it, restart the SDK Manager after the update.
I'm not posting this as an answer but a confirmation to Paresh's accepted answer. I recently updated SDK tools to Revision 22 and I noticed my code changes was not being affective on the device i'm testing at all. Such as the url I was using, I was getting errors for connection time out regarding the url I was "previously" using. Therefore I cleaned the project and built again only to find out that autogenerated R.java file is missing.
After reading Paresh's answer and checking what's going on with my sdk manager this is what I saw:
SDK Build-tools 17 was not installed and there was already a new update to SDK tools even though it does not mention any change related to this problem in the changelog, this update brought back my R.java file and the related problems were gone after an eclipse restart and final clean/rebuild on the project.
The R file can't be generated if your layout contains errors. If your res folder is empty, then it's safe to assume that there's no res/layout folder with any layouts in it, but your activity is probably calling setContentView and not finding anything -- that qualifies as a problem with your layout.
Try to delete the import line import com.your.package.name.app.R, then, any resource calls such as mView= (View) mView.findViewById(R.id.resource_name); will highlight the 'R' with an error, a 'Quick fix' will prompt you to import R, and there will be at least two options:
android.R
your.package.name.R
Select the R corresponding to your package name, and you should be good to go. Hope that helps.
In addition to install the build tools and restart the update manager I also had to restart Eclipse to make this work.
I had a fully working project to which I was doing a minor change when this occured after updateting the SDK.
Eclipse updated the SDK and the ADT but I could still not build the project. Exlipse said there were no further updates available.
The problem persisted until I manually uninstalled the ADT from eclipse and re-installed it.
Only then would my project build. I had restarted eclipse inbetween each step.
I'm developing an android application and I've gotten pretty far already.
but recently I opened my eclipse again to continue my work, but there was a problem with my settings for the google play services. (I'm kinda sure it happened after I installed the new version (revision 7) from the android SDK manager.)
So I imported the google-play-services_lib and the google-play-services.jar again and the errors went away, so far so good I thought.
But now eclipse can't resolve R to a type and I can't run the app either...
I've searching the whole day to save my project from these errors and now I'm getting this one...
btw the project ran perfectly for 4 months...
can anyone tell me wat to do?
EDIT:
what I tried so far:
I've added all android build tools, google play services (libraries and projects),... Imported the google play services project into workspace and cleaned the project like 30 times. I Already checked private libraries, android dependencies etc. to export
I had the same problem I think.
In /gen there was no R.java for me but when I updated my SDK-Tools everything was fine since they seem to have changed the order in the last version.
Try that maybe!
Found it:
the SDK was already updated, but the device settings were changed somehow (now it was compiling for android 4.2.2 instead of 4.0.3) and when I cleaned the project, it updated some code I didn't notice, when setting the 4.0.3 build target again it wouldn't compile nor generate the R.java file (giving me loads of errors).
So what I did was change the project build target to 4.0.3 again, but I must have missed some lines of code that were updated to the 4.2.2 target... (leading to the R file not being generated, leading to more errors that were leading to more errors... just a vicious circle)
I didn't exactly remember what line caused the error, I was too happy it was solved I guess :)
This question already has answers here:
"R cannot be resolved to a variable"? [duplicate]
(30 answers)
Closed 9 years ago.
I am getting this classic error in Eclipse IDE. I am bored of Eclipse's bugs. They driving me mad.
I almost tried everything which suggested as solution (by Googling). None of them worked.
My project was working normally but not code changes.
I see that my code changes does not acting on my app (on AVD) then I cleaned my project (under Project > Clean...). R.java file was gone and res folder was empty.
Now I am getting that error: R cannot be resolved to a variable.
What should I do?
And also I tried to delete project and create again with Android Project from Existing Code I've backed-up before. It already gives same error after cleaning.
Any ideas would be appreciated.
I assume you have updated ADT with version 22 and R.java file is not getting generated.
If this is the case, then here is the solution:
Hope you know Android studio has gradle building tool. Same as in eclipse they have given new component in the Tools folder called Android SDK Build-tools that needs to be installed. Open the Android SDK Manager, select the newly added build tools, install it, restart the SDK Manager after the update.
I'm not posting this as an answer but a confirmation to Paresh's accepted answer. I recently updated SDK tools to Revision 22 and I noticed my code changes was not being affective on the device i'm testing at all. Such as the url I was using, I was getting errors for connection time out regarding the url I was "previously" using. Therefore I cleaned the project and built again only to find out that autogenerated R.java file is missing.
After reading Paresh's answer and checking what's going on with my sdk manager this is what I saw:
SDK Build-tools 17 was not installed and there was already a new update to SDK tools even though it does not mention any change related to this problem in the changelog, this update brought back my R.java file and the related problems were gone after an eclipse restart and final clean/rebuild on the project.
The R file can't be generated if your layout contains errors. If your res folder is empty, then it's safe to assume that there's no res/layout folder with any layouts in it, but your activity is probably calling setContentView and not finding anything -- that qualifies as a problem with your layout.
Try to delete the import line import com.your.package.name.app.R, then, any resource calls such as mView= (View) mView.findViewById(R.id.resource_name); will highlight the 'R' with an error, a 'Quick fix' will prompt you to import R, and there will be at least two options:
android.R
your.package.name.R
Select the R corresponding to your package name, and you should be good to go. Hope that helps.
In addition to install the build tools and restart the update manager I also had to restart Eclipse to make this work.
I had a fully working project to which I was doing a minor change when this occured after updateting the SDK.
Eclipse updated the SDK and the ADT but I could still not build the project. Exlipse said there were no further updates available.
The problem persisted until I manually uninstalled the ADT from eclipse and re-installed it.
Only then would my project build. I had restarted eclipse inbetween each step.
I am a new Android developer (4 weeks into porting my iPhone app to Android). I have 8 projects (the app, and 6 small UI experiments, and a vanilla Hello World project that I just created with Eclipse). All fail to compile, and the issue is that every reference to the generated file R is flagged as "R cannot be resolved to a variable".
Up until yesterday afternoon -- every project compiled and ran (albeit very slowly) in the Android emulator. I've changed something, and since yesterday, all projects fail to compile, all in the exact same manner "R cannot be resolved to a variable". I every case, the generated files are missing. I believe they disappeared as I tried to clean and rebuild each project in the course of debugging this problem.
Two things that I know changed when this problem started, but that I can't say caused the problem, were: 1) shifting to debugging on a real Android device (a Samsung Galaxy Tab 2, which worked like a champ after struggling with the slow emulators), and 2) allowing Android (and perhaps Eclipse) to update themselves from the web.
I've spent many hours trying other user's suggestions and none have helped. Most suggestions refer to file naming issues, xml syntax errors, but I haven't changed these files and filenames since compilation was working. I have tried:
cleaning and rebuilding the projects
checking for subsequent updates to the Android SDK (and there were 2 subsequent ones)
Eclipse->File->Android Tools->Fix Project Properties
making small source changes to force rebuilding
rebooting Eclipse, as well as the Mac host, adb, the emulator, the Android SDK Manager
deleting a project, restarting Eclipse, and adding the project back in (bad idea - this fails with an error "Failed to load properties file for project 'ListViewFragmentTest'"
creating a brand new Android App project, which has worked many times before, but now fails
There's something going systematically wrong, and while I won't claim all these projects are bug-free, they did run up until 6pm yesterday, and then all stopped compiling thereafter.
I wonder if anyone has other suggestions, before I embarking with a complete reinstall of the development environment?
My environment is:
Macbook Pro (OS X 10.7.5, 8GB RAM, 2.53GHx Core i5)
Eclipse (Indigo Service Release 2, Build: 20120216-1857) (too old?)
Android SDK Manager Rev 22
Android SDK Tools (22), Platform Tools (17), Build Tools (17)
API's 11-17, all up-to-date
Seems like lots of people experience trouble with missing generated files (R), and I have had trouble when I've had layout XML errors as well, but that doesn't seem to be causing this problem. Thanks in advance for your help!
I am not sure but you are facing issue of R.java file is not getting generated after updated with ADT rev 22.
If this is the case then here is the solution:
Hope you know Android studio has gradle building tool. Same as in eclipse they have given new component in the Tools folder called Android SDK Build-tools that needs to be installed. Open the Android SDK Manager, select the newly added build tools, install it, restart the SDK Manager after the update.
Check in the Java build path library, whether "src" check box is checked or not.
If you are using any additional Libraries then make sure libs/android-support-v4.jar is same for project as well as the Libraries.
Thanks everyone. None of these suggestions resolved my problem. And while I'm curious as to why it happened, I was more impatient with not making any progress. I've reloaded Eclipse and the Android tools (this time with the bundled version from developer.android.com), and everything is working smoothly again.
I updated tools in my Eclipse first by going to Help->Check For Updates and installing everything i that it suggested. Then by going to Window->Android SDK Manager and updating multiple things including my SDK version.
After I have finished my update all my Android projects got a nice red box with an x inside it. I explored the projects and noticed that none of them had any errors inside the project just the project itself had the error icon. I searched online and i found that other people had similar problems. So i thought i found the solution. Alas after cleaning and building the project I got additional error icons next to multiple java files in my projects. Eclipse cannot locate the automatically generated R files when it tries to import them and all the imports are selected red.
I tried deleting the whole content of .android directory (starting with specific few files then the whole content) but that did not bring desired results.
So i have deleted the newly generated files and restored all the old ones.
When I clean and build the projects again all the errors disappear but only until I try to run the project again and then same error appears:
Your project contains error(s), please fix it before running it.
I have also found a related question. It claims that there must be a problem with my xml files. I did not modify any of my xml files since updating the tools so I dont know what could cause them to have errors.
Any ideas as to what is going on??
I've found that eclipse is now picking up errors that it didn't pick up before, because they updated lint, you may have to check all your files and see if there is an error because of this, if it doesn't work try removing Android from the build and reattach it, clean the project, build project, make sure the activities are using the right R files and check what lint says, its like a little square with a tick in it I think.
I had exactly the same problem, solved by removing any imports of R in my code and then cleaning the project
Strangest thing just happened. Even though I have done this 2 times before I have again deleted all my files in .android folder exited my Eclipse and opened it back up again. All the errors were gone and most of my projects work correctly. I have spend a lot of time on this problem and i dont know how it got resolved but Im glad its working again.