Eclipse/Android error: R can not be resolved to a variable - java

I often randomly receive "R can not be resolved variable" errors, and when it happens I can never fix them unless I create a new project and copy and paste all the code. I think this shows that these are not errors from my code. I have cleaned the projects, restarted eclipse, my computer, and even reinstalled Eclipse, but none of those work.
I Have noticed that the gen file (Generated auto file) does not contain any file. I have not deleted them my self and this has frequently happened before.
I know that many people has posted questions on this topics but they have never worked for me and they usually receive low rating so not many people comments on them either. Also if it requires cmd or terminal, please give the commands for Windows, Linux/Mac. I use Mac. I have recently installed GooglePlayService in the SDK although it worked after I installed it.
I am very sorry for lack of useful information, as I have no idea what the issue is.
Here are some of my screen shots to show MainActivity.java, Package explorer and res.values.strings.xml.
I apologize for describing the situation in a confusing way but I tried my best, please tell me what you find confusing if you do find this confusing.
Aftr all Thank You Very Much!!!

Your "gen" folder is empty. It should contain R.java
[1]
Try this:
-Right click your project
-Select properties
-Select Java Build Path
-Click add Folder
-Select the gen folder
-Click OK
[2]
if [1] doesn't work
Check your Res folder for any errors in your XML files, if one of the files has errors, then the R file will not be built

This error was caused by a bug on the Eclipse where even, if you click on re-build it does not regenerate the resource file.
To fix this, even if your eclipse claim that it is the latest version, you should go on the homepage and manually reinstall the latest eclipse with ADK or just install the android studio

Related

Can't get Atom editor ide-java package to work on new Mac installation

I have recently been using the Atom editor with its ide-java package to do some Java development. It has worked well enough for me and I'd like to continue to use it.
I have just refreshed my Mac from scratch after having some repairs done on it that required erasing the disk. Since installing on this refreshed Mac, I am getting red error highlights on pretty much every line of code, including the first line of files which start with a comment. Most of the errors have a message something like this:
The type java.lang.Object cannot be resolved. It is indirectly referenced from required .class files
A Google search shows this error and some fixes within Eclipse projects, but I am not (directly) using Eclipse and I've had a hard time figuring out how to fix the problem in ide-java.
I've tried deleting the .project file and the .settings folder and allowed them to be auto-regenerated. I've tried uninstalling and re-installing the ide-java package. I've tried setting the package's Java Home to both a Java 8 and a Java 10 home folder. None of these have made a difference.
Can anyone offer any advice on how to troubleshoot and make this work as it has for me in the past?
To fix this - you can try to reset atom settings.
For linux:
mv ~/.atom ~/.atom.bak
You will have to install packages again, but this helped me to fix the issue

IntelliJ strange behavior

I've installed 30 day trial of IntelliJ 15.0.2 and cloned my project using git (I've created this project in community version). Project compiles (maven), runs, works. But new IntelliJ does not underline my errors, misspellings etc. When I wanted to commit, IntelliJ shows big number of errors, mostly on imports, as it can't resolve them. All dependencies are inside pom.xml. Once again, there were no errors in community version of IntelliJ. Ultimate version builds project just fine, but doesn't underline any errors and shows almost every import as unsolvable. What could go wrong? How to fix it?
Go to Build -> Make Project. After that errors should be visible in the project tree and in the specific project files.
You may need to mark the source dir, by right-clicking it on the project tab and select mark directory as -> source root
Check that you have a correct project sdk set in modules configuration. If IJ doesn't found any classes, jdk classes included, probably there is no sdk set.
You can also try to invalidate caches (in File menu) and rebuild project
I have faced with strange behaviour of Intelij Idea after update (syntax highlight stopped working). If you want to understand what is going on with yor Idea and can not quickly find an answer in internet, just go to Log files (for Mac OS the path is
~/Library/Logs/IntelliJIdea< your version>
List all files in that directory
ls -la
in terminal and find the latest one. Usually it should be idea.log (without numbers, logs with numbers identify logs for previous days). View that log. If that log contains a lot of ERRORS, try to find the reason (you can just type
grep "ERROR" idea.log
in terminal to find all lines that contain errors). Usually log files shouldn't contain errors, just info and warnings.
In my case syntax highlight stopped working. The log looked like
You can see here that error is in plugins that called like haxe.
I found that plugin in my idea, uninstalled it and idea started working properly. I investigated the log after and what I have seen there:
You can see just INFO in new rows.
Investigating a log can be really useful if you can not find the rootcase of your problem quickly in the internet. I hope it can help you even if it can be quite tricky.
Good luck!

Sudden weird errors on a project

Today I came to work, happy. But when I opened my Eclipse, I saw that one of my projects has errors.It's weird because it shows that it has errors only in the window bar, and not in the Navigator. I don't have any Java errors, this is a valid project that was fine all the time:
Some of the errors on the error log of Eclipse:
JavaBuilder handling ImageBuilderInternalException while building: SP_Procedure
Cannot connect to VM
File <SomeFile> has been skipped, problem while reading ('Resource is out of sync with the file system')
Unhandled event loop exception
Internal error
When I run an application from this project, I get a warning message but when I proceed, it works fine, but still. It's very disturbing and I'm not sure if it's harmless.
I tried to:
Restart Eclipse
Restart my machine
Clean projects and recompiling them.
Refresh projects
Pray
Nothing helped. What could be the problem? (I'm using Indigo Service Release 2)
The following nuclear option has desperation written all over it. But I have been where the OP has been with the Juno version of Eclipse.
Run a "Synchronize with Repository" and save all of your local updates to a different directory.
Delete the project. (Check the box to delete the contents on disk. Scary step, but that's OK, because you saved it in a different directory in the previous step, right?)
Read in a fresh project from the repository. It builds happily at this point.
Integrate your local updates.
Keep on praying.
Looks that one unused JAR was deleted, but for some reason, I didn't get errors in any file, even in the files that imports this JAR! So what I did was restoring this JAR, delete unused imports and deleted the JAR again.
I've found this error after two days of navigating on this project on each file.. This is weird that Eclipse didn't recognize that1 this is an error, and throw many unrelated errors such as:
Cannot connect to VM
File has been skipped, problem while reading ('Resource is out of sync with the file system')
Unhandled event loop exception
Is this a bug in Eclipse? (All errors and warnings are enabled!)
1 As seen in the image in the question..
A class from the list of imports for the file seems to have moved out or the jar file containing the class is missing.
Expand the imports section and check if you find some classes that are missing but have been imported.
Though it is a pain, sometimes the easiest solution is to back up all your projects (either in a repository or somewhere else on your computer) then uninstall and reinstall eclipse. No it's not fun, but it should reset eclipse so everything works again. The downfall though is that you have to reconfigure eclipse to any special settings you had/reinatall any extra functionality currently installed (eg. android add-on) and reconnect to any repositories you have. While punting isn't fun, it can be effective... I hope you don't have to resort to this though.
I have went through that problem a lot of times, and tried everything you tried. Rebuild, recompile, refresh, remove and add JDK, remove and reinstall Eclipse... nothing worked
The only thing I concluded is that the workspace metadata was corrupted.
What I did (every time it happened) was
Create an empty workspace
Import -> existing projects into worskpace
Mark the "copy projects" (else it will only link them)
Wait for the copy, and start working with the new workspace
If you work with SCM systems (Git, SVN, etc), making a full checkout will do the trick too, but the worskpace import will let you retrieve those changes you didn't get to commit (if any).
It's a little painful if you have somethings already set (like JDK names, servers, etc), but then I realized it was faster than keep searching how to fix the workspace
Regards!
PS : I've been working with Kepler lately, and everything works fine till now
Click Window -> Show View -> Other -> General -> Problems
This view will show you what is wrong.
Did you, by any chance, update your virtual machine outside of Eclipse? I can't help but feel that we're both missing a finer detail here. I just keep seeing "cannot connect to VM" and thinking that it's a major clue.
Have you tried running anything from the terminal? Does it work there?
If so, do you know where your current edition of Java is located? Is Eclipse looking somewhere else?
Is this exclusive to one project? Do you use any additional libraries to the JDK?
Maybe try this for Resource is out of sync with the file system error:
Right click project in Eclipse Package Explorer
Close Project.
Right click project in Eclipse Package Explorer
Open Project.
Other things not mentioned:
project properties > java build path, see if any of those tabs got changed, local file got moved? read/write permissions on some file you are linking to?
project properties > java compiler, see if workplace settings have changed? maybe under errors/warnings, you can systematically set them to 'ignore' until the error goes away to determine what type of error it is?
maybe update some of the eclipse plugins?
I saw something like this happening for a number of reasons. Mainly because of validation in files other Java source code. See if you are validating XML for instance.
Right click your project and chose Properties (Alt+Enter) and Validation to see the related configuration.
As for the danger, I lived with those marks for ages and nothing wrong ever happened.

Java/Eclipse - No more R file ever

I'm on Eclipse for hours now and I didn't found a solution yet for my problem even after many searches on internet: I have no more R.java file on my projects.
On just created or on my old projects, i don't have R file anymore and I tried so many solutions (uninstall, re-install Eclipse, clean my project, check all my XMLs, fix problem with android tool and so on ...)
Please someone can tell me what to do in this case?
Hey If you just updated to ADT Rev 22 :
I had the problem too. There is a new component in the Tools folder called "Android SDK Build-tools" that needs to be installed.
Step 1
Open the Android SDK Manager
Step 2
Select the newly added Build Tools and install. (If problem stays then go to Project Properties => Java Build Path => Order and Export and check Android Private Libraries, then clean and build project.
It may be necessary to repeat the process, restart the SDK Manager after the update and make sure it looks like this (all tools installed):
More info:https://groups.google.com/forum/?fromgroups=#!topic/android-developers/rCaeT3qckoE%5B1-25-false%5D
Perhaps in Project Properties -> Java Build Path -> Libraries you don't have:
Android 4.2.2 (or other version)
Android Dependencies ?
If so, then right click project - > Android tools -> fix android properties
and see if this library showed up.
Thank you all for saving me! I've spent the whole afternoon on search this error.
Finally, my project works.
By the way, I also encountered one problem which i wanna share with you:
After upgrading, even if my project has not errors anymore. During runtime, it seems it couldn't find the classes from the jars placed in \libs.
Go into Project=>properties => Java build path= > Order and Export.
Please make sure all your jars are checked.
If this problem occurs suddenly in a well working project,
the first step is to find whether the problem occurs only in the current project or in all other projects.
if all other projects in the current workspace are working then 90% problem is with XML / mainfestfile/resourse file that you edited recently.
This error is not shown as red mark we have to find out what we have done recently in these files.
try this
sudo apt-get install lib32stdc++6 lib32z1 lib32z1-dev
it solved my problem
Close your eclipse and after refreshing system, try to open Eclipse again. I think you are using Emulator along with the eclipse. It may be because of the low Memory problem (RAM) of your system. I used to face the same problem when I use Emulator
whenever there is any mistakes in any of the xmls the R goes missing when a build or clean happens so check for any xml errors in your project unless you fix it you cant get back your R on clean or build. fix the xml files and perform a clean you will have the R generated. Also check in File->properties->Builders and see if everything is checked
I was using Eclipse Indigo and nothing I tried worked. I ended up downloading Juno SR2, reinstalling the ADT, and now everything works again.
Reinstall everything and it'll work.. i.e. go back to Google SDK or w.e. you're using and download it.
Update it to latest in SDK Manager.
Go into Eclipse-Project-Prefs-Java build path-order/export TICK EVERYTHING.
problem: No R file get generated.
guess: Try cleaning project if it is old one. Else create new project with no R get generated and with no compile errors but this: no project.apk
In this case you have to check your SDK for the built-tools. May not be installed after updating SDK.
Thus download them if not download here, then put them under directory: SDK/built-tools folder. Lastly, and most important, is to Run the SDK As Administrator. This guarantees refreshing SDK with all packages appearing in it.
Install the SDK-Built-Tools or any missing packages according to the above link and you're done.
hope this helps.
Try one thing, create a new Android Project and transfer all those files which are in the previous project. That worked for me.
In my case there is error due to "&" inside strings.xml file(but error not shown) for declaring string for a array type. Now the problem has been solved as I changed "&" to "and".
So, please make sure that you do not have such silly use of symbols, and clean the project.
I have had the same kind of problem, however Rechecking all XML files in the Resources folder was helpful in my case. I found syntax error in my XML files. Cleaning and building the project again can be helpful sometimes too.
I had the dreaded not more R.java.
Some of the things I've used in the past:
Clean / rebuild (the first thing we all try)
Restart eclipse (optionally reboot pc/mac)
Update both SDK/ADT eclipse plugin to latest version
Create new eclipse workspace and import project
Enable Verbose AAPT build output Eclipse menu>Preferences>Android>Build
Port project to Android Studio / Gradle (this helped my actually see the AAPT error i was getting Error Code:138)
Delete recent XML changes - Ultimately I found deleting recent menu.xml files I'd added and commenting out where they were referenced fixed the issue and I finally got R.java.
I got the error recently and had found no fault in any layout or value file. After a lot of tries I add another Activity and the R.java was build and the error disappeared. I don't know why this occur, but it takes me hours.

Eclipse doesn't import java libraries on cold start, plus other compiling errors

Eclipse is giving me a few problems.
After a cold start and the loading of android libs, Eclipse underline the import statements or says that java.lang.Object couldn't be found.
Closing it and reopening often fix the problem. If it doesn't, another close-open fix it definitely. But it shows at each cold-start.
It also gives
"The type java.lang.Enum cannot be resolved. It is indirectly referenced from required .class files"
"The project cannot be build until build path errors are resolved"
But if i restart the build path errors and the enum problem are not show any more(sometimes the enum proble got fixed some time after eclipse's loading finished)
"Project 'xxx' is missing required source folder: 'gen' "
that should be generated automatically generated while building, and still restarting will fix them
In addition, in many projects, while building or cleaning, eclipse says that it couldn't delete the bin/. directory. I noticed that that directory is read-only, and if i try to remove the attribute(even from dos), it immediately return to read-only.
This problems aren't show-stoppers, i still can code and i still can get my apps exported, but it is quite annoying to have to restart eclipse a few times before being able to use it(and eclipse isn't that fast at opening), and i would really know how to fix it.
I searched in the net a bit, but i dind't found nothing useful or that worked.
Is there a way to fix them?
I didn't "unistalled"(it is just stored in a directory) Eclipse, since i should then reinstall android sdk, mercurial plugin, and re download and set up a few libraries i use in quite all my project, and i really hope there is another way.
final notes:
everything works when this problems doesn't show: the app works, logcat too, the right device is used to install the app, so i think java and android sdks are installed just right
I had that problem before so I just saved my projects to a different file and uninstalled everything ( java, android sdk, eclipse ). When I reinstalled it all I put the android sdk on the root of my c drive as I have a windows machine and then instead of picking where java was installed I let it do its own thing. I dont use a mercurial plug in but your "read only" problem could be related to that. Its possible your downloading files that are "read only" and there for you have no way to alter them. Im guessing since you said youve been programing you already know how to set the build paths and stuff. It might just be where everything is installed or something silly like privilege settings on your machine.
What were you using the mercurial plug in for anyway? just curious :)
Have you included the java lib in your project or? For a couple of weeks ago I sat with an project where i absolutly needed some of the methods, so because android just have some of the java lib I imported the need libs and used that.

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