Android R Cannot be resolved issue - android

I have just been working on my android project in eclipse and all of a sudden this error appeared, my manifest file matches the name of my application etc.............!
What I have noticed is that that the auto generated Java files are missing from the gen folder its completely empty now.
orginally I had to create a default.properties file as there wasn't one present and it was working fine uptil the point i tried to add a button into one of my xml files. Tried to clean project too and that hasn't resolved the issue either.
Any ideas?

This error is usually caused because you have an error in one of your resources. Check to make sure that there are no errors in the xml resource files or the drawable directories. In the list of errors you are seeing you should look at the top most error and see if you can resolve this. What tends to happen is that an error in one of your resource files is causing the generation of the R file to fail. Once the R file fails to generate you will see a huge list of errors but they are all caused by the one error.

Remove the gen folder from Project Name ->Properties -> Java Build Path ->Source. You will get an error message after removing it. Now Add the gen folder again in the same way. You can now see the R class. If the problem remain, then try to remove both src and gen; add them again.

use "Project" -> "Clean" in Eclipse to re-generate your R file and fix other android issues.
...sometimes this helps a lot! ;D

Related

R.Java error - Android Developer Studio -Eclipse-

I have a nasty problem with R.Java in Eclipse, when trying to add new images to a newly created folder on my Res (drawable). what could be the problem ? Nothing happens after cleaning the project...
Maybe you are using non-compliant names for your resources (like file with uppercase letters).
Please read the Android naming conventions.
Make sure the image you copy have all letters in the filename as smallcase . This could be one issue. File name: must contain only [a-z0-9_.]
I had faced many times same problem.
try the below steps. it could help you.
In Eclipse
1. Enable Problems view by clicking,
Windows->ShowView->Problems
check the problem and solve.
2. Remove R.java from gen folder of your eclipse try to build it again.
3. Check for Import R in your project. sometime eclipse imports android.R instead of yourclassname.R
4. Check for your XML file where sometimes id will not generate if you add it manually in xml file.
5. Reopen the project.
Hope it helps.

Debug configurations R error in eclipse?

In the (Debug Configurations) menu in Eclipse,after I click on (Debug),it shows me an error: (R cannot be resolved to a variable).Am still new to Eclipse and this error confused me a little bit!
R.java is an automatically generated file which contains references to everything you have in your project. The fact it is not resolved may be caused by many reasons.
Check whether the gen folder and and R.java file exist. In case not, do the following:
Clean your project by selecting Project - Clean
if the R.java is not created, there can be an error in some XML file, check the console output
In your code, hover your mouse cursor over your R which should be highlighted red and check if Eclipse offers to import it (in case it does, select the R from your project and not from android package)
Let me know if it solved the problem
You can also fix it by creating new project and pasting all xml and java codes inside new project. It will recreate R.java so problem will solve by this way.

R.java file missing from gen folder in eclipse

My PC went to sleep while battery was low. But when it recovered I found R.java file missing from my gen folder. My entire application is under crash.
The error is shown below:
If you recently added a new resource file and happen to use upper case letters in the file name, change the file name to lowercases and rebuild your project. That is what happened to my project.
The R.java file should be regenerated every time you do a rebuild of your project.
Clean the project,
Go through your code and remove all references to android.R.*
So when your R.java is corrupt or missing Eclipse tries to be helpful and thinks that the references in your code for R.something are missing the import file and inserts the android.R.* to your import list.
If you are using IntelliJ it has a rebuild R.java command.
If it is still missing then it means that something in your code is preventing it from being built. Pay attention to resource file names etc. Usually you can sport these naming problems in console view of eclipse
There are possible chances, you have a problem in your layout xml or in your code.
Try looking at file that you had open in your eclipse when it went to sleep, and code snippet that you were working at.
Edit:
R (resource file) regenrates at every rebuild of your project. For some error in your project your project wasn't able to build that why your R file is missing. All that you need to do is to fix issue in your files, code and xml files.
I got the same issue. Nearly I spent whole day working on it to figure out the reason and tried all the 100 solutions provided in the blogs. But nothing helped!!! After setting up a new workspace I figured out. Remove unnecessary libraries in your project. You can check this by Project-> right click-> properties-> Android-> and remove unnecessary added libraries. It worked :) Hope it helps some one.

Magic behind R.java file

Recently I have been having quite some problems with R.java file. Now I have decided to do a backup and delete the file to see what happens.
Nothing happened, so I created an empty R.java file and hoped for the best. Now Eclipse seems to figure out that the file was tampered with and even issues a warning:
R.java was modified manually! Reverting to generated version!
And that's all there is. I tried building it manually but got no results.
So, I have two questions:
what should I do to force Eclipse to regenerate the file
what is happening here? How is the file created, where is the code that is generating the file?
I would appreciate any help. As usual the problem occurred just a few days before the deadline :)
I had a problem getting my Android app to compile, with seemingly inexplicable errors about failure to generate R.java.
The problem was caused by my previously killing the Android emulator during the build. Don't do that! A clue was the appearance of several left over *.out.xml files.
The solution was to select the project, click Project->Clean, and then manually delete all the *.out.xml files. Only then could I click Run->Run and have a successful build.
One more thing: I'm using Eclipse. I had to make sure that the project was selected in Package Explorer, and not just some random source file. Easy to not notice!
R.java is autogenerated on build. It's content is based on the resource files (including layouts and preferences).
When you deleted it, it was recreated, but if you create your own, you will get into trouble as the build system will not replace it.
You can simply delete it again (manually or by choosing Project->Clean) and rebuild your program.
I had this problem several times, and most of the times it is caused by some mistake in the "res" files, check everything is OK in all your res files, mainly XML, and after you can built.
For example, two common causes of this problem can be:
Didn't properly spell the name of a property in a Style in a XML file.
Didn't properly close a string in the XML of a locale file.
I found the problem - I have created a 9patch image with the patch area defined only on the Y axis (I was trying to prevent resizing on the other one).
The question remains: Why isn't there a warning about the error? Or if there is - where is it buried?
Sorry, but try to check the output in Eclipse. May be you have some errors that prevents Eclipse to finish build proccess(check your AndroidManifest.xml, is it correct?).I mean, that you should check all your resource files(string.xml, layouts, ...) and interfaces(*.aidl), may be there are some problems(inconsistent syntax, or something....) that prevent eclipse to generate R.java.
I had the same issue and it was that I had named a resource file (a .png image) using uppercase letters. (ImageButton001.png instead of imagebutton001.png).
Afther changing the name of the file my R.java came back.
Rgards,
Juan
If there's insufficient free memory the build tool will silently fail (Eclipse will not show any errors or report anything in the error log). Close your other open applications (e.g. the emulator and browser) then add a space to the application manifest file and save it.
As ponkin stated - you probably have one single problem that causes R not to re-generate itself, because of which you now have one million and one problem.
Do not try to create R class yourself. Try to think of the last XML you've been messing with, and check it for errors
I've had the same problem here
Make sure there are no errors is your Manifest file.
If you delete the resource string app_name in /res/values/strings.xml, it doesn't know how to generate R.java right.
I found this a problem when doing the HelloSpinner tutorial.
I found that an unwanted resource was causing an issue. As soon as I deleted the resource R.java was generated.
I've had this problem, to rebuild R.java I cut the code in the xml file I've just been working on (or try others if this doesn't work), deleting the file then creating another with the same name and pasting the code back into it. Hope this helps.
Something that can be good to know is that if an XML file contains a ?, then R.java is not regenerated and the error is not shown in the XML file (sometimes it shows up after a while)
I you have a line similar to:
< string name="questionmark"\>?< /string> <br>
try to change the ? to something else and see what happens to the R.java file - worked for me
I had a similar problem, I had renamed a .wav file in the Raw folder with a capital letter. When I changed to all lower case, cleaned the project and it rebuilt R.java fine.
As others stated, stay away from creating your own R.java file. I ran into the same problem when I first started with Android, and it took some time to figure out what caused by compilation errors.
What were you trying to do with the R.java file?
I had the same problem. I just went to:
Project -> Properties -> Android
and chose the right Emulator for my project, I had 3 different to choose from in that moment. I realized that i changed the Emulator in some given moment. So try to change the Emulator, that might help!
Good luck
I had the same issue with IntelliJ. The problem was that I had app_name defined twice in strings.xml For some reason, IDEA inspections didn't pick this up automatically.
I read this on another site and it helped me:
"If that doesn't fix your problem, try modifying your AndroidManifest.xml (just add a space and save). I've heard that will force the R.java to rebuild. "
So just add a space in the manifest file and then rebuild!
As a side note, usually those *.out.xml files are generated by trying to build your project whilst an xml file is focused in the editor
I had similar problem.Cleaning project didn't solve the issue and there was no error in the code or the uppercase or spaces in file names.
The solution was going to a popup window which came when you choose PROJECT-->CLEAN and then UNcheck the "Start a build immediately" option. Clean the project. Close and reopen Eclipse and then build the project (PROJECT-->BUILD).
The question remains why simple clean and build without closing Eclipse didn't worked.

Android - How to regenerate R class? [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Developing for Android in Eclipse: R.java not generating
I have imported a project into my Eclipse IDE, but it's giving me an error since R file is not generated automatically.
How can I edit the R file so that it matches my project requirements?
In another stackoverflow question, somebody answered this : you must get rid of warnings and errors (syntax and links) in your xml files. This plus doing a clean / build project.
Project -> Clean, and choose the option to build the project.
I found this happening to me with a broken layout and everything blows up. Relax, it's like that old mistake when you first learned programming where you forget one semicolon and it generates a hundred errors. Many panic, press all the buttons, and makes things worse.
Solution
Make sure that anything the R. links to is not broken. If it's broken, ADK may not regenerate R. Fix all errors in your XML files.
If you somehow hit something and created import android.R in your activity, remove it.
Run Project -> Clean. This will delete and regenerate R and BuildConfig.
Make sure Project -> Build Automatically is ticked.
Wait a few seconds for the errors to disappear.
If it doesn't work, delete everything inside the /gen/ folder
If it still doesn't work, try right-clicking your project -> Android Tools -> Fix Project Properties.
What to do if R doesn't regenerate
This usually happens when you have a broken xml file.
Check errors inside your XML files, mainly within the /res/ folder
Common places are /layout/ and /values/ especially if you've changed one of them recently
Check AndroidManifest.xml, I find that often I change a string, and forget to change the string name from AndroidManifest.xml.
If you can't find the issue. right click /gen/ -> Restore from local history... -> tick R.java -> click Restore. This doesn't solve the problem, but it will clear out the extra errors to make the problem easier to find.
I know there's already a lot of answers here, but this is the first link on Google, so I'm compiling all the advice here and hope it helps someone else new to this :)
Ok, I fixed it:
When I changed manifest to target 1.5 version, million errors appeared and only one wasn't related to inexistance of R class - in manifest file attributes "targetSdkVersion" and "maxSdkVersion" did not exist in sdk 1.5
Because of this R class was not able to generate.
I had a similar problem where the R.java file was not being regenerated after I'd added some icons and layout files. I tried cleaning and rebuilding and things got worse since then the original R.java file was gone and still wasn't regenerated. Eventually it dawned on me that there must be compiler errors for the compiler that generates R.java and we aren't being shown those in the console. Fortunately, I had noticed earlier that
it's an error if one .xml file refers to another which is non-existent and
it's an error to have upper case letters in your file names (why is that forbidden, I LOVE camel case).
Anyways, after renaming my icons and .xml files to all lowercase and then fixing all the references inside the .xml files, voila, R.java was regenerated. Just in time to feel good when I stopped for lunch :-)
To generate the R file again:
Modify something in layout->activity_main.xml
Save the file
Project->Clean...
Just delete the R file located in gen directory, and then try Project->Clean.
Then build your app again.
You can also right click on the project -> Android Tools -> Fix Project Properties. That should cause the R.java class to be re-generated.
I reopen eclipse, edit one of my xml files and then discover that my activy class was refering android.R instead of my package "R" :-)
My problem was in Manifiest file.
I have deleted launcher icons and did not reference the new ones on Manifiest :)
In order to regenerate the R.class, you will have to try multiple techniques.
Remove any R imports from your java source files: import R.android
Make sure to open the "Problems" panel by going to Window->Show view->Problems
If you do have some errors in your xml resources, you will need to correct those errors. In my case I had to change my id attributes to include the "+" sign as follows: android:id="#+id/grp_txt"
Now proceed to do Project->Clean
Finally do Project->Close, Project->Open
The "+" sign indicates a new resource id and the forces the aapt tool to create a new resource integer in the R.java class.
If you use Intellij IDEA you can click Build - Rebuild Project
If you accidently deleted your R in eclipse by "project clean" (don´t do this)
Rightclick on your Projectfile -> Restore from local History...
recreate your R
My Case:
Broken xml caused bug in R. (because of ä, ö, ü, letters in id)
clean project deleted my R.
What I Did:
recreated R from local History
checked for wrong R imports in my classes (like import android.R) and removed them
fixed that xml file and saved its content in an external txt file
deleted the xml completely from my project.
ran my project one time
put that fixed xml back at its place
and...
gave my girlfriend a big hug without a reason after freaking out like a Hulk.
My problem was errors in my XML files. Errors aren't always automatically detected in the Android Common XML Editor or Android Common Manifest Editor, so try using the regular text editor instead. For example, somehow some random gibberish from a .java file had been inserted into my manifest and strings.xml files.
Right click on any XML files (most likely in the /res folder or AndroidManifest.xml) and click "Open With," then select "Text editor." Make sure everything looks good and then save. Also, make sure to enable "Build Automatically" for your project. I had deleted my R.java file and it was rebuilt from scratch, so no need to restore it from local history.
Try to add a new "Android XML file" to, for example, the /res/layout folder. This might cause the plugin to to regenerate the R class.
You can just modify any xml files in /res folder and even just add a space and save, it will be regenerated.
I had the same problem - "R" missing. And none of the advices given here helped. Fortunately, I've found the reason - somehow Eclipse got lost the Project-Properties-target. It was unset. I don't know till now, what had done it, but setting it back helped.
So, attention - missing R can mean the missing target, too!
I have tried all the solutions above. But they unfortunately it did not solve my problem.
My R.java was gone as soon as I pasted a new picture to my drawable folder.
After reading the answers for this question I tried to delete the icon I have previously pasted (while Build Automatically Enabled) and everything was fine afetr. Hope this will help someone!
I had that problem and I just right-clicked on packet of my project and Build Project. Instantly the class R appeared in packet gen.
In case someone else finds this thread when Googling, like I did:
I had what appeared to be the same problem for a while, and after some digging I noticed that the R.java file got correctly built, but was ignored for only one of my source files. The problem for this particular file was that Eclipse had "helpfully" added the following line at the top:
import android.R;
That effectively hides the project R stuff. Just remove it and everything will be fine again...
You can use Eclipse's "Restore from local history" to restore your old R file if it has been deleted. After that you possibly see what keeps Eclipse from building your files (I've seen other errors than before which really helped fixing the problem).
May be you can go to project properties and select Android option and then define the target for the project. Once you apply the selected target API for this project, it will automatically generate R.java.
Mostly a problem with an invalid layout file.
Open the 'Problems' view and look for erros in XML layout files. Fix them and the R class will be recreated.
In my case there wasn't a real error. The problem view showed an error in a xml layout. The editor showed the xml error too. Just reformatting the xml using the auto formatter with 'ctrl-f' 'fixed' the xml 'error' and the R class was recreated.
You can just delete the R.java file from your project and it will regenerate assuming you have build automatically enabled. If you do not have build automatically enabled simply goto project->build all
For me, it was a String value Resource not being defined … after I added it by hand to Strings.xml, the R class was automagically regenerated!
This problem normally happens when importing from an existing project. Try to fix all errors from all .xml files in res folder, as well as Manifest file. Most likely the errors are shown at "match_parent" parameter, change it to "fill_parent". When all errors are clear, R.java will be appeared.
If there is no error on any .xml file. Try edit any xml file (like delete a letter and type it back) and then save the file, this will cause to generate the R.java.
I have a problem that the findViewById(R.id.edit_text) but return a TextView not a EditText. I think the problem is the R.id class has wrong id number, then, i clean the project then its works fine.
In my case it was an improperly named XML file that caused my R file not to rebuild. This did not show up in the package explorer, but it was shown in the LogCat. Look out for any warnings there about your res files. No matter how many times you clean your project, the R file will not rebuild until those errors are taken care of.

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