Ok,
I am working on a new app and everything worked fine as long as I used a Relative View. However, I want a tabbed layout so I switched what I had (not much so far since I just got it reading from a DB and settings working) over to a tabbed view. Since that time, any class that has any R. statement in it has an "R cannot be resolved" error. I am following the tutorial from the Android "Hello Views" tutorial so I am assuming that isn't the issue (but it could still be).
I have a few suggestions:
Make sure you don't have any other errors other than the R-related errors. Right-click your project folder in Eclipse, Android Tools -> Fix Project Properties.
Check to make sure you have the correct R imported. Sometimes the default Android.R can be imported.
Check for errors in your layout XML files.
You can try to "clean" your project.
The default tech solution helps sometimes: restart Eclipse (seriously)
If you have an error (something in your XML maybe, or something else), R cannot be compiled. If this is the case, try to find the first error noted. If you fix this, R will be compiled and found. If necesairy, use point 1. and 2. after fixing stuff.
Remove all "import R" stuff in the import sections. You don't want that.
If you're using Eclipse, trying giving it a kick by doing a Project/Clean and re-building your project. It sometimes has random trouble with the classpath on Android projects.
Along with the great suggestions in the previous answers, make sure your Android target is set:
Right-click on your project
Choose Properties
Choose Android in the left menu
Tick a box next to the appropriate Project Build Target.
Click Apply and OK
Edit: A year later I found another cause. I had a .jpg image in my drawable folder with the same name as a .png image. Referencing this image in my code must have confused the program and it gave the "R cannot be resolved" error.
If anything in your 'res' directory is named using illegal characters, this can happen.
Note that android only allows lower case letters (no capitals!!!), numerals, and the underscore. THAT'S ALL!
Almost every operating system allows other characters, so moving a file into your 'res' directory can easily create this problem.
Fix? Rename the file. This is done by right-clicking the file in your package or project explorer and selecting Refactor->Rename. You may need to clean your project after, but beware of the dreaded "import android.R" that may creep in.
Good luck!
-scott
Check that all of the strings you think you're using (e.g. "#string/Hello_world") actually exist in your strings.xml file. I got the OP's error after declaring a menu item using android:title="#string/Navigation", but I hadn't added <string name="Navigation">Navigation</string> to strings.xml
I had the sample problem too and this worked for me.
1.) Check for any errors in your Layout XML. Especially when it comes to text and titles
You should use
android:text="#string/hello"
instead of
android:text="hello"
.2) Clean your project
.3) Restart Eclipse
You should import your own projects R class rather than androids default R class ie.
your.app.package.R
This will make the values defined under the res folder in your class . After that refresh and then clean your project .
In my case it was caused since I refactored my project and moved some classes inside a folder structure. Those classes couldnt find the R as usual, since its based on the root source folder.
You need to make sure you import R. If your main package is com.example try importing "com.example.R" at the top of your files. For some reason eclipse does not do this for you.
Related
I am running windows 7 and eclipse and keep getting this error. My XML seems to be fine and have downloaded all the Sdk build tools. What could be the problem?
Try to clean and re build the project.
The most all the time, the problems with R.java is caused by an error in your xml files, if you are sure that your xml are ok, and if you are working with Eclipse.
Follow the next instructions,
Go to Project menu -> Select Clean and verify that "Build automatically" is checked, and is ready.
If the problem don't disappear check if all your xml are correct.
Go to Project > Clean. If it doesn't work, check all your drawable files:Does any has a capital letter? space? underscore?
or dashes?
All the files name should all be in small, no space & no numbers.
In Eclipse view the problems view (window->show view->problems), it is almost always the fact that a file in your res/ folder has not actually been accepted by adt (an xml error or a file naming error usually, keep it lowercase), the red X indicates which one too..it will help you find the bad line or file. Once that is fixed R exists because it can now compile, and the import will work because that class now exists, good luck.
I added one xml file in layout. After that this error is coming. But the problem is I haven't touched R.java file.
Now in my new activity i m going to set its content view as my newly created xml file, but when i m doing R.layout., the newly created xml is not coming in suggestion. Do anybody have any idea how to correct this.
I have cleaned my project several times but it is not working.
Delete R.java and let eclipse regenerate it, then project --> clean will fix it.
Check if you have any existing errors in your code, if yes correct it and then try refreshing and building your Project.If your Project is properly build,you will get the new xml file in suggestion
It happened to one of my Eclipse projects today. This is what fixed it mysteriously. Don't know why or how.
Changed Properties->Android->Project Build Target to a higher (different) version of Android and hit the Apply button. Then did a clean build. The problem went away.
After the above steps, I could even go back to the original Project Build Target without the problem re-appearing.
May this Help you...
I think your xml file name might be having some capital letters or some special characters..
Delete them and then try again to run the project..
Try cleaning the project this will do the work.
make sure your not importing any thing that ends with com.R
make sure your naming convention of the layout is correct
R.java file have all the resources IDs provided to resources(drawables, layouts, styles etc) either by Programmer, or generated through sdk. So check your xml files as well as your drawable folders. If any of them including wrong format it will show an error in R.java file like sometime R.java is not generating or our class file shows R.id.xxx is not found or R.class is not defined error.Then clean your project.
There must be some mistake in one of your xml files. Eclipse does not always show error messages if there is something wrong with your xml. Mostly code gets errors, in this case 'R', so you will need to go through your xml manually, it could just be a simple mistake. Good luck
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.
Right Click on Project->Bulid Path->Configure Build Path
ther you see error android-support-v4.jar remove this library and add library again this works fine for me.
Else
Try
Go to gen Folder delete R.java and from Project option choose Clean Project.
Very late on the scene...
I had this line mysteriously appear at the start of my imports:
import android.R;
I deleted it and shazam error was gone.
I had similar error, but when I import new project to my eclipse. and the solution was, I should check the option (copy project to work space) specially when our project has library.
I recently downloaded the Android Support Package and have been using it trying to get my application, running at SDK 10, to use a GridLayout.
Anyway, I cleaned my project a few times working on this error in my XML files, and then when I went back to my classes in /src, every single reference to R.* was an error.
This has happened to me before, but it usually fixes itself, and it has not yet. Does anyone know what to do?
The R.java file is no longer in my /gen folder.
It sometimes happens when you import another project First i suggest you to build it, it will create automatically .
If it's not working then try to create new project from existing source and specify the downloaded project . It worked for me
Hope this works for you let me know..
Sometimes if there is an error in your XML files R.java won't build. Go through your XML files to make sure that everything is in order (typo, forgetting to close a bracket, etc). When you fix that it should build itself again.
You can also try Adnroid Tools>Fix Project. That may help you to create gen/R.java file
Follow following steps :
In Eclipse,
=> Right Click on Project > Android Tools > Fix Project
By this way, you can fix many common problems which can help generate R.java in gen/R.java file.
There can be several reasons why this occurs. The following I have found happen to me and I have included the steps I took to resolve them.
First step is to try and clean the project (from the Project menu option I believe)
Check there are no errors with your XML files. Sometimes this is obvious from the red 'x' that appears next to an XML filename in the Project exlporer window and sometimes it is not. If it is not obvious check the 'Errors' window (whic is founf in the 'Windows' Menu option
Failing that I have found that by disabling the automatic build option, adding some arbitrary comment to an arbitrary source file, saving the source file, clean the project, remove the comment and then re-selcting automatic build can work too.
Apologies for the approximate locations for some of the Eclipse functions but I am not currently in front of Eclipse to check.
This happens when you have an error in the res folder.
Fix the error first, then do :
Project --> Clean --> Ok
Et voila !
After I added some .png files into my Project Workspace drawable folder I refreshed my drawable folders in Eclipse and the newly added files showed up. But when I tried to access those resources using R.drawable.xyzimage, xyzimage although in the folder could not be resolved.
So I did a Project Clean and guess what after this clean R.java is totally gone and all my classes accessing resources using R.java is showing all sorts of error and Eclipse won't let me run the code anymore.
I have backup of my source code but I want to explore if R.java can be regenerated and how?
Thanks for all the help.
Try Project->Clean in Eclipse. In my limited experience if R.java is not being automatically created then there is an error somewhere in your xml. Triple check everything.
You have to build the project to be able to use the newly added resources.
Cleaning a project removes all auto-generated files. Building the project it should automatically create them. When you Clean a project, there's an option to start a build immediately after clean up.
Here's a few things you can try (did the same procedure after manually deleting the "gen" directory.
After you have deleted the gen directory, go to Project > Clean ...
You should have errors indicating that R cannot be resolved to a variable. Right click on your project from the Package Explorer and select Build Project. Be sure Build Automatically option is turned off (uncheck in Project > Build Automatically).
Errors regarding R should have now disappeared. Now, perform a Project Clean once again. All errors should be gone.
Let me know if this works for you.
Here is what the problem was. I added those new png images to the project and android has rules as to what characters are allowed in the names of these images. Once I changed the uppercase letters in the image name, it was back on track again and Build Automatically generated the R.java file and all errors were gone. Eclipse console is the place where I found all the errors related to my resources.
Thanks Guys....I tried your solutions but my error was something specific which was due to my image naming convention so this is the way I fixed it.
I would agree this is usually a XML problem but moreover that it is something within your res folder that is the problem and may be highlighted with a red cross after the clean attempt.
I have just had this problem and it was because I had created my own folder called 'data' within res folder. After the clean it had a little red cross against it. I removed this folder and R built again.
Regards,
Mark
Several things you should check in your project:
Check the Problems tab in your Eclipse IDE. Are you sure that you did not introduced building problems while making changes with drawables? To check that you need to check xml source of affected layout and see if something is marked red.
In File explorer go to the directory where your Android project is. Check that you have file default.properties (.classpath, .project and AndroidManifest.xml should be there). If default.properties is missing it may be easily replaced by correct version.
Which is the Android version you are working with? If that is 1.5 or lower be sure that in the res directory you have directory named drawable, not drawable-hdpi, drawable-mdpi and drawable-ldpi. Last three are valid for version 1.6 and higher.
Right click on your project in Package explorer in Eclipse. You will get a number of options. Go to Android Tools-> Fix Project Properties so see if that helps.
I had an invalid jpg in my res/drawable folder. I removed the jpg and it worked.
I had this problem on my Mac too and I think it could be good to know for all Mac users how I managed to solve this error.
I had a .DSStore file automatically imported to my project inside the res directory and when I removed it and rebuilt the project all went well.
Everytime you clean the project and it rebuilds, it imports
import.android.R
so, delete this import and remove all errors from xml files. It will work.
This happens to me if I move my project to a new location. I have found that the answers above didn't fix my problem, but that creating a new project and importing the source did.
This may be simple but check to make sure you don't use
import android.R;
If you add an external resource file with capital letters for example
"Hello.png or WelcomeSound.mp3 etc etc" like if you add upper case letters and clean your project you'd surely loose your R.java file. So if you already lost it, either rename the file externally and then clean your project or else right click on the project Refractor->Rename and then rename your file with all letters in lower casing. Next, delete the 'gen' folder in the project explorer and now right click and "Build Project". If Build Project option is grayed out, go to Project-> Deselect "Build Automatically" option.
Regards,
Kshitij Thube
Check at the Console View If there in message Error, It will Help you to find out the source of the probleme.
I had i similar probleme and i find out that the probleme was from the pic name even if the name respect the Syntax so I change it to img1 and it worked fine.
Try editing one line of code in your project, then build the project once more.
Another thing: never try to run an application with the texteditor opened with a xml file. That will create a wierd run configuration that can only be fixed by project clean-up and sometimes can make the xml file to vanish (happened to me twice already).
All my R.* files stopped working after I did a Project->clean in Eclipse. The issue was that I backed up a XML file attached to one of my activities in the layout directory. This causes errors in every activity of my project.
After deleting the file I still had R errors in one of my Activities and it only was resolved after I tried importing different files and then deleting them. I actually made no change to the previous imports but for some reason deleting them all and re-pasting them fixed it.
I have got the same problem after lots of cleaning and building project again and again. I found that on console there is this error:
res/drawable-hdpi/Blue Blank.png: Invalid file name: must contain only [a-z0-9_.]
and this is not appearing as an error in xml. I changed the name and save the file, clean project and build. Now it's working. My suggestion check your res folder and name of files you use in it and name only [a-z0-9_.].
Delete related tag in xml, save xml, clean project, build project. Now again put that resource in xml and save!
Check your file in drawable folder ensure that all are resource file (image) remove unwanted file Like thumb.db. Remove those all files and check again
Make sure your png files have lowercase names. That is what kept throwing mine out, because I capitalized the first letter, or I used an unallowed non alpha numeric in the naming. Check that before destroying any of your code.
just check your image folder (usually created res > drawable files) and be sure dont use capital letters on .png files, every type must be in small letters then you can find again your R.java under the gen file folder
i removed 'import android.R;' then commented out the offending lines, then did a build, ok
then i removed the comment and it fixed it
I had the same problem when I cleaned my project. I got crazy to solve it, I searched and searched but solved it in my way.
First of all, delete all needless files in your /res folder. I had some notes in it, I took them to another project that I don't work on it and build the project manually. It worked! Try this I'm sure it will help.
Good developing!
Was there an XML file with the naming convention of "somthing.out.xml" generated? If so you should delete this file (an unwanted file of this name can cause major problems for your somthing.somthing.R file import).
In some versions of eclipse (I know eclipse javaEE does this for sure), running the project while viewing an XML file will create a file called filename.out.xml in your res->layout folder. You must delete this generated file if this has occurred otherwise you wont be able to get the java.R file to import.
Try Project -> check Build Automatically
If you are using 64-bit Ubuntu, try to install the 32-bit libraries (ia32-libs)
$ sudo apt-get install ia32-libs
it worked for me
This exact same thing happened to me. coincidentally I needed to update my adk that day, so i did so and after restarting eclipse it worked again. My recommendation would be to build the project and restart eclipse. It is not due to any error in your code.
I read and tried many of the above after simply doing a clean on one project. Eclipse would not build anything afterwards.
Fortunately I had last-nights backup of the workspace and my source is copied in from VS 2010.
No more cleaning!
Delete your project from workspace witout source deleting and then import it into workspace.
RightClick on your Project -> Delete /Don't select "Delete project content on disk (cannot be undone)"/ -> Ok
File -> Import -> General -> Existing Projects into Workspace -> Brouse -> /Look for your workspace(!) folder/ -> Ok -> /your cleaned project will be automatically checked/ -> Finish
I had the dreaded missing R problem yesterday with Eclipse Juno after a routine clean. StackExchange is full of suggestions and extensive googling revealed only the usual suspects (XML naming conventions problems, etc) none of which seemed to apply directly, although it is certainly possible I missed something.
The best summary comprehensive list of possible causes and fixes was here:
http://www.techrepublic.com/blog/software-engineer/a-comprehensive-troubleshooting-guide-for-androids-r-cannot-be-resolved-error/
One useful tip there was to try to create and run a simple "Hello World" in my workspace. If that does not run, the setup is corrupted. My Hello World was just as full of errors as my custom app.
The solution that worked for me (perhaps great overkill but nothing else worked) was to completely uninstall Android SDK and delete Eclipse (Juno), download Eclipse for Developers (Kepler) and reinstall Android ADT plugin and ADK and recreated my AVDs using the latest "compile with" version in options.
So far so good, although I am recreating the app from scratch. I will be more cautious about using clean from here on.
I have same problem occur just now I renamed invalid png file like *demo.1.png as demo.png * and its work.
Proven successful method, check the file (AndroidManifest.xml) and delete all comments in it, and make sure there are no errors in this file, I tried and did work with me.
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.