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R cannot be resolved - Android error

I am having a issue which I have had before and I don't understand the cause. My project and code is fine as it was running yesterday. I have open Eclipse today and the whole project looks like it contains errors.

I believe it is some sort of build path issue. I don't understand why it randomly occurs? But in the code where there is R.Layout.LayoutName there is an issue... can anyone help?

I have tried cleaning and building it, I have tried importing android.R but I didn't have this before, it then gives and error and says the layout file doesn't exist.

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  • I have got two projects in eclipse, one is running fine and the other one isnt? Commented Feb 8, 2011 at 11:09
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    Kindly check the following link stackoverflow.com/questions/885009/… Commented Feb 8, 2011 at 11:14
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    this happens to me whenever I clean my project, it can stop me for days. there seems to be a dozens of different answers to this question involving changing settings deep in the project, which usually don't work and can cause other issues as well. Commented Sep 24, 2013 at 14:30

8 Answers 8

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I think I found another solution to this question.

Go to Project > Properties > Java Build Path > tab [Order and Export] > Tick Android Version Checkbox enter image description here Then if your workspace does not build automatically…

Properties again > Build Project enter image description here

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11 Comments

This guy needs some votes. After half an hour of going through StackOverflow, this is the answer that worked for me and will probably work for many other people. Eclipse probably unchecks these automatically.
Totally agree with @AndrewLatham
Seriousy, this answer should be the accepted one. Either that, or make this a community wiki.
Wow, this also worked for me. Eclipse and adt seem to conspire often to make the most subtle and absurd of errors. I don't know how reason alone could solve this one - thanks for your tip!
I agree with @AntonI.Sipos. I have no idea why this a) happens or b) fixes the issue but it does. Ensure you tick the target SDK verion AND the Android Dependencies. Previously I have removed and reimported the source into the workspace to fix the issue. It seems a 'clean' will trigger it.
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Are you targeting the android.R or the one in your own project?

Are you sure your own R.java file is generated? Mistakes in your xml views could cause the R.java not to be generated. Go through your view files and make sure all the xml is right!

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12 Comments

How do i check if the r.java class is being created?
hmmm that is curious. Anyway, when I had such a problem once, I later realized my problem was in the xml files. Not necessarily a syntactic error which eclipse would detect, but a semantic one. Well, YMMV.
I'm not sure why this is the selected answer - since it does not give a solution.
@EasyCoder Mistakes in your files can prevent R.java from being generated. In that case, R will not resolve because it does not exist.
normally your answer is right. if something wrong with xml, R is not generated. but in this case, the problem is yesterday was working, but today not working with all projects. all projects make error is not kinda xml problem i think
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I've fixed the problem in my case very easy:
go to Build- Path->Configure Build Path->Order and Export and ensure that <project name>/gen folder is above <project name>/src
After fixing the order the error disappears.

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6 Comments

This worked for me. I have no idea how it ever would've changed, i've been working on the same project for 2 years and all the sudden this issue appeared. Ugh, eclipse and Android are so frustrating sometimes!
This was the case for me, but it did not end up fixing the problem.
Same here, I swapped them and same error.
The order was messed up for me. But, your answer also did not work for me. Do you know the reason why it causes an error ?
Swapped them, but no change.
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check your R directory ...sometimes if a file name is not all lower case and has special characters you can get this error. Im using eclipse and it only accepts file names a-z0-9_.

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4 Comments

I had just created a new xml file and I had used an uppercase letter. Woops!
I had a double extension for a file (e.g. image.png.old). 10x!
This worked for me. Voted up.
Yep, I had an image with uppercase (ButtonTouch.png). Gotta rename all those images I'm copying over from the iOS version. :-)
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You want Clean Project Like this

click on

Projects>Clean>select your project

this will help to u

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1 Comment

Clean step helped identify xml issues
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Agree it is probably due to a problem in resources that is preventing build of R.Java in gen. In my case a cut n paste had given a duplicate app name in string. Sort the fault, delete gen directory and clean.

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1 Comment

Delete the gen [Generated Java files]>Clean the project>Rebuild worked for me
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Fought the same problem for about an hour. I finally realized that I was referencing some image files in an xml file that I did not yet have in my R.drawable folder. As soon as I copied the files into the folder, the problem went away. You need to make sure you have all the necessary files present.

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This worked for me. It's unobvious from the long list of errors that some of them are actually causing all the others.
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Save all layouts, and replace them from the previous version. Start to copy one by one and clean the project everytime, sometimes one of the layouts has something, that eclipse doesn't like. It worked for me.

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