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Unidentified R.java after blue screen of death

My computer crashed (Got the blue screen of death).
After that I was unable to open my project again, however, it's files were still present.
So I opened a new project and created all the files again and then copied the content inside.
Everything went well except for errors in all of my java files: "R cannot be resolved to a variable".
Additional info:
My Android SDK Build-tools are installed
The new project I created has the same name exactly, except for an aditional char "3" at the end of it [example: test3 instead of test],
and I editted the menifest file properly and also every java file to
contain the propper package name.
My R.java file is present [I'm using Eclipse, Windows7]
Would very appreciate help in solving this.

It is a quite common issue when using Eclipse for Android development but for some reasons, Eclipse isn't exit properly; re-opening the project will see the error logs of R.java ....
I suggest to remove the project from workspace (don't delete local files), copy your project source code to another directory. From Eclipse, File -> Open Existing Android Project, find the project source directory to re-add into workspace. Update the SDK version and dependencies. Usually, it should be fine at this step.
For experienced developers, I guess you know how to check file lock (#ChuongPham mentioned in comment above) and check for wrong resources references in projects manually...

R.java is missing on a clean Android Project

I'm creating a clean project on ADT and I noticed that the gen folder is empty (with no R.java in it), not letting me run the project. I'm running ADT with all stuff up-to-date (as you can see here)
I already cleaned and built it in every possible way. I also tried to reimport the project, and nothing. There are no errors in the XML files.
I searched for a solution and I found a lot of people with the same problem, and in most cases the solution was to update the SDK tools, but it didn't work for me.
Is there a reason for this?

at the top of screen, click build -> rebuild project
Give it a few seconds. it worked for me, i hope it save you aswell
im using Android Studio(beta) 0.8.9
My R disappeared after i fiddled with sound files in my res/raw directory(converted them to different formats, figuring out how SoundPool class works...and suddenly there is red "R"'s everywhere!

Try right clicking on the project, then going to Android Tools > Fix Project Properties.
If that doesn't work, then try cleaning it before and possibly after that.

If R.java disappears, you usually have to recreate the project from scratch again.

There are many reasons for R.java missing issue, i use to face this issue frequently, some of my thoughts to debug this issue.
Try creating another test project using File->New->Project->Android->Android Application Project. After creating the project run the project in emulator. If every thing works then your setup is perfect.
Check your imports section of your java files, some times default R.java gets included which is from android package. In this case Remove that import and add correct import statement.
Check your "res" folder all the xml's should be well formed and valid.
Hope these debugging steps may help to find the root cause.

try deleting the r.java file in gen folder. when you run again after cleaning and building the project. It should recreate those files and it should work after that. Try that.
Other wise you might have to reinstall Eclipse as you have tried in so many different projects

Something I just noticed was that after I removed the auto-generated code for the menus (which I wasn't using) it started causing errors. Eventually when I cleaned with the menu xml's still in the file structure, my R file disappeared. I removed all entries in the menu folder and then cleaned again. This worked for my specific instance. Hope this helps others as well.

Newly Created Android Application Project missing R.java file [duplicate]

This question already has answers here:
Another R.Java file missing [duplicate]
(5 answers)
Closed 9 years ago.
I opened an android application project called Test Canvas and later cleaned it by
Project > Clean ...
'Bulid Automatically' option was ticked.
Then the R.java file was deleted and it did not regenerated.I tried all the other options mentioned in the questions of stackexchange.But the R.java file remained missing.
One answer said that R.java generation fails because of errors in .xml files.But there were no errors.I'm 100% sure.
Then i created a new android application project which cannot have any issues in xml files.
When i created the new project it didn't came with the R.java file. I tried cleaning and building with different combinations.It still doesn't work.
I am using eclipse Helios
Android API 15
Android SDK Manager Revision 22
JDK 7U25
Can any one help me on this please?

I understand you have tried cleaning the project. What I would like you to do is Build the project and check the console for any errors.
The R.java also doesn't gets generated if the your project contains errors and these errors are clearly mentioned in your console.
Have a look and see if you can resolve your problem.

Try the following
Close and Reopen the project
Ensure your project folder has 777 rights
Use a later version of Android, that triggers a clean build
Check Problems tab, sometimes errors are not shown on the project files/folder, but a error shows up in this tab
Check top to see the amount of memory you have left, sometimes OOM screws things up
Please use a more later version 1.5 is like decades old

Try this.
Open the properties of your Project
Go to the Android Build target of your Application
Just change the from the currently checked one to another version(can be anything, but one that is supported to at least the minSDK declared in the Manifest)
Do a clean build, if your Project has no issues like in your resources like hyphens in draw able names,unrecognized strings,missing dimension values etc ... your Project should generate the R package with the R class

R.java not generated or updating. Deleting itself for no known reason. HELP every solution tried,

I've checked every site I can find for the last two days and read more that I could imagine it would take to fix this.
I had an app half made and then I couldn't get java to see a layout I had made. I hit clean like I had on many other things. Then R.java disappeared.
I deleted the layout just to be sure it wasn't the cause. R.java did not come back.
I then decided to rebuild from the previous project. About a quarter of the way through the same thing happens.
Now, half the time I start a new project R.java isn't there to begin with. And when it is there it doesn't update at all.
I have made sure to update to the newest software. I've tried "Build Project" I've tried restarting eclipse.
I have tried saving my R.java file and then when it auto deletes I replace it with the recent save. I get aapt.exe has experienced a problem and needs to close" which also happens when I try to clean the old projects to fix them.
This is wrecking my coding.

I often have problems with the R file as well. Here are some things you can try:
Delete R.java and see if it regenerates (make sure Auto build is turn on)
Turn off auto build and manually compile the project
Go to your hidden .android folder and delete debug_keystore, then restart Eclipse and rebuild. May need to restart the computer as well.
Completely uninstall and reinstall Eclipse
Then there's the other suggested answers... check your XML files for errors, make sure your classes import the correct R file instead of android.R, etc.
Do you get any specific error messages in the console?
This happens for ALL your projects?

On eclipse package explorer menu (left menu that your projects are listed) right click, select android tools,select fix project properties,
if it works, let everyone know so other people can benefit.

Check if you accidentally imported android.R, this can cause problems also. See answer from Lars here: Missing R.java file even though project cleaned

Issue in accessing R. resources in Android 2.2

I am very new to Android application development.
I successfully added some backgrounds to several layouts. And added media files to play. However when I rename a file in the folder structure, it shows an error that the resource does not exist.
But I can see those files in gen-><mypackage>->R.java->drawable.
Now my background pictures and resources do not appear in code.
R.layout.splashforproduct1 it shows an error for splashforproduct1.
not only splashforproduct1 but this issue is the same for R.raw.media.mp4
This is not first time I have got this issues. Please help me.
I am using Android 2.2 with eclipse.

If cleaning your project doesn't work try this: Scroll up to the top of the file and delete the import lines. Then wait for Eclipse to detect your changes and let it work out what you need to import and accept its suggestions.

I guess you just need to clean your project.
In Eclipse you do it clicking:
Project -> Clean and then you choose your android project.