R class missing after creating android project from existing source [duplicate]

Question

I downloaded the source for SpriteMethodTest, and I want to build it in Eclipse. So I Went:

File >> New >> Android Project >> Create Project From Existing Source >> SpriteMethodTest

It created the project alright, but the R class is not generated. Any file that references a resource in R says R cannot be resolved.

Importing android.R just results in R.drawable.background cannot be resolved. How do I generate R again?

Note that android.R is a completely different class from the.package.name.of.your.app.R — Tyler
– Tyler, Commented Jul 13, 2010 at 4:23
hi, I have the same problem. I also create new project from existing source. The source I use is sample code from Android SDK. R is missing. Did you fix it? — emeraldhieu
– emeraldhieu, Commented Jun 10, 2011 at 15:03
No, I never actually did. I've never had much luck with Eclipse. — cstack
– cstack, Commented Jun 10, 2011 at 22:36
@Emerald214: I had the same problem too, and I posted my solution below. — Steve Blackwell
– Steve Blackwell, Commented Aug 22, 2011 at 5:50

Tyler · Accepted Answer · 2011-07-28 20:50:00Z

5

You are having an issue because you are importing Androids R, not your project specific R. Simply delete the import android.R;, then hover your mouse over the reference to the R that is giving the R cannot be resolved to a variable. From there you will have possibly a few different options on which R to import. You want to import the R that is in your package.

answered Jul 28, 2011 at 20:50

Tyler

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draq · Accepted Answer · 2011-02-22 10:51:16Z

4

Create empty file inside "gen" folder and name it "R.java"
click Project --> Clean...
click Android Tools --> Fix Project...

answered Feb 22, 2011 at 10:51

draq

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Sogger · Accepted Answer · 2012-04-23 23:04:55Z

4

The generated R resource file can only be generated by eclipse if the files it reads can compile, meaning errors in a file (such as the manifest file) prevent compilation. So, resolve your errors (listed in the 'Problems' tab) first, then save the changes and it should then be generated.

The reason it usually seems to be related to API versions is because different versions cause compatibility errors. This usually happens when people grab sample code and don't set the same API version as the code creator was using. Changing to the correct version resolves the errors and allows the R file to be generated.

answered Apr 23, 2012 at 23:04

Sogger

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Steve Blackwell · Accepted Answer · 2011-08-22 05:47:17Z

2

I had this exact same problem with SpriteMethodTest. It has nothing to do with package names or imports. As tarkeshwar says, if R is not being generated, then the problem is prior to compilation. In this case it's AndroidManifest.xml.

The last tag in the manifest is

<uses-sdk android:minSdkVersion="3" android:targetSdkVersion="4"/>

but android:targetSdkVersion is not a supported attribute. Change the line to

<uses-sdk android:minSdkVersion="3"/>

and that should allow Eclipse to generate the R class.

answered Aug 22, 2011 at 5:47

Steve Blackwell

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Raphael Villas Boas · Accepted Answer · 2012-06-26 19:26:33Z

2

In my enviroment android SDK was missing the folder platform-tools and I had to start android and install platform-tools. Now it is working.

answered Jun 26, 2012 at 19:26

Raphael Villas Boas

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Adi Lester · Accepted Answer · 2012-11-13 22:54:10Z

2

Had a similar problem, which seemed to be caused by the SDK versions as well:

Project -->properties --> android: select the suitable API lvl and click OK. That caused the R class to finally be generated, how ever it will not compile yet.
Delete the project and import it again (now it has the R class) and worked on first attempt.

*Happened when tried to check out the snake example code.

edited Nov 13, 2012 at 22:54

Adi Lester

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answered Aug 22, 2011 at 13:29

Nim

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Chris Thompson · Accepted Answer · 2010-07-12 21:09:04Z

1

Project -> Clean (select your project) -> Ok

This will trigger a re-build and so long as the project is configured as an Android project, R.java will be regenerated.

answered Jul 12, 2010 at 21:09

Chris Thompson

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Macarse · Accepted Answer · 2010-07-12 21:09:58Z

1

Try the following:

Delete the gen folder
Project => clean
Right click => Android Tools => Fix project properties
Right click => Run as... => Android application

answered Jul 12, 2010 at 21:09

Macarse

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4 Comments

cstack Over a year ago

Hmm... None of this works. The gen folder always remains empty.

Macarse Over a year ago

After deleting it and making a "Fix project properties" what does Eclipse say?

cstack Over a year ago

It doesn't say anything.

Macarse Over a year ago

Where did you get the SpriteMethodTest src code?

tarkeshwar · Accepted Answer · 2011-04-30 22:00:51Z

1

R.java not being generated usually indicates problems elsewhere, for example: Manifest.xml having errors.

Fix those errors and rebuild. R.java should get generated then.

If if it still not there, do project -> android -> fix android settings.

answered Apr 30, 2011 at 22:00

tarkeshwar

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msEmmaMays · Accepted Answer · 2012-09-02 21:47:09Z

1

Running this in the project folder fixed it for me

 android update project -p .

I had "Build automatically" turned off when I created the new project, so certain files weren't created like they should have been

answered Sep 2, 2012 at 21:47

msEmmaMays

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