R class missing after creating android project from existing source

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, Jul 13 '10 at 04:23
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, Jun 10 '11 at 15:03
No, I never actually did. I've never had much luck with Eclipse. — cstack, Jun 10 '11 at 22:36
@Emerald214: I had the same problem too, and I posted my solution below. — Steve Blackwell, Aug 22 '11 at 05:50

score 5 · Answer 1 · answered Jul 28 '11 at 20:50

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.

score 4 · Answer 2 · answered Apr 23 '12 at 23:04

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.

score 4 · Answer 3 · answered Feb 22 '11 at 10:51

4

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

answered Feb 22 '11 at 10:51

draq

41
2

score 2 · Answer 4 · answered Jun 26 '12 at 19:26

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 '12 at 19:26

Raphael Villas Boas

229
3
3

score 2 · Answer 5 · answered Aug 22 '11 at 05:47

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.

score 2 · Answer 6 · edited Nov 13 '12 at 22:54

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.

score 1 · Answer 7 · answered Sep 02 '12 at 21:47

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 02 '12 at 21:47

msEmmaMays

1,073
7
7

score 1 · Answer 8 · answered Jul 12 '10 at 21:09

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 '10 at 21:09

Chris Thompson

35,167
12
80
109

score 1 · Answer 9 · answered Jul 12 '10 at 21:09

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 '10 at 21:09

Macarse

91,829
44
175
230

Hmm... None of this works. The gen folder always remains empty. – cstack Jul 12 '10 at 21:21
After deleting it and making a "Fix project properties" what does Eclipse say? – Macarse Jul 12 '10 at 21:28
It doesn't say anything. – cstack Jul 13 '10 at 13:42
1

Where did you get the `SpriteMethodTest` src code? – Macarse Jul 13 '10 at 14:07

score 1 · Answer 10 · answered Apr 30 '11 at 22:00

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 '11 at 22:00

tarkeshwar

4,105
4
29
35

R class missing after creating android project from existing source

10 Answers10

Linked