Cannot resolve R.java, duplicate class

Question

I just start using Android Studio for a week and it works great for me, but when I started Android Studio today I get the error: 'error: duplicate class: mypackage.R'. I saw this error before when I used Eclipse so I tried to rebuild the project a few times and restarting Android Studio, this didn't help.

After reading some Stackoverflow questions I tried to deleted R.java and rebuild again, now I don't get any error while rebuilding. The only problem is that Android Studio cannot resolve R, so every line which uses R gets an error (project builds and run).

I also tried to delete all the R.class files but this doesn't help either. I checked if some class imports android.R, but they all don't, they just import 'mypackage.R'. I even deleted all my files and checked out a older version of my project but I still have the same problem.

Edit:

If I don't delete R.java the compiler doesn't give any error. Just when I try to build I get a lot of errors like: 'error: cannot find symbol variable button_login'. If I search the R.java file for 'button_login' I just find it. I did this with multiple errors.

Edit2:

When I deleted all the libaries the project now builds. But the problem is that I need those libaries (HTTPComponents). I added them from maven (File --> Project Structure --> Libaries --> +-sign') and added them to my settings.graddle:

buildscript {
    repositories {
        maven { url 'http://repo1.maven.org/maven2' }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:0.4'
    }
}
apply plugin: 'android'

dependencies {
    compile files('libs/android-support-v4.jar')
    compile group: 'org.apache.httpcomponents', name: 'httpclient', version: '4.2.5'
    compile group: 'org.apache.httpcomponents', name: 'httpmime', version: '4.2.5'

    //compile 'org.apache.httpcomponents-httpclient:4.2.5' doesn't work either
    //compile 'org.apache.httpcomponents-httpmime:4.2.5' doesn't work either
}

android {
    compileSdkVersion 17
    buildToolsVersion "17.0.0"

    defaultConfig {
        minSdkVersion 15
        targetSdkVersion 16
    }
}

When I run gradlew.bat --stacktrace --info assemble I get errors that Gradle is unable to find the libaries from the maven repository. I checked the repository but they are available. http://search.maven.org/#browse%7C1628757896

is there an error in one of your xml files preventing .R from being built? — IAmGroot, Jun 14 '13 at 08:17
I didn't change anything on my xml files, they don't have any error. The project builds and run, the compiler just can't find R — ObAt, Jun 14 '13 at 08:18
Check if you have one R.java file or not? This happens generally if you have two R.java files — Jainendra, Jun 14 '13 at 08:19
I just have one R.java file, I tried to delete the file but that doesn't help either — ObAt, Jun 14 '13 at 08:20
@ObAt Make a search for the R.java manually or using windows search in your project folder you must be having two R.java files. — NetStarter, Jun 14 '13 at 11:26
@NetStarter, I did but the weird thing there is only one R.java file and one R.class file. I even searched 'C:\Users\{USERNAME}\.AndroidStudioPreview' for R.java (only one file when I build the project) — ObAt, Jun 14 '13 at 11:44
Did you uncheck the use extern build, (as explained here http://stackoverflow.com/questions/16633956/android-studio-where-is-the-error-output-window/16876993#16876993)? Because unchecking this produces the "duplicate class" errors. — Moberg, Jun 14 '13 at 21:46
I tried, when I deleted all the libaries it works! But I need those libaries (HTTPComponents from Apache) — ObAt, Jun 18 '13 at 07:52

score 3 · Accepted Answer · answered Jun 14 '13 at 08:32

Unfortunately I run into this as well, sometimes frequently, mostly happens when I put my computer to sleep and back on while Eclipse is on. Sometimes recompiling and validating the project works.

I did find this solution online somewhere, lost the link and do not claim credits for this:

Disable auto build, and clean the project then
Right click your project -> properties -> Java Build Path -> Source -> Add Folder -> add gen and src
Then compile

If that doesn't work, try to delete the gen folder and do that process

Let me know.

Android Studio does not have a 'gen'-folder, I added the 'src' folder but this doesn't change anything. Android Studio still doesn't generate the R.java file, if I restore it manually I get the duplicate file error — ObAt, Jun 14 '13 at 11:23

score 2 · Answer 2 · answered Jun 14 '13 at 10:53

2

Delete the Build folder generated by Android Studio automatically!

answered Jun 14 '13 at 10:53

abdelali

29
1

Unfortunately this doesn't work, I still have the same issues – ObAt Jun 14 '13 at 11:17
This solution works for me. My setup is different from that of @ObAt. It's 3 years later, I'm on Linux and @ObAt appears to be on windows, and my `settings.gradle` is much simpler than the one in question. This solution is much simpler to try than the other one, so hoping the up-vote and this comment help others with the same problem. – Robin like the bird Dec 23 '16 at 22:19

Artem Zinoviev · Answer 3 · 2013-11-20T11:34:33.470

Problem is simple usually. You have fresh instal of studio? So you just fogot add SDK support for those version Android in wich try to compile project. Android Studio can`t generate R file. Start SDK manager, install all missing SDK version and rebuld project.

Another problem can be if you use 64bit OS. You ned to install 32 bit lib, because aapt can`t work with 64bit libs.

in Ubuntu install ia32-libs
Fedora described here
in other distr find libs in google (just google:ia32-libs for "mydistr"), i cant describe all of them ;)

P.S. sorry for my English ;)

score 0 · Answer 4 · edited Jan 11 '16 at 12:11

0

Delete all class file in your_package_name(androisTest) folder only keep ApplicationTest file.

edited Jan 11 '16 at 12:11

Haroldo Gondim

7,725
9
43
62

answered Jan 11 '16 at 11:03

Kishor Patil

41
3

score 0 · Answer 5 · answered Aug 06 '16 at 16:26

If you are using some library from which you are getting this error, just delete the build folder under your app source and rebuild the project. I was using OpenCV library for which I w as getting this error and that got resolved by deleting the build folder and rebuilding the project.

score 0 · Answer 6 · answered Aug 25 '16 at 04:48

0

Delete all generated code inside "gen" folder.
Uncheck Project->Build Automatically in eclipse.
compile android source once again.
Error will be removed, worked for me.

answered Aug 25 '16 at 04:48

Shiv Buyya

3,770
2
30
25

score 0 · Answer 7 · answered Feb 26 '17 at 11:54

0

This still happens sometimes in Android Studio, but a simple Build / Clean Project followed by a Build / Rebuild Project takes care of it.

answered Feb 26 '17 at 11:54

Carl

15,445
5
55
53

score 0 · Answer 8 · answered Nov 10 '21 at 18:38

I have not had this problem for a long time until today.

Error:(10, 14) java: duplicate class: com.domain.name.R

After 2 hours of wasting time on the project and getting this error,

Finally I removed the .idea, gen and out folders and also iml file.

Then I closed the project and then re-import it using import project of main menu again.

Its working well right now.

Cannot resolve R.java, duplicate class

8 Answers8

Linked