gen already exists but is not a source folder

Question

I am developing my Android project, After I removed a unused library, I got the error:

myproject/gen already exists but is not a source folder. Convert to a source folder or rename it

In my Activity code, all resources from R.java can not be resolved.

I tried, right click on my project => Java Build Path => under "Source" tab, I added gen/ as source. But it does not help with the problem...

Why, how to get rid of this problem?

----UPDATE----

I found that, the eclipse also complain that "Project has no project.properties file! Edit the project properties to set one." , but I do have project.properties file under my project. Why it complains? I have cleaned the project and "fix project properties" but it does not help.

check your src folder contains any gen folder. if there delete it. .no need to create it manuallly. Clean your project once. — Padma Kumar, Mar 02 '12 at 11:02
You have a very good answer, currently rated 79, yet you haven't accepted it. You should accept it. And your "UPDATE" should be a separate question (and you might want to see if anyone has already answered it). — steveha, Jan 07 '14 at 21:10
I think my answer will help in this problem.. http://stackoverflow.com/questions/9738203/eclipse-android-gen-already-exists-but-is-not-a-source-folder/22346099#22346099 — Ranjit, Mar 12 '14 at 08:43
I had this happen after mistakenly adding Project.Properties to the .gitignore file when setting up my Git repository. — Rben, Jan 28 '15 at 20:25

AntoineP · Answer 1 · 2013-03-17T23:49:27.370

234

I get the same problem.

Two actions, first:

1.Right click on the project and go to "Properties"

2.Select "Java Build Path" on the left

3.Open "Source" tab

4.Click "Add Folder..." and check "gen" and "src"

second: (because the previous action asked me to remove something... I do not remember what it was...)

1. Right click on the project and go to "Properties"

2. Select "Java Build Path" on the left

3. Open Libraries "tab"

4. Add an external JAR. Add the Google API that is in your android directory (android-sdk\platforms\android-yourversion

And now it works for me!

edited Mar 17 '13 at 23:49

answered Mar 05 '12 at 17:43

AntoineP

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In my case I only needed to do the first part mentioned above. Thank you! – tm_forthefuture Sep 24 '13 at 11:17
First solution also helped me in first try :) – Saad Qureshi Apr 04 '14 at 07:09
2

Worked...but how did this happen? Stupid Android. :-) – Ryan Detzel May 05 '14 at 17:03
First step worked for me. Not sure how or why Eclipse decided to just drop these folders (.classpath didn't appear to change)... – ssawchenko Jul 16 '14 at 19:41

score 37 · Answer 2 · answered Aug 13 '13 at 07:13

37

Solution :

Step 1 :

Right click on the project and go to "Properties"
Select "Java Build Path"
Switch to "Source" tab Remove all sources from source folder on Build Path
Restart Eclipse

Step 2 :

Right click on the project and go to "Properties"
Select "Java Build Path"
Switch to "Source" tab
Click "Add Folder..." and check "gen" and "src" source folder on Build Path
Restart Eclipse

Final

Build Project(s)

Happy Coder :)

answered Aug 13 '13 at 07:13

Vinayak

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check gen only solves the problem and does not work with src folder – Manikandan Aug 20 '14 at 06:54
I would have wasted my day. Thank you – Prakash Feb 10 '15 at 21:24

score 17 · Answer 3 · edited Jun 29 '15 at 05:43

17

Right click on the project and go to Properties
Select Java Build Path on the left
Open Source tab
Click Add Folder... and check gen and src

edited Jun 29 '15 at 05:43

Ely

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answered Dec 26 '13 at 11:31

Shubham Das

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That is the best answer. Concise, problem solved, boom! – Ely Jun 29 '15 at 05:29

score 8 · Answer 4 · answered Nov 25 '14 at 19:26

8

This is caused by using the wrong importer in Eclipse. If you have Android projects, you need to import them into your workspace with Android->Existing Android Code, not General->Existing Projects.

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answered Nov 25 '14 at 19:26

Eric Cloninger

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score 3 · Answer 5 · answered Jul 31 '13 at 00:14

3

i had to delete the entire gen folder within eclipse not from file explorer. then did a clean and it was rebuilt. funny this occured right after i ran a Lint HTML report.

answered Jul 31 '13 at 00:14

j2emanue

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This also worked for me. Just deleted the gen file, and a few seconds later is was regenerated and everything is back to normal. – Sandy Nov 14 '13 at 15:45

score 2 · Answer 6 · answered Mar 02 '12 at 10:55

The gen folder is where ADT creates the R.java file, which specifies your resource definitions. i.e. your resources (colours, dimensions, layouts, etc) are converted to code, and placed in R.java in the gen folder.

So when you build the app you need to ensure the gen folder is treated as a source code folder by your IDE, as it contains the R class.

In your IDE, you need to mark the gen folder as a source folder, so its content are built alongside your source.

Your acceptance rate is very low. If you want people to help you, you need a high acceptance rate.

but how can I accept if there is no correct answer? I do check the answers, but no one is the solution... For example, my current post, I know what is gen/ and how it works in Android, I am seeking a solution to my current problem. But not yet have one. — Leem.fin, Mar 02 '12 at 12:06

score 1 · Answer 7 · answered Apr 26 '13 at 02:50

1

I met the same problem, solved it as following:

In Package Explorer, right-click the gen folder, find "Build Path - Use as Source Folder" and click it.

That is it. I hope it will help.

answered Apr 26 '13 at 02:50

hywl51

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score 1 · Answer 8 · answered Oct 03 '13 at 12:18

I had SVN configured for a project with the same problem, deleted all folders and files, retrieved it again from SVN and still no luck. The only thing that helped was reverting the changes, and deleting/re-importing projects to the workspace. Hope this helps

score 0 · Answer 9 · answered Jan 17 '13 at 21:06

0

The last time I had this issue, it was because I switched the source to another branch behind the scenes. Once I closed Eclipse and relaunched, the issue went away.

answered Jan 17 '13 at 21:06

themarshal

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score 0 · Answer 10 · answered May 30 '13 at 12:50

I had some of the same symptoms, but solved it differently:

I found out that I had two files in the drawable dir that were conflicting: icon.png and icon.xcf. This made R fail generation. I moved the icon.xcf out of the way and R generated and the project compiled.

score 0 · Answer 11 · answered Oct 14 '13 at 05:36

0

Go to the project properties then Go to Java Build Path then Remove already exist folder then Click Add Folder then Add the Source and gen folder. then Press ok............It will work.......

answered Oct 14 '13 at 05:36

Singhak

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score 0 · Answer 12 · answered Oct 28 '13 at 09:34

My solution was to paste the following into the .classpath file:

<?xml version="1.0" encoding="UTF-8"?>
<classpath>
    <classpathentry exported="true" kind="con" path="com.android.ide.eclipse.adt.ANDROID_FRAMEWORK"/>
    <classpathentry exported="true" kind="con" path="com.android.ide.eclipse.adt.LIBRARIES"/>
    <classpathentry kind="src" path="src"/>
    <classpathentry kind="src" path="gen"/>
    <classpathentry kind="output" path="bin/classes"/>
</classpath>

score 0 · Answer 13 · answered Mar 31 '14 at 14:40

0

We also need to check our import statements, If we have imported 'android.R' got to remove that.

answered Mar 31 '14 at 14:40

Jehoshuah

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score 0 · Answer 14 · answered May 07 '14 at 06:08

This happens because your .classpath file got wiped out somehow. This file contains all the information from the Java Build Path tab under Project Properties. You could add in all information manually but there's an easier way of fixing this problem.

If you have a copy of the .classpath file on your machine, you can just copy and paste it into your project directory.

score 0 · Answer 15 · answered Feb 27 '15 at 09:06

I tried the suggestions given here and still had the problem. Finally, it turned out that Eclipse got its imports wrong. For some reason it added the words "gen" and "src" to the beginning of the import line. I had to change all the import lines from

import gen.org.qtproject.qt5.android.bindings.QtApplication;

to

import org.qtproject.qt5.android.bindings.QtApplication;

Once I did that, everything came back to normal.

gen already exists but is not a source folder

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