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I accidently deleted my R.java after cleaning the project (Project->Clean). Is there any way to restore or re-create the file?
I tried to build the project but R.java still missing from the project.
Here's a the things I ahve tried.
Rebuilding the project (failed)
Manually creating R.java and wait until the adt will generate the content (failed)
Did Project->clean another time (failed)
Deleted the gen folder and waited until adt will re-create it (failed)
The answer:
Created new project and copied the files that not auto generated (succeeded)
You have to build the project to be able to use the newly added resources.
Cleaning a project removes all auto-generated files. Building the project it should automatically create them. When you Clean a project, there's an option to start a build immediately after clean up.
Here's a few things you can try (did the same procedure after manually deleting the "gen" directory.
After you have deleted the gen directory, go to Project > Clean ...
You should have errors indicating that R cannot be resolved to a variable. Right click on your project from the Package Explorer and select Build Project. Be sure Build Automatically option is turned off (uncheck in Project > Build Automatically).
Errors regarding R should have now disappeared. Now, perform a Project Clean once again. All errors should be gone.
Let me know if this works for you.
Build the project again an do not worry, R.java is generated each time the project is built
I will automatically create by eclipse no need to create by us. just build the project i.e save the changes will automatically build it for u.
R.java file is automatically created when you build the workspace, so it should be generated again with the next cleaning of project, unless you have errors in java or xml files, so check if you have errors in your project and correct them first.
In the eclipse you have down to the clean project you have option Build Automatically try to enable it....
Just click Project > Build Project
When you build the project, you don't get R.java.
You should check external library. Just remove the external library and add external library.
Android projects get tangled easily.
Just Restart the Eclipse will solve this Issue as the workspace will be freshly Build ! go to
File -> Restart
Try this method by first right click on ur project folder -> Close Unrelated Projects!
Its the fastest way to avoid frustration by going it into Build,preferencen,properties,blah blah.....
Moreover, this technique always works when the R.java file is deleted and not restored back immediately !
Evenafter the problem persists then make a new project and add copy ur xml and java files to that project , delete the previous one . . . .
I had a similar problem: building the project, the R.java file was missing. I built the project, but there were errors in the resource XML file. Correct them, then rebuild. When there were no errors anymore, the R.java was recreated and contained all the R.id.xxx items I had inserted in the resource.
This recently happened to me (10 mins ago) for my Android project, and my solution was a mix of things I read in some answers here.
What I did to fix was:
revert to older version (I used Github)
R.java still missing so I deleted "gen" and "bin" folders
R.java was generated and errors disapeared
This was done using Eclipse Luna. Good luck.
Gradle Project Tab
I tried clicking all the stuff under Gradle Projects tab, and noticed a few small errors, example: I had a capital letter in the drawable folder. I ran anything that had to do with processing or updating or generating resources. final one I did was "processDebugResources"
missing R folder
I had also noticed the folder circled in the above image was missing, running "processDebugResources" seemed to have regenerated the folder, although the others I clicked under the Gradle Projects tab could have also helped
I'm trying the new Android Studio. I've exported a project from eclipse, using the build gradle option. I've then imported it in Android Studio. The R.java file under gen has a j in a little red circle on it. And in my source files, I get "cannot resolve symbol R" wherever I have a reference to a resource, e.g. "R.layout.account_list" etc.
I have never used Intellij before. Would appreciate any help as there obviously aren't many answer yet about Android Studio. Thanks!
Press F4 into Project Structure, Check SDKs on left
Click Modules ---> Source Tab, check gen and src as sources
PS: The answer over a year old and the menus have changed.
File -> invalidate caches
then
Restart application
None of the answers on the web so far have helped. Build > Make Project did not work for me. For me it was as simple as choosing this other option (on Android Studio 1.3.1):
Build > Make Module 'module name'
In my case I had an Activity file imported from Eclipse that had the line:
import android.R;
So all of my R classes were resolving to the SDK, as soon as I commented out that line everything compiled correctly to my package. I only noticed the issue when I was moving the project from my Mac to my Windows machine.
This issue starting occurring for me when I started working with build.gradle to incorporate the data necessary (signingConfigs) to build a signed .apk. After what appeared to be a successful build from the command line, I discovered that going into any class using R.* that all R.* references were unresolved.
The answers here didn't help me. I decided to re-import the project and it magically fixed the issue. File/Import Project... and select the build.gradle file in my apps root folder. I would love to know why re-import fixed this :)
This is probably due to a failed resource build
Once the issue is fixed, a mere Build > Rebuild Project will do the trick
Goto File -> Settings -> Compiler now check use external build
then rebuild project
I've been frustrated on many occasions with this problem, especially when intergating a project library as part of another project. In the most recent occurrence of this plagued problem, my Android lib project was using a WebView. It turns out that Gradle builds the R.class file in a sub directory called "web" whose path does not have anything to do with my source code path. When I imported this, my problem was gone. What have I learned? In the future, simply do a file search for R.class and note the path where it is located. Then import the package into your code using that path. It really sucks that you have to manually perform this. Gradle should automatically import packages it generates.
I was also facing the same issue and I went through lot of answer on stackoverflow. Then i found one solution which help me resolve this issue.
Check package name in AndroidManifest.xml file. I forgot to change it while copy pasting another project into new project.
At first check if there is import android.R; in top of your class this happens when auto import in enable in android studio.
after that comment all lines of your code that you use R variable (you can comment entire class or ...)
then run application it regenerates R variable and you can uncomment your code.
Here's what worked for me in IntelliJ (Not Studio), in addition to the replies presented above:
You need to attach an Android facet to an existing Android module. To do this, select the module from the module list in 'Module Settings', hit the '+' button on top and select 'Android'. See https://www.jetbrains.com/idea/webhelp/enabling-android-support.html.
The solution is to open project structure window. [by press command+; on mac ox s. i don't what's the key shortcut for other platforms. you should be able to find it under "File" menu.]
and click "Modules" under "Project settings" section, then your project is revealed, finally mark the generated R.java as Sources.
I am using Intellij idea 14.0 CE.
The generated R.java is located at build/generated/source/r/debug/com/example/xxx
Really not easy to find for the first time.
Follow the five steps below:
Step 1 ===>Delete(CTRL X) the additional tag(s) in XML manifest file.
Step 2 ===>Open Build-->Clean project.
Step 3 ===>Open XML manifest file and past the last additional tag(s) like:
Tag Manifest file example:
(<uses-permission android:name="android.permission.VIBRATE"></uses-permission>)
Step 4 ===>Step 2 again.
Step 5 ===> Open Tool-->Android-->Sync project with 'Gradle'.
I have had the same problem but after all the steps it's work for me.
On IntelliJ 14
Check if the generated sources are excluded. Usually in Project Structure -> [module] -> Paths -> Compiler output: "Inherit compile output path"
My problem was that I had file 'default.jpg' in drawable folder and for some reason every resource was not resolved. Fixed after deleting that file!
You should check all your files if it don't have errors and again rebuild your project in:
Build > Rebuild Project.
Or in:
File > Settings > Build, Execution, Deployment > Compiler
Check use external build and after rebuild the project.
After you tried Clean and Rebuild without success, check your res folder for corrupted files.
In my case a corrupted .png file caused all the trouble.
Regarding the following, from Crossle Song's answer
Press F4 into Project Structure, Check SDKs on left
Click Modules ---> Source Tab, check gen and src as sources
Despite the message "We will provide a UI to configure project settings later....etc" this worked for me.
None of these answers helped me!
My problem was not a problem! The program could compile completely and run on the device but the IDE has given me an annoying syntax error. It has underlined the lines of codes that included "R.".
The way that I could solve this issue:
I just added these three classes in "myapp/gen/com.example.app/" folder:
BuildConfig
package com.example.app;
public final class BuildConfig {
public final static boolean DEBUG = true;
}
Manifest
package com.example.app;
public final class Manifest {
}
R
package com.example.app;
public final class R {
}
I solve that problem setting JAVA_HOME, CLASSPATH.
People sometimes skip JAVA_HOME and CLASSPATH when setting Java_path.
So try to check Environment Variable.
CLASSPATH -> .;
JAVA_HOME -> C:\Program Files\Java\jdk(version) or where Java installed
and then check the xml file which can have error(Do not naming well-known things such as button,text etc)
In my case (Linux, Android Studio 0.8.6 ) the following helps :
File > Project Structure > Modules > select main module > select its facet > Generated Sources
change value of "Directory for generated files:"
from
MY_PATH/.idea/gen
to
MY_PATH/gen
Without that code is compiled, apk is build and run successfully
but Android Studio editor highlights mypackage.R.anything as "cannot resolve" in all sub-packages classes
I had the same problem and got it fixed by deleting an extra library.
To do try this solution go to File > Project Structure (on a mac you can use the command "Apple ;")
Then select app on the left tab. Go to the dependencies tab and delete the extra library.
check the build tools version in build.gradle(for module app). Then go to android sdk manager see if the version is installed if not install it or change the build tools version to the one which is installed like below.
android {
buildToolsVersion "22.0.1"
..
..
..
}
The solution posted by https://stackoverflow.com/users/1373278/hoss
above worked for me. I am reproducing it here because I cannot yet comment on hoss' post:
Remove import android.R;
from your activity file in question.
My setup:
Android Studio 1.2.2
Exported project from one Mac to Git (everything was working). I then imported the project on another Mac from Git. Thats when it stopped resolving the resource files.
I tried everything on this thread:
invalidating cache and restart
Delete .iml files and .idea folder and reimport project
Clean and Rebuild project
Nothing worked except removing import android.R; from my activity java file.
To avoid this issue in the future add .idea folder to your .gitignore file. There is a nice plugin from git for gitignore in Android Studio. Install this plugin and right click in .idea > Add to .gitignore
just clean project and then sync your project with gradle file.
In my case, I found that "android.R.layout.account_list" was referenced instead of "R.layout.account_list". Simply remove "android." can fix the problem. Hope this help because sometimes you may overlook when you are too focusing.
In my case:
I had to Copy Reference the R file; i.e. right click gen/<package>/R and Copy Reference. Then paste that over the R in your code where it fails to resolve.
That solved it for me (after trying everything else here). Still not sure why it worked to be honest.
I had this same issue. The package name was wrong in two of the following three files. I manually updated the package name and everything started working again.
gen/com/example/app/BuildConfig.java
gen/com/example/app/Manifest.java
gen/com/example/app/R.java
I'm not sure what caused them to change as I've never modified these files before.
Had this error when importing project from Eclipse. The reason was some of the xml files had errors. Check ALL your XML files for errors. Including androidmanifest.xml, and values, themes, styles, layouts folders, etc. Warnings in xml are ok, but errors will generate this error.
Afterwards, do a Clean Project and rebuild.
For me, with Android Studio 1.5.1, the solution was to recreate the whole project with a slightly different name.
I think it didn't handle the app name "Kommentator_AS", because several places the package was named"Kommentator" instead.
other answers relating to this did not help me out. Hence, I am posting a new question. I am trying to test a sample app of android that comes with their SDK. I get the error "R cannot be resolved to a variable". Looks like my R.java is not being generated. I don't know if I checked in the right place. I checked in the 'gen' folder of where I had downloaded my SDK and could not find the R.java file in the app which I am trying to test.
Could you please provide me with some ideas?
Thank you so much.
It happens when resources are not compiled. If you don't use automatic builds then just build your project. Otherwise it may happen because of some errors in resources.
I had the same problem(there was nothing under gen folder) and tried other solutions such as "cleaning project, checking if not android.R package is imported instead of mypackage.R, moving gen folder over src in java build path => order export tab and checking permissions of SDK executables" but none of them solved it.
Finally when I was checking one of the layout xml files in the res=>layout whether it has a problem or not Eclipse warned me with "The project target (Android 2.3.3) was not properly loaded" text. So I wanted to double check Android SDK Manager from Eclipse and found out that related SDK had an update. I did not see it before because it has a confusing structure with new or installed check boxes in my opinion.
When the 2.3.3 SDK updated all the problems gone...
Just clean the project and build again.
This is the most common problem I've found while developing for android.
Also try this Link for a detailed description about this issue.
Try to remove the read only in the properties of the sample sdk folder. That fix my problem i guest. Then remove the project in the eclipse. Restart eclipse. Then import it again.
I have an Android project developed on Eclipse (GNU/Linux) that I last touched half a year ago. I am trying to import the project into Eclipse 3.6 on Windows (with ADT installed) installed using File -> Import Project in Eclipse. When the project is imported, I see the following error twice on the console:
[2010-12-10 02:17:12 -
com.android.ide.eclipse.adt.internal.project.AndroidManifestHelper]
Unable to read C:\Program
Files\Android\android-sdk-windows\AndroidManifest.xml:
java.io.FileNotFoundException:
C:\Program
Files\Android\android-sdk-windows\AndroidManifest.xml
(The system cannot find the file
specified)
Why is Eclipse looking for AndroidManifest.xml on the Android SDK path? The file actually seems to be in the project's directory. How do I fix this problem and get the project to compile?
A simple solution is to either reimport the AndroidManifest.xml file or make a change to the file and save it. This worked for me.
If you see an error about AndroidManifest.xml, or some problems
related to an Android zip file, right click on the project and select
Android Tools > Fix Project Properties. (The project is looking in the
wrong location for the library file, this will fix it for you.)
from: http://developer.android.com/resources/tutorials/notepad/notepad-ex1.html
The way you are importing the Android project into Eclipse is wrong. The Correct way of doing is File -> New Android Project. In the Contents Tab in "New Android Project", select "Create project from existing source" and choose the Build Target. That should fix your problem.
It appears that this error is produced because Eclipse thinks the default location for new Android projects is the Android SDK path. Even if the project location is changed, the error fails to be resolved, so the trick is to change the project location before Eclipse is aware of the condition generating the error.
To circumvent this quirk I imported the old project with the following steps:
File -> New -> Android Project
Un-check 'Use default location' and browse to project root directory.
Click 'Create project from existing source'
It's important to do step (2) before (3) otherwise the error persists and prevents running the project.
I had the same problem, all of the above did not work. I cleaned the project and it worked.
Instead of using File ---> New Android Project --> "Create project from existing sources", which will result in the error your are seeing, choose "Create project from existing sample" and choose it from the drop down. This will work.
Experienced JAVA developers tend to go with the first option which is normally there and works for classic Eclipse projects. But this is not your typical project and I bet the Google developers put this special case in the wizard to accommodate the differences.
I had the same problem. I was trying to compile the JakeWharton view page sample, so I checked out the GIT in a directory in a different folder then the workspace which caused the problem.
Eclipse was maintaining 2 folders:
1. A new workspace folder was made under the workspace directory, which eclipse checks for libraries and others source code including the AndroidManifest.xml file
2. The existing folder which was not under the Root workspace
To fix the problem after importing I had to manually move the files in the new workspace folder created by eclipse.
I met this problem when using Facebook SDK, now I solve it by doing this:
Close the project;
Copy "AndroidManifest.xml" file to the project's root path;
Open the project and refresh it, it's Done!
this worked for me by the way:
I changed the project name to the exact name of the project that I am importing.
Eclipse seems somewhat fragile in its naming conventions. One of the causes for this error is a difference between the project name and the folder name in the workspace. I imported a zip file for a project named "HelloDialogs" into a workspace folder named "HelloDialog". This caused the "AndroidManifest.xml file missing" error. Once I renamed the folder correctly, everything worked fine.
Because of the multiple different answers here, I thouhgt I'd add yet another one that worked for me, as I had exactly the same issue when first working with Phonegap android dev tools.
So I found (as mentioned by Gintautas in comments to the accepted answer), that I had to create a new project using the phonegap 'create' script, then when importing the project into eclipse. the only way to get this to work successfully was if the project was originally created in some temp folder somewhere other than the place I actually want to work with it.
So I created a project in windows like this in a cmd window...
c:\phonegap\phonegap-2.6.0\lib\android\bin>create.bat c:\temp\android_boilerplates\test app.test test
Then I imported the project in eclipse like this...
File > New > Project
Within the new project wizard select: "Android Project from Existing Code"
Click "Next"
Now navigate to the temp location of your project and set that to the root directory, check the project you want and check "Copy projects into workspace" as the example below...
Click "Finish"
And that's it, Eclipse should copy all your project files into your workspace and there shouldn't be any errors in your project (fingers crossed).
Your project should look something like this...
Hope that helps, it took me an age to work out why Eclipse didn't like creating a new project from existing code when the new project was being setup in the same place as the existing code. This isn't a problem for other languages I've used, so it was a little weird, but understandable as Eclipse (I'm guessing) seems to want to overwrite certain files.
Eclipse randomly decided to make another folder instead of the one that i had specified, but doesnt have any resources or data or layout etc in it..
it has some conflicts i guess..
anyway, a noob approach to this was, copying the original file to some other location(i put it to desktop)..
now create new project-create existing project, select this one from desktop, n VOILA.. its all fine.. :D
I am a little late to this game but I caused this same problem by generating the initial application into the exact location I was going to work on it. That is to say I put it directly into my current workspace. I then did File, Import, Existing Android Code Into Workspace. The import process blanked out my android.xml file.
I tried above solutions and had no joy. I then generated the initial application into a temp directory and imported from there. This worked for me.
The only way to import a project into eclipse workspace is to create an empty project and then drag and drop all the folders and files into this project. Why is this so is beyond me.
The answer from Raunak is wrong.
I found a .classpath file in the root directory of my Android project. I opened it and updated the file paths in it, and it seemed to fix the problem for me.
I had the problem when I tried to update an old project with recent code from the SVN. I had the Manifest.xml exported to my local file system as backup and deleted it. I've then reverted my complete project to the most recent version from the SVN and then it worked :)
This is what I had to do to get this to work. Fortunately I had backups of earlier "project".
1) Import the project as usual.
2) If the errors with empty xml etc. comes up, close the project.
3) Go to the original project if you have backup.
4) Copy all of the projects root files and directories and paste it over where Eclipse expects the projects root directories and files to be.
5) Open the project and refresh. Make "Clean" if necessary and you're done!
Always make backups because Eclipse f--kups! I learned this the hard way when suddenly my Android project refused to work because of empty manifest-file.
Sometimes if you automatically fix imports in MainActivity IDE imports android.R class instead of one that will be generated for the project. Remove the import and recompile.
when importing project from another workspace add existing project in workspace. and tick to the copy projects in workspace.then check the api level and supporting library from project.properties files.then rebuilt project and clean it.. it is works for me.
2017 Solution: Much Easier and tested solution is to remove your application folder from elipse project only then Import it again and the problem will be fixed immediately!
I just reformatted my computer. I have windows xp sp3 32 bit.
I install java jdk
android sdk
eclipse ide
When I go to make a new android project i get this error.
Project 'HelloAndroid2' is missing required source folder: 'gen'
Please help i'm new to eclipse so give detail responses.
I just got this problem when I was trying to import a project that was originally created with a version of the SDK that is no longer installed on my machine.
Right click the project. Select Properties. Go to Android. Select a Project Build Target. Click Ok. You might have to clean and rebuild the project as well.
Right-click on the "gen" folder in Eclipse and select Properties. Then, remove the "Derived" checkbox. Then clean the project.
Most likely, there is a problem with one of your resources, preventing R.java from being generated in the gen/ folder. You should have error messages in your Console related to this problem.
Delete the "gen" folder. Then clean the project. Then build the project again. In my case it worked.
try this...
Right click on the project in eclips
Android tools -> Fix project properties
its works for me
ok , here's what worked for me:
delete the project and make sure you are not deleting it from the disk!
import it again and it will solve the problem.
Good luck....
My case was: I imported Zhou Weikan's cocos2d-android and the error emerged. The most straight-forward solution that came to my mind was to create the folder (right-click on the project in Package Explorer -> New -> Folder and then create new folder named 'gen'. It worked in my case.
delete the gen and its content and clean the project again.
Go to project
Right Click
New Folder (Res)
In my case it works Fine
I tried all these things and none of them worked. One day all my projects are running, next day all my projects have an empty gen folder?
After a series of tests to resolve the phantom missing R.java, the one that led me to a drastic action is when I looked at the Properties > Android and the Project Build Target was greyed out and the project wasn't linked to any SDK, almost as if there were no SDKs installed. This was after I uninstalled 4.2 and reinstalled all tools and SDKs...
Long story short, after trying everything I could find online, I just deleted the whole "adt-bundle-mac-x86_64" folder in my workspace folder, unzipped the original download, and dragged the original folder back into the workspace.
This works as a last resort, however you will have to import all of your projects back into the package explorer by New > Project... > Android Project from Existing Code, and make sure you have the "Copy projects into workspace" UNCHECKED.
IMPORTANT: You will find that you can't do this if your "MainActivity" file is always named "MainActivity," so just for future project creating, it's good practice to always name your main activity something different each time.
This error occurred when I tried to graphically add a grid layout. Deleting the grid layout folder fixed the problem for me.
My solution was to install android sdk build tools with Android SDK Manager.
The probkem was that whenever I clean the project, the gen directory becomes empty.
Hope it will help!
if gen folder or R.java file is not generated then first check error in XML file and make sure android menifest.xml is present.
Right click on the project> Properties> Android > use the latest API
takes care of everything!
In my case, the solution was downgrading the target from android-22 to android-19 at project.properties