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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.
I have been working on an android application in which I have to integrate In-app billing. I am following the procedure given on the following link but it is not paying off.
http://developer.android.com/guide/google/play/billing/billing_integrate.html#billing-permission
On this link there is a section named Adding AIDL file to your project, When I follow the steps given in the section, I do not find any " IMarketBillingService.java" file in the "gen" folder of the project. What can be the issue? Has anybody faced this issue..?
Any help is regarding the issue is appreciated.
Move .aidl file from project's src folder into some temporary folder.
Clean & build the project (build can fail, its just important that you start it).
Move .aidl file back to its place.
Clean and build again. This time everything should be ok.
Well nothing worked for me like Cleaning and rebuilding project time and again....However creating a new project from the existing project solved the issue. In the new project I was able to add aidl file and then a corresponding java file was created in the gen folder. It might not be the best solution butt only this is the only thing that worked for me after 2 to 3 days of searching and mindstorming, so if someone has a better solution please do share...:-)
right click on project-->select property-->select java compiler-->set compiler compliance level to 1.6 or more than that
This question already has answers here:
Developing for Android in Eclipse: R.java not regenerating
(64 answers)
Closed 9 years ago.
In Eclipse, I've created a project from a source and now it shows errors - "R cannot be resolved to a variable". From what I found here, I had cleared and rebuilt the project, but still the R file doesn't appear in the /gen folder.
Any ideas?
Dont worry. First you may clean the project, then run the project. If this does not work then follow the following links:
Here is the best way to solve this problem: [Android Development- Where is my R.Java file?][2]
R.java not regenerating
R cannot be resolved - Android error
R cannot be resolved to a variable
R cannot be resolved to a variable -- mailing list entry
Fixed: R cannot be resolved to a variable
If Clean/Rebuild Project doesn't work try to check our package name in AndroidManifest.xml.
The problem "R cannot be resolved" happens when you change your package name in the AndroidManifest.xml file. It uses your Android package name to create a subdirectory under the "gen" directory where it stores the R.java file.
For me the error got fixed by making some changes in Android SDK Manager.
Whatever be the latest API level available, install its "SDK Platform". For me latest API level available was 16, so I installed its's SDK Platform as shown in the image below. It works fine now.
Cheers, Mayank
Did you just update both sdk and adt(from 21 to 22), then you need to install a new item: Android SDK Build-tools
Refer to:
Eclipse giving error, missing R.java file after recent update
For me somehow the Project properties; Android; Project Build Target was not set. I chose a Android version there (e.g. 4.2) and it fixed it.
for me, the best solution to suggest to people that have problems with the "R" file would be to try the next steps (order doesn't matter) :
update ADT & SDK , Eclipse and Java.
remove gen folder , and create it again .
do a clean-project.
right click the project and choose android-tools -> fix-project-properties .
right click the project and choose properties -> java-build-path -> order-and-export. make sure the order is :
Android 4.3 (always the latest version)
Android private libraries
android dependencies
your library project/s if needed
yourAppProject/gen
yourAppProject/src
make sure all files in the res folder's subfolders have names that are ok : only lowercase letters, digits and underscore ("_") .
always make sure the targetSdk is pointed to the latest API (currently 18) , and set it in the project.properties file
For me, there was a missing slash at the end of my SDK. In Eclipse > Preferences > Android > SDK Location
For example, change
/home/matt/android-sdk-linux
to
/home/matt/android-sdk-linux/
your android manifest must start with correct package
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="HERE - Correct package NAME"
android:versionCode="1"
android:versionName="1.0" >`
I got similar problem and solution I found out was in resources any of
the file aka background, sound etc must not contain capital letters or
any special symbol other than _
What you really need to do it just install "build-tools" from sdk manager,
and r.java will be generated automatically.
I had the same error. Error was that, I had placed a file in res/raw folder with invalid filename.
As soon as I corrected the file name to a valid one, error was resolved!
Allowed characters for naming a file:-
1. a-z
2. . _
3. 0-9
4. no capital letters
Capital letters were the issue in my case!
Sometimes you can accidentially add an import to "R", so if at the top of your code you see some weird import about that that you did not add yourself, delete the reference, and everything should go back to normal
My problem was strange and took some time to find. Somehow the package of the src file changed so that the last entry in the package was deleted. So for example initially my class MyActivity.java was in package com.abc.client.test.app but after I added a user permission, the app got removed and the package was renamed to com.abc.client.test. I don't know how it happened. Renaming the package and putting the java file in the correct place fixed the problem.
I found this problem when trying to run the Notepadv3 programme from Googles 'first lesson'..
For me it was an issue with the xml file, due to the API level I was using. I renamed each case of Match_Parent to the older type of Fill_Parent. Oh and if you have already auto-built the project then you need to delete 'import android.R' on NoteEdit.java and Notepadv3.java, clean the project (click 'Project', then 'clean...') before saving.
Solved it for me. Came from this post Android NDK r4 san-angeles problem
Can't believe Google dosen't warn of this problem - I have been setting up another PC to start programming again and even with a bit of prior knowledge this was a pain.. How do you set the API when importing an existing project??? Can't see where there is any dialogue option when you 'File' 'Import' etc ..
Scamparelli
Check the androidmanifest.xml file and layoutfolder xml files. They should be created properly as the starting and ending clause in xml should be placed properly. Update the files, clean and build. And all set!
I had this problem and none of the other guides helped, and then I realized I didn't have the java jdk installed on my system. If you haven't done this either go download the version corresponding to the version of eclipse you installed (x86 or x64)
It is possible you have an error in your *.xml files: layouts and etc.
Try to modify AndroidManifest file.
For example add space and delete this space. After this OPERATION, save project. Resources will be refreshed. It can help.
I solved the problem with resolving R resource on fc19.x86_64 and ADT v22.0.5-757759 by installing additional libraries after Fedora and ADT upgrade.
yum install ld-linux.so.2
yum install libstdc++.so.6
yum install libz.so.1
Those libraries are required by adb (Android Debug Bridge version 1.0.31).
Then restart Eclipse and perform project clean Project->Clean check project you would like to clean.
Hope it helps :)
Project > Clean...
usually regenerates R.java file located in gen/com.mypackage
In my case, R.java wasn't getting generated because of a hierarchical parent error, which in turn was cured by updated one or more Eclipse plugins (Go Eclipse-->Help-->Check for Updates)
I got this error when I added a js file to the res folder.
An error indicator was set on the res folder icon. In all the classes where I used R I got this error.
I moved the js file to the assets folder and everything worked.
Problem was eclipse was not generating R.java.
To resolve this issue please go to project->clean... and select your project and select ok and then clean and build project and import your package name R file(Ex com.demo.R). It works.
This can happen when the android naming convention isn't followed. Check if you have placed a file/photo into one of the android folders and make sure that the file name contains only lower case letters
I know this is an old question but I just solved my own version of it and perhaps this might help someone.
After two days of tearing my hair out with this, I finally got around it by deleting the raw folder, then recreating it and dropping the file(s) back in.
After that, another Project > Clean and it at last compiled.
I got this when I renamed a project. Although the project is renamed, some references are not. Clearing lint, and then rerunning lint helped. (Right click project > Android Tools > Clear Lint Markers, then Run Lint)
My setup was broken after a recent update where the SDK build tools need to be installed separately after the SDK installation. So build tools update + Eclipse restart fixed this for me.
Credit goes to the Android reply here
When other solutions fail, select your project and delete it. MAKE SURE YOU DO NOT REMOVE FILES FROM DISK.
Then use file>import>existing android code into workspace, and select the location of your project.
I been having this and i did trace it back to the layout files.. It happend to me again however i could not find noting in the layout files. I looked in the string.xml and there was it.. one of the string names started with cap and that was causing the problem.
Fix any XML formatting errors in the XML Files in your /res/menu folder.
Might be a compile time error from the XML file being improperly formatted.
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've found out that my R.java is never updated, so it doesn't contain information about my new resources, so I decided to delete it and thought that Eclipse would generate a new one. But that didn't happen, and I don't have R.java now. How can I regenerate one?
I'm using Windows 7.
From one of the comments: "Doing Project -> Clean is what caused the problem for me. Cleaning deletes R.java...and for whatever reason the plugin is not regenerating the file."
I found this happening to me with a broken layout and everything blows up. Relax, it's like that old mistake when you first learned programming C where you forget one semicolon and it generates a hundred errors. Many panic, press all the buttons, and makes things worse.
Solution
Make sure that anything the R. links to is not broken. Fix all errors in your XML files. If anything in the ADKs are broken, R will not regenerate.
If you somehow hit something and created import android.R in your activity, remove it.
Run Project -> Clean. This will delete and regenerate R and BuildConfig.
Make sure Project -> Build Automatically is ticked. If not, build it manually via Menu -> Project -> Build Project .
Wait a few seconds for the errors to disappear.
If it doesn't work, delete everything inside the /gen/ folder
If it still doesn't work, try right-clicking your project -> Android Tools -> Fix Project Properties.
Check your *.properties files (in the root folder of your app folder) and make sure that the links in there are not broken.
Right-click your project > properties > Android. Look at the Project Build Target and Library sections on the right side of the page. Your Build Target should match the target in your AndroidManifest.xml. So if it's set to target 17 in AndroidManifest, make sure that the Target Name is Android 4.2. If your Library has an X under the reference, remove and re-add the library until there's a green tick. This might happen if you've moved a few files and folders around.
What to do if R doesn't regenerate
This usually happens when you have a broken XML file.
Check errors inside your XML files, mainly within the /res/ folder
Common places are /layout/ and /values/, especially if you've changed one of them recently
Check AndroidManifest.xml. I find that often I change a string and forget to change the string name from AndroidManifest.xml.
Check that Android SDK Build-tools is installed. Window -> Android SDK Manager -> Tools -> Android SDK Build-tools
Make sure when you update the Android SDK Tools, you also update the Android SDK Platform-tools and Android ADK Build-tools. Build fails silently if they don't match.
If you can't find the issue, right click /gen/ -> Restore from local history... -> tick R.java -> click Restore. Even if it doesn't solve the problem, it will clear out the extra errors to make the problem easier to find.
This site suggests:
if you run a clean on the project it should regenerate all the generated Java files, namely R.
...and...
In Eclipse, under the Project menu, is an option build automatically.
That would help you build the R.java file everytime modifications are
made. The Clean... option is also there under Project.
This site suggests another solution.
I had the same issue. When I checked it out I found that the name of the XML resource under layout was not having the correct naming convention. It had some capital letters. So I renamed it to make all letters lowercase and the magic worked.
One reason the R.class can go missing suddenly is when there are errors in you XML files. For instance, when you add an XML file with uppercase letters in the name like myCoolLayout.xml which is not allowed. Or when you have references that don't point to existing files, etc.
In Eclipse, simply use Project --> clean to clean the project. The
R.java is going to be automaticly (re)-created.
If for some reason that dosn't work: Make sure your layout.xml files don't contains errors. Eclipse seems to be a bit buggy here: sometimes it doesn't mark the errors within the XML nor the package explorer. In such a case: Take a look at the "console" or "problems" view after using "clean". All errors should be displayed there. Fix them and redo a clean.
NOTE: It is NOT neccessary to fix the errors you get because of a missing R file! Just fix the XML files and other project errors and use clean!
Quick fix:
The package name in the manifest needs to be the same as the one in the /src folder, the /gen folder package will be automatically reproduced.
Detailed observation:
Observe the name of package in the /gen folder. In my case it was different than the one in the /src folder.
The package referenced in the manifest was that of the /gen folder.
I attempted to add a package with the name of the /src folder to the /gen folder too see what would've happened, but this did not solve the issue. I proceeded then to remove the package name that was not the same as the package name of the /src folder. This package with the name that did not correspond to the /src folder was recreated as soon as I removed it.
Since the package reference in the manifest corresponded to the one that was being senselessly recreated and that did not correspond with the package in the /src folder, this prompted to rename package = "oldPackage" with the package = "srcFolderPackage".
I had the same issue, and I finally found the problem: In the strings.xml, I did not keep the line <string name="app_name">program-name</string> which is present by default when creating a new Android project. I thought it was only used for the program HelloWord, which is the original program.
However, the AndroidManifest.xml refers to this value, hence:
=> A compile error;
=> the R.java isn't updated;
=> ID are not recognized...
Android has added in SDK build tool ADT 22 for the building mechanism. You just need to do the following steps.
Update Android SDK Tool
Update Android SDK Platform Tool
Update Android SDK Build Tool
Add the path of your build tool to the path variable. (path up to---- YOUR DIRECTORY-PATH\android-sdk\build-tools)
This will solve the issue.
If your R.java isn't getting generated, one of the solutions is to delete the layout file named "blabla.out.xml".
After deleting this file, try cleaning the project from menu Project -> Clean.
As a generalization of Glaux's answer, if you have any errors in the res directory, then R.java may not generate - even if you clean and rebuild. Resolve those errors first.
As an example: when you add an image file of say, "myimage-2.jpg", the system will consider this an error, since file names are limited to alphanumeric values. Do a refresh on your 'res' directory after adding any files and watch the output in your console window for any file name warnings.
If your OS is Ubuntu, I can provide some suggestion:
Install or upgrade ia32-lib:
sudo apt-get upgrade ia32-libs
Check if you have the right permission on the aapt folder:
cd ANDROID/adt-bundle-linux-x86_64-20130522/sdk/build-tools/android-4.2.2
chmod 777 aapt
Start Eclipse:
sudo eclipse
Run Project -> Clean in Eclipse
You 100% have an error in an XML-file, but the XML verification does not show you the error. This is the reason why you need to check your XML files first!
It is ALWAYS helpful to take a look at the Problems Tab in Eclipse. In my case, I was getting a "android unable to resolve target 'android-8'" error message that kept the R.java from being generated. So, I corrected the imported target to the one I was using in the default.properties file, then I performed a clean via Projects->Clean and voila! R.java is automatically generated! Hope it helps!
Cleaning project, closing Eclipse, re-opening it and launching my project finally made my R.java to reappear... Hope it helps
Make sure you are not importing
android.R;
R.java will never be generated if there are any errors in the res folder. For example, in the drawable subfolder there are two files which have the same name, one is icon.png and the other is icon.html.
You can see some error in the Eclipse console log window which is saying "Resource entry icon is already defined.". After deleting icon.html, you can clean or just delete the gen folder. You will find that R.java is created.
I've found that any file that has capital letters in the res folder will create this error. This happened to me with a PNG file I added and forgot about.
After reading through many posts and YouTube videos, I found that each of us have R.java missing for different reasons.
Here's how I fixed this in Eclipse:
Create R.java in gen folder manually and save.
After that go to Project and click "Clean"
The following message will display and your file will automatically be rewritten:
R.java was modified manually! Reverting to generated version!
For me, I had linked v7 appcompat twice. Anyhow, in Eclipse, right click the project name in Package Explorer or Navigator, go to Properties, Android, and uncheck any duplicates in the Library section. You may need to Build --> Clean afterwards.
There's obviously no one final answer to this, but here's another one I don't see here already:
I've had R.java disappear after (attempting) a Team Synchronize, and there were conflict resolution files in the project (i.e., thingy.xml.mine,thingy.xml.r35, etc.). Deleting them/resolving the conflicts regenerated R.
I had this problem. Accidentally I deleted this
xmlns:tools="http://schemas.android.com/tools"
which started causing build errors all over the project in my XML files as well as my Java files. As soon as I retyped what I deleted, it worked again :)
OK so it's clear that there can be a lot of causes for this problem. If you're on a 64 bit linux machine and you are just setting up the ADT for the first time, you may get this problem where R is not automatically generating. Check the console tab and you may see an error similar to:
'No such file or directory' while attempting to get adb version from '/home/patrick/code/android-sdks/platform-tools/adb'
If that's the case you need to install ia32-libs, using something like:
sudo apt-get install ia32-libs
See here for details: Android adb not found
I've came across this problem a few times. I found that if I didn't import the package R through my application's name, for example, if my application had the package name example.test then I found that I had to import example.test.R in order to access any of the resources.
If this wasn't imported then the resources that where getting returned were the default resources with none of my own included.
With that said if you find that you are only getting a list of default resources then just check to make sure that you're importing application_package_name.R and not android.R.
My problem was that appcompat was not in the same directory as my project.
I found this out when compiling my app with Ant.
Also make sure that you have the latest version of the ADT plugin, and open the Android SDK manager to update all SDK tools to the latest version. Check for updates in Eclipse itself as well. Non-matching versions caused the problem for me.
My problem was inside a menu file.
The compiler doesn't seem to warn you if strings which do not exist inside strings.xml are referenced in menu files. Check if your items in your menu XML files reference any strings which do not exist in your strings.xml. Usually in android:title.
For me, this error was caused when I tried to duplicate an existing res/menu instead of creating one with the wizard.
All of these answers could not work if you use Maven. The solution for me was to add
<genDirectory>${project.basedir}/gen</genDirectory>
to the configuration section of android-maven-plugin.
I found a solution why R.class is not made by Eclipse after making it again - 2 clean, build, etc.
The problem is here in strings.xml:
<string name="hello">Hello World, HelloAutoComplete!</string>
<string name="app_name">HelloAutoComplete</string>
These are by default created by Eclipse when you create projects.
Definitely you are changing the strings.xml for your own requirement. Sometimes you clear the string.xmls these two lines from your code:
It is making a problem in the AndroidManifest.xml file:
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".HelloAutoComplete" android:label="#string/app_name">
So it can't communicate with strings.xml.
I changed my layout XML file name and found out later that of the XML file (widget provider in this case) still refers to the old layout XML which doesn't exist, and that prevented the auto generation/correction of R class.