Develop Reference

Android Studio cannot resolve R in imported project?

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.

Can't import projects into Eclipse workspace

So, I have been using eclipse in Windows for years. I have a few android projects that I have been working on lately. But I'm getting stuck on something so weird.
The problem is I'm using eclipse on both windows and Linux now. (Yeah i feel linux is better and much faster). I want to get all my projects that I was using on Windows into Linux Eclipse workspace (Yes I created another workspace because I didnt know if I could work on same workspace in both versions viz linux and windows eclipse). Now, the weird part is I CANNOT IMPORT THOSE PROJECTS INTO MY OTHER WORKSPACE! This is driving me crazy.
I go to my Linux Eclipse workspace -> Import -> Add existing android proj -> browse -> Root dir of my android project -> (Ecipse does show the projects on the frame below -> I click finish -> NOTHING. I just sit there, waiting, and nothing happens. I have searched around here in stackoverflow, but none of the problems resembles this.
Yes I have access to the workspace folder, yes I can create folders, etc etc.
Please can someone tell me how I can import projects that are being detected but NOT imported?
thanks.

I solved this by importing the project in the following manner:
File > Import > Android > Existing Android Code Into Workspace
Click Next, then Browse...
Select your project root directory, and check the box for Copy projects into workspace. Click Finish.
Hope it will help you.

I also faced the same problem for long, today only I found out the solution!
It's all lies in .project and .classpath files inside project's root directory. While trying to import any project into workspace, if your project does not gets listed, that means .project and/or .classpath files are either missing or corrupt. Usually these files are hidden, so you never know what is the issue.
For Ubuntu, follow steps below:
step 1. go to any project root directory in your workspace and press Ctrl+H to see hidden files.
step 2. copy .project and .classpath files from there and paste to the other project directory that you wanted to import.
step 3. Open the .project file and update name tag to project name.
<?xml version="1.0" encoding="UTF-8"?>
<projectDescription>
<name>Name of the project</name>
<comment></comment>
....
step 4. close the folder and import the project, it will be definitely listed in the import wizard now!!

I also encountered the same problem.
you need to update ADT (Eclipse Plugin) to work with new Android SDK.
click Help > Check for Updates
after ADT updated, you can import your project from File > Import

Make sure to check to see if the AndroidManifest.xml file is present in either the folder or a sub folder. You must have that file in order to import.
This is the issue I had. Luckily I have the unlimited history feature in DropBox so I was able to use that to get the last existing version of the file. Once I added it, importing worked just fine.

I'm facing the same issue, here what i have done.
- In Eclipse, Go to windows -> Preferences
- choose Android, set your Android SDK Location
make sure you have at least one of the Android platform in the table.
- Apply and Ok.
done, I try import, and it's fine.
Hope it help.

It could be that the project already exists in the workspace. The solution is to either change your workspace location or just rename the project you're importing.

After importing the file, you can deselect the in library from properties section. It worked for me

if all the sulotions above didnt help you, open a new project with the same name as the imported project,after you do that, go to the Original project,open it and selcet all files with ctrl+A,and than copy paste it inside the new project,then click yes to all inside the alaert and it should work.

If none of the above answers help, check the permissions of the folder which contains the projects. In Ubuntu from command line try this:
sudo chmod 777 Folder_Containing_Projects -R
The above command will give permissions recursively.

Missing AndroidManifest.xml when importing an old Android project into Eclipse

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!

Problem importing Android project archives into Eclipse

My apologies if this is a stupid newbie question...
I'm using Eclipse (Helios release) and have the Android SDK all configured as per the developer.android.com recommendations. I can create and run new projects without any problem but I can't import archived project code samples (found on the web etc.) using Import > Existing Projects Into Workspace.
Importing a zip creates a project but it doesn't create it as an Android project and the console displays the error: "Project has no default.properties file! Edit the project properties to set one."
I've tried going into the project Properties but as soon as I click on 'Android' in the properties tree a pop-up appears saying "Could Not Accept Changes: The currently displayed page contains invalid values"
See: http://screencast.com/t/ZmY3ZWQ4
But if I do this on one of my own projects I have no such error, and I'm able to change things such as the Android Platform/API level. I'm also able to archive my own projects (using export) and import them again without any problems... nut not other people's archives! Am I being really stupid?
Any help would be really appreciated!

All the baseline default.properties needs is a line like:
target=android-8
You can most likely copy another projects' default.properties into this project. A (not-so-)quick restart of Eclipse, a rebuilding of the workspace, and you're off to the races.
It's really lame that this is needed -- it should happen as part of the import process, I would think.

just change your
project.properties file to default.properties
and restart your eclipse
it's done..

Right click on the project in navigator window, go to android tools and click on fix project properties. It might work, as it did for me ;-)

You can look at this section, it works for me:
Project has no default.properties file!

If you want to change the library of your project, do that :
- right click on the project name
- Build Path
- Configure build path
- click Android on the left, and select the library you need.

I had the same problem.
What you are trying is little difficult.Just unzip the files ,copy res and src folders
to ur existing project.The problem is the files starting with "." which have settings for their android and eclipse.
So you need to modify all that,so simply create new project or to ur existing one copy res, src and AndroidManifest.xml file.
It worked for me .

In the project right click Android Tools -> Fix Project Properties

Eclipse - HelloWorld - Android error?

I created a Hello world app but get this strange error:
The project cannot be built until the build path errors are resolved
I haven't changed the project, jut created it and tried to run it.

to avoid that annoying problem i have 3 solutions that worked for me.
Solution 1)
delete your generated R.java file
inside your gen/ folder
Solution 2)
a)Delete your project from Eclipse
(i said ONLY from Eclipse, uncheck option: Delete project
contents on disk)
b) import your project to Eclipse:
file > Import > Existing Projects into
Workspace (Look for your project
previously deleted from Eclipse) >
Finish.
Solution 3)
make Solution 1 then Solution 2

It is either a spurious message you can solve by forcing Eclipse to recompute its library paths
I found the resolution for this at Scott D. Strader's blog.
To summarize the solution I only needed to add a library to my project and then remove it to force Eclipse to perform the necessary actions to resolve the problem. I would post the detailed steps here but I don't want to steal his content.
The resolution was to force a resave of the selected projects (and their .classpath files):
Open the project properties
Select Java Build Path > Libraries
Add a new, arbitrary library (to be deleted later) > OK
Wait for the workspace to refresh (or force a refresh of the project)
The error(s) will go away
Remove the dummy library
Note: as the OP mentions, a simple restart of the IDE can be enough.
Or you actually miss one critical library like a JRE library:
I needed to add the JRE library to the project for it to run. Not sure if this was due to the updated version or something else…. Any way this fixed the issue:
Project > Properties
Java Build Path
Libraries tab
Click add library
Select JRE System Library
Next
Finish

Sounds like you are missing an import or a jar. In your project in the project explorer there should be a red x on the file icon that contains the error.

In addition to the listed answers, there is one other scenario I've seen this error appear when using the sample projects included with the Android SDK. For some reason, the generated R.java file can be invalid or corrupt. You can get around it by expanding the "gen" folder in the Package Explorer and deleting the R.java file. It will immediately get regenerated and the error goes away.

Right click on your project, choose "Build Path", "Configure Build Path" -> and choose Android 2.2, or that target you specified when you created your project

I have had similar issues. for me simply closing the emulator and re-running the project works