The title says most, but I have created a new project in Eclipse. I have everything set up, and as soon as I create a new Android Application Project, once everything has Generated there are 2 Errors: both "R cannot be resolved to a Variable", on Line 19 and Line 12. In the Video Tutorial Series I am watching it says there should be a file called R.java in the gen folder, but there isn't, just an empty folder. The Android project is completely new. Here are some of the things I have tried after googling, none solved the Issue:
Clean Project
Uncheck/Re-Check Build Automatically
Build Project
Close/Open Project
Check XML files for Errors - only the Two Errors as mentioned above in the Error Log
add "import android.R.*"
Create R file manually (Add -> Class)
It is my first time writing an app in eclipse, I know there are a lot of questions like this but none seem to solve my problem. The Java Errors (R not resolved to a variable) Errors are the only errors, no errors in the XML or Anything.
So that you can check my project, I have put it in my Dropbox if you want to have a look at it in eclipse.
Project Download Link
You can create the new Project and then copy the contents of this project into the new one.
This problem is with Eclipse. I recommend you to use Android Studio.
What might help, would be to create a new project and transfer the current project to that one. When the R file is not created when creating a new project, try and re-download the development tools and sdk.
I'm sure that the problem may be with your ADT tools in eclipse. Sometimes, this errors may occur due to some installation mistakes or some sort of software cracking problems. I also faced the same problem at my starting stage. The best thing that you can do is to move on with re-installation of ADT in you eclipse. It may help you. Try this!! Create you new Android Project and Enjoy buddy !!
I was having this exact problem, and found the solution after much headache.
In eclipse, find and click the button labelled Android SDK Manager (next to save, and all that jazz on the toolbar).
In the manager, make sure that under the "Tools" folder all of the relevant "Android SDK Build-tools" have been installed. Once they are, restart eclipse, and your R.java file should be generated. Hope that helps!
Related
I'm trying to learn how to develop an Android App from scratch using Eclipse, but I keep running into the "R cannot be resolved into a variable" error. I tried everything from completely removing Eclipse and downloading it again, to deleting my project and workspace and starting over, but I just cannot get away from this error. The thing is, it's coming up without me even doing anything. I just start a new Android project and it opens with this error so I can't move forward in learning this stuff.
Any ideas on what I can do? Keep in mind I'm at the absolute beginning of learning how to work with Eclipse, so if you have a possible solution, I'd really appreciate a step-by-step answer.
Thank you!
EDIT: As it turns out, I didn't have any of the build-tools installed. I remember installing them but I have no idea what happened and they were just not listed as installed. After re-installing, I'm good to go. Thanks for the help everyone!
Right click on your project and clean it, if there are any errors it will prompt you or else the R.java file will be created in your gen folder and imported in your project.
If there is any problem with the xml file in android, then R.java won't be generated. Please make sure that you don't have any error in xml file, then clean the project by clicking clean button in "Project" option and click "Build Project", Build Automatically is not selected. This should solve your problem. Best of luck.
You have updated the android sdk but not updated the adt to match with it.
You can update the adt from here
You might need to update the software source for your adt update
Go to eclipse > help > Check for updates.
It should list the latest update of adt. If it is not working try this
go to eclipse > help > Install new software
Click on add
add this url : https://dl-ssl.google.com/android/eclipse/
give it any name.
It will list the updates available- which should ideally be adt 20.xx
Eclipse will restart and hopefully everything should work fine for you.
Try to fix all error in your XML file. Look drawable, layout and other res folders closely for any error.
If it does not fix your problem then try
THIS answer :
I am a newbie to android programming .I was doing tutorial from Commsware tutorial , to be precise T3 tutorial during which I cleaned the project.After that R class file has stopped generating.
I deleted that project,looks like the same error is getting propagated to other new projects I am creating.
This error is coming for the newly created project also.
I tried all the solutions in stackoverflow like : cleaning project,selecting android version in build path , deleting my workspace,freshly install eclipse etc..
The other intimidating thing is my res folder does not show any errors and my xml file does not contain any capital letters.
It must be some silly error which is causing this?
Perhaps you should take a look at this if you've recently updated SDK tools.
After updating to SDK Tools to rev. 22 for the first time, you may need to relaunch Android SDK Manager again and install a new item: Android SDK Build-tools.
After installing this, clean your projects and rebuild.
this happened to me after updating the android dev kit and esclipse.
couple of things you should try.
if you updated ADT, you must restart ADB server. you probably haven't read the message that says after update. or maybe restart whole pc.
if you're using external jar files, rename the libs folder to lib and revert it back to libs (from eclipse, f2)
There seems to be a problem with the target build settings within your projects.
The R file will not be autogenerated if there is the slightest error in your project. E.g if you use elements in a layout xml file that are available only in Android 2.2 but your project targets android 2.0. Sometimes the offending elements don't show up as errors because, syntax-wise, they are correct.
I advice you look at your target builds in android manifest.
Or target a higher android build (Get the latest one via SDK manager)
I get a null pointer exception opening about half of the android XML files in my layout directory. There seems to be no pattern to why some files open and some files don't.
I upgraded eclipse to Juno. Re-installed all the plugins (ADT), re-installed the android SDK. I brought in my old workspace and adjusted my projects to point at the new android SDK.
Stack
java.lang.NullPointerException
at com.android.ide.eclipse.adt.internal.editors.layout.configuration.ConfigurationComposite.setLocaleCombo(ConfigurationComposite.java:1566)
at com.android.ide.eclipse.adt.internal.editors.layout.configuration.ConfigurationComposite.syncRenderState(ConfigurationComposite.java:3049)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.activated(GraphicalEditorPart.java:1158)
at com.android.ide.eclipse.adt.internal.editors.layout.LayoutEditorDelegate.delegatePageChange(LayoutEditorDelegate.java:679)
at com.android.ide.eclipse.adt.internal.editors.common.CommonXmlEditor.pageChange(CommonXmlEditor.java:359)
at org.eclipse.ui.part.MultiPageEditorPart.setActivePage(MultiPageEditorPart.java:1081)
at org.eclipse.ui.forms.editor.FormEditor.setActivePage(FormEditor.java:607)
I found one way to resolve this. My eclipse recently crashed (and wouldn't start again) for an unrelated reason. To get it to start again I deleted most of the files in ${workspace}/.metadata/.plugins. These files regenerate (but will wipe some of your saved plugins and settings). Resolved my startup problem and my xml editor problem.
Just close all the xml files and restart your Eclipse SDK
An additional solution that worked for me and might work for others:
Create a new workspace and import your existing projects into it. I felt a little better about trying this than I did blowing away or moving my .plugins directory in the existing workspace. After I created the new workspace and imported the project that was giving me the cryptic "Failed to create parts controls" message, it worked fine. I'm pretty sure it's something bad in the .plugins or elsewhere in the old workspace, but I'll just keep using this new one until it starts to crap out on me.
Note that this can also happen if the containing folder contains too high a resolution
Example:
layout-sw500dp (this folder works okay)
layout-sw1000dp (this folder causes "Failed to create the part's controls" error)
I finally found out...
I had the problem even after deleting and setting a new copy of eclipse. The problem was because of the wrong Java version. You should find the right Java version for your eclipse.
In my case I have a project which uses Java 8 and for that I use eclipse Luna. But my other project which I develop it vie eclipse kepler uses java 6 (The project with the problem!).
Since Kepler and Java 8 are not compatible, I got this weird behavior from kepler. As soon as I ran Kepler via Java 6, everything was back to normal.
If you wanna know how to sets different Environment Variables and sets your Windows Path without setting up the Environment variable everytime for each project, let me know, I would be happy to share how to write a batch file to do that...
Every time I open Eclipse, I get the following error messages:
Android SDK Content Loader:
parseSdkContent failed java.lang.NullPointerException
Initializing Java Tooling
An internal error occured during: "Initializing Java Tooling". java.lang.NullPointerException
Loading data for Android 2.2
Parsing Data for android-8 failed java.lang.NullPointerException
Loading data for Android 2.3.3
Parsing Data for android-10 failed java.lang.NullPointerException
Loading data for Google APIs (Google Inc.)
Parsing Data for Google Inc.: Google APIs:8 failed java.lang.NullPointerException
See link for screenshot:
http://i.stack.imgur.com/lhhQQ.png
(I am using OS X Lion, and Eclipse Helios)
First i read some posts saying that it was the AVD.ini file in the .android profile that was causing the trouble. I tried deleting all the entire .android profile folder as suggested in Android SDK Content Loader failing with NullPointerException. This didn't correct my problem.
I tried deleting the entire Android SDK folder, downloaded it again and installed a couple of Android versions through it. Still the same error messages...
To ensure that I didn't have any old plugins or something that were the issue, I uninstalled eclipse, downloaded it again and installed the Android plugin again. (So the plugin is up to date).
When I go into one of my Android projects, I get error messages on places where I acces resources by using the R file. Regular Java projects work fine, but all Android projects gets small red boxes with white crosses on them. I have been searching for a solution to this problem since yesterday, but at this point I'm completely qlueless and would appreciate any help I can get!
Close all open projects and exit Eclipse. Now you can open Eclipse without getting the error. Start opening your projects one by one to find which one causes the problem. This is most likely because you deleted a Device profile inside the AVD manager.
Do not delete all the full .metadata
Backup .metadata
delete only .metadata/.plugins/org.eclipse.core.resources/.project
restart eclipse
Observation : the projects folders are created
Further - if you are using svn/git/hg have code repository links it would be destroyed, so to reinstate
close eclipse
copy relevant projects from backup to merge with current projects in .metadata/.plugins/org.eclipse.core.resources/.project
restart eclipse
Downfall - sporadic fail error may occur (sync or something) - harmless
backagain
I encountered exactly the same issue this morning. This is a workspace related issue.
Solution 1
I looked into my .metadata and read .bak_number.log files . Some layouts failed to parse and my projects were out of sync with the file system.
So I deleted all the .bak_number.log files. Relaunch Eclipse and the whole worskspace should work again the way you left previously.
Solution 2
However if it's not due to out of sync with the file system. Change the workspace then import all the eclipse projects from the previous workspace.
Thanks the project.properties files , the dependencies are still kept.
PS : I should return to IntelliJ :)
first close your Eclipse
Go to your workspace and rename .metadata to tushmetadata and go to
tushmetadata- >.plugins -> org.eclipse.core.runtime -> .settings
and copy all files from it.
now open the Eclipse and go to your workspace there you can see the
newly generated .metadata folder in that go to .plugins ->
org.eclipse.core.runtime -> .settings and paste here and do not
overwrite any file.
Try to "Hello World" project and run it.
Try to delete file .metadata from your android workspace folder. .Metadata folder contains all configuration files for eclipse. It works for me.
Your answers might be right. What I did was to change my workspace. I redownloaded the project I was going to work on from git, and reimported it. Now it works fine :) Maybe there was some files in this project that made the error messages apear? Dunno....
I have remove the .metadata folder but after it, when I run the eclipse, I cannot creates any Android project. To solve it, I have done the follow:
Go to the main work directory of eclipse
Localize the folder com.android.ide.eclipse.adt It should be in .oldMetadata/.plugins/
Copy it to the new eclipse configuration: .metadata/plugins/
See the full solution here:
http://www.jiahaoliuliu.com/2011/06/running-android-sdk-in-eclipse-errors.html#solution4
For me, the source of the NullPointerException problem was a host-side Junit test project that references (and tests) code from an Android project. It didn't have a project.properties file. It's not an Android project, but for some reason the newer versions of the SDK somehow expects the file there. To fix the problem, I just copied a project.properties file from an Android project to the host unit test project.
When I met this problem about a year ago, I had some projects in my workspace that needed a specific Android SDK level (let's say 2.1) and i didn't have it installed in the Android SDK.
slott's answer helped a lot. Deleting the .metadata or reinstalling eclipse didn't though. The trick was to isolate the project causing the problem, delete its .settings folder and .project file and reimport it.
I discovered another cause, where I'd added a space character into an otherwise blank line in the project.properties file. When I eventually ran android update project -p .
the program (android.exe) threw a NPE exception. When I deleted the space from the blank line the android update project command worked and eclipse started behaving (after running clean a few times).
This happened with r20 of the Android SDK on a Windows 7 64-bit machine.
FYI my change that fixed the problem in project.properties is public at http://code.google.com/p/android-daisy-epub-reader/source/detail?r=517
This is just weired.
In my case when I took a subversion update, I was getting this problem. The reason was the corruption of my project.properties file (due to subversion conflict).
I just corrected the file and problem got solved.
I found it's just missing project.properties file in the project folder. After copying one from another project the error is gone. The only valid line in project.properties is
target=android-8
If you are using SVN or GIT please check whether the project.properties has conflicts or not.
Sometimes project can not be open because of this.
I hope this is useful to someone and saves his/her time: My colleague was facing same issue and we did almost everything mentioned here, with no luck. In the end we changed the Android SDK version in the manifest file and it worked.
This solution worked for me.
Close Eclipse and delete all .markers inside your workspace folder.
Restart Eclipse (once I had to restart it twice, it hang on the first but worked on the second for no aparent reason).
Of course, it's always safe to back them up first.
I am getting an error in my Problems tab for my Android Project in Eclipse. The error is "Android Packaging Problem" with an Unknown location.
Unknown Error NullPointerException
I cannot determine what this problem is. My project was working a few hours ago. The only change I made was to add a public interface ITrackDao to my project and implement it. There are no errors associated with this.
I am not even sure where to begin to look. I cannot launch the application. Can someone give me an idea on what area I can look into?
Thanks
Peter
I was confronted with this problem too, and I solve it by clicking Menu->Project->Clean. The error goes away after cleaning the project.
I had a similar error - but instead of a NullPointerException it was an InvalidoperationException from somewhere in Eclipse.
A Project > Clean solved that one too.
Cleaning the project was not enough for me. I had to first remove a <classpathentry/> that specified the interface from the .classpath file and a <linkedResources>'s <link> to the same interface in the .project file before cleaning the project would remove the error.
I had the same problem. I tried the clean up option but for some reason it still did not work. I copied my project and pasted it as a new project and that cleared it up for me.
I had this same error in an imported project and cleaning was not helpful, however by deleting the library references in the .project and .classpath eclipse files, and then relinking things and cleaning, I was able to get things building again.
First I should recommend that you start using subversion or other versioning on your apps, that way you can pinpoint every change between each iteration. If your project was in subversion you could compare with previous and then pinpoint what changed.
With that said, I would also check through any recently changed layout XML, make a change and hit save and make sure you don't get errors. I've experienced strange null pointer/errors in Eclipse at times when my layout was fine, and by making a change and saving, the errors go away.
I ran into the same problem coz of my blackberry sdk installation. I think it messed up my eclipse 3.6.2 install . I just reinstalled eclipse and it all worked like a charm
I worked with a SVN project and one installation have eclipse Galileo. The other have updated to Helios.
In Helios I found this problem and clean is no solution.
After Galileo reinstall (all installations equals now), I deleted workspace and a new checkout resolved the problem.
I had the same problem. I tried the clean up option but for some reason it still did not work. I solved this problem using this step
Project name ->Android tool ->Add support Library