I just installed Eclipse on my computer. And I make a blank Android project via its wizard step by step. That means this project should work fine after it is created. But it cannot and show error of "R cannot be resolved to a variable". And I found that the gen directory is empty and it won't generate anything new in this directory even that I try to Clean and select Build Automatically option already.
I download an existing Android project from my Github and it can work. But after I run Clean, it gave the same Error information and its gen directory is empty again.
Why and how to solve it? Thanks!
Make sure that you have installed the followings in Android SDK Manager
Android SDK Tools
Android SDK Platform-tools
Android SDK Build-tools
By clicking Window-> Android SDK Manager in Eclipse
Wait a bit to let it fetch the content and you will see if they are installed or not.
It is an error of Eclipse. Create a new Project, copy all the scr and res file to new Project.
It will work fine.
1- Check for errors, if there are just comment it. The idea is to build the project et reconstruct the /gen. After that you can uncomment in good order.
2- Use Clean/refresh/build as many as you need.
3- Sometimes eclipse needs to be restarted..
4- Try to reinstall your sdk tools
5- If nothing is working you should concider reinstalling your ADT if you are using the bundle. If you are using classique eclipse reinstall android sdk retry and if it's still not working reinstall eclipse too.
hope it helps
Most of the times the error comes from wrong formatting in the XML files, which Eclipse doesn't always detect.
Make sure to go through the XMLs and check for potential errors.
If all looks good, rebuild the project.
If that fails restart Eclipse.
If that also fails, as a last resort - copy your project somewhere, reinstall Eclipse and Android SDK tools and re-import your project.
Related
I am facing a problem when I try to create new android project in eclipse adt plugin tools.
ERROR/EXCEPTION::
Errors occurred during the build.
Errors running builder 'Android Resource Manager' on project 'test'.
java.lang.NullPointerException
I have faced this problem two times previously. Only solution was to re-install Windows operating system which actually did solve the problem. But I want a real solution without re-installing Windows.
Switching to a new workspace worked for me.
File-> Switch Workspace.
found a better solution. in the create project wizard. don't create an activity in the wizard. just untick create an activity and just create the activity manually in the manifest.
I guess you upgrade your java to java7u55.
because I am using mac, but, FYI
I solve this by edit eclipse.ini, force the ide to use java 1.6
-vm
/System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Commands/java
you could try the same.
In my case, the error was solved by changing the workspace folder permissions with chmod 777.
I am using Mac OS X and downloaded the ADT bundle for Mac.
If you close eclipse and then look in your system processes and still see adb running, then that's the problem - it crashed. In my case it was because I have extension files for other programs in my JRE that the adb doesn't seem to like. Remove all your ext files, force shut down your adb.exe and then restart eclipse.
Root exception:
java.lang.NoClassDefFoundError: org/apache/log4j/Priority
Usually this means that they have one more time introduced a bug.
The "magic passes" that may help or not help are:
Pressing F5 (refresh)
Updating Android, Eclipse and ADT (knowing that you do have such a problem, I myself definitely will not do any such updates in the near future)
Creating a project from the command line, building it and trying to import
If you have any project that already works, you may try to take files from that project.
Read the logs, they are usually more informative than just the last 30 lines, but on Windows you will have to either configure the screen buffer height to be about 300-600, or redirect the output to a file.
Clean and build again.
You usually get this after an SDK/ADT update.
Go to your SDK manager and ensure that there are no updates. Then in Eclipse go to Help > Check for Updates and install any updates it finds.
Restart eclipse and hopefully it should all work.
Failing that uninstall Eclipse and re-install Eclipse and the plugins again should fix it as well, no need to re-install your whole PC.
I use maven to build and integrate android projects with jenkins/netbeans. For editing android resources, I often use Eclipse because of the ADT plugin and better android resources support.
Eclipse (Kepler) has serious problems when you import maven-based android projects. It expects the project.properties file in the root folder and will NOT generate it on its own no matter what. Example content:
# this file is needed by eclipse (adt plugin).
# Project target.
target=Google Inc.:Google APIs x86:19
Additionally, create a sym link called "gen" pointing to target/generated-sources/r if using maven to build the android project on the command line. That way, you should be able to do "File->Import...->Existing Android Project". You get an error message, but it didn't matter in my case.
Additional hints in case you have problems with m2e-android plugin:
always check that the output folders for source dirs and resource dirs are correct.
check that source dirs are set as source dirs (you usually get a corresponding warning)
if resources from dependencies are not included in the final apk, check the filter settings for your resource dirs
you may need to "import maven project from existing sources" before importing it as android project from existing sources.
make sure dependencies are imported into the workspace and open and referenced (project props -> android -> add lib)
eclipse adt does not support aar libs, use apklib instead
It can happen if you are changing the location of files that your
eclipse project uses.
In that case you can copy the files directly to your resources folder inside the workspace instead of linking them with "import"
These simple steps put me out of this trouble -
In Eclipse, Help menu -> Check for Updates.
Select all Android related plugins.
Click Next, Accept the agreement page then proceed to install the
plugin.
Make sure your java path points to the java SDK bin directory.. make sure you have installed the latest JDK t be safe..
You can also try one of these:
Close and open the project in Eclipse
Click right on the project and choose: Android Tools -> Fix Project Properties
I beat my head against a wall for a day because of the same problem. My solution (OS X): I had a stale "java_home" definition in my profile pointing to a dead symlink, as well as old classes in /Library/Java/Extensions. I removed the definition and symlink, along with two classes in Extensions (ActiveMQ and Geronimo, FWIW) and the problem went away. Not sure which step was the actual "rectifier" but if any of those conditions apply, you might want to check them.
I faced same problem on my New Macbook Pro so I just Downloaded JDK and installed it and problem fixed.
I was experiencing the same issue - I refreshed and updated Eclipse and Android plugins and was still seeing the NPE. What worked for me was changing the order of operations.
In order:
1. update Eclipse & Android plugins
2. after the update has completed, perform the F5 Refresh in the current workspace
Make a copy of your project in Explorer/Finder. Delete the project in ADT/Eclipse. Import the project again using Eclipse. Project/Clean then build. This works for me.
I have tried every solution I found on the web and they did not work.Then I remember java version on my Mac was 1.7 and I have installed subversion version 1.6 and the problem occured after that installation.Also I have deleted eclipse and used a clean eclipse and Android sdk installation I still got the problem, then I uninstalled the JDK 7 as it is told in here http://docs.oracle.com/javase/7/docs/webnotes/install/mac/mac-jdk.html and my problem is solved.
I have several projects in my folder. Every time I start a new one I close the others. I got this error because appcompat_v7 was closed.
Right click on appcompat_v7 and select Open Project.
This solved my problem.
Solved after changing a setting in eclipse.ini. I am using OS X 10.11.4 and Eclipse Mars 4.5.2.
Go to the folder of Eclipse.app in Finder.
Right click to open a menu, and click Show Package Contents.
Go to /Contents/Eclipse.
Open eclipse.ini in your favorite text editor.
change -vm path like below:
BEFORE: /Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home/jre/bin
AFTER: /Library/Java/JavaVirtualMachines/jdk1.8.0_73.jdk/Contents/Home/jre/bin
reopen Eclipse.
enjoy :D
Today, I update ADT to 22.0.1.v201305230001--685705, and found that Eclipse stopped generating R.java. I believed that it is problem of Eclipse, because I create a whole new clean android project, and I cannot even run it as android application. I cannot find any files under gen folder.
The version of Eclipse is 4.2.2, is there any way to solve it?
I try to use Eclipse 4.3 with the latest version ADT, but the problem is still there.
I had the same problem.
Open up the android SDK Manager, and install the new android build tools. Without this you will no longer be able to build anything.
For some reason they have seperated them, and a lot of people are not noticing.
Try deleting bin folder and clean the project..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 It seems to be a common issue with many different answers
Update android-sdk, I think sdk need Android SDK Build-tools. For update it follow some steps--
Go to Window->Android SDK Manager.
Update and Install all tools (Android SDK Tools, Android SDK Platform-tools,Android SDK Build-tools) which are in Tools folder.
Check the xml files of your layout whether they are properly saved with no error or not.
I have faced similar problem that suddenly R.java is disappeared and eclipse could not regenerate it after building SDK. I checked SDK manager and saw that Android SDK build tool is perfectly installed. Finally, I have noticed that there are some errors in xml files. After fixing and saving those, R.java generated automatically in my case.
I have installed eclipse juno and also added the plugin's of the android sdk. After installing android SDK manager, I've created a new android project, but a problem arises in R.java file. R.java doesn't open. Please give me a solution. I am new to android.
Click on Project -> Build Project
Edit
Remove your gen directory and bin directory
Click on Project -> Clean (wait till cleaning complete)
Click Project -> Build Project
Make sure you have Android SDK Build-Tools installed from the Android SDK Manager
Click this guy:
Then make sure the top three are all installed:
Ensure the code, resources and AndroidManifest.xml do not have any problem.
First, delete the R.java file. As soon as you delete, that file should be re-generated automatically if you have enabled automatic build (Project->Build Automatically).
If that doesn't work try to clean the project by clicking on Project->Clean.
If it still doesn't work then, confirm you have android sdk build tools installed. For this, open Android SDK Manager and ensure Android SDK Build-tools has the status of Installed.
Also confirm that the ADT is up-to-date. To update ADT, in eclipse go to:
Help -> Check for updates. Select the necessary entries like: Android Development Tools and update them.
Hopefully one of these solutions will solve your problems :-).
After upgrading to Android ADT version 22 and cleaning my project, the R.java files went missing. I can't use setViewContent(R.layout.activity_main) because the activity cannot reference to the xml layout (due to the missing R.java). Also, when using the (ctrl + space) to get suggestions for setContentView, the code is not typed in. Upon looking at the error log, it shows that there was an "Unhandled event loop exception". The plug-in involved is the org.eclipse.ui.
Also, whenever I create a new Hello World project, the gen folder is empty.
After a few hours, I tried the android studio. But I didn't like it there. Then, when I went back to Eclipse, there was an update for SDK platform tools and build tools. I updated them but I still get the errors.
I tried cleaning the project but no luck. What seems to be the problem?
I had the same problem just solved it.
check:Java/Eclipse - No more R file ever
More info:https://groups.google.com/forum/?fromgroups=#!topic/android-developers/rCaeT3qckoE%5B1-25-false%5D
Update Android SDK Tools and Android SDK Platform-tools and Android SDK Build-tools from Android SDK Manager
Add abover dir to your ENV $PATH
Not enough credits (yet :-) ) to vote up or comment directly on Rany A. Ishak's answer, but after one day lost trying to fix these silly problems, I'm very confident I've found the right solution...I'm installing Android SDK Build-tools right now, I'll get back soon on this!
The solution for this is, open "Android SDK Manager". Download "Android SDK build tools". Then for safety, restart your eclipse. That's it. Back to normal. All apps start building.
Android SDK now has a special package: Build Tools. It was not present in earlier SDK versions, and seems like it MUST be installed in order to generate those R files. It is now the one package that does that stuff. (And probably everything else regarding building for Android). So, if you not have that installed (and you will likely not have if you just upgraded the SDK), it's like missing a compiler - you can't ever expect your code to be compiled if there is no compiler.
I had the same exact problem after updating to SDK 22. There seems to be an issue in the Android SDK update process that the process needed to run twice to update the SDK Tools completely. Make sure you check the SDK manager a few times by closing and re-opening the SDK manager (not Eclipse) to load the new updates. Then restart eclipse and check the SDK manager again. Make sure all items are updated. Then clean your projects and R.java will get created again.
In Eclipse, go to Project menu,there is an option build automatically, click it. That would help you build the R.java file everytime modifications are made in your project. The Clean option is also there under Project. It will help you.
I tried the following. Let the application name be "My First Application". Then the name of the package should be com.xx.myfirstapplication.yy. Make sure that you add a yy after the application name in the package field while creating the application. Hope it helps.
The Same problem happened to me also,
1.Check that Android SDK Build-tools is installed. Window->Android SDK Manager->Tools->Android SDK Build-tools
2.Make sure when you update the Android SDK Tools, you also update the Android SDK Platform-tools and Android ASK Build-tools. Build fails silently if they don't match.
Solution
1.Update Android SDK Tools and Android SDK Platform-tools and Android SDK Build-tools from Android SDK Manager (Window->Android SDK Manager->Tools->Android SDK Build-tools).Then restart the eclipse.
This is.... "Much ado about nothing"!!!
In my case there is error due to "&" inside strings.xml file(but error not shown) for declaring string for a array type. Now the problem has been solved as I changed "&" to "and".
So, please make sure that you do not have such silly use of symbols, and clean the project.
I had the same problem,
I just removed all the errors in my source files and xml files then R.java was generated.
I have a big project into eclipse.
After I upgraded from SDK manager, R.java gave problems and I deleted it.
Now it remains only the folder "gen" empty.
I tried, without success, these things:
-clean project with and without "Build automatically", without any error (reported by eclipse) in the file inside the folder res
-ctrl-shift-o
-remove android.import.R
-F5
space and then remove the add-in manifest
-check the PACKAGE of the project
-restart eclipse
-restart the pc
-exclude the project from eclipse and then import it again
.. and anything I read in these 2 DAYS
What can I do??
It happened the same thing to me yesterday. I re-open the SDK Manager and suprisely some stuff in the tools folder wer'ent upgraded. Launch the SDK manager and check if you got the last revisions of this stuff. Then restart Eclipse and rebuild your project.
I had the same thing, did you update the SDK the last 2 days? (API 17)? There is probably a problem with that, try updating it again, it will probably work again.
If not you can try Project > Clean. Also the drawable and layouts mustn't contain any errors or capitals...
Might be the same as this.
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.