[Solved]-Error: Unable to open class file R.java-eclipse

I would say that once you have created your project and you've mention the R.class error --> just restart the Eclipse IDE and everything will be fine ;)

1.-Open Eclipse 2.-Open Window/Preference 3.-Expand JAVA option 4.-Select Build Path 5.-Check the option "Projec"t and uncheck "folder" options 6.-Click on OK 7.-Restart eclipse IDE

Let's go to code !!

This problem can be solved by merely cleaning and rebuilding the project. How ever there is a link to the latest version of Eclipse for Android. **Eclipse Java EE IDE for Web Developers.

Build id: 20100218-1602

(c) Copyright Eclipse contributors and others 2005, 2009. All rights reserved. Visit http://www.eclipse.org/webtools**

Here is a link to Android Tutorial with Eclipse http://developer.android.com/resources/tutorials/hello-world.html

In mac, I select Project>Clean after that, i unchecked Build Automatically then i run the project and it works :)

Windows 7 64bit, run eclipse as administrator, solved the problem for me.

In my case there was no gen folder after pressing clear...

To solve it, i created a new gen file, then when to Build Path => Configure Path, and pressed ok.

All went smooth after that :-)

Following steps are done as solutions:

1. Collapse the project tree structure

2. Go to the workspace and remove the readonly permission of the workspace.

3. right click "default.properties" and go to properties and uncheck the readonly permission in eclipse.( this is done when the workspace shows build error even though there are no compilation issues)

I had this exact same problem with no helpful errors. finally, I tried deleting my debug keystore and it worked:

rm ~/.android/debug.keystore

I had seen people mention that, but I figured it wasn't my problem because I wasn't getting any errors relating to the debug keystore. I found the answer here:

"Debug certificate expired" error in Eclipse Android plugins

apparently the debug keystore is only valid for one year.

Had a almost identical issue with Eclipse Helios 64 bit on Linux, but I had the "1.6.0" API selected like you. The bizarre thing was I could type;

cat <the path it was moaning about>

in a console it would display correctly.

I created a new AVD which used Android 2.1, the issue magically vanished. Perhaps it's a bug in Android SDK or Eclipse?

Right click on your project name in package explorer. Then click 'Validate'. It will be fine.

Here is how to fix it: Go to your "workspace" folder and make sure it's not "read-only"

Eclipse Menu > Projects > clean

Had the same issue.I was able to solve it by doing the following:

1. go to Window/Preferences/Java/Build Path
2. select 'Folders' and change the output folder to 'gen' (this is where Android looks for the generated java files,but the default in eclipse is 'bin').
3. restart Eclipse

Windows 7,Eclipse 3.5.2

Configure buildpath.. check android , it worked, of course i followed one of the posts mentioned above window, preferences, java, java build path and selected project, then created a project, and tried to build same error, then i checked build path and saw android is unchecked, checked it and build again, it works!

After creating the Project, Right click the Project Folder within the Project Explorer on the Left Tab of Eclipse.

Click on Source->Format.

The Console will say:

[2010-11-24 11:57:42 - YourProject] R.java was modified manually! Reverting to generated version!

Then you're good to go. Try running your Project and it will compile.

Check your imports. If this has sneaked in, then delete it.

import android.R;

I had a similar error on the creation of new projects myself. After messing around I tried moving the R.Java file into the same location as my projects java file (the src file). Eclipse then saw I removed the R.Java file from its location and created another and that seemed to clean up the error.....I dont know if it was because eclipse rebuilt the file and then saw it or what but that seemed to work for now.

Removing Read Only attribute on Eclipse workspace directory and Project->Clean->Build Project did the trick for me. I then clicked on the project directory from within Eclipse and did a F5 (Refresh) . R.java was generated in the gen folder.

Have a look at your console. It is an aapt aborted error. Since aapt is the tool that auto-generates R.java, therefore, R.java was not getting generated.

Since R.java is a auto-generated file that stores information about your drawables you should rebuild your project. Before that have a look at your layout xml files and check them for errors.

Notice that Project -> Build All should be selected. Also try to run your project.

This is a mighty annoying error.

It happens 100% of the time when I create a new android project.

What seems to work for me is to just delete the file (which DOES exist and is accessible by my user), then hit build, and it will regenerate it and stop moaning.

It's clearly a bug as there are too many people getting it simply by filling in the boxes in the new project dialog (like me) without even modifying any code!

I have had same issue, all what I needed to do, was create project and restart eclipse.

//Edit: Complete collapsing of "Package" tree works as well.