Eclipse Error: R Cannot Be Resolved to a Variable

R cannot be resolved to a variable ?

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

R cannot be resolved to a variable ---

this error occurs when some xml file under /res folder have some issues or you have some errors in your manifest file. see error log on eclipse to find the real problem.

Eclipse error: R cannot be resolved to a variable

I assume you have updated ADT with version 22 and R.java file is not getting generated.

If this is the case, then here is the solution:

Hope you know Android studio has gradle building tool. Same as in eclipse they have given new component in the Tools folder called Android SDK Build-tools that needs to be installed. Open the Android SDK Manager, select the newly added build tools, install it, restart the SDK Manager after the update.

Sample Image

R cannot be resolved to a variable even after new Eclipse install

This looks like a 64bit issue, as android is looking for a 32bit ADT, there are a few options to solve this. Have a look at this question: Android SDK Setup under Windows 7 Pro 64 bit

I solved this under linux by doing sudo apt-get install ia32-libs

R cannot be resolved to a variable

you are using support library right?? ok lets try some options

1: goto your support library folder and open libs and copy support V7 appcompat jar,
   pat it to your project and add  to build path-(thats if you've not done that)
   if its already done delete what's there-(in ur project) & redo.

it happens most of the time..

2: check your resource folder for both support library and project.. right click on
   support library and click properties and select android and choose the latest
   build target.. and clean and rebuild

an error there can make your project not rebuild correctly

3: R is an automatically generated class that holds the constants used to identify
 your >resources. If you don't have an R.java file I would recommend closing and reopening your
 project or going to >Project > Build all (and selecting "Build Automatically"). If that doesn't work than try making a new project

lastly do you have android build tools? check this post
hope it helps

Edit: on your d.format(planetWeight) i dont see any where in your code that you instantiated "d" as variable to use it..(java is object onriented)...hope am right