The “package r does not exist” error message is a problem that shows up in Android Studio. Android Studio is a program for Android application advancement and development. It is associated with an important file used in building the application. Unfortunately, it is not as easy to solve as a code mistake.
The circumstances of this error.
This message tends to occur when compiling an application and the package r file cannot be found in the proper directory. Because it may not be a command line or source code problem it cannot be fixed by simply correcting a coding mistake. Unfortunately, this message can be triggered by a problem in any number of files that can prevent the r class package file from being created. This makes finding and correcting the error more difficult than simply tracking down some poorly written code in your new project data. Unfortunately, this means that the solution is usually more complicated in correcting decoding mistake.
What is causing this error?
The main cause of this message is that the software cannot find the package r.java. This manifest file contains critical class definitions for compiling your application. It is automatically generated by the software based on information contained in an XML file. This means that any errors that occur in AndroidManifest.xml or any other of these XML resource java files will stop the generation of the r.java layout file. If this happens r.java will not be in the folder your project looks for it in to import the needed default r packages. Put simply if r.java is not in the right working directory the program will return the message that the required package r does not exist in the project root directory.
How to fix this error.
Since this error is not a problem with the code you will not be correcting it at the command line. Since your problem is not with multiple packages one step is to actually check your app or project root directory for r.java. If you cannot find it then it was simply not created due to an error in some other java files.
The most common solution is to clean your Android project and then rebuild it. To do this find “build” on the menu in Android Studio and find the third item down. Selecting this option will clean up your new project or app. Next, go back to “build” on the menu in Android Studio and find the fourth item down. Selecting this option rebuilds your Android project. In most cases, this should fix the problem.
If you have enough experience you may want to look through Android Manifest.xml file for any problems. For example, the package value and launcher activity class attached package should match. So correcting this mismatch should correct it.
If all else fails try restarting Android Studio or if needed your computer. These actions have also been known to fix this problem.
The “package r does not exist” message is something you do not want to get when working with Android Studio. However, it does have simple solutions for you to try that should fix it. As with most problems in programming, this message is a nuisance but not an insurmountable one.
R Error: package r does not exist