Question: 1. Can not extract resource from com.android.aaptcompiler.ParsedResource@ef79973.
2. Can not extract resource from com.android.aaptcompiler.ParsedResource@4c95ce87.

C:\Users\User.gradle\caches\transforms-3\4948de165b5218454019e0897afa16ee\transformed\material-1.6.1\res\values\values.xml:829:4: inner element must either be a resource reference or empty.

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:mergeDebugResources'.

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> A failure occurred while executing com.android.build.gradle.internal.res.ResourceCompilerRunnable
> Resource compilation failed (Failed to compile values resource file D:\AndroidStudioProjects\AndroidStudioProjects\NewProject\app\build\intermediates\incremental\debug\mergeDebugResources\merged.dir\values\values.xml. Cause: java.lang.IllegalStateException: Can not extract resource from com.android.aaptcompiler.ParsedResource@4c95ce87.). Check logs for more details.
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BUILD FAILED in 2s

How to fix this error?

Answer: 
I got the same issue because i had in string resource a ' character and i had to change to \'
Usually these type of errors occurred when you try to add a string or any other resource with the same name that was already exist. e.g. If you have a string resource named 'alpha' ABCDEF in strings.xml file and if you are trying to extract another string e.g. "aeiou" and giving the same name 'alpha' that was already exists then the compiler automatically generates aeiou string resource in ids.xml. Therefore when you try to build the project the above error will be occurred. So to solve this problem you should to delete a new string resource from ids.xml then you can to solve the problem.