Problems with Android Studio! Unable to resolve character R, no resource found matching the specified name

I'm having big problems with Android Studio. I recently ordered a project that I was developing with a friend of mine, and when I open it, all the Rs in the project go to RED ("can't resolve R character").

I searched for an answer to this problem and tried almost everything ... Sync Gradle, Clean class, etc. Oh, and when I use Build -> Clean Project it returns 118 errors. Here is the (almost complete) OUTPUT console:

 Executing tasks: [:app:assembleDebug]

Configuration on demand is an incubating feature.
Relying on packaging to define the extension of the main artifact has been deprecated and is scheduled to be removed in Gradle 2.0
:app:preBuild
:app:compileDebugNdk
:app:preDebugBuild
:app:checkDebugManifest
:app:preReleaseBuild
:app:prepareComAndroidSupportAppcompatV72100Library UP-TO-DATE
:app:prepareComAndroidSupportSupportV42100Library UP-TO-DATE
:app:prepareDebugDependencies
:app:compileDebugAidl UP-TO-DATE
:app:compileDebugRenderscript UP-TO-DATE
:app:generateDebugBuildConfig UP-TO-DATE
:app:generateDebugAssets UP-TO-DATE
:app:mergeDebugAssets UP-TO-DATE
:app:generateDebugResValues UP-TO-DATE
:app:generateDebugResources UP-TO-DATE
:app:mergeDebugResources UP-TO-DATE
:app:processDebugManifest UP-TO-DATE
:app:processDebugResources
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:7: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:9: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Body1'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:11: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Body2'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:13: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Button'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:15: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Caption'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:17: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Display1'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:19: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Display2'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:21: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Display3'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:23: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Display4'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:25: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Headline'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:27: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Inverse'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:29: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Large'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:31: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Large.Inverse'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:33: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.PopupMenu.Large'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:35: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.PopupMenu.Small'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:37: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Medium'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:39: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Medium.Inverse'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:41: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Menu'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:43: error: Error retrieving parent for item: No resource found that matches the given name '@android:TextAppearance.Material.SearchResult.Subtitle'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:45: error: Error retrieving parent for item: No resource found that matches the given name '@android:TextAppearance.Material.SearchResult.Title'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:47: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Small'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:49: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Small.Inverse'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:51: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Subhead'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:53: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Title'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:55: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.ActionBar.Menu'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:57: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.ActionBar.Subtitle'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:59: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.ActionBar.Subtitle.Inverse'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:61: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.ActionBar.Title'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:63: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.ActionBar.Title.Inverse'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:65: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.ActionMode.Subtitle'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:67: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.ActionMode.Title'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:69: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.PopupMenu.Large'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:71: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.PopupMenu.Small'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:73: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Button'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:75: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.ActionBar.Subtitle'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:77: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.ActionBar.Title'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v11\values.xml:39: error: Error: No resource found that matches the given name: attr 'android:actionModeShareDrawable'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v14\values.xml:12: error: Error: No resource found that matches the given name: attr 'android:actionModeShareDrawable'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v11\values.xml:46: error: Error: No resource found that matches the given name: attr 'android:actionModeShareDrawable'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v14\values.xml:20: error: Error: No resource found that matches the given name: attr 'android:actionModeShareDrawable'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v11\values.xml:53: error: Error: No resource found that matches the given name: attr 'android:actionModeShareDrawable'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v14\values.xml:28: error: Error: No resource found that matches the given name: attr 'android:actionModeShareDrawable'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v11\values.xml:60: error: Error: No resource found that matches the given name: attr 'android:actionModeShareDrawable'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v14\values.xml:36: error: Error: No resource found that matches the given name: attr 'android:actionModeShareDrawable'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:87: error: Error retrieving parent for item: No resource found that matches the given name 'android:ThemeOverlay.Material'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:89: error: Error retrieving parent for item: No resource found that matches the given name 'android:ThemeOverlay.Material.ActionBar'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:93: error: Error retrieving parent for item: No resource found that matches the given name 'android:ThemeOverlay.Material.Dark'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:100: error: Error retrieving parent for item: No resource found that matches the given name 'android:ThemeOverlay.Material.Dark.ActionBar'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:108: error: Error retrieving parent for item: No resource found that matches the given name 'android:ThemeOverlay.Material.Light'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:267: error: Error retrieving parent for item: No resource found that matches the given name 'android:Widget.Material.ActionBar.TabText'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:269: error: Error retrieving parent for item: No resource found that matches the given name 'android:Widget.Material.ActionBar.TabView'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:271: error: Error retrieving parent for item: No resource found that matches the given name 'android:Widget.Material.ActionButton'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:273: error: Error retrieving parent for item: No resource found that matches the given 
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:259: error: Error: No resource found that matches the given name: attr 'android:colorPrimary'.
C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug\values-v21\values.xml:260: error: Error: No resource found that matches the given name: attr 'android:colorPrimaryDark'.

 FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:processDebugResources'.
> com.android.ide.common.internal.LoggedErrorException: Failed to run command:
    C:\Users\Juliano\Downloads\Compressed\adt-bundle-windows-x86_64-20140321\adt-bundle-windows-x86_64-20140321\sdk\build-tools\20.0.0\aapt.exe package -f --no-crunch -I C:\Users\Juliano\Downloads\Compressed\adt-bundle-windows-x86_64-20140321\adt-bundle-windows-x86_64-20140321\sdk\platforms\android-14\android.jar -M C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\manifests\debug\AndroidManifest.xml -S C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\res\debug -A C:\Users\Juliano\Documents\Projects\HueLoc\app\build\intermediates\assets\debug -m -J C:\Users\Juliano\Documents\Projects\HueLoc\app\build\generated\source\r\debug -F 

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 9.873 secs

      

        
        
        
      

    

Yes, this is ... Please help me! (I am using W7, latest Android Studio)

// UPDATE: I fixed it by deleting the value.xml file in the "value21" folder ... apparently Android Studio had an update and it forced me to use Android L ... I changed the appcompat library version to 19 (I used 21 so I did a downgrade) in my project's build.grade (in dependencies) ...