Android Studio marks R in red with error message cannot resolve symbol R but build succeeds

Question

In every project I ve tried to create in Android Studio  all usages of R are marked in red with the error message  cannot resolve symbol R   but the compilation succeeds and the application runs  This is really annoying  as it blocks auto-completion and shows huge red waved lines all over my code   I m running Android Studio 1 7 0 and creating the project with default settings  A screenshot is attached     This is my build gradle   buildscript       repositories           mavenCentral             dependencies           classpath  com android tools build gradle 0 4          apply plugin   android   dependencies       compile files  libs android-support-v4 jar      android       compileSdkVersion 17     buildToolsVersion  17 0 0       defaultConfig           minSdkVersion 7         targetSdkVersion 16           This is how the Project Structure looks like     Any idea how to fix this

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In most cases  there is some problems with your resources  i e  layouts  styles  etc  so try to find and fix the problem in your resources then clean your project

User · Answer

Rebuild the project  If  1  does not work  restart the Android Studio Eclipse    If neither works  check all your xml files  This error occurs when your xml file is incorrect

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Cleaning the Project helped in my case  Go to  Build - gt  Clean Project

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DO NOTHING  Just Update Android Studio  Resolve my problem  Work perfectly

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When I was beginner at Android studio  this was general issue I face through   Generally the problem arises when the R java files during conversion of hex code properly donot recognize the appropriate magic number   So we should kept in mind that all the XML files are properly wriiten This is oftenly arises due to problem in XML files   Go in each XML files n be sure all the files are true means valid   Then go to File and synchronize the project  My error remove many times by such steps

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In my case  it was gradle issue  I solved it by refreshing gradle   Firstly  Click on gradle icon which right side on Android Studio Then click on the refresh button

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The problem  like most people have submitted  is most likely from the  xml files  But it can be quite a chore locating it   In my case  there was an attribute in the manifest xml file that caused the problem  I had sleepless nights until I discovered it and simply deleted the line   The attribute was      android fullBackupContent

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I had same problem while using exercise files from a training website and tried resolving the problem by uninstalling android studio and deleting all associated directories and reinstalling it but this yielded no result  However  I noticed that The tutorial i was viewing stored its exercise files on the DESKTOP while mine was in a folder in my DOWNLOADS directory so I Simply copied all exercise files to my Desktop  this made my exercise folder structure identical to that of the tutorial creator and this did the trick

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Recheck the naming convention of the images and the validity of the XML in your resource files- then rebuild the project after cleaning

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I had similar issue with  com android tools build gradle 3 3 1   I tried all above solutions nothing worked  It was actually build gradle 3 3 1 issue  I changed it to 3 2 1 then it worked    So it can be issue with build gradle version

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I resolved it by    1  Sync Project with gradle files 2  Build - gt  Clean Project 3  Build - gt  Rebuild Project 4  File - gt  Invalidate caches    imp step 5  Check your xml files properly

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I had the same problem when I added some image files in drawable folder  where the files name was in  Uppercase  I renamed them to normal format name and pressed rebuild project  It worked for me

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This worked for me    Close and reopen project  Press   Sync Project with Gradle file    is next to AVD manager icon in top menu  repeat 1-2 if Gradle could not Sync for first time   mine worked in second time     Worked with Android Studio 1 2 2

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The problem is that R is a pojo file generated when you build the project and it consist of references to resources in the res directory such as strings  drawable  icons or images  xml layouts etc  You may find it interesting to read the R java file although you may have to exit android studio to do so  You may find it helpful to ignore this type of error because when you compile and build it will go away   What not to do is import the R file

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It has also worked for me by doing manually cleaning the folder  idea libraries and clicking afterward on  Sync Project with Gradle Files  solves the problem  Apparently this Sync does not remove elements  but keep the old ones and add the current ones  Probably a bug to report

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If other solutions does not working   Install new Android Studio version

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Select the File   Project Structure menu option  Press OK on the message box  Project Structure changes don t update build gradle   Select  Modules  on the  Project Settings  side pane  For each module  project   check that the  Excluded Folders  section does not contain the  build  folder  If they do  press the  x  button next to the  build  folder  Press OK   You should now see the  MyAppProject MyApp build source  folder  This should contain the  r  folder  where the R java file is generated   Here  you should either see  debug    release  in blue  if you have a projectFlavour in your build gradle  these will be under the    folder   Within that debug release folder should be your app s package name and then an R java file that contains all your resource ids

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Just add this sentence in your build gradle   compile  com android support design 23 1 1

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I had this issue too  I deleted the extra images from my project s drawable folder

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You have to change the path    for example  import it example project myproject R   change in   import it example project R

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This problem occurs when you rename the package name  After renaming the package name  you must change the older package name to the newer one   For me it solved the problem once I changed that   After that  you might get errors in xml files  that you have to change the package name there also  That s it

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Had the same problem with android studio  I found out that build generated source r contained only release folder and not debug  So for some reason debug build did not generate usable R class   I solved it by opening the project iml file and fixed this line    lt option name  RES FOLDERS RELATIVE PATH  value      gt    to   lt option name  RES FOLDERS RELATIVE PATH  value  file    MODULE DIR  src main res    gt    resynced with gradle  commented out lines using R  run debug to generate the R  uncommented lines using R and run the debug again  fixed

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If you are getting this error  then clean your project    Go to build on top of your android studio Choose the option clean project   The reason behind this is that by cleaning your previous  apk file that is present in your android studio project folder on your system is deleted

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For some reasons  Android studio use different configs for the editor and for the compiler  If it works for the compiler then it s good  If it doesn t work for the editor   it sees unresolved files     You need to add some directories to the source of your project  For example all resources should be marked as  source    File- Project Structure  Select  Modules   then your project  And select the sources tab  On the right find your resources directory and click on the blue  source  button  Close all and it should work   Also  you ll have to make sure that  build source r debug is also a source  In I have all my build source   debug marked as source    main module  iml   lt  xml version  1 0  encoding  UTF-8   gt   lt module external system id  GRADLE  type  JAVA MODULE  version  4  gt     lt component name  FacetManager  gt       lt facet type  android  name  Android  gt         lt configuration gt           lt option name  SELECTED BUILD VARIANT  value  debug    gt           lt option name  ASSEMBLE TASK NAME  value  assembleDebug    gt           lt option name  ALLOW USER CONFIGURATION  value  false    gt           lt option name  MANIFEST FILE RELATIVE PATH  value   src main AndroidManifest xml    gt           lt option name  RES FOLDER RELATIVE PATH  value   src main res    gt           lt option name  ASSETS FOLDER RELATIVE PATH  value   src main assets    gt         lt  configuration gt       lt  facet gt       lt facet type  android-gradle  name  Android-Gradle  gt         lt configuration gt           lt option name  GRADLE PROJECT PATH  value   SherlockHolmes    gt         lt  configuration gt       lt  facet gt     lt  component gt     lt component name  NewModuleRootManager  inherit-compiler-output  true  gt       lt exclude-output   gt       lt content url  file    MODULE DIR   gt         lt sourceFolder url  file    MODULE DIR  build source r debug  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  build source aidl debug  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  build source rs debug  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  build source buildConfig debug  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  build res rs debug  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  build source r test  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  build source aidl test  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  build source rs test  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  build source buildConfig test  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  build res rs test  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  src debug aidl  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src debug assets  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src debug java  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src debug jni  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src debug rs  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src debug res  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src debug resources  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src main aidl  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src main assets  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src main java  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src main jni  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src main rs  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src main res  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src main resources  isTestSource  false    gt         lt sourceFolder url  file    MODULE DIR  src instrumentTest aidl  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  src instrumentTest assets  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  src instrumentTest java  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  src instrumentTest jni  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  src instrumentTest rs  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  src instrumentTest res  isTestSource  true    gt         lt sourceFolder url  file    MODULE DIR  src instrumentTest resources  isTestSource  true    gt         lt excludeFolder url  file    MODULE DIR  build apk    gt         lt excludeFolder url  file    MODULE DIR  build assets    gt         lt excludeFolder url  file    MODULE DIR  build bundles    gt         lt excludeFolder url  file    MODULE DIR  build classes    gt         lt excludeFolder url  file    MODULE DIR  build dependency-cache    gt         lt excludeFolder url  file    MODULE DIR  build exploded-bundles    gt         lt excludeFolder url  file    MODULE DIR  build incremental    gt         lt excludeFolder url  file    MODULE DIR  build libs    gt         lt excludeFolder url  file    MODULE DIR  build manifests    gt         lt excludeFolder url  file    MODULE DIR  build symbols    gt         lt excludeFolder url  file    MODULE DIR  build tmp    gt       lt  content gt       lt orderEntry type  jdk  jdkName  Android 4 2 2  jdkType  Android SDK    gt       lt orderEntry type  sourceFolder  forTests  false    gt       lt orderEntry type  library  name  Sherlock aar  level  project    gt       lt orderEntry type  library  name  SlidingMenu aar  level  project    gt       lt orderEntry type  library  name  support-v4-13 0 0  level  project    gt     lt  component gt   lt  module gt    project iml   lt  xml version  1 0  encoding  UTF-8   gt   lt module external system id  GRADLE  type  JAVA MODULE  version  4  gt     lt component name  FacetManager  gt       lt facet type  android-gradle  name  Android-Gradle  gt         lt configuration gt           lt option name  GRADLE PROJECT PATH  value       gt         lt  configuration gt       lt  facet gt     lt  component gt     lt component name  NewModuleRootManager  inherit-compiler-output  true  gt       lt exclude-output   gt       lt content url  file    MODULE DIR   gt         lt excludeFolder url  file    MODULE DIR   gradle    gt         lt excludeFolder url  file    MODULE DIR  build    gt       lt  content gt       lt orderEntry type  inheritedJdk    gt       lt orderEntry type  sourceFolder  forTests  false    gt     lt  component gt   lt  module gt    Black magic  Not sure about this one  but I heard it working while I m pretty sure it shouldn t change anything  Try compiling and saving the project after commenting all lines that requires R  Then when everything is not red  Try adding them back  The strange this is that your build source doesn t get generated    Also this question suggest checking  compiler use external build   Android Studio don  39 t generate R java for my import project  Side note  Also make sure that in your java code there is no  import android r  from what you shown  everything seems fine  Just strange that the build source isn t being created  For example  I have no build apk  May be you re in release mode and it doesn t create those directories

User · Answer

I had a similar issue for weeks but i had the design lib version with   in my build gradle which made it download the latest version  So i set it to  the version of the package and it worked

User · Answer

Make sure in your AndroidManifest xml the package name is correct  That fixed the problem for me when my R whatever was marked red   I would also recommend checking all your gradle files to make sure those package names are correct  That shouldn t make everything red  but it will stop your gradle files from syncing properly

User · Answer

In my case  I followed all answers I could find on Stackoverflow and none of them seemed to solve this problem  All the answers would point to a possible xml file corruption or conflict with Gradle names  Some answers claimed that it would be necessary to clean the project or Sync Project With Gradle files  none of these solutions would solve the problem  Also  once I was following a tutorial on how to build a Hello World app and I just followed the Android Studio wizard windows without any coding at all  it wouldn t make any sense to suspect it was a typo ar anything like this   TLDR  The problem turned out to be the Build Tools Version  My was set to 23 0 0 rc1  so I changed it to 22 0 1  I suppose it was because I m using the last available release of Android Available   To change this value you can open your Project browser on the left window   right click  app   Open Module Setting  and look for it on the  Properties Tab

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Recently I import my project into Android studio  a part of R are marked in red with the error meesage  cannot resolve symbol R  but the compilation succeeds and the application runs   Develop evirment      IDE  Android studio 3 1 2 System  Mac Os   Solution   step1   Find the configuration file for Android studio My path      Applications Android Studio app Contents bin idea properties   step2   Change 2500     idea max intellisense filesize 2500     to 5000 or more    idea max intellisense filesize 5000

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It s Very important to know that android studio has two type of import    java import type android studio innere import type   and our problem with android import type as import android R  it s work good  but you did t import android R    android studio add this automatic but with different syntax  to solve our problem    firstly you need to make a new project  Blank  then copy all files from your first project to the new project except java files then you need to make new java class with the same name   and Easily copy the all contents of you Activity java class      Don t copy modules and package only copy the content of class       and don t forget to add extends      to your class   you will see message ask you to import some of modules   you must deselect android R and press OK  it s will work correctly         If you find android R only at the dialog box you must click cancel      See Next Image  Select Class To Import if you don t know exactly where the java class file which cased this problem do this solution with all java file in your project     Good Luck    ABT

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Already this has a lot of useful answers but here is something which might work  it did in my case   Remove unnecessary imports from your class then Clean project or restart Studio

User · Answer

Try to first clean and rebuild the project using these command   1  Sync Project with Gradle files 2  Build - gt  Clean Project 3  Build - gt  Rebuild Project   before doing that check if any error in the XML file  If XML  file contains any error its create problem to rebuild the project and affecting the      R

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I ran into the same error  turns out that the manifest file had some errors  After fixing it  clicked Make Project again  it worked fine  Android studio sometimes do not give very helpful error messages

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This error happens to me because there is an invalid input in my activity main xml file    When you try to build or clean your project you will see error messages   I resolved mine by reading those error messages  correct what is wrong in my xml file  then rebuild project

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Android studio-  Build -  Make Project Or Make Module  xxx  fix the problem  Yes  run app can not fix the problem    Yes  clean can not fix the problem    Yes  File -  Invalidate cache can not fix the problem    by the way  should I use yes  or may be no is right in English

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Just Click on Build -  Rebuild Project option in your Android Studio

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For me I had this problem after I changed the name of one of my raw resources from extra to extra jet  then all Rs became red and it wouldn t build  I tried all the above solutions and nothing worked  then i tried to make another copy of it with the original name extra and deleted it from within android studio then Rs returned back to normal and build succeeded

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This happened to me   i found it was caused by some cache files which were invalid  so i disabled cache by adding  android enableBuildCache false   to gradle properties

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Issue   Android Studio marks R in red with error message    cannot resolve symbol R              Solution   I resolved the  R  error by adding the following to the import  amp  then rebuilding the project and the error went away   import com mkyong android R   Explanation  Sometimes the Android Studio does not add the import even when you do build multiple times or run the  optimize import  command  Sometimes the error is resolved when you  restart Android Studio  but at times even after restarting Android Studio multiple times the error remains  Thanks

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Here is my temporary solution until I find a better one    Using Everything  find where R java is created  In my case it was C  Program Files  x86  Android android-studio system compiler  lt project-name gt  cb969c52  generated aapt  lt module-name gt  6badd9a4 production com  lt project-name gt   lt module-name gt  In the Project view  click the module and press F4  Ignore the warning  Click    Add Content Root  and select the aforementioned folder  Make sure it s marked in blue  as a source     After I did this  suddenly all the warnings are gone  The problem is that if you collaborate with other people  the folder name is different on each machine so be careful when synchronizing

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I get bitten by this every now and then and there s another thing to try  match your compileSdk and buildSdk versions to the latest available   I had changed my compileSdkVersion from 21 back to 19 because the Android Studio  1 1 canary channel  debugger was not tracing properly into prebuilt libraries  I found that it seemed to be tracing based on the buildToolsVersion  19 1 0   which I verified by clicking an error in the stack trace  and then choosing 19 instead of 21   Though I changed it directly in the build gradle file  a graphical walkthrough is here  https   www blogger com comment g blogID 4722727826918942842 amp postID 3875998513888772255 and I ll summarize    Android Studio IDE  select File   Project Structure  Choose your module  like  app  In Compile SDK field  choose the latest version Also choose the latest version in Build Tools   Confirm  and the project should automatically sync properly   The lesson I m getting from this is that they should both be the same

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Sometimes these build errors will continue out of nowhere  If this happens to you  try this   Recheck the validity of the XML in your resource files  If your R java file was not generated for the last build  you will see errors in your project wherever you reference a resource  This can be caused by a typo in one of your XML files  Layout XML is not always validated  so typos in these files may not be pointedly brought to your attention  Finding the typo and saving the file should cause R java to regenerate   Clean your project  Select Build   Clean Project This will rebuild the project from scratch  which may result in an error-free build   Sync your project with Gradle  Select Tools   Android   Sync Project with Gradle Files Android Studio will rebuild the project from scratch with the correct project settings  which can help to resolve issues after changing your Gradle configuration   Run Android Lint   Lint may give you good information regarding a problem  If the above does not work  this is where you will most likely find your problem   To run Lint  select Analyze   Inspect Code   select Whole project   OK  Carefully analyze Lint suggestions  start with errors and then warnings    Good luck

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Just go to Android Top menu list  click on Build Menu  in under Build click on Rebuild Project

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Many a times this usually happens when you have changed any of your layout files - where you might have included a new library component  happens generally during copy paste of code   Due to this copy-paste  you might tend to forget adding the dependency in the build gradle file   Hence  when you build compile your project  Android Studio isn t able to understand that newly added component of the library  because the library hasn t become a part of the project yet    Therefore  make sure you ve added the new dependency in the  build gradle  Then do a gradle-sync

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Click on Build - gt  Rebuild Project and then click Tools - gt  Android - gt  Sync Project with Gradle Files

User · Answer

you need to IMPORT your project R file   import  lt YOUR-PROJECT-PACKGENAME gt  R

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The solution is simple   Go to File  gt  Project Structure  gt  app and choose the Flavours tab  select API 21  Android 5 0  Lollipop  in the drop down list for Min Sdk Version

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The better way to resolve this problem is to restart your Android Studio  If you don t want to do a restart  then click on Build - gt  Clean Project

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Check the version of Gradle install in Android Studio and the one mentioned in Build Grable file    dependencies           classpath  com android tools build gradle 3 1 1          NOTE  Do not place your application dependencies here  they belong        in the individual module build gradle files      I replace 3 1 1 to 3 0 0 and it worked for me  check your own version of Gradle  Or try to create new project and check its build gradle file to know the installed version

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One thing which works for me every time is   go to --  build gradle  Module  app  file of your project --  do a little change  for example  put a space somewhere and remove it back  --  then android studio will ask you to sync your gradle file--  at top right corner of the file --  select  sync now    After syncing completes  it ll resolve the issue in most of the cases

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When creating a project from a sample while not importing the existing project is good  prevents clashes with gradle   idea   iml  build  jars and apks  i e  all unnecessary build-generated files   after creating a new project  copying and pasting all relevant resources  I d recommend    checking packages and imports from packages within the project  AndroidManifest declaration and all imports in java classes   all resources  drawable  mip-map  layouts and menus  amp  your build gradle  a sample of build gradle to use with the latest sdk can be provided on request   to see if they are there  amp  if declared strings and ids actually exist and have been used  after which your only error should be the question asked   Bulid- Clean Project  Tools- Android- Sync Project with Gradle Files  File- Invalidate Caches and Restart  In worst cases restarting your machine helps   The above should work  Feel free to ask questions if necessary   i e  post comments

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I had a copy paste reuse error in the package declaration for the manifest   lt manifest xmlns android  http   schemas android com apk res android  package  wrong package name  gt    the Main activity name had the correct path so the manifest didn t have any checked errors   After resolving this  the source file still showed errors although build succeeded   I just ran app and then the source error indicators cleared up

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this causes mainly because of errors in xml file  check your latest xml changes and rebuild it  same issue with me

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I had this bug few days ago  I tried looking around until I decided to re-install Android Studio  It worked for me

User · Answer

Just sync with gradle file It works for me

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I found that this issue was caused because I had errors in my XML files  Once you fix the XML errors  do a clean build  it fixed the issue

[android] Android Studio marks R in red with error message "cannot resolve symbol R", but build succeeds

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