Cannot find R layout activity main

Question

I was trying to work out with multiple layout using some online tutorials  The thing is my program was building and compiling correctly as long as there was only one XML file  When I added multiple XML files  I am getting errors saying  activity main cannot be resolved or is not a field  for the line setContentView R layout activity main    In fact  every item which I used previously in R   is now reporting error  I don t know what went wrong  Can anyone suggest what needs to be done   Edit 1  I tried cleaning and rebuilding the project but that didn t help  Plus  I am importing the correct R java file as in mypackage R java  According to  RubberDuck s comment  I as soon as I deleted the files again  the R java file was being generated after building the project  However  when I create new XML files and add elements in it  build the project  R java gets deleted

User · Accepted Answer

If your XML s contain errors your generated file might not build try erasing most of their content and making sure id s and file names are not duplicated and no capitals and spaces are used  If it works you can start adding stuff

User · Answer

Happened once  Don t know the reason    Build  Clean Project removed the error for me

User · Answer

I removed import android R and added import android support v7 appcompat      However this had to be done after importing appcompat by right click project and import

User · Answer

The stupid mistake I made to cause this error was to have the wrong package string in my AndroidManifest xml file  I d left the string set in the tutorial  but had used my own when setting up the project    lt  xml version  1 0  encoding  utf-8   gt   lt manifest xmlns android  http   schemas android com apk res android  package  COM YOU YOURAPPNAME  android versionCode  1  android versionName  1 0   gt

User · Answer

or you can write  import R layout    at the top   It will work for sure

User · Answer

In Android Studio go to Tools -  Android -  Sync project with gradle files or File -  Sync project with gradle files in latest Android Studio version

User · Answer

I have a few suggestions    Make sure you don t have any other errors other than the R-related errors  Right-click your project folder in Eclipse  Android Tools -  Fix Project Properties   2 Check to make sure you have the correct R imported  Sometimes the default Android R can be imported   3 Check for errors in your layout XML files

User · Answer

My error got removed by importing the line   import com example myapplication R    your import line may be different depending upon your project name in which my project name is myapplication

User · Answer

what I tried    check every XML file for some famous known errors  cleaned the project multiple times  synced Gradle with the project file    What Worked   1  Invalidate caches and restart

User · Answer

I used maven as build tool  after I build my project and dig a lot in the internet to solution  My problem resolved by adding to the main activity xml     tools context   MainActivity

User · Answer

There is probably an issue with the layout files  correct it and the auto generated class will appear

User · Answer

Ivwd simply removed line   import android R   and call Project- Clean    That was enough for my on Win-7 x64 and Eclipse Kepler and last  02 2014  Android SDK

User · Answer

I had the same problem  fixed by replacing R with com example appname R obviously put your package reference in there instead  Or just add this line to your file   import com your package R   Or even better  try removing this line from your code if exists   import android support compat R

User · Answer

This solved my problem   apt-get install ia32-libs   and restart     Android adb not found

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it happens when you change the project name in my case  I just change  lt manifest xmlns android  quot http   schemas android com apk res android quot      xmlns tools  quot http   schemas android com tools quot      package  quot xxxx newName quot

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This is happening due to resources are not loading properly and the similar issue can occur any view also so Below are some technics which you can use to remove this error -   Clean your project  Build -  clean Project Rebuild project  Build -  Rebuild Project Open manifest and check if there s any resource missing Check-in layout to particular id if missing add it If the above steps did not work then restart android studio with invalidating the cache    Note  In the above-mentioned steps  the last step will work for this issue for sure

User · Answer

You re importing invalid R class  check imports

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In my case   i accidentally imported my library s R  class not my app module s R  After editing this  it is resolved

User · Answer

First Doing This -- gt  Select Build  gt  Clean Project from the Android Studio toolbar  wait a few moments  and then build your project by selecting Build  gt  Rebuild Project  if Problem Not solved then doing This -- gt  File  gt  Invalidate Caches   Restart  gt  Invalidate and Restart from Android Studio   s toolbar

User · Answer

JUST REMOVE the import android R   Then the R layout  XML LAYOUTNAME  will turn to BLUE  IT TOOK ME HOURS TO FIND THIS ONE ERROR

User · Answer

Thanks to  RubberDuck s comment and  Emil s answer I was able to figure out what the problem was  The IDs of most elements in my XML file were exactly the same  So  I renamed each and every one of them  Also  my XML file contained capital letters  The filename should be in  a-z0-9   so I renamed my files too and the problem was solved

User · Answer

I ve got this when an inappropriate character   -one slash  was added to the values strings xml  and  of course  renaming of problematic resource was helpful   And one more important thing - check the date and time on your device

User · Answer

in 2019 I faced the same problem and I searched the internet and found the following which I am sharing with all  In android studio letter R stands for the resources and this error occurs because of the build process not able to sync resources with your project  In other words  this error is caused when Android Studio can   t generate your R java file correctly  This problem happens when you shift code to another system or while building the android project for the first time  So when you create a new activity or new class you will see an error message like    cannot resolve symbol r    with a red underline  Below you can find the possible ways to fix cannot resolve symbol r in android studio  Update Project Gradle To Latest Version Always use the latest version of Gradle to work android studio properly  Sync Project With Gradle File Once you update the Gradle plugin you need to sync project with the Gradle file  Open android studio and click on Files  gt  Sync Project with Gradle Files option  Clean and Rebuild Project The most effective solution is the simplest  clean and rebuild your project  Select Build  gt  Clean Project from the Android Studio toolbar  wait a few moments  and then build your project by selecting Build  gt  Rebuild Project  Invalidate Caches   Restart If you encounter this error after moving some files and directories around  then it   s possible that the R layout error is being caused by a mismatch between Android Studio   s cache and your project   s current layout  If you suspect this may be the case  then select File  gt  Invalidate Caches   Restart  gt  Invalidate and Restart from Android Studio   s toolbar  Issues with the names of your resources can also prevent the R java file from being created correctly  so check that you don t have multiple resources with the same name and that none of your file names contain invalid characters  Android Studio only supports lowercase a-z  0-9  full stops and underscores  and a single invalid character can cause an R layout error across your entire project  even if you don   t actually use this resource anywhere in your project  My problem and its solution  In my case  I applied all the above but could not solve the problem  Thus I started a new project and pasted my code one by one and validated my code with running the app  Finally  at one point when I first deleted the code in colors xml and copied and pasted code below in colors xml file  I got the error   lt color name  quot bg login quot  gt  26ae90 lt  color gt   lt color name  quot bg register quot  gt  2e3237 lt  color gt   lt color name  quot bg main quot  gt  428bca lt  color gt   lt color name  quot white quot  gt  ffffff lt  color gt   lt color name  quot input login quot  gt  222222 lt  color gt   lt color name  quot input login hint quot  gt  999999 lt  color gt   lt color name  quot input register quot  gt  888888 lt  color gt   lt color name  quot input register bg quot  gt  3b4148 lt  color gt   lt color name  quot input register hint quot  gt  5e6266 lt  color gt   lt color name  quot btn login quot  gt  26ae90 lt  color gt   lt color name  quot btn login bg quot  gt  eceef1 lt  color gt   lt color name  quot lbl name quot  gt  333333 lt  color gt   lt color name  quot btn logut bg quot  gt  ff6861 lt  color gt   when I undo my changes the error vanished again  Thus my code in colors xml is not the code above and the code already in colors xml i e  lt color name  quot colorPrimary quot  gt  008577 lt  color gt   lt color name  quot colorPrimaryDark quot  gt  00574B lt  color gt   lt color name  quot colorAccent quot  gt  D81B60 lt  color gt   lt color name  quot bg login quot  gt  26ae90 lt  color gt   lt color name  quot bg register quot  gt  2e3237 lt  color gt   lt color name  quot bg main quot  gt  428bca lt  color gt   lt color name  quot white quot  gt  ffffff lt  color gt   lt color name  quot input login quot  gt  222222 lt  color gt   lt color name  quot input login hint quot  gt  999999 lt  color gt   lt color name  quot input register quot  gt  888888 lt  color gt   lt color name  quot input register bg quot  gt  3b4148 lt  color gt   lt color name  quot input register hint quot  gt  5e6266 lt  color gt   lt color name  quot btn login quot  gt  26ae90 lt  color gt   lt color name  quot btn login bg quot  gt  eceef1 lt  color gt   lt color name  quot lbl name quot  gt  333333 lt  color gt   lt color name  quot btn logut bg quot  gt  ff6861 lt  color gt    quot Maybe its because i did not have color primary defined quot  Hope it will help someone like me who is new in programming

User · Answer

Either your gradle or build need to know where resources are

User · Answer

I had a similar problem  It happened suddenly  after deleting some pictures from res  drawable  I did two things      First I checked all my images in the drawable folder if they all have preview  one of mine was damaged  Secondly  I closed all opened android studio and emulator  After that every things worked fine

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After cleaning the project and syncing with gradle no result   i removed all my import statement  and brought them back in using alt Enter

User · Answer

Check if you not imported android R accidentally

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goto tools- android- Sync project with gradle file then click on S

User · Answer

You re importing invalid R class   import yourpackage R class for example com example R  what actully happends that u import android R class not yourpackages R

[android] Cannot find R.layout.activity_main

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