Android Studio “cannot resolve symbol R” but project compiles and runs

Question

Android Studio displays in all java files in red : “cannot resolve symbol R” but the project compiles and runs.

I have tried every solution here: Android Studio "cannot resolve symbol" but project compiles and works, but with no luck.

I tried to :

invalidate caches and restart android studio
delete .gradle and .idea folders
clean and rebuild the project
install a new version of android studio
mess up with gradle file then undo changes and sync project

One thing that I want to try, but I don't know how to achieve, is to reopen the project from scratch as I was opening it for the first time, but I don't know how to do this.

I also tried answers from here: Android Studio says "cannot resolve symbol" but project compiles, but again with no luck.

Android studio version = 3.2.1

dependency versions in gradle project file:

classpath 'com.android.tools.build:gradle:3.4.0-alpha01'
classpath 'com.google.gms:google-services:4.0.0'

Also, check if you have added a resource file with a not allowed name. It must contain only lowercase a-z, 0-9, or underscore. If you have anything different, you'll have a problem. — George, Nov 18 '18 at 19:51

score 11 · Accepted Answer · answered Nov 28 '18 at 11:06

11

For some reason that i do not understand ,

this combination of build versions made the issue :

grade version = 4.10.1

classpath 'com.android.tools.build:gradle:3.4.0-alpha01'

when i switched to these build versions :

grade version = 4.6

classpath 'com.android.tools.build:gradle:3.2.1'

The issue was solved !

answered Nov 28 '18 at 11:06

user2469133

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ditto for me, though I left 4.10.1 and only reverted from com.android.tools.build:gradle:3.3.1 --> 3.2.1 – CSmith Feb 26 '19 at 19:56
Unfortunately, my project demands gradle version 4.10.1 as a minimum version. – Aliton Oliveira Nov 26 '19 at 23:56

score 2 · Answer 2 · answered Nov 18 '18 at 11:20

2

File -> Close project
Open an existing Android Studio Project
Open you project

Hope it will work.

answered Nov 18 '18 at 11:20

Muhammadjon

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score 2 · Answer 3 · answered Oct 14 '19 at 11:10

2

sometimes, R file is not generated because of package name on android manifest is not match with package module that you have.

answered Oct 14 '19 at 11:10

nsaudria

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score 1 · Answer 4 · answered Nov 18 '18 at 11:27

1

Is any wrong syntax or spelling in your xml?

Check your layout or any xml file.

answered Nov 18 '18 at 11:27

eltoryn7

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Check this option, OP. It's a common issue. – George Nov 18 '18 at 11:45
i'm working on a large project , so it's hard to iterate over all layout files to know if there were syntax errors... do you know something that i can do that could determine if i have syntax errors inside the layout filse? – user2469133 Nov 19 '18 at 13:39
@user2469133 Try Analyze->Inspect Code, then you can find some errors and warnings in inspection results. – eltoryn7 Nov 19 '18 at 14:12

score 1 · Answer 5 · answered Mar 09 '20 at 09:48

Android Studio seems to have a caching issue with R.java occasionally. I rarely have a problem with this, but when I do, I actually open R.java (double press shift and type "R.java") or navigate to R.java under "app/build/generated/source" directory, opening the file and checking if the relevant XML id has been created. If it has, it forces Android Studio to now recognise the id's that are not being resolved. It's quick to try, and doesn't require clean and rebuild.

Nikos Hidalgo · Answer 6 · 2018-11-18T11:21:37.167

0

From your programs menu, open android studio. instead of opening your project from the recent files, select to open a project from your computer and then locate the path to your project. When all else fails, sometimes this works.

Also, try commenting out the support libraries from your gradle implementation, sync your project, and after sync fails comment them back in and sync again. (not sure if that's what you tried already when you said you messed with the gradle file)

edited Nov 18 '18 at 11:21

answered Nov 18 '18 at 11:17

Nikos Hidalgo

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i tried this also and i did not work , i even changed the project location and removed it from android studio recent projects , then opened it again from the new location , but it seems to sync very fast , as there was something still cached there ! – user2469133 Nov 18 '18 at 11:21
also tried what you mentioned in the second part of the answer (commenting support libraries .....) , but with no luck – user2469133 Nov 18 '18 at 11:22

score 0 · Answer 7 · answered Feb 19 '19 at 08:41

In my case,

I am using - Android Studio version 3.3.1 at home - Android Studio version 3.2.1 at office

When i pulled projects to my office computer that are firstly created at my home computer , Android Studio can not resolved R file but runs application with no error. Because projects gradle and Android Studio version are incompatible.

Only thing that you sholud do, change the gradle version in project level gradle file

  classpath 'com.android.tools.build:gradle:3.3.1'

to

  classpath 'com.android.tools.build:gradle:3.2.1'

score 0 · Answer 8 · edited Oct 14 '19 at 12:23

I was facing same issue,

first thought the issue might because of some xml file or naming of drawable resources incorrectly. After analysing, this case wasn't applicable to me. So

Updating Android studio from older version 3.2 to newer version 3.3.2 along with new build tool version from SDK manager resolved this issue for me.

I've tried invalidate cache and Restart AS with clean rebuild all the options but didn't work for me.

score 0 · Answer 9 · edited Jun 03 '20 at 06:52

0

It says cannot resolve symbol, but it can run.

In my case, I just reload the needed *.jar files to the libs folder.
File >> invalidate caches/restart
Rebuild Project
Sync
Run

Works for me!
It looks like the library did not load my "imports" properly the first time.
That's why the import methods cannot be seen in my main_activity.xml.

edited Jun 03 '20 at 06:52

סטנלי גרונן

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answered Jun 03 '20 at 02:28

Jay Jay

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score 0 · Answer 10 · answered Sep 18 '20 at 01:31

This happened to me when I was going back and forth between different SDK versions.

Apparently SDK manager copied all the source files but it didn't finish cleanly. As a result I could compile and run my project just fine but IDE didn't recognize the SDK and reported all java symbols unresolved.

None of the above and other solutions in SO didn't work for me, but just uninstalling/reinstalling the specific SDK version did a job.

score 0 · Answer 11 · answered Dec 20 '21 at 15:22

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If you renamed your package (inside java folder), make sure you change your Manifest package name to the same

answered Dec 20 '21 at 15:22

Kelvin Kiprop

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score 0 · Answer 12 · answered Feb 28 '22 at 21:49

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The only thing that worked for me was,

replacing,

import package_name.R

with

import package_name.*

answered Feb 28 '22 at 21:49

Mohammed Khan

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score 0 · Answer 13 · answered Apr 24 '22 at 22:22

0

simply go to project settings : settings.gradel and change the rootProject.name to your current name

rootProject.name = "write the project name here"

answered Apr 24 '22 at 22:22

devio

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score 0 · Answer 14 · answered Jul 24 '23 at 03:49

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Close Android Studio Project, Delete .idea .gradle folder, and reload the project after reopen Android Studio

answered Jul 24 '23 at 03:49

Trinea

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Android Studio “cannot resolve symbol R” but project compiles and runs

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