unresolved reference : BuildConfig in Kotlin

Question

So I started a new android application,
here is my Android Studio info

Android Studio 3.6.1
Build #AI-192.7142.36.36.6241897, built on February 27, 2020
Runtime version: 1.8.0_212-release-1586-b04 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Windows 7 6.1

I also added

buildConfigField "String", "MODE", "FREE"

in my product flavor.

When I'm now getting this in my MainActivity's onCreate,

BuildConfig

is unresolved reference.

Prison

Answer 1

If you are in 2023 or 2024 and having this issue, add

android.defaults.buildfeatures.buildconfig=true

to your gradle.properties file.

Rewire

Blog post about this: medium.com/androiddevelopers/… – Piker

That's deprecated already – Heer

Answer 2

Starting from Android Studio Flamingo release and Android Gradle Plugin (AGP) 8.0 generating BuildConfig files is disabled by default and should be enabled manually only for modules that need it

Add this to required module's build.gradle:

android {
  ...
  buildFeatures {
    buildConfig = true
  }
}

Instead, if you need the old behavior for all modules, set the android.defaults.buildfeatures.buildconfig=true in your gradle.properties file

Permit

Thanks this was the problem in my case. – Eosin

Good news - it worked. Bad news - now I crave violence. – Aurochs

Someone give this man a gold star. Correct answer FTW!! – Hoplite

Addition step that works for me: Android Studio Hedgehog | 2023.1.1 Patch 2 1) Go to Refactor menu -> Migrate BuildConfig to Gradle Build Files 2) Go to Build menu -> Make selected modules – Aquamarine

Answer 3

Here are some simple steps which resolved this issue:

1. Go to File menu > Build > Clean Project
2. Now go to File menu > Build > Rebuild Project

(Above steps may resolve the issue, if not, follow step 3)

3. Now go to the file where you are facing this issue(RetrofitClient.kt in my case) and manually add line import com.example.myapplication.BuildConfig

(Replace "com.example.myapplication" with your package name)

That's all.

Zins

For anyone who still faces the issue after Step 3, try to invalidate your IDE's cache (File -> Invalidate Caches...). If the latter doesn't work, your last option would be to comment out (temporarily remove) any reference to BuildConfig in your project, make a successful build, then uncomment the references again. – Transcendental

Answer 4

unresolved reference

• Make sure you choose build variant. Like DEBUG mode.
• Finally Clean-Rebuild-Restart IDE.

Don't

buildConfigField("String", "MODE", "FREE")

Do

buildConfigField("String", 'MODE', '"FREE"')

Beveridge

Why does single quote instead of double quote make a difference? – Corinnacorinne

I don't know, but I simply does – Lark

The important details is '"FREE"': double quotes string wrapepd in single quotes. That is how you define a string in build.gradle. – Fibriform

Answer 5

If you call the BuildConfig class from your module code, you must enable buildConfig in the android {} block in your module’s build.gradle.kts file starting from AGP v8.0. Otherwise the BuildConfig file isn’t automatically generated anymore.

android {
  buildFeatures {
    buildConfig = true
  }
}

More details on how to prepare your app build for Android Studio Flamingo can be found in this post from Android Developers.

Swarth

Answer 6

This worked for me: Clean the project, then add this line to the gradle.properties file:

android.defaults.buildfeatures.buildconfig=true

Finally, rebuild the project and you will have the BuildConfig variable available.

P.D.: I am using Android Studio Girafle | 2022.3.1 (2023) and Gradle 8

Indemnification

Yes, here it worked. Android Studio Iguana | 2023.2.1 – Townie

Answer 7

For me, it wasn't enough to clean the project for some reason. I had to delete the generated BuildConfig file and rebuild. After that, BuildConfig was automatically resolved again.

Meaghan

Answer 8

I know it's been a while, but I found a reproducible solution to this problem...

Even though the "unresolved reference" error shows up in the IDE, everything compiles just fine. And as several people mentioned, cleaning and re-building the project doesn't fix the issue. Neither does the "Invalidate Caches" option in Android Studio.

What does work is temporarily adding a new new BuildConfig variable into the app gradle defaultConfig section. Something like:

buildConfigField "boolean", "TEST", "false"

And then rebuild the "unresolved reference" error goes away, and you can delete the BuildConfig variable you added, but the error still won't com back.

I should also mention that any time I clean the project, the error comes back, and I have to repeat this process.

Charlottcharlotta

Answer 9

I had two distinct android studio projects with this BuildConfig.APPLICATION_ID unresolved problem. The first one was cured by the clean and build sequence. The other one wasn't. Difference was an import androidx.viewbinding.BuildConfig on the latter one. Removed it and then clean + build removed the problem. I don't recall why the import was there, probably it had been used at some point.

Bang

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center. – Poppo

Answer 10

For me, the issue was that another module which was a library module(named common), had the same namespace as my main app module. My app module's namespace was common.example.myapplication and my common module was using the same name. So I changed the namespace from

...
android {
    namespace = "com.example.app"
}
...

to

android {
    namespace = "com.example.common"
}
...

Niacin

Answer 11

As of Android Studio 3.5, BuildConfig.APPLICATION_ID is deprecated and replaced with BuildConfig.LIBRARY_PACKAGE_NAME

Alternatively you can use Context.getPackageName()

Tend

Answer 12

I had this issue for the last 3 weeks and all of the suggestions didn't work.

• clean&rebuild
• invalidate cache&restart
• changing flavors
• changing/adding buildConfigFields
• trying out every combination of quotes " ' '"'
• install fresh Android Studio version in parallel

When I realized that it was not only my main project but every project including my 1-Screen-Test app I choose to reset Android Studio like described here: How to reset Android Studio

After going through the setup everything is back to normal.

Titanesque

Answer 13

For me, it was due to the wrong namespace written in build.gradle should be com.appName consistent throughout. Also in MainActivity.kt, getMainComponentName(): should return the right appName. Check if the package name are right throughout.

Ardellaardelle