'Unresolved reference' errors for android library module referenced in app module

Question

I have problems referencing my android library modules in my projects. Beside the main app module I use to have an android library module with either util stuff or as data module. I reference it in app module like that:

dependencies {
    implementation project(":data")
}

When I build the project, it´s giving me lot of error messages 'Unresolved reference: ...' for all stuff that I reference in the app module to the android library module. But the IDE itself doesn´t have a problem, Intelligent finds all classes, interfaces etc., imports are fine, nothing is red. The android library module itself builds and creates aar-file in the output. It´s the compileDebugKotlin task that fails

Any general idea what may be related to that?

Nikunj · Accepted Answer · 2018-03-06 07:11:23Z

104

Found the problem, my android library module was missing the kotlin configuration:

apply plugin: 'kotlin-android'

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlinVersion:<version>"
}

Although I used kotlin .kt files in it, it could build without and also

Tools -> Kotlin -> 'Configure Kotlin in projects'

had told me 'All modules with Kotlin files are configured'

edited Mar 6, 2018 at 7:11

Nikunj

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answered Mar 6, 2018 at 7:01

Lemao1981

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4 Comments

The Tokenizer Over a year ago

I'm having the same issue except.. my project is not missing any dependencies.. I wish this error was more descriptive.

gMale Over a year ago

That was a nasty and annoying thing to debug. Android Studio should make this less painful.

speedynomads Over a year ago

Wow. This really helped. Excellent find!

Keith Loughnane Over a year ago

a year and a half later and they haven't fixed this. google please throw a real error. it's not cool when the IDE tells you everything is cool.

GeralexGR · Accepted Answer · 2018-06-02 08:31:43Z

20

Your module's build.gradle file should have:

apply plugin: 'com.android.library'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'

dependencies {
    ...
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    ...
}

edited Jun 2, 2018 at 8:31

GeralexGR

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answered Jun 2, 2018 at 6:30

Ankit Kumar

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Comments

Douglas Mesquita · Accepted Answer · 2018-11-10 16:31:22Z

16

In my case It was apply plugin: 'kotlin-android',

implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"

and also added it on build.gradle

androidExtensions {
  experimental = true
}

edited Nov 10, 2018 at 16:31

answered Jun 21, 2018 at 20:25

Douglas Mesquita

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Comments

Ememobong AkpanEkpo · Accepted Answer · 2018-10-27 21:36:39Z

8

If it is a kotlin module make sure to add in its build.gradle file

apply plugin: 'kotlin'

answered Oct 27, 2018 at 21:36

Ememobong AkpanEkpo

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2 Comments

Some random IT boy Over a year ago

This one is useful if it is a general purpose library!

Ganso Doido Over a year ago

This one fixed the problem for me. In my case, I had a Kotlin module without Android dependencies for a general-purpose library. Thank you very much.

Siddharth Jaswal · Accepted Answer · 2020-11-09 05:41:58Z

0

I was using CoroutineWorkers and in my case I had to add work-runtime-ktx dependency to use it

implementation "androidx.work:work-runtime-ktx:2.4.0"

answered Nov 9, 2020 at 5:41

Siddharth Jaswal

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