Develop Reference

Can you use Hilt in a Java-only Android project?

According to the official integration guide, you need to add
plugins {
id 'kotlin-kapt'
...
}
and
dependencies {
implementation "com.google.dagger:hilt-android:{hilt_version}"
kapt "com.google.dagger:hilt-compiler:{hilt_version}"
}
to your build.grade file. However, when I do a gralde sync, I get the following error:
Plugin [id: 'kotlin-kapt'] was not found in any of the following
sources:
is it possible to use Dagger-Hilt in a pure java project? Or do you have to either use plain Dagger or use Kotlin?

Yes, you can use the following instead of kotlin-kapt:
dependencies {
implementation "com.google.dagger:hilt-android:{hilt_version}"
annotationProcessor 'com.google.dagger:hilt-compiler:{hilt_version}'
}
plugins {
id 'dagger.hilt.android.plugin'
}

Android Hilt won't work with plugins added

I have questions about android hilt.
I have added hilt plugin.
//build.gradle(:project)
buildscript {
ext.hilt_version = '2.37'
dependencies {
...
classpath "com.google.dagger:hilt-android-gradle-plugin:$hilt_version"
}
}
//build.gradle(:app)
plugins {
...
id 'kotlin-kapt'
id 'dagger.hilt.android.plugin'
}
dependencies {
implementation "com.google.dagger:hilt-android:$hilt_version"
kapt "com.google.dagger:hilt-compiler:$hilt_version"
}
//MyApplication.kt
#HiltAndroidApp
class MyApplication : Application() {...}
When I build the project,
I get the error message saying
"Expected #HiltAndroidApp to have a value. Did you forget to apply the Gradle Plugin?"
Do you have any idea?

I am also having same problem in my new projects. This error had gone after lowering kotlin version to 1.5.10. I think hilt has compatibility issues with latest kotlin plugin.

As mentioned by others, Kotlin 1.5.20 has a bug in Kapt which causes this issue.
It is fixed in 1.5.21. Just increase the version and you're good.

There is a bug in 1.5.20
To avoid this bug there is a workaround.
in build.gradle (app) file paste this code below.
generally, in the hilt Gradle plugin, these options are set automatically. in 1.5.20 it is not. if you set it manually it will resolve the issue.
kapt {
javacOptions {
option("-Adagger.fastInit=ENABLED")
option("-Adagger.hilt.android.internal.disableAndroidSuperclassValidation=true")
}}

Expected #HiltAndroidApp to have a value. Did you forget to apply the Gradle Plugin?

I have Google this problem, but the results are not work for me.
The detail as following.
public final class App extends com.zhixin.wedeep.common.BaseApplication implements androidx.lifecycle.LifecycleOwner {
^
// Expected #HiltAndroidApp to have a value. Did you forget to apply the Gradle Plugin?
The App code.
#HiltAndroidApp
class App : BaseApplication(), LifecycleOwner {
#Inject
lateinit var service: EventService
private val mLifecycleRegistry = LifecycleRegistry(this)
}
This module gradle file.
apply plugin: 'kotlin-kapt'
apply plugin: 'kotlin-allopen'
apply plugin: 'androidx.navigation.safeargs.kotlin'
apply plugin: 'dagger.hilt.android.plugin'
dependencies {
implementation rootProject.ext.dependencies["hilt-android"]
implementation rootProject.ext.dependencies["hilt-lifecycle-viewmodel"]
kapt rootProject.ext.kapt["hilt-compiler"]
kapt rootProject.ext.kapt["hilt-android-compiler"]
}
Who has ideas? Thanks!

I just hit this problem this morning. Do you have anything in your build.gradle that adds arguments to the annotationProcessOptions? For example:
android {
...
defaultConfig {
...
javaCompileOptions {
annotationProcessorOptions {
arguments = ["room.schemaLocation":
"$projectDir/schemas".toString()]
}
}
}
}
If so, try changing from "arguments =" to "arguments +=", as just using equals overwrites anything set previously.

EDIT: Looks like kotlin gradle plugin 1.5.21 solves the problem without using the bellow javacOptions.
UPDATE Kotlin and try again!
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.21"
If you are not using Room and still get the error put this in the android block of build.gradle:
kapt {
javacOptions {
// These options are normally set automatically via the Hilt Gradle plugin, but we
// set them manually to workaround a bug in the Kotlin 1.5.20
option("-Adagger.fastInit=ENABLED")
option("-Adagger.hilt.android.internal.disableAndroidSuperclassValidation=true")
}
}
It's a kapt bug on kotlin 1.5.20: https://github.com/google/dagger/issues/2684

SOLUTION 1 : Downgrade kotlin
If you are using kotlin-gradle-plugin:1.5.20 (in your project level build.gradle), downgrading it to 1.5.10 should fix the issue.
The issue will probably be fixed in the next versions, then you will upgrade to the new version.
SOLUTION 2 : Disable Gradle worker API
Add this line to your gradle.properties file:
kapt.use.worker.api=false
It will disable the gradle worker API.
It works for me, but as said in the documentation:
Using the worker API lets Gradle run independent annotation processing tasks from a single project in parallel, which in some cases significantly decreases the execution time.
So by disabling it, your build may be slowed down.

Just don't forget to add Hilt classpath dependency to your project level gradle file:
classpath "com.google.dagger:hilt-android-gradle-plugin:$versions.daggerHiltCoreVersion"
Define the specific version number instead of $versions.daggerHiltCoreVersion above.
And add plugin to your app level gradle:
apply plugin : 'dagger.hilt.android.plugin'
For later Gradle versions, add the plugin as follows
plugins {
id 'dagger.hilt.android.plugin'
}

Adding to sitatech's answer, I've also encountered this issue using kotlin-grade-plugin-1.5.20. The new 1.5.21 patch solved it for me.
Kotlin Grade Plugin v1.5.21 release notes: https://github.com/JetBrains/kotlin/releases/tag/v1.5.21
Issue in Jetbrains issue tracker: https://youtrack.jetbrains.com/issue/KT-47416

To backup #SteveC answer, when using Kotlin Gradle DSL is a bit different
We can't use either += or arguments = mapOf(). As stated in the official Dagger-Hilt documentation here & the github issue here regarding the docs as well
See below image for explanations:
arguments = mapOf() will call setArguments with this.arguments.clear(), thus will overwrite previous argument (in this case Hilt)
Workaround approach:
javaCompileOptions {
annotationProcessorOptions {
arguments(
mapOf(
"dagger.gradle.incremental" to "true",
"room.incremental" to "true"
)
)
}
}
Wrapping the arguments() as a functions instead of calling setter, it'll retain the previous arguments as well.

in my case, multi module in presentaion layer, I just removed :
javaCompileOptions {
annotationProcessorOptions {
arguments = ["room.schemaLocation":
"$projectDir/schemas".toString()]
}
}
}
in defaultConfig block

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

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?

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'

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"
...
}

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
}

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

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"

Unresolved reference DaggerApplicationComponent

I'm trying to create my app component, but Dagger does not generate my app component.
here is MyApplication class
class MyApplication : Application() {
companion object {
#JvmStatic lateinit var graph: ApplicationComponent
}
#Inject
lateinit var locationManager : LocationManager
override fun onCreate() {
super.onCreate()
graph = DaggerApplicationComponent.builder().appModule(AppModule(this)).build()
graph.inject(this)
}
}
and here is my AppComponent class
#Singleton
#Component(modules = arrayOf(AppModule::class))
interface ApplicationComponent {
fun inject(application: MyApplication)
}
here is screenshot
this is my project on github
here is error log
Error:(7, 48) Unresolved reference: DaggerApplicationComponent
Error:(28, 17) Unresolved reference: DaggerApplicationComponent
Error:Execution failed for task ':app:compileDebugKotlin'.
> Compilation error. See log for more details
Information:BUILD FAILED
Information:Total time: 21.184 secs
Error:e: .../MyApplication.kt: (7, 48): Unresolved reference: DaggerApplicationComponent
e: Unresolved reference: DaggerApplicationComponent
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:compileDebugKotlin'.
> Compilation error. See log for more details
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
Information:4 errors
Information:0 warnings
Information:See complete output in console

my solution is to add
apply plugin: 'kotlin-kapt'
and remove
kapt {
generateStubs = true
}

This helped me to fix this issue
Add this in the top of the build.gradle
apply plugin: 'kotlin-kapt'
Inside android tag add
kapt {
generateStubs = true
}
And then replace
annotationProcessor 'com.google.dagger:dagger-compiler:2.11'
to
kapt 'com.google.dagger:dagger-compiler:2.11'
Now Rebuild the project by
Build -> Rebuild project

Please try enabling stubs generation, this might be the reason why the class is not visible at this stage of the build process. In your build.gradle file, top level:
kapt {
generateStubs = true
}

I've already downloaded your Github project. Thanks for sharing!
The answer for your issue is pretty simple:
Build -> Rebuild project
Dagger dependencies files will be recreated and app after would launched with any problem.
I checked already this with Android Studio 2.1.2 version. It works

you should remove
kapt {
generateStubs = true}
and add to the top of application gradle file
apply plugin: 'kotlin-kapt'
then Dagger will take care of the rest :)

Add this on Top of build.gradlle
apply plugin: 'kotlin-kapt'
Add this in Dependencies
kapt 'com.google.dagger:dagger-compiler:2.15'
kapt 'com.google.dagger:dagger-android-processor:2.15'
After that rebuild your project . i hope it will work.
Thanks

In my case missing kapt compiler dependency. Please make sure to have below dependency too.
kapt 'com.google.dagger:dagger-compiler:2.15'
app build.gradle
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-kapt'
apply plugin: 'kotlin-android-extensions'
android {
compileSdkVersion 27
defaultConfig {
applicationId "com.usb.utility"
minSdkVersion 14
targetSdkVersion 27
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
implementation 'com.android.support:appcompat-v7:27.1.0'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
compile 'com.google.dagger:dagger-android:2.15'
compile 'com.google.dagger:dagger-android-support:2.15' // if you use the support libraries
kapt 'com.google.dagger:dagger-android-processor:2.15'
kapt 'com.google.dagger:dagger-compiler:2.15'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}

Also for Java users, the solution is simply to Rebuild your project.

Answer is simple :
Build -> Rebuild project
It works for me.

Only two steps should be required for mixed Java/Kotlin projects:
Add apply plugin: 'kotlin-kapt' to the top of the build file
Replace annotationProcessor 'com.google.dagger:dagger-compiler:2.14.1' with kapt 'com.google.dagger:dagger-compiler:2.14.1'

In the new version of hilt, you need to use SingletonComponent::class instead of ApplicationComponent::class

Please try adding this to your build.gradle
android {
dexOptions {
incremental false
}
EDIT: apparently a year later this can happen if you don't apply kotlin-kapt plugin. Also make sure you use kaptinstead of annotationProcessor.

In my case Rebuild didn't help. I injected two dependencies in <module> component (BookComponent):
fun inject(fragment: ListFragment)
fun inject(fragment: NotFoundFragment)
When I removed one inject, the project had built. But both injects together broke build process. Then I simply swapped them:
fun inject(fragment: NotFoundFragment)
fun inject(fragment: ListFragment)

For anyone using the newest Dagger version (above 2.30):
ApplicationComponent has been replaced by SingletonComponent.
#Module
#InstallIn(SingletonComponent::class)
class RoomModule() {
. . .
}
See this answer.

This must solve your problem:
Update (March 29, 2020)
Inside your app-level build.gradle inside dependencies block, add these lines:
//dagger2
api 'com.google.dagger:dagger:2.24'
api 'com.google.dagger:dagger-android:2.24'
api 'com.google.dagger:dagger-android-support:2.24'
annotationProcessor 'com.google.dagger:dagger-compiler:2.24'
kapt 'com.google.dagger:dagger-compiler:2.24'
annotationProcessor 'com.google.dagger:dagger-android-processor:2.24'
kapt 'com.google.dagger:dagger-android-processor:2.24'
compileOnly 'javax.annotation:jsr250-api:1.0'
implementation 'javax.inject:javax.inject:1'
Inside android block of app-level build.gradle,
kapt {
generateStubs = true
}
At the top of the app-level build.gradle, Do this in exactly below order.
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-kapt'
apply plugin: 'kotlin-android-extensions'
Finally, You need to configure Annotation Process as provided in the screenshot below. You can do this File>Other Settings>Settings for New Projects>search"Annotation processor"
After this, do from Menu Build > Rebuild. You are done!
Test:
#Component
public interface ApplicationComponent {
}
Now, you can use DaggerApplicationComponent that was generated at compile-time for your ApplicationComponent interface.
public class MyApplication extends Application {
ApplicationComponent applicationComponent = DaggerApplicationComponent.create();
}

In my case, I did everything in al answers but did not fix it!
my solution: go to Directory path of your project and delete
build, app>build, .idea , .Gradle
and go back to the android studio and rebuild the project and Done!