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Cannot resolve symbol repeatOnLifecycle in Android

I'm following this article to collect flows in UI. But I couldn't resolve repeatOnLifeCycle API in my code. I have added the below dependency, though.
lifecycle:lifecycle-runtime-ktx:2.4.0-alpha03
Please help

It's not
lifecycle:lifecycle-runtime-ktx:2.4.0-alpha03
but
androidx.lifecycle:lifecycle-runtime-ktx:2.4.0-alpha03

I hope this gradle config can help you.
def lifecycle_version = "2.4.0"
implementation("androidx.lifecycle:lifecycle-viewmodel-ktx:$lifecycle_version")
implementation("androidx.lifecycle:lifecycle-livedata-ktx:$lifecycle_version")
implementation("androidx.lifecycle:lifecycle-runtime-ktx:$lifecycle_version")
implementation("androidx.lifecycle:lifecycle-viewmodel-savedstate:$lifecycle_version")
implementation("androidx.lifecycle:lifecycle-common-java8:$lifecycle_version")
With this set, i resolve "repeatOnLifecycle" with this import:
import androidx.lifecycle.repeatOnLifecycle

I also had a similar issue. For me, adding the following in the dependencies section of the build.gradle file (the App Module one and not the Project one) helped to resolve the issue:
implementation "androidx.lifecycle:lifecycle-runtime-ktx:2.4.0-alpha03"
I also removed the import androidx.lifecycle.Lifecycle that was already there in the problematic file and got Android Studio to import the right one just in case the old one was wrong.
Found the latest version number to use(i.e. the "2.4.0-alpha03" part) from the following link but I think Android Studio would have later given a hint on the latest version to upgrade to anyway even if I hadn't done this:
https://mvnrepository.com/artifact/androidx.lifecycle/lifecycle-runtime-ktx/2.2.0-alpha01

Note: These APIs are available in the lifecycle:lifecycle-runtime-ktx:2.4.0-alpha01 library or later.
lifecycle-runtime-ktx

for me changing gradle from offline to online somehow solved the problem :/

Hilt integration crashes application MainActivity_GeneratedInjector

Trying to integrate hilt using android Api Documentation but app crashed with following exception. https://developer.android.com/training/dependency-injection/hilt-android
java.lang.RuntimeException: Unable to start activity
ComponentInfo{com.package.application/com.package.application.MainActivity}:
java.lang.ClassCastException: com.package.application.DaggerAppApplication_HiltComponents_ApplicationC$ActivityRetainedCImpl$ActivityCImpl
cannot be cast to com.package.application.MainActivity_GeneratedInjector

What worked for me:
Removed the #AndroidEntryPoint annotation from the activity.
Ran the code and of course, it failed.
Had a fragment inside the activity. So, I deleted the fragment code as well.
Ran the code, it failed.
Added the #AndroidEntryPoint annotation to the activity again.
Ran the code. It ran and the error disappeared.

For me, as a dependency declaration inside my app build.gradle, i had to use api instead of implementation:
api project(':features:feedModule')
Learn more here: https://github.com/google/dagger/issues/2064
Update:
Dagger team released classpath aggregation feature which can resolve this issue. You can learn more here:
https://dagger.dev/hilt/gradle-setup#classpath-aggregation
Basically, in your app module build.gradle, you need to add:
hilt {
enableExperimentalClasspathAggregation = true
}
If your Android Gradle plugin version used in the project is less than 7.0, make sure to also add this to you build.gradle file:
android {
...
lintOptions {
checkReleaseBuilds false
}

In my case, I was getting a similar ClassCastException because the module where my #HiltAndroidApp app class was didn't have access to the module where my #AndroidEntryPoint activity was. Moving my App class to the app module (that has access to all the other Gradle modules) solved the problem.
From the docs:
Because Hilt's code generation needs access to all of the Gradle modules that use Hilt, the Gradle module that compiles your Application class also needs to have all of your Hilt modules and constructor-injected classes in its transitive dependencies.

Solved it by adding missing dependency for androidx hilt.
kapt 'androidx.hilt:hilt-compiler:1.0.0-alpha01'
Other dependencies that I have in my gradle file.
implementation "androidx.hilt:hilt-lifecycle-viewmodel:1.0.0-alpha02"
implementation 'com.google.dagger:hilt-android:2.28-alpha'
kapt 'com.google.dagger:hilt-android-compiler:2.28-alpha'
implementation "androidx.fragment:fragment-ktx:1.2.5"
Plus fragment and its activity who are injecting viewmodel using hilt both are annotated as
#AndroidEntryPoint

I spent a couple of hours fixing this exact issue but solved it by doing Invalidate cache/restart + Rebuilding of all modules.
This is related to this issue from Hilt:
Hilt: More meaningful error messages

Dagger sometimes doesn't work well, even if the code is correct.
One possible solution is to rename the class to something else("Class2"), rerun the app, and check if it works. If it works, rename the class back to its original.

This is solved by invalidate cache and restart

I had the same problem and here are the steps I followed:
appModule starts with internal
In your app level build.gradle inside android section add the following line:
enableExperimentalClasspathAggregation = true
}
My dependencies are in this order:
classpath "com.google.dagger:hilt-android-gradle-plugin:2.40.5"
app-level build.gradle:
top plugin section
plugin{
...........
id 'kotlin-kapt'
id 'dagger.hilt.android.plugin'
}
dependencies section
//dagger-hilt
implementation 'com.google.dagger:hilt-android:2.40.5'
kapt 'com.google.dagger:hilt-android-compiler:2.40.5'```

It is really silly solution but just comment out the injection annotation and injected fields, run the app then uncomment them and run again

It's also happened to me when I'm importing an .aar with "implementation".
(an .aar which includes hilt)
Like Sher Sanginov said instead of using "api" who increase compilation time, you can add the following lines in your build.gradle(app)
hilt {
enableAggregatingTask = true
}
enableExperimentalClasspathAggregation is now deprecated,
see https://dagger.dev/hilt/gradle-setup#aggregating-task

I was having the same java.lang.ClassCastException after adding Hilt.
Steps to fix the problem:
1. Build -> Clean Project
2. Build -> Rebuild Project
Also kapt doesn't work any more. Just add one plugin:
id 'dagger.hilt.android.plugin'
Then, add Hilt dependencies:
implementation "com.google.dagger:hilt-android:2.38.1"
annotationProcessor "com.google.dagger:hilt-compiler:2.38.1"

Steps need to perform:
Remove .gradle file in app's directory
Invalidate cache and restart android studio
Hopefully it will resolve your problem.

For me it was that I forgot to add #AndroidEntryPoint to a parent activity that was calling a second activity and this one calling the fragment. Obviously everyone of them need to have an #AndroidEntryPoint

You can delete you app's build folder as well as delete the gradle build cache on your system.
rm -rf app/build
rm -rf ~/.gradle/caches/build-cache-1
Deleting just the build cache is better than removing all the Android Studio cache.

In my case file does not contain the package, so hilt is not able to map the file and generate it in the generated folder. For that reason, hilt is not able to resolve the file.
I added the package in the fragment, and it resolve my issue

'javax.annotation.processing does not exist; cannot find symbol class Generated' despite adding dependecy into build.gradle

I wanted to contribute to one app, but when I set my IDE up and wanted to build the project, compiler thrown an error javax.annotation.processing does not exist; cannot find symbol class Generated. I've searched Google for the problem, people was suggesting to add compileOnly 'org.glassfish:javax.annotation:10.0-b28' to the main.gradle file, but author included such line already. I have turned Annotation processing on in IDE settings already. Dev said today that he can compile project. I have no idea, what's going wrong?
Maybe it's connected to the fact, that he's using Android Studio, and I - IntelliJ IDEA? But, as said by JetBrains here, that shouldn't matter, as Idea has all of the features of Android Studio. Both IDEs are up-to-date.

I had to face the same issue. I found the solution somewhere and it resolves the problem. Add the below line in build.gradle file.
implementation 'org.glassfish:javax.annotation:10.0-b28'
compileOnly 'com.github.pengrad:jdk9-deps:1.0'

Android studio is not able to resolve import

I am trying to work on a sample project to learn MvRx. However, seems something is wrong. Android Studio is not able to find and import activityViewModel automatically.
1) I tried to import it manually by writing its package name but it is still gray.
2) From Gradle tab, I selected my root project and clicked on Refresh Gradle Project in order to refresh all dependencies. It did not help, too.
What is the problem?

If someone is getting same error even when using activityViewModel() in fragment, this answer may be helpful.
In my case I was using activityViewModel() inside fragment. Still I was getting this as well as many other errors. Finally I figured out that mvrx is now using kotlin coroutines and all dependencies on rxjava are removed in 2.0.0-beta1.
To solve this use
implementation "com.airbnb.android:mvrx-rxjava2:2.0.0-beta3"
in place of
implementation "com.airbnb.android:mvrx:2.0.0-beta3"
in dependencies section of your build.gradle.

Your feature code must be in a Fragment (that extends BaseMvRxFragment), not in an Activity.

Because you have other com.airbnb.mvrx. references that have resolved correctly, it means you do have a reference to the com.airbnb.mvrx library. However, it is likely that you have a different version of the library referenced than the sample's original author. Look in your build.gradle file for dependencies and see if you have the library referenced there. If so, compare its version to the one in the sample, if different, then modify your reference to the sample's version number. If not, then add a reference to the library with the appropriate version number of the library where that object exists.
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.airbnb.mvrx:mvrx:12.0.1'
}

ERROR : error.NonExistentClass Kotlin In multi module Dagger project

I'm using Dagger 2 and Kotlin for Android development.
My project is also a multi-module project.
My settings.gradle file is like this:
include :app
include :lib
I'm also maintaining the lib module.
In the Dagger Files (for example in the component), I try to get the item from other module. For example:
#Component
interface AppComponent{
fun getPresenter() : Presenter
}
The Presenter object is defined in lib module. I was working in linux environment and I'm using Android Studio 3 preview canary 5. The code is working well and I am able to generate APK.
But my company wanted to generate the APK using stable version of Android Studio. I'm using Android Studio 2.3.3.
When compiling the Android Project, I encountered this error:
error: error.NonExistentClass
The error appears when
:app:kaptDebugKotlin
is performed and caused by the dagger class cannot found, the class is defined in the other project. What can be the possible workaround for this? Sorry for my bad English.

Just add this to build gradle file to avoid the issues related NonExistentClass
kapt {
correctErrorTypes true
}
https://kotlinlang.org/docs/reference/kapt.html#non-existent-type-correction

The Root Cause
Basically, there's not much that can be done to fix this when using kapt. To quote this link that tackles the same problem in another library that uses pre-processors (OrmaDatabase):
Because Kotlin makes its stubs before Java Annotation Processing runs,
Kotlin knows just nothing about OrmaDatabase, and the name of the
declaration in stubs will be error.NonExistentClass. This breaks the
Annotation Processing tool. It's a kind of kapt limitation
How to fix it (the workaround)
Just use plain apt or annotationProcessor for running Dagger compiler. As soon as I changed:
kapt libs.daggerCompiler
to
annotationProcessor libs.daggerCompiler
in my module level build.gradle file, I was able to get the errors. After you've fixed the errors, you gotta revert the line back to kapt because otherwise dagger classes wouldn't be generated since they're defined in Kotlin.

I had a very similar situation with a NonExistentClass error in a multi-module project using Dagger and turns out I forgot to add the kotlin library dependency. So, just adding it in the sub-module solved my problem:
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$rootProject.kotlinVersion"

tldr: Change kapt to annotationProcessor in build.gradle and you will see the real problem.
I got the same error, and it turned out that I just commented out a class that I was using in my AppComponent. Unfortunately the kapt tool didn't give me the proper error message. If you change the kapt to annotationProcessor at your library's compiler, and try to build, it won't succeed neither, but you will get a more detailed error message.

In my case, I had #Nullable annotation from support-annotations while I had removed it in order to migrate to AndroidX.
When building, because the annotation was not imported correctly, it was detected as invalid.
What I did was to check the code and fix all imports.

After removing the outdated library
implementation 'androidx.hilt:hilt-lifecycle-viewmodel:1.0.0-alpha03'
kapt 'androidx.hilt:hilt-compiler:1.0.0-alpha03'
I got this error:
incompatible types: NonExistentClass cannot be converted to Annotation
Looking at https://dagger.dev/hilt/view-model.html I changed in a ViewModel:
class MainViewModel #ViewModelInject constructor(
...
) : ViewModel() {
to
#HiltViewModel
class MainViewModel #Inject constructor(
...
) : ViewModel() {

I've found if you're using
kapt {
generateStubs = true
}
changing to false will then present the actual error, you will probably have issues building the Dagger Graph once it's compilation issues have been corrected, but simply change back to true, and you should be good

It seems, there is a bug with kapt, project cleaning should help.
./gradlew clean

I got this error when I had moved by mistake a test class into my main sourceset. Moving it back to the test sourceset got rid of the error.

I received this error, when there was a compilation error in my Injected class. Please ensure that there aren't any compilation errors.

For all those arriving like me on this topic with a similar error.
Check your annotation imports.
For me the problem was I had the #MicronautTest annotation same as another test just the wrong one. Somehow intellij seems to think the import is fine while it really is not.
I had
import io.micronaut.test.extensions.junit5.annotation.MicronautTest
yet needed the kotest one.
import io.micronaut.test.extensions.kotest.annotation.MicronautTest
The kapt error is, while technically correct, quite uninformative.
So just check the imports and if they are all correct.

ERROR : error.NonExistentClass
This means there is a problem with providing dependencies( and not the dependency itself!).
Sometimes annotation processor(in this case Dagger) is unable to build dependency graph on the first build iteration due to a provider absence.
For instance: You are passing GlideApp as a parameter in your provider while GlideApp class is not generated yet! So, watch out for your providers for NonExistentClass errors.

I had the same issue recently. As I sometimes commit through the Android Studio (3.4.c6) I use the "Optimize imports" option to remove unused imports. For some reason, it removed the import for the Parcelize annotation.

It appeared the errors after I upgraded the .gradle version.
Upgraded the version for mockito from 2.7.21 to 2.+ fixed the issue for me.
- androidTestCompile "org.mockito:mockito-android:2.7.21" // remove this
+ androidTestCompile "org.mockito:mockito-android:2.+" // add this

If you come across this problem after Android X migration and start loosing your mind here is one thing you can try.
My Case:
Our project had few modules in it, lets call one of them myModuleProject.
After migration to Android X it was compiling and running fine if I run it from android studio, but when code moved to cloud and CI starts build, it was failing with ':myModuleProject:kaptDebugKotlin' and with long list of errors such as
e: /home/circleci/code/myModuleProject/build/tmp/kapt3/stubs/debug/package_name_here/reporter/bindingadapter/SomeBindingAdapterKt.java:14: error: incompatible types: NonExistentClass cannot be converted to Annotation
#error.NonExistentClass()
After two days of nightmare I found that not only root project gradle.properties but also module projects should include following!
android.databinding.enableV2=true
android.useAndroidX=true
android.enableJetifier=true

It seems kapt cannot find the class, or cannot determine which class to use. e.g.
import foo.* // class foo.Abc
import bar.* // annotation bar.Abc
#Abc
class Xyz { ... }

I had a project with Dagger injecting something into Presenters
At one moment I got a persistent
"NonExistentClass.java:3: error: error.NonExistentClass must be INTERFACE" error
The root cause was trivial: a rogue copy of the valid #Inject annotated file with unsatisfied dependencies somehow slipped into the project. How can we find it? The project in Android Studio looks OK.
Look at the error message, it looks like:
/home/alex/AndroidProvects/TopProject/app/build/tmp/kapt3/stubs/onlineDebug/error/NonExistentClass.java:3: error: error.NonExistentClass must be INTERFACE
public final class NonExistentClass {
Search at the compiled by kapt build files in
/home/alex/AndroidProvects/TopProject/app/build/tmp/kapt3/stubs/onlineDebug/app for "NonExistentClass" string
You will find the exact file with the exact unsatisfied Dagger dependency (in my case it was a rogue orphan file in the place where it shouldn't exist)

I had similar issues with dagger. Adding the following helped solve it :
// dagger
implementation dep('com.google.dagger:dagger')
implementation dep('com.google.dagger:dagger-android-support')
implementation dep('com.spotify.dagger.android:dagger')
kapt dep('com.google.dagger:dagger-android-processor')
kapt dep('com.google.dagger:dagger-compiler')