I am trying to use Firebase Realtime database in Kotlin.
I have followed this tutorial but I think that something is wrong, because I get an error before compiling when I want to retrieve an instance of the database (Unresolved reference DataBasereference (or database if I uncomment the first line of the function tryToRead).
This is the code:
MainActivity.kt
package com.example.spesapp
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import com.google.firebase.ktx.Firebase
class MainActivity : AppCompatActivity() {
private lateinit var database: DataBasereference //Here I see "Unresolved reference"
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
}
fun tryToRead(){
//val database = Firebase.database
val myref = database.getReference
}
}
Gradle (module level)
plugins {
id 'com.android.application'
id 'org.jetbrains.kotlin.android'
id 'com.google.gms.google-services'
}
android {
compileSdk 32
defaultConfig {
applicationId "com.example.frangelapp"
minSdk 21
targetSdk 32
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
kotlinOptions {
jvmTarget = '1.8'
}
}
dependencies {
implementation 'androidx.core:core-ktx:1.7.0'
implementation 'androidx.appcompat:appcompat:1.4.1'
implementation 'com.google.android.material:material:1.5.0'
implementation 'androidx.constraintlayout:constraintlayout:2.1.3'
implementation platform('com.google.firebase:firebase-bom:30.0.1')
implementation 'com.google.firebase:firebase-analytics-ktx'
implementation 'com.google.firebase:firebase-auth-ktx'
implementation 'com.google.firebase:firebase-firestore-ktx'
implementation 'com.google.firebase:firebase-firestore'
testImplementation 'junit:junit:4.13.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
}
Gradle (Project level)
// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
repositories {
// Check that you have the following line (if not, add it):
google() // Google's Maven repository
}
dependencies {
// Add this line
classpath 'com.google.gms:google-services:4.3.10'
}
}
plugins {
id 'com.android.application' version '7.1.1' apply false
id 'com.android.library' version '7.1.1' apply false
id 'org.jetbrains.kotlin.android' version '1.6.10' apply false
}
task clean(type: Delete) {
delete rootProject.buildDir
}
I don't know what is the error. The tutorial seemed to be very easy, but I am facing with this problem.
Thanks in advance
You get the following error:
Unresolved reference DataBasereference
Because you have not added the Realtime Database dependency in your project. To solve this, simply add:
implementation 'com.google.firebase:firebase-database-ktx'
Inside your build.gradle file.
Related
`I have an error on:
``
package com.example.movietime
import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import com.example.movietime.databinding.ActivityRegisterBinding
import com.google.firebase.ktx.Firebase
class RegisterActivity : AppCompatActivity() {
DatabaseReference database = FirebaseDatabase.getInstance().getReference(); // also here with all sentence
// binding
private lateinit var binding: ActivityRegisterBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityRegisterBinding.inflate(layoutInflater)
setContentView(binding.root)
// move to login after click
binding.submitButton.setOnClickListener {
startActivity(Intent(this, LoginActiivty::class.java))
}
}
}
building grade(:app)
plugins {
id 'com.android.application'
id 'org.jetbrains.kotlin.android'
id 'com.google.gms.google-services'
}
android {
namespace 'com.example.movietime'
compileSdk 33
defaultConfig {
applicationId "com.example.movietime"
minSdk 21
targetSdk 33
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildFeatures {
viewBinding true
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
kotlinOptions {
jvmTarget = '1.8'
}
}
dependencies {
implementation 'com.google.firebase:firebase-database-ktx'
implementation 'androidx.core:core-ktx:1.9.0'
implementation 'androidx.appcompat:appcompat:1.5.1'
implementation 'com.google.android.material:material:1.7.0'
implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
implementation platform('com.google.firebase:firebase-bom:30.0.1')
implementation 'com.google.firebase:firebase-analytics-ktx'
implementation 'com.google.firebase:firebase-auth-ktx'
implementation 'com.google.firebase:firebase-firestore-ktx'
implementation 'com.google.firebase:firebase-firestore'
implementation platform('com.google.firebase:firebase-bom:31.0.2')
testImplementation 'junit:junit:4.13.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
}
build grade(project)
buildscript {
repositories {
// Check that you have the following line (if not, add it):
google() // Google's Maven repository
}
dependencies {
classpath 'com.android.tools.build:gradle:7.3.1'
classpath 'com.google.gms:google-services:4.3.14'
}
}
// Top-level build file where you can add configuration options common to all sub-projects/modules.
plugins {
id 'com.android.application' version '7.3.1' apply false
id 'com.android.library' version '7.3.1' apply false
id 'org.jetbrains.kotlin.android' version '1.7.20' apply false
}
``
`I'm kind of lost already,
tried this
Unresolved reference:database for Firebase Realtime database in my Kotlin program
but it didnt help either.
any suggestion will be welcome!
Unresolved reference:database for Firebase Realtime database in my Kotlin program
Reconnection the firebase to project and import from begging.`
I actually answered that question but in your case, the problem isn't related to the import but to the name of the class. So you're getting the following error:
Unsolved reference: Databaserefernce
Because there is no class that is called Databaserefernce but DatabaseReference. See the capital R? To solve this, please change the type of the variable to DatabaseReference, add the corresponding import and the error will go away.
Besides that, the way you're initializing the variable is not correct. That's how you do it in Java. In Kotlin you should do it like this:
val db = FirebaseDatabase.getInstance().reference
I have been using hilt in my several android projects. But since I have updated my android studio to latest version Chipmunk// 2021.2.1, this error comes every time when I just build project
Execution failed for task ':app:kaptDebugKotlin'.
A failure occurred while executing org.jetbrains.kotlin.gradle.internal.KaptWithoutKotlincTask$KaptExecutionWorkAction
java.lang.reflect.InvocationTargetException (no error message)
I am checking it on sample app which is just just one dependency injection, using hilt and kapt.
// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
allprojects {
repositories {
google()
mavenCentral()
maven { url 'https://jitpack.io' }
}
}
dependencies {
// Hilt Classpath for Java
classpath 'com.google.dagger:hilt-android-gradle-plugin:2.38.1'
}
}
plugins {
id 'com.android.application' version '7.2.1' apply false
id 'com.android.library' version '7.2.1' apply false
id 'org.jetbrains.kotlin.android' version '1.7.10' apply false
}
task clean(type: Delete) {
delete rootProject.buildDir
}
apply plugin: 'com.android.application'
apply plugin: 'org.jetbrains.kotlin.android'
apply plugin: 'kotlin-kapt'
apply plugin: 'dagger.hilt.android.plugin'
android {
compileSdk 32
defaultConfig {
applicationId "com.example.hiltkotlinpractice"
minSdk 21
targetSdk 32
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
kotlinOptions {
jvmTarget = '1.8'
}
}
dependencies {
implementation 'androidx.core:core-ktx:1.7.0'
implementation 'androidx.appcompat:appcompat:1.4.2'
implementation 'com.google.android.material:material:1.6.1'
implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
testImplementation 'junit:junit:4.13.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
implementation("com.google.dagger:hilt-android:2.38.1")
kapt("com.google.dagger:hilt-android-compiler:2.38.1")
kapt 'androidx.hilt:hilt-compiler:1.0.0'
}
#HiltAndroidApp
class App: Application()
#Module
#InstallIn(ActivityComponent::class)
class AppModule {
#Provides
fun provideInterface(): APIProvider {
return APIProvider()
}
}
class Repo #Inject constructor(
val apiProvider: APIProvider
) {
fun get() = apiProvider.getData()
}
#AndroidEntryPoint
class MainActivity : AppCompatActivity() {
private val TAG = "MainActivity"
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val repo = Repo(APIProvider())
Log.d(TAG, repo.get())
}
}
Try using "annotationProcessor" instead of the "kapt" in the build.gradle dependencies. Worked for me.
I have been trying to implement comet Chat sdk into my project. I followed the documentation for kotlin but each time i try to initialize comet chat i get several errors. Here are my codes. 1. Main Activity
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
initCometChat()
}
private fun initCometChat() {
private val appID = "208314db190ca55b"
private val region = "us"
val appSettings = AppSettingsBuilder().subscribePresenceForAllUsers().setRegion(region).build()
CometChat.init(this, appID, appSettings, object : CallbackListener<String>() {
override fun onSuccess(successMessage: String) {
}
override fun onError(e: CometChatException) {
}
})
}
project level build gradle
plugins {
id 'com.android.application' version '7.1.1' apply false
id 'com.android.library' version '7.1.1' apply false
id 'org.jetbrains.kotlin.android' version '1.6.10' apply false
}
task clean(type: Delete) {
delete rootProject.buildDir
}
The CometChat.init() function returns an error marked with red. I am new to kotlin and so i do not know how sdks work. Please help me. Thank you
app level build gradle
plugins {
id 'com.android.application'
id 'org.jetbrains.kotlin.android'
}
android {
compileSdk 31
defaultConfig {
applicationId "com.chat.comet"
minSdk 21
targetSdk 31
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-`rules.pro'`
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
kotlinOptions {
jvmTarget = '1.8'
}
}
dependencies {
implementation 'androidx.core:core-ktx:1.7.0'
implementation 'androidx.appcompat:appcompat:1.4.1'
implementation 'com.google.android.material:material:1.5.0'
implementation 'androidx.constraintlayout:constraintlayout:2.1.3'
testImplementation 'junit:junit:4.13.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
implementation 'com.cometchat:pro-android-chat-sdk:3.0.4'
}
After going through documentations and trying solutions of similar questions here on stackoverflow, nothing seems to fix the issue.
I tried altering all related dependencies, trying additional dependencies and tweaking the versions. Gradle builds successfully but there is a runtime error that through trial and error, the only method I found that could fix it was removing the argument from the ViewModel which is not desirable for me as the same setup used to work in my older projects.
RuntimeException
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example, PID: 17527
java.lang.RuntimeException: Cannot create an instance of class com.example.ui.MainViewModel
at androidx.lifecycle.ViewModelProvider$NewInstanceFactory.create(ViewModelProvider.kt:188)
build.gradle(:app)
plugins {
id 'com.android.application'
id 'org.jetbrains.kotlin.android'
id 'kotlin-kapt'
id 'dagger.hilt.android.plugin'
id 'com.google.devtools.ksp' version '1.6.10-1.0.2'
}
kotlin {
sourceSets {
debug {
kotlin.srcDir("build/generated/ksp/debug/kotlin")
}
release {
kotlin.srcDir("build/generated/ksp/release/kotlin")
}
}
}
android {
compileSdk 31
defaultConfig {
multiDexEnabled = true
applicationId "com.example"
minSdk 23
targetSdk 31
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
vectorDrawables {
useSupportLibrary true
}
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
compileOptions {
coreLibraryDesugaringEnabled true
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
kotlinOptions {
jvmTarget = '1.8'
freeCompilerArgs += '-Xopt-in=kotlin.RequiresOptIn'
}
buildFeatures {
compose true
}
composeOptions {
kotlinCompilerExtensionVersion compose_version
}
packagingOptions {
resources {
excludes += '/META-INF/{AL2.0,LGPL2.1}'
}
}
}
dependencies {
implementation 'androidx.core:core-ktx:1.7.0'
implementation "androidx.compose.ui:ui:$compose_version"
implementation 'androidx.compose.material3:material3:1.0.0-alpha04'
implementation "androidx.compose.ui:ui-tooling-preview:$compose_version"
implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.4.0'
implementation 'androidx.activity:activity-compose:1.4.0'
testImplementation 'junit:junit:4.13.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
androidTestImplementation "androidx.compose.ui:ui-test-junit4:$compose_version"
debugImplementation "androidx.compose.ui:ui-tooling:$compose_version"
debugImplementation "androidx.compose.ui:ui-test-manifest:$compose_version"
//lifecycle
implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.4.0"
implementation "androidx.lifecycle:lifecycle-viewmodel-compose:2.4.0"
//Hilt
implementation "com.google.dagger:hilt-android:$hilt_version"
kapt "com.google.dagger:hilt-compiler:$hilt_version"
implementation "androidx.hilt:hilt-lifecycle-viewmodel:1.0.0-alpha03"
kapt "androidx.hilt:hilt-compiler:1.0.0"
//Coroutines
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.6.0'
//DataStore
implementation "androidx.datastore:datastore-preferences:1.0.0"
//Desugaring
coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:1.1.5'
//Compose Destinations
implementation "io.github.raamcosta.compose-destinations:core:1.2.1-beta"
ksp "io.github.raamcosta.compose-destinations:ksp:1.2.1-beta"
build.gradle(Project)
buildscript {
ext {
compose_version = '1.2.0-alpha02'
hilt_version = "2.40.5"
}
dependencies {
classpath "com.google.dagger:hilt-android-gradle-plugin:$hilt_version"
}
}// Top-level build file where you can add configuration options common to all sub-projects/modules.
plugins {
id 'com.android.application' version '7.2.0-beta01' apply false
id 'com.android.library' version '7.2.0-beta01' apply false
id 'org.jetbrains.kotlin.android' version '1.6.10' apply false
id 'org.jetbrains.kotlin.jvm' version '1.6.10' apply false
}
task clean(type: Delete) {
delete rootProject.buildDir
}
MainViewModel.kt
#HiltViewModel
class MainViewModel #Inject constructor(
private val dataStoreRepository: DataStoreRepository
) : ViewModel() {...}
MainActivity.kt
#AndroidEntryPoint
class MainActivity : ComponentActivity() {
private val mainViewModel: MainViewModel by viewModels()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
DestinationsNavHost(navGraph = NavGraphs.root)
}
}
}
Did you create module class? like below:
#Module
#InstallIn(SingletonComponent::class)
class RepositoryModule {
#Provides
#Singleton
fun provideDataStoreRepository(): DataStoreRepository = DataStoreRepository()
}
I was trying to explore Hilt with simplest possible example, but my application isn't building. I added all the dependencies but when I try to build, it shows an error indicating not finding the hilt gradle plugin.
Here are my codes:
build.gradle(project)
ext.kotlin_version = "1.5.20"
ext.hilt_version = '2.35'
repositories {
google()
mavenCentral()
}
dependencies {
classpath "com.android.tools.build:gradle:4.2.1"
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
classpath "com.google.dagger:hilt-android-gradle-plugin:$hilt_version"
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}
}
allprojects {
repositories {
google()
mavenCentral()
jcenter() // Warning: this repository is going to shut down soon
}
}
task clean(type: Delete) {
delete rootProject.buildDir
}
build.gradle(app)
plugins{
id 'com.android.application'
id 'kotlin-android'
id 'kotlin-kapt'
id 'dagger.hilt.android.plugin'
}
android {
compileSdkVersion 30
buildToolsVersion "30.0.3"
defaultConfig {
applicationId "com.bonny.tutorial.hilttest"
minSdkVersion 23
targetSdkVersion 30
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
kotlinOptions {
jvmTarget = '1.8'
}
}
dependencies {
implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
implementation 'androidx.core:core-ktx:1.5.0'
implementation 'androidx.appcompat:appcompat:1.3.0'
implementation 'com.google.android.material:material:1.3.0'
implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
testImplementation 'junit:junit:4.+'
//hilt
implementation "com.google.dagger:hilt-android:$hilt_version"
kapt "com.google.dagger:hilt-android-compiler:$hilt_version"
androidTestImplementation 'androidx.test.ext:junit:1.1.2'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}
Application Class (included in the Manifest too)
import android.app.Application
import dagger.hilt.android.HiltAndroidApp
#HiltAndroidApp
class TextApplication : Application() {
}
Dependency class (MyTexts.kt)
class MyTexts #Inject constructor(){
val text = "Hello World"
}
MainActivity.kt
#AndroidEntryPoint
class MainActivity : AppCompatActivity() {
private lateinit var tv: TextView
#Inject lateinit var myTexts: MyTexts
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
tv = findViewById(R.id.myText)
tv.text = myTexts.text
}
}
and the error looks like this:
public final class MainActivity extends androidx.appcompat.app.AppCompatActivity {
^
Expected #AndroidEntryPoint to have a value. Did you forget to apply the Gradle Plugin? (dagger.hilt.android.plugin)
See https://dagger.dev/hilt/gradle-setup.html
[Hilt] Processing did not complete. See error above for details.
Please suggest.
Kotlin 1.5.20 just came out (24 jun 2021) so there seems to be some compatibility issue. You can bring down to ext.kotlin_version = "1.5.10" in your build.gradle(project)
Also, Update hilt to latest 2.37
project build
classpath "com.google.dagger:hilt-android-gradle-plugin:2.37"
app build:
//Dagger - Hilt
implementation "com.google.dagger:hilt-android:2.37"
kapt "com.google.dagger:hilt-android-compiler:2.37"