Unresolved reference:database for Firebase Realtime database in my Kotlin program

Question

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

Answer 1

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.