A step by step Firebase Remote Config example.

1. Firebase Remote Config Quickstart

This is a simple Firebase Remote Config example project. Here is the demo screenshot of what is created:

firebase Example Tutorial

Step 1. Dependencies

We need to add some dependencies in our app/build.gradle file as shown below:

(a). build.gradle

Our app-level build.gradle.

We Prepare our dependencies as shown below. You may use later versions.

We will enable view binding by setting the viewBinding property to true.

We then declare our app dependencies under the dependencies closure. We will need the following 7 dependencies:

  1. Our Material library.
  2. Our Firebase-bom library.
  3. Our Com.google.firebase library.
  4. Our Com.google.firebase library.
  5. Our Com.google.firebase library.

Here is our full app/build.gradle:

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id 'com.google.gms.google-services'
}

check.dependsOn 'assembleDebugAndroidTest'

android {
    compileSdkVersion 33

    defaultConfig {
        applicationId "com.google.samples.quickstart.config"
        minSdkVersion 19
        targetSdkVersion 33
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    buildFeatures {
        viewBinding = true
    }
}

dependencies {
    implementation project(":internal:lintchecks")
    implementation project(":internal:chooserx")

    implementation 'com.google.android.material:material:1.6.1'

    // Import the Firebase BoM (see: https://firebase.google.com/docs/android/learn-more#bom)
    implementation platform('com.google.firebase:firebase-bom:30.5.0')

    // Firebase Remote Config (Java)
    implementation 'com.google.firebase:firebase-config'

    // Firebase Remote Config (Kotlin)
    implementation 'com.google.firebase:firebase-config-ktx'

    // For an optimal experience using Remote Config, add the Firebase SDK
    // for Google Analytics. This is recommended, but not required.
    implementation 'com.google.firebase:firebase-analytics'

    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    androidTestImplementation 'androidx.test:rules:1.4.0'
    androidTestImplementation 'androidx.test:runner:1.4.0'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
}

Step 2. Create Firebase App

You will need to create or setup a Firebase app first. This link explains how to do so.

Step 3. Our Android Manifest

(a). AndroidManifest.xml

Our AndroidManifest file.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.google.samples.quickstart.config" >

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >

        <activity
            android:name=".java.MainActivity"
            android:label="@string/app_name" />

        <activity
            android:name=".kotlin.MainActivity"
            android:label="@string/app_name" />

        <activity
            android:name=".EntryChoiceActivity"
            android:label="@string/app_name"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Step 4. Create Remote Config XML

Create a directory known as xml inside your res directory and add the following xml file:

(a). remote_config_defaults.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- START xml_defaults -->
<defaultsMap>
    <entry>
        <key>loading_phrase</key>
        <value>Fetching config…</value>
    </entry>
    <entry>
        <key>welcome_message_caps</key>
        <value>false</value>
    </entry>
    <entry>
        <key>welcome_message</key>
        <value>Welcome to my awesome app!</value>
    </entry>
</defaultsMap>
    <!-- END xml_defaults -->

Step 5. Design Layouts

(a). activity_main.xml

Our activity_main layout.

Inside your /res/layout/ directory create an xml layout file named activity_main.xml and add the following widgets:

  1. androidx.constraintlayout.widget.ConstraintLayout
  2. ImageView
  3. TextView
  4. Button
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".java.MainActivity">

    <ImageView
        android:id="@+id/icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/firebase_lockup_400"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/welcomeTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/icon"
        android:layout_marginTop="16dp"
        android:text="Welcome..."
        app:layout_constraintEnd_toEndOf="@+id/icon"
        app:layout_constraintStart_toStartOf="@+id/icon"
        app:layout_constraintTop_toBottomOf="@+id/icon" />

    <Button
        android:id="@+id/fetchButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/fetch_remote_welcome_message"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/welcomeTextView" />

</androidx.constraintlayout.widget.ConstraintLayout>

Step 6. Write Code

Finally we need to write our code as follows:

(a). EntryChoiceActivity.kt

Our EntryChoiceActivity class.

Create a Kotlin file named EntryChoiceActivity.kt and create a class that derives from BaseEntryChoiceActivity and add its contents as follows:

We will be overriding the following functions:

  1. getChoices(): List<Choice>.

Here is the full code:

package replace_with_your_package_name

import android.content.Intent
import com.firebase.example.internal.BaseEntryChoiceActivity
import com.firebase.example.internal.Choice

class EntryChoiceActivity : BaseEntryChoiceActivity() {

    override fun getChoices(): List<Choice> {
        return listOf(
                Choice(
                        "Java",
                        "Run the Firebase Remote Config quickstart written in Java.",
                        Intent(
                            this,
                            com.google.samples.quickstart.config.java.MainActivity::class.java)),
                Choice(
                        "Kotlin",
                        "Run the Firebase Remote Config quickstart written in Kotlin.",
                        Intent(
                            this,
                            com.google.samples.quickstart.config.kotlin.MainActivity::class.java))
        )
    }
}

(b). MainActivity.kt

Our MainActivity class.

Create a Kotlin file named MainActivity.kt. We will be overriding the following functions:

  1. onCreate(savedInstanceState: Bundle?).

We will be creating the following methods:

  1. fetchWelcome().
  2. displayWelcomeMessage().

(a). Our displayWelcomeMessage() function

Write the displayWelcomeMessage() function as follows:

    private fun displayWelcomeMessage() {
        // [START get_config_values]
        val welcomeMessage = remoteConfig[WELCOME_MESSAGE_KEY].asString()
        // [END get_config_values]
        binding.welcomeTextView.isAllCaps = remoteConfig[WELCOME_MESSAGE_CAPS_KEY].asBoolean()
        binding.welcomeTextView.text = welcomeMessage
    }

(b). Our fetchWelcome() function

Write the fetchWelcome() function as follows:

    private fun fetchWelcome() {
        binding.welcomeTextView.text = remoteConfig[LOADING_PHRASE_CONFIG_KEY].asString()

        // [START fetch_config_with_callback]
        remoteConfig.fetchAndActivate()
                .addOnCompleteListener(this) { task ->
                    if (task.isSuccessful) {
                        val updated = task.result
                        Log.d(TAG, "Config params updated: $updated")
                        Toast.makeText(this, "Fetch and activate succeeded",
                                Toast.LENGTH_SHORT).show()
                    } else {
                        Toast.makeText(this, "Fetch failed",
                                Toast.LENGTH_SHORT).show()
                    }
                    displayWelcomeMessage()
                }
        // [END fetch_config_with_callback]
    }

Here is the full code:

package replace_with_your_package_name

import android.os.Bundle
import android.util.Log
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.google.firebase.ktx.Firebase
import com.google.firebase.remoteconfig.FirebaseRemoteConfig
import com.google.firebase.remoteconfig.ktx.get
import com.google.firebase.remoteconfig.ktx.remoteConfig
import com.google.firebase.remoteconfig.ktx.remoteConfigSettings
import com.google.samples.quickstart.config.R
import com.google.samples.quickstart.config.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

    private lateinit var remoteConfig: FirebaseRemoteConfig
    private lateinit var binding: ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        binding.fetchButton.setOnClickListener { fetchWelcome() }

        // Get Remote Config instance.
        // [START get_remote_config_instance]
        remoteConfig = Firebase.remoteConfig
        // [END get_remote_config_instance]

        // Create a Remote Config Setting to enable developer mode, which you can use to increase
        // the number of fetches available per hour during development. Also use Remote Config
        // Setting to set the minimum fetch interval.
        // [START enable_dev_mode]
        val configSettings = remoteConfigSettings {
            minimumFetchIntervalInSeconds = 3600
        }
        remoteConfig.setConfigSettingsAsync(configSettings)
        // [END enable_dev_mode]

        // Set default Remote Config parameter values. An app uses the in-app default values, and
        // when you need to adjust those defaults, you set an updated value for only the values you
        // want to change in the Firebase console. See Best Practices in the README for more
        // information.
        // [START set_default_values]
        remoteConfig.setDefaultsAsync(R.xml.remote_config_defaults)
        // [END set_default_values]

        fetchWelcome()
    }

    /**
     * Fetch a welcome message from the Remote Config service, and then activate it.
     */
    private fun fetchWelcome() {
        binding.welcomeTextView.text = remoteConfig[LOADING_PHRASE_CONFIG_KEY].asString()

        // [START fetch_config_with_callback]
        remoteConfig.fetchAndActivate()
                .addOnCompleteListener(this) { task ->
                    if (task.isSuccessful) {
                        val updated = task.result
                        Log.d(TAG, "Config params updated: $updated")
                        Toast.makeText(this, "Fetch and activate succeeded",
                                Toast.LENGTH_SHORT).show()
                    } else {
                        Toast.makeText(this, "Fetch failed",
                                Toast.LENGTH_SHORT).show()
                    }
                    displayWelcomeMessage()
                }
        // [END fetch_config_with_callback]
    }

    /**
     * Display a welcome message in all caps if welcome_message_caps is set to true. Otherwise,
     * display a welcome message as fetched from welcome_message.
     */
    // [START display_welcome_message]
    private fun displayWelcomeMessage() {
        // [START get_config_values]
        val welcomeMessage = remoteConfig[WELCOME_MESSAGE_KEY].asString()
        // [END get_config_values]
        binding.welcomeTextView.isAllCaps = remoteConfig[WELCOME_MESSAGE_CAPS_KEY].asBoolean()
        binding.welcomeTextView.text = welcomeMessage
    }

    companion object {

        private const val TAG = "MainActivity"

        // Remote Config keys
        private const val LOADING_PHRASE_CONFIG_KEY = "loading_phrase"
        private const val WELCOME_MESSAGE_KEY = "welcome_message"
        private const val WELCOME_MESSAGE_CAPS_KEY = "welcome_message_caps"
    }
    // [END display_welcome_message]
}

Reference

Below are the reference links:

No. Link
2. Read more here.
3. Follow code author here.
Read More.