Facebook Login Integration in Android Kotlin


Here is the Gradle

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

android {
    compileSdk 31

    defaultConfig {
        applicationId "com.shyptsolution.subscribetothechannel"
        minSdk 23
        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 'com.facebook.android:facebook-login:latest.release'
    implementation 'com.squareup.picasso:picasso:2.71828'
    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 'com.google.firebase:firebase-auth-ktx:21.0.1'
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
}

Here is the Manifest File

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

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.SubscribeToTheChannel">
        <activity
            android:name=".Login"
            android:exported="true" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

        <meta-data
            android:name="com.facebook.sdk.ApplicationId"
            android:value="@string/facebook_app_id" />
        <meta-data
            android:name="com.facebook.sdk.ClientToken"
            android:value="@string/facebook_client_token" />

        <activity
            android:name="com.facebook.FacebookActivity"
            android:configChanges="keyboard|keyboardHidden|screenLayout|screenSize|orientation"
            android:label="@string/app_name" />
        <activity
            android:name="com.facebook.CustomTabActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />

                <data android:scheme="@string/fb_login_protocol_scheme" />
            </intent-filter>
        </activity>
        <activity
            android:name=".MainActivity"
            android:exported="true">

        </activity>
    </application>

</manifest>

Here is the Login Activity Code

package com.shyptsolution.subscribetothechannel

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.widget.Toast
import com.facebook.AccessToken
import com.facebook.CallbackManager
import com.facebook.FacebookCallback
import com.facebook.FacebookException
import com.facebook.login.LoginManager
import com.facebook.login.LoginResult
import com.facebook.login.widget.LoginButton
import com.google.firebase.auth.FacebookAuthProvider
import com.google.firebase.auth.FirebaseAuth

class Login : AppCompatActivity() {
    var callbackManager = CallbackManager.Factory.create()
    var auth=FirebaseAuth.getInstance()
    var TAG=""
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_login)


        var loginbutton=findViewById<LoginButton>(R.id.login_button)
        loginbutton.setOnClickListener {
            if(userLoggedIn()){
                auth.signOut()
            }
            else{
                LoginManager.getInstance().logInWithReadPermissions(this, listOf("public_profile","email"))
            }
        }

        LoginManager.getInstance().registerCallback(callbackManager, object :
            FacebookCallback<LoginResult> {
            override fun onSuccess(loginResult: LoginResult) {
                Log.d(TAG, "facebook:onSuccess:$loginResult")
                handleFacebookAccessToken(loginResult.accessToken)
            }

            override fun onCancel() {
                Log.d(TAG, "facebook:onCancel")
                // ...
            }

            override fun onError(error: FacebookException) {
                Log.d(TAG, "facebook:onError", error)
                // ...
            }
        })
        // ...


    }

    private fun userLoggedIn(): Boolean {
        if(auth.currentUser!=null && !AccessToken.getCurrentAccessToken()!!.isExpired){
            return true
        }
        return false
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)

        // Pass the activity result back to the Facebook SDK
        callbackManager.onActivityResult(requestCode, resultCode, data)
    }
    private fun handleFacebookAccessToken(token: AccessToken) {
        Log.d(TAG, "handleFacebookAccessToken:$token")

        val credential = FacebookAuthProvider.getCredential(token.token)
        auth.signInWithCredential(credential)
            .addOnCompleteListener(this) { task ->
                if (task.isSuccessful) {
                    // Sign in success, update UI with the signed-in user's information
                    Log.d(TAG, "signInWithCredential:success")
                    val user = auth.currentUser
                    startActivity(Intent(this,MainActivity::class.java))
                } else {
                    // If sign in fails, display a message to the user.
                    Log.w(TAG, "signInWithCredential:failure", task.exception)
                    Toast.makeText(baseContext, "Authentication failed.",
                        Toast.LENGTH_SHORT).show()

                }
            }
    }

}


<?xml version="1.0" encoding="utf-8"?>
<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"
    tools:context=".Login">

    <com.facebook.login.widget.LoginButton
        android:id="@+id/login_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Here is the Main Activity Code

package com.shyptsolution.subscribetothechannel

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.ImageView
import android.widget.TextView
import com.google.firebase.auth.FirebaseAuth
import com.squareup.picasso.Picasso

class MainActivity : AppCompatActivity() {
    var auth=FirebaseAuth.getInstance()
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        var name=findViewById<TextView>(R.id.textView)
        var image=findViewById<ImageView>(R.id.imageView)
        name.setText(auth.currentUser?.displayName)
        Picasso.get().load(auth.currentUser?.photoUrl).into(image)
    }
}

<?xml version="1.0" encoding="utf-8"?>
<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"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:textSize="24sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="100dp"
        android:layout_height="100dp"
        app:layout_constraintBottom_toTopOf="@+id/textView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:srcCompat="@tools:sample/backgrounds/scenic" />

</androidx.constraintlayout.widget.ConstraintLayout>
Thank you for reading.