How to integrate facebook in Android App?

This example demonstrates about How to integrate facebook in Android App

Step 1  − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2  – Please follow Q21 to integrate Facebook.

Step 3  − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"
   android:id="@+id/rlMain"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:layout_margin="16dp"
   android:orientation="vertical">
   <com.facebook.login.widget.LoginButton
   android:onClick="fbClick"
   android:id="@+id/login_button"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_gravity="center_horizontal"
   android:layout_marginTop="30dp"
   android:layout_marginBottom="30dp" />
</LinearLayout>

Step 4  − Add the following code to src/MainActivity.java

package app.com.sample;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import com.facebook.CallbackManager;
import com.facebook.FacebookCallback;
import com.facebook.FacebookException;
import com.facebook.login.LoginManager;
import com.facebook.login.LoginResult;
public class MainActivity extends AppCompatActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
   }
   public void fbClick(View view) {
      CallbackManager callbackManager = CallbackManager.Factory.create();
      LoginManager.getInstance().registerCallback(callbackManager,
      new FacebookCallback<LoginResult>() {
         @Override
         public void onSuccess(LoginResult loginResult) {
            Toast.makeText(getApplicationContext(),"Success",Toast.LENGTH_SHORT).show();
         }
         @Override
         public void onCancel() {
            Toast.makeText(getApplicationContext(),"Cancel",Toast.LENGTH_SHORT).show();
         }
         @Override
         public void onError(FacebookException exception) {
            Toast.makeText(getApplicationContext(),exception.toString(),Toast.LENGTH_SHORT).show();
         }
      });
   }
}

Step 5  − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="https://schemas.android.com/apk/res/android"
   package="app.com.sample">
   <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/AppTheme">
      <activity android:name=".MainActivity">
         <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"/>
      <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>
   </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and Click Run  Icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen –