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Chat Application in Android Source Code with Example Available. In this tutorial, you'll learn to build your own Android Chat Application using Android Studio. We will use a simple 'Sign In with Google' and allow the user to create a username and start chatting. Chat application in Android Source Code Getting Started Open Android Studio and create a new Project (AndroidDvlpr Chat App) with an empty activity. In this project we have to create two activities, one Main Activity that'll check if the user is signed in and if not then sign up or sign in back. Second, is the Chat activity which will contain an Edittext with a send button and where all chat happens. Firebase Setup Chat application in Android Source Code Create an empty project in Firebase and add your android app to Firebase project. Next, enable Sign in with Google and download and sync google-services.json file with Android Studio. Learn more about enabling 'Sign In With Google' in your Android project from link here. Adding Libraries Add the following libraries to your build.gradle (app level) file and sync the project: implementation 'com.google.firebase:firebase-core:16.0.8' implementation 'com.google.firebase:firebase-auth:16.2.1' implementation 'com.google.android.gms:play-services-auth:16.0.1' implementation 'com.google.firebase:firebase-database:16.1.0' implementation 'com.firebaseui:firebase-ui:0.6.2' Creating Layouts Sign in Screen (activity_main.xml) For Sign in Screen we need an Edittext field where user will put a random username and a Google SignInButton for user to sign in to the account. The XML code for activity_main.xml is as follows: <TextView android:id"@+id/title" android:layout_width"wrap_content" android:layout_height"wrap_content" android:layout_marginStart"8dp" android:layout_marginTop"156dp" android:layout_marginEnd"8dp" android:fontFamily"monospace" android:text"AndroidDvlpr\nChat Room" android:textAlignment"center" android:textColor"@color/colorAccent" android:textSize"50sp" app:layout_constraintEnd_toEndOf"parent" app:layout_constraintStart_toStartOf"parent" app:layout_constraintTop_toTopOf"parent" /> <EditText android:id"@+id/editText" android:layout_width"300dp" android:layout_height"wrap_content" android:layout_marginTop"50dp" android:layout_marginStart"8dp" android:layout_marginEnd"8dp" android:hint"Enter a random username" android:textAlignment"center" android:textColor"#FFF" android:textColorHint"#7AFFFFFF" android:textSize"20sp" app:layout_constraintTop_toBottomOf"@id/title" app:layout_constraintEnd_toEndOf"parent" app:layout_constraintHorizontal_bias"0.496" app:layout_constraintStart_toStartOf"parent" tools:layout_editor_absoluteY"204dp" /> <com.google.android.gms.common.SignInButton android:id"@+id/signInBtn" android:layout_width"300dp" android:layout_height"wrap_content" android:layout_marginStart"8dp" android:layout_marginTop"20dp" android:layout_marginEnd"8dp" app:layout_constraintEnd_toEndOf"parent" app:layout_constraintHorizontal_bias"0.494" app:layout_constraintStart_toStartOf"parent" app:layout_constraintTop_toBottomOf"@+id/editText" /> Chat Activity and Chat Bubble Layout (activity_chat.xml) We need to create a new Blank Activity first to have activity_chat.xml in our project with name 'ChatActivity' as an activity name. Here is the code for our Chat screen also known as activity_chat.xml: <ListView android:id"@+id/list_message" android:layout_width"match_parent" android:layout_height"match_parent" android:layout_marginBottom"50dp" app:layout_constraintBottom_toTopOf"@+id/linearLayout" app:layout_constraintEnd_toEndOf"parent" app:layout_constraintStart_toStartOf"parent" app:layout_constraintTop_toTopOf"parent" android:stackFromBottom"true" android:transcriptMode"alwaysScroll" android:dividerHeight"16dp" android:divider"@android:color/transparent" /> However, in the chat screen, the chat messages as shown by other users need to appear in a chat bubble, for this we need to create a layout to appear in listView widget. Create a new Android Layout resource file named list_msg.xml and create layout as follows: <TextView android:layout_alignParentStart"true" android:layout_marginTop"5dp" android:layout_below"@id/message_user" android:textAppearance"@style/TextAppearance.AppCompat.Body1" android:textColor"#FFF" android:textSize"18sp" android:id"@+id/message_text" android:layout_width"wrap_content" android:layout_height"wrap_content" android:padding"10dp" /> The code for the 'Send Button' which is an android drawable asset can be created by creating a drawable xml file in res/drawable named ic_send.xml. The code for this will be as follows: Creating Models For the signed up users and chat messages, we will need two Model classes in this project i.e, Model_chat (for the chat messages)and Model_User (for the user). To create Models, right click on the main directory of your app in the java folder (com.androiddvlpr.chatapp) and create a Java Class. (Model_Chat and Model_User) The code for Model_Chat for chat messages is as follows: package com.androiddvlpr.chatapp; public class Model_Chat { private String message; private String name; private Long timestamp; public Model_Chat() { } Model_Chat(String message, String name, Long timestamp) { this.message message; this.name name; this.timestamp timestamp; } public String getMessage() { return message; } public void setMessage(String message) { this.message message; } public String getName() { return name; } public void setName(String name) { this.name name; } public Long getTimestamp() { return timestamp; } public void setTimestamp(Long timestamp) { this.timestamp timestamp; } } The code for Model_User for user registration is as follows: package com.androiddvlpr.chatapp; public class Model_User { private String username, name, uid, email; private Long lastLogin; public Model_User() { } public Model_User(String username, String name, String uid, String email, Long lastLogin) { this.username username; this.name name; this.uid uid; this.email email; this.lastLogin lastLogin; } public String getName() { return name; } public void setName(String name) { this.name name; } public String getUsername() { return username; } public void setUsername(String username) { this.username username; } public String getUid() { return uid; } public void setUid(String uid) { this.uid uid; } public String getEmail() { return email; } public void setEmail(String email) { this.email email; } public Long getLastLogin() { return lastLogin; } public void setLastLogin(Long lastLogin) { this.lastLogin lastLogin; } } Coding the Chat Application in Android Source Code MainActivity.java Starting with MainActivity, this is the launcher activity that opens first whenever user opens the app. Here we will check if user is logged in or not and if current user is null (i.e, not logged in) then we will prompt user to sign up before he goes to ChatActivity.class package com.androiddvlpr.chatapp; import androidx.annotation.NonNull; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.os.Bundle; import android.widget.EditText; import android.widget.Toast; import com.google.android.gms.auth.api.signin.GoogleSignIn; import com.google.android.gms.auth.api.signin.GoogleSignInAccount; import com.google.android.gms.auth.api.signin.GoogleSignInClient; import com.google.android.gms.auth.api.signin.GoogleSignInOptions; import com.google.android.gms.common.SignInButton; import com.google.android.gms.common.api.ApiException; import com.google.android.gms.tasks.OnCompleteListener; import com.google.android.gms.tasks.Task; import com.google.firebase.auth.AuthCredential; import com.google.firebase.auth.AuthResult; import com.google.firebase.auth.FirebaseAuth; import com.google.firebase.auth.FirebaseUser; import com.google.firebase.auth.GoogleAuthProvider; import com.google.firebase.database.DatabaseReference; import com.google.firebase.database.FirebaseDatabase; import com.google.firebase.database.ServerValue; import java.util.Objects; public class MainActivity extends AppCompatActivity { SignInButton signInButton; EditText editText; final int RC_SIGN_IN 123; GoogleSignInClient mGoogleSignInClient; FirebaseAuth mAuth; DatabaseReference mUserDatabase; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); signInButton findViewById(R.id.signInBtn); editText findViewById(R.id.editText); if(editText.getText() ! null){ signIn(); } else { Toast.makeText(MainActivity.this,"Username needed",Toast.LENGTH_SHORT).show(); } // // Configure Google Sign In GoogleSignInOptions gso new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN) .requestIdToken(getString(R.string.default_web_client_id)) .requestEmail() .build(); // mGoogleSignInClient GoogleSignIn.getClient(this, gso); // // Initialize Firebase Auth mAuth FirebaseAuth.getInstance(); // } private void signIn() { Intent signInIntent mGoogleSignInClient.getSignInIntent(); startActivityForResult(signInIntent, RC_SIGN_IN); } @Override public void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); // Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...); if (requestCode RC_SIGN_IN) { Task task GoogleSignIn.getSignedInAccountFromIntent(data); try { // Google Sign In was successful, authenticate with Firebase GoogleSignInAccount account task.getResult(ApiException.class); assert account ! null; firebaseAuthWithGoogle(account,editText.getText().toString()); } catch (ApiException e) { // Google Sign In failed, update UI appropriately //Log.w(TAG, "Google sign in failed", e); // ... } } } private void firebaseAuthWithGoogle(GoogleSignInAccount acct, final String username) { //Log.d(TAG, "firebaseAuthWithGoogle:" + acct.getId()); AuthCredential credential GoogleAuthProvider.getCredential(acct.getIdToken(), null); mAuth.signInWithCredential(credential) .addOnCompleteListener(this, new OnCompleteListener () { @Override public void onComplete(@NonNull Task task) { if (task.isSuccessful()) { // Sign in success, update UI with the signed-in user's information //Log.d(TAG, "signInWithCredential:success"); FirebaseUser user mAuth.getCurrentUser(); mUserDatabase FirebaseDatabase.getInstance().getReference().child("users"); assert user ! null; mUserDatabase.child(Objects.requireNonNull(mAuth.getUid())).setValue(new Model_User(username,user.getDisplayName(),mAuth.getUid(),user.getEmail(), System.currentTimeMillis())); updateUI(user); } else { // If sign in fails, display a message to the user. //Log.w(TAG, "signInWithCredential:failure", task.getException()); Toast.makeText(MainActivity.this, "Authentication Failed.", Toast.LENGTH_SHORT).show(); updateUI(null); } // ... } }); } void updateUI(FirebaseUser user){ if(user ! null){ Intent intent new Intent(MainActivity.this, ChatActivity.class); startActivity(intent); } } @Override public void onStart() { super.onStart(); mAuth FirebaseAuth.getInstance(); // Check if user is signed in (non-null) and update UI accordingly. FirebaseUser currentUser mAuth.getCurrentUser(); updateUI(currentUser); } } ChatActivity.java Once the user has successfully signed in, we will now allow user to initiate chat. In the ChatActivity.class we will not only load chat messages but also check, once user prompts to send a message it should not be blank. Here is the code for ChatActivity.class: package com.androiddvlpr.chatapp; import androidx.annotation.NonNull; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.text.format.DateFormat; import android.view.View; import android.widget.EditText; import android.widget.ImageView; import android.widget.ListView; import android.widget.TextView; import com.firebase.ui.database.FirebaseListAdapter; import com.google.firebase.auth.FirebaseAuth; import com.google.firebase.database.DataSnapshot; import com.google.firebase.database.DatabaseError; import com.google.firebase.database.DatabaseReference; import com.google.firebase.database.FirebaseDatabase; import com.google.firebase.database.ValueEventListener; import java.util.Objects; public class ChatActivity extends AppCompatActivity { ImageView sendImage; EditText userMessage; FirebaseAuth mAuth; DatabaseReference mChatData, mUserData; String username "null"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_chat); mAuth FirebaseAuth.getInstance(); sendImage findViewById(R.id.send_image); userMessage findViewById(R.id.user_message); mChatData FirebaseDatabase.getInstance().getReference().child("chats"); mUserData FirebaseDatabase.getInstance().getReference().child(Objects.requireNonNull(mAuth.getUid())); displayChatMessage(); mUserData.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(@NonNull DataSnapshot dataSnapshot) { username Objects.requireNonNull(dataSnapshot.child("username").getValue()).toString(); } @Override public void onCancelled(@NonNull DatabaseError databaseError) { } }); sendImage.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if(userMessage.getText() ! null){ if(!userMessage.getText().toString().equals("") && username ! null){ mChatData.push().setValue(new Model_Chat(userMessage.getText().toString(),username,System.currentTimeMillis())); } } } }); } private void displayChatMessage() { ListView listOfMessage findViewById(R.id.list_message); FirebaseListAdapter adapter new FirebaseListAdapter (this, Model_Chat.class, R.layout.list_msg, FirebaseDatabase.getInstance().getReference().child("chats").limitToLast(100)) { @Override protected void populateView(View v, Model_Chat model, int position) { TextView messageText, messageUser, messageTime; messageText v.findViewById(R.id.message_text); messageUser v.findViewById(R.id.message_user); messageTime v.findViewById(R.id.message_time); messageText.setText(model.getMessage()); messageUser.setText(model.getName()); messageTime.setText(DateFormat.format("dd-MM-yyyy (HH:mm:ss)", model.getTimestamp())); } }; listOfMessage.setAdapter(adapter); } } Using FirebaseUI, we have created the Chat messages adapter to display chat messages, while send button checks that the user doesn't sends a blank message. Here is the direct link for complete Chat application Source Code.

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Chat application in Android Source Code with Example Available

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