Androidstudio实现在线交流功能的完整代码，现在还没有搭建服务器

要实现在线交流功能，需要搭建服务器。如果你还没有搭建服务器，可以使用第三方的聊天API，例如环信、融云等。这些聊天API提供了完整的SDK和文档，可以帮助你快速地实现在线交流功能。

以下是一个使用环信聊天API实现在线交流功能的示例代码：

1. 在Android Studio中创建一个新项目。在项目的build.gradle文件中添加环信SDK的依赖：

dependencies {
    implementation 'com.hyphenate:hyphenate-sdk:3.7.0'
}

2. 在AndroidManifest.xml文件中添加以下权限：

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.CAMERA" />

3. 在Application类中初始化环信SDK：

public class MyApplication extends Application {

    @Override
    public void onCreate() {
        super.onCreate();
        EMOptions options = new EMOptions();
        options.setAutoLogin(true);
        EMClient.getInstance().init(this, options);
        EMClient.getInstance().setDebugMode(true);
    }
}

4. 实现登录功能：

public class LoginActivity extends AppCompatActivity {

    private EditText usernameEditText;
    private EditText passwordEditText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        usernameEditText = findViewById(R.id.username_edit_text);
        passwordEditText = findViewById(R.id.password_edit_text);

        findViewById(R.id.login_button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String username = usernameEditText.getText().toString().trim();
                String password = passwordEditText.getText().toString().trim();
                EMClient.getInstance().login(username, password, new EMCallBack() {
                    @Override
                    public void onSuccess() {
                        startActivity(new Intent(LoginActivity.this, MainActivity.class));
                        finish();
                    }

                    @Override
                    public void onError(int code, String error) {
                        Toast.makeText(LoginActivity.this, "登录失败：" + error, Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onProgress(int progress, String status) {

                    }
                });
            }
        });
    }
}

5. 实现注册功能：

public class RegisterActivity extends AppCompatActivity {

    private EditText usernameEditText;
    private EditText passwordEditText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);

        usernameEditText = findViewById(R.id.username_edit_text);
        passwordEditText = findViewById(R.id.password_edit_text);

        findViewById(R.id.register_button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String username = usernameEditText.getText().toString().trim();
                String password = passwordEditText.getText().toString().trim();
                EMClient.getInstance().createAccount(username, password, new EMCallBack() {
                    @Override
                    public void onSuccess() {
                        Toast.makeText(RegisterActivity.this, "注册成功", Toast.LENGTH_SHORT).show();
                        finish();
                    }

                    @Override
                    public void onError(int code, String error) {
                        Toast.makeText(RegisterActivity.this, "注册失败：" + error, Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onProgress(int progress, String status) {

                    }
                });
            }
        });
    }
}

6. 实现聊天功能：

public class ChatActivity extends AppCompatActivity {

    private RecyclerView recyclerView;
    private EditText messageEditText;
    private Button sendButton;

    private EMConversation conversation;
    private EMMessageListener messageListener;

    private MessageAdapter messageAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_chat);

        recyclerView = findViewById(R.id.recycler_view);
        messageEditText = findViewById(R.id.message_edit_text);
        sendButton = findViewById(R.id.send_button);

        messageAdapter = new MessageAdapter();
        recyclerView.setAdapter(messageAdapter);

        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);

        String username = getIntent().getStringExtra("username");
        conversation = EMClient.getInstance().chatManager().getConversation(username);

        messageListener = new EMMessageListener() {
            @Override
            public void onMessageReceived(List<EMMessage> messages) {
                messageAdapter.addMessages(messages);
                recyclerView.smoothScrollToPosition(messageAdapter.getItemCount() - 1);
            }

            @Override
            public void onCmdMessageReceived(List<EMMessage> messages) {

            }

            @Override
            public void onMessageRead(List<EMMessage> messages) {

            }

            @Override
            public void onMessageDelivered(List<EMMessage> messages) {

            }

            @Override
            public void onMessageRecalled(List<EMMessage> messages) {

            }

            @Override
            public void onMessageChanged(EMMessage message, Object change) {

            }
        };
        EMClient.getInstance().chatManager().addMessageListener(messageListener);

        sendButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String content = messageEditText.getText().toString().trim();
                if (!TextUtils.isEmpty(content)) {
                    EMMessage message = EMMessage.createTxtSendMessage(content, username);
                    EMClient.getInstance().chatManager().sendMessage(message);
                    messageAdapter.addMessage(message);
                    recyclerView.smoothScrollToPosition(messageAdapter.getItemCount() - 1);
                    messageEditText.setText("");
                }
            }
        });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        EMClient.getInstance().chatManager().removeMessageListener(messageListener);
    }

    private class MessageAdapter extends RecyclerView.Adapter<MessageViewHolder> {

        private List<EMMessage> messages = new ArrayList<>();

        public void addMessages(List<EMMessage> messages) {
            this.messages.addAll(messages);
            notifyDataSetChanged();
        }

        public void addMessage(EMMessage message) {
            this.messages.add(message);
            notifyDataSetChanged();
        }

        @Override
        public int getItemViewType(int position) {
            EMMessage message = messages.get(position);
            return message.direct() == EMMessage.Direct.RECEIVE ? 0 : 1;
        }

        @NonNull
        @Override
        public MessageViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
            View view = viewType == 0 ? layoutInflater.inflate(R.layout.item_message_receive, parent, false)
                    : layoutInflater.inflate(R.layout.item_message_send, parent, false);
            return new MessageViewHolder(view);
        }

        @Override
        public void onBindViewHolder(@NonNull MessageViewHolder holder, int position) {
            EMMessage message = messages.get(position);
            holder.bindMessage(message);
        }

        @Override
        public int getItemCount() {
            return messages.size();
        }
    }

    private class MessageViewHolder extends RecyclerView.ViewHolder {

        private TextView messageTextView;

        public MessageViewHolder(@NonNull View itemView) {
            super(itemView);
            messageTextView = itemView.findViewById(R.id.message_text_view);
        }

        public void bindMessage(EMMessage message) {
            messageTextView.setText(message.getBody().toString());
        }
    }
}

以上代码仅供参考，具体实现还需要根据自己的需求进行调整。