How to implement sending and receiving messages in the chat?

Question

Android

Hello! I understand the logic of sending and receiving messages in order to receive and send messages to the chat. I just can’t understand why the messages that I receive arrive from the right (from the same side that I send). Who will tell you how to register to recognize received messages and place them on the left? I am posting my code below.

public class DataAdapter extends RecyclerView.Adapter<DataAdapter.ChatViewHolder> {

    public static final int MSG_TYPE_LEFT = 1;
    public static final int MSG_TYPE_RIGHT = 0;
    ArrayList<String> messages;
    LayoutInflater inflater;
    DataChat dataChat;

    public DataAdapter(Context context, ArrayList<String> messages) {
        this.messages = messages;
        this.inflater = LayoutInflater.from(context);
    }

    @NonNull
    @Override
    public ChatViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        switch (viewType) {
            case MSG_TYPE_RIGHT:
                View view = inflater.inflate(R.layout.item_chat, parent, false);
                return new ChatViewHolder(view);
            case MSG_TYPE_LEFT:
                View v = inflater.inflate(R.layout.item_chat_left, parent, false);
                return new ChatViewHolder(v);
            default:
                return null;
        }
    }

    @Override
    public void onBindViewHolder(@NonNull ChatViewHolder holder, int position) {
        String msg = messages.get(position);
        holder.tvMessage.setText(msg);
    }

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

    }
    @Override
    public final int getItemViewType(int position) {

        if (dataChat.isMine()) return MSG_TYPE_RIGHT;
        else return MSG_TYPE_LEFT;
    }

    class ChatViewHolder extends RecyclerView.ViewHolder {
        TextView tvMessage;
        ChatViewHolder(View itemView) {
            super(itemView);
            tvMessage = itemView.findViewById(R.id.tvMessage);
        }
    }

    static class DataChat {

        private boolean isMine;
        private String content;

        DataChat(String message, boolean mine) {
            content = message;
            isMine = mine;
        }

        public String getContent() {
            return content;
        }

        public void setContent(String content) {
            this.content = content;
        }

        public boolean isMine() {
            return isMine;
        }

        public void setIsMine(boolean isMine) {
            this.isMine = isMine;
        }
    }

}

public class MessageActivity extends AppCompatActivity implements View.OnClickListener {

    RelativeLayout relative_layout;
    Button btn_message_chat;
    EditText et_message, edId;
    ImageView iv_smile_chat, iv_camera_chat, iv_gallery_chat, iv_gif_chat, iv_highsignal_chat;
    ListView listView;
    TextView tvMessage;
    RecyclerView recyclerView;
    WebSocket ws;
    private static final String TAG = "My Log Test";
    private ArrayList<String> arrayList = new ArrayList<>();
    private DataAdapter dataAdapter;
    private MessageActivityViewModel messageActivityViewModel;
    public SocketManger sm;
    private static Handler h;

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

        messageActivityViewModel = ViewModelProviders.of(this).get(MessageActivityViewModel.class);

        // Передача данных в LiveData
        MutableLiveData<List<Message>> liveDataLoadHistory = messageActivityViewModel.getLiveDataLoadHistory();
        liveDataLoadHistory.observe(this, new Observer<List<Message>>() {
            @Override
            public void onChanged(List<Message> messages) {
                for (Message msg: messages) {
                    arrayList.add(msg.getText());
                }

                dataAdapter.notifyDataSetChanged();
            }
        });

        messageActivityViewModel.getLiveDataSendMsg().observe(this, new Observer<String>(){

            @Override
            public void onChanged(String s) {
                if(s.equals(ENTER_EMPTY_MSG)){
                    Toast.makeText(getApplicationContext(),
                            "Вы ввели пустое сообщение", Toast.LENGTH_LONG)
                            .show();
                    return;
                }

                if(s.equals(VERY_LONG_MSG)) {
                    Toast.makeText(getApplicationContext(),
                            "Вы ввели очень длинное", Toast.LENGTH_LONG)
                            .show();
                    return;

                }

                arrayList.add(s);
                dataAdapter.notifyDataSetChanged();
                int newMsgPosition = arrayList.size() - 1;
                dataAdapter.notifyItemInserted(newMsgPosition);
                recyclerView.scrollToPosition(newMsgPosition);
                et_message.setText("");
            }
        });

        App myApp = (App) getApplication();
        sm = myApp.getSocketManger();
        sm.setHandler(h);

        listView = (ListView) findViewById(R.id.listView);
        recyclerView = (RecyclerView) findViewById(R.id.message_recycler);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getApplication());
        linearLayoutManager.setStackFromEnd(true);
        recyclerView.setLayoutManager(linearLayoutManager);
        dataAdapter = new DataAdapter(getApplicationContext(), arrayList );
        recyclerView.setAdapter(dataAdapter);

        et_message = (EditText) findViewById(R.id.et_message);
        relative_layout = (RelativeLayout) findViewById(R.id.relative_layout);
        tvMessage = (TextView) findViewById(R.id.tvMessage);
        iv_smile_chat = (ImageView) findViewById(R.id.iv_smile_chat);
        iv_camera_chat = (ImageView) findViewById(R.id.iv_camera_chat);
        iv_gallery_chat = (ImageView) findViewById(R.id.iv_gallery_chat);
        iv_gif_chat = (ImageView) findViewById(R.id.iv_gif_chat);
        iv_highsignal_chat = (ImageView) findViewById(R.id.iv_highsignal_chat);
        btn_message_chat = (Button) findViewById(R.id.btn_message_chat);
        edId = (EditText)findViewById(R.id.edId);
        iv_smile_chat.setOnClickListener(this);
        btn_message_chat.setOnClickListener(this);

    }


    @Override
    public void onClick(View v) {

        String method = "message/send";

        String to = edId.getText().toString();
        String text = et_message.getText().toString();
        String attachments = "";
        String type = "";
        String file_id = "";
        String message_id = "";
        String url = "";
        String vote_id = "";
        String product_id = "";
        String user_id = "";
        String group_id = "";

        messageActivityViewModel.sendMessageToServer(method, to, text, attachments, type, file_id, message_id, url,
                vote_id, product_id, user_id, group_id);
    }

Answer 1

Send messages with flag, by flag and change position