java - 为什么不使用click参数(Spring boot和vaadin)

Question

我创建了一个聊天，但无法发送消息，但消息保存在 MySQL 数据库中。我认为问题是我的 Click and Event 参数未使用

您可以检查代码。我写的一切都是正确的，也许我犯了一个错误。我使用 Spring Boot 和 Vaadin Framework 14。我点击发送按钮，但它对我不起作用，但它会将发送者的姓名和消息保存在数据库中

import com.vaadin.flow.component.Component;
import com.vaadin.flow.component.Key;
import com.vaadin.flow.component.UI;
import com.vaadin.flow.component.button.Button;
import com.vaadin.flow.component.button.ButtonVariant;
import com.vaadin.flow.component.dependency.StyleSheet;
import com.vaadin.flow.component.html.H1;
import com.vaadin.flow.component.html.Paragraph;
import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
import com.vaadin.flow.component.orderedlayout.VerticalLayout;
import com.vaadin.flow.component.page.Push;
import com.vaadin.flow.component.textfield.TextField;
import com.vaadin.flow.router.Route;
import com.vaadin.flow.server.PWA;
import org.springframework.beans.factory.annotation.Autowired;
import org.vaadin.marcus.spring.config.MessagesInfoManager;
import org.vaadin.marcus.spring.config.MessageConfigurator;
import org.vaadin.marcus.spring.model.Message;
import org.vaadin.marcus.spring.model.MessageInfo;
import org.vaadin.marcus.spring.service.RestService;

import java.util.LinkedHashMap;
import java.util.List;
import org.springframework.scheduling.annotation.Scheduled;

@StyleSheet("frontend://styles/styles.css")
@Route
@PWA(name = "Vaadin MessagesInfoManager", shortName = "Vaadin MessagesInfoManager")
@Push
public class MainView extends VerticalLayout {
    private final MessagesInfoManager messagesInfoManager;
    private final RestService restService;
    private String username;
    private TextField textField;
    private Message messageLast;


    @Autowired
    public MainView(RestService restService) {
        this.messagesInfoManager = MessageConfigurator.getInstance().getChatMessagesInfoManager();
        addClassName("main-view");
        setSizeFull();
        setDefaultHorizontalComponentAlignment(Alignment.CENTER);

        H1 header = new H1("Vaadin Chat");
        header.getElement().getThemeList().add("dark");

        add(header);

        askUsername();
        this.restService = restService;
    }

    private void askUsername() {
        HorizontalLayout layout = new HorizontalLayout();
        TextField usernameField = new TextField();
        Button startButton = new Button("Start chat");

        layout.add(usernameField, startButton);

        startButton.addClickListener(click -> {    // Click parametr not used(Why?)
            username = usernameField.getValue();
            remove(layout);
            showChat(username);
        });

        add(layout);
    }

    private void showChat(String username) {
        MessageList messageList = new MessageList();

        List<Message> lasts = restService.getLast();
        for (Message message : lasts) {
            messageList.add(new Paragraph(message.getFromV() + ": " + message.getMessageV()));
        }

        messageLast = lasts.get(lasts.size() - 1);

        add(messageList, createInputLayout(username, messageList));
        expand(messageList);
    }

    private Component createInputLayout(String username, MessageList messageList) {
        HorizontalLayout layout = new HorizontalLayout();
        layout.setWidth("100%");

        TextField messageField = new TextField();
        messageField.addKeyDownListener(Key.ENTER, keyDownEvent -> sender(messageField, messageList));
        Button sendButton = new Button("Send");
        sendButton.addThemeVariants(ButtonVariant.LUMO_PRIMARY);

        layout.add(messageField, sendButton);
        layout.expand(messageField);

        messageField.addFocusListener(event -> {
            for (Message message : messagesInfoManager.getMessagesByUI(getUI())) {
                if (!message.getFromV().equals(username)) {
                    message.setUnread(false);
                    this.restService.updateMessage(message.getId(), message);
                }
            }
        });

        sendButton.addClickListener(click -> sender(messageField, messageList)); // Click parametr not used(Why?)
        messageField.focus();

        return layout;
    }

    private void sender(TextField textField, MessageList messageList) {
        Message message = new Message(username, textField.getValue());
        message = restService.saveMessage(message);
        messageLast = message;
        this.textField = textField;
     //   messagesInfoManager.updateMessageUIInfo(new MessageInfo(messageList, message, this));
        textField.clear();
        textField.focus();

    }

    @Scheduled(fixedDelay = 1000)
    public void scheduleFixedDelayTask() {

        MessageList messageList = new MessageList();

        List<LinkedHashMap> lasts = restService.getUnreadMessages(messageLast);

        for (LinkedHashMap message : lasts) {
            messageList.add(new Paragraph(message.get("fromV") + ": " + message.get("messageV")));
        }

        messagesInfoManager.updateMessageUIInfo(new MessageInfo(messageList, messageLast, this));

    }

}

Answer 1

如果它将其保存到数据库，那么显然该监听器可以工作。未使用 event 和 click 参数，因为您没有使用它们，这很好。

在发送消息时，您没有将消息添加到 MessageList 中，也没有以任何其他方式刷新列表，因此消息无法显示。