Question

我有两个应该沟通的课程，但事实并非如此。一个叫做Chatter，当一个监听器在Chatter中收到一条消息时，它应该在第二个类中调用一个叫做ClassView的方法。但我不认为该方法被调用。

以下是Chatter的代码：

package instantmessengerplugin;

import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.TableItem;
import org.jivesoftware.smack.Chat;
import org.jivesoftware.smack.ChatManager;
import org.jivesoftware.smack.MessageListener;
import org.jivesoftware.smack.PacketListener;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.filter.MessageTypeFilter;
import org.jivesoftware.smack.filter.PacketFilter;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;

public class Chatter {

    public XMPPConnection connection;
    public String user;
    public ClassView classView;
    public Chat chat;
    public PacketFilter packetFilter;
    public PacketListener listener;




    public Chatter(XMPPConnection connection1,String user1, Display dist)
    {
        connection  = connection1;
        user = user1;

        openChat();
        classView = new ClassView(dist,chat);
    }

    public void  openChat()
    {
        ChatManager cm = connection.getChatManager();
        chat = cm.createChat(user, new MessageListener()
        {
            public void processMessage(Chat chat ,Message message)
            {
                if(message.getType().equals(Message.Type.chat))
                {
                    //TableItem item = new TableItem(classView.chatViewer,SWT.NONE);
                    //item.setText("Them: " + message.getBody());
                    System.out.println(message.getBody());
                    classView.updateChat(message);
                }


            }
        }




        );


    }





}

以下是ClassView的代码：

package instantmessengerplugin;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableItem;
import org.eclipse.swt.widgets.Text;
import org.jivesoftware.smack.Chat;
import org.jivesoftware.smack.ChatManager;
import org.jivesoftware.smack.MessageListener;
import org.jivesoftware.smack.Roster;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;


public class ClassView {

    public Display displayChat;
    public Shell shellChat;
    final Table chatViewer;
    public Chat chat;

    public ClassView(Display dist,Chat chat1){

        chat = chat1;

        displayChat = dist;
        shellChat = new Shell(displayChat);
        GridLayout gridLayout = new GridLayout();
        gridLayout.numColumns = 2;
        shellChat.setLayout(gridLayout);

        Label contact = new Label(shellChat,SWT.NONE);
        GridData data = new GridData();
        data.horizontalAlignment = GridData.FILL;
        data.horizontalSpan = 2;
        data.grabExcessHorizontalSpace = true;
        data.grabExcessVerticalSpace = true;

        chatViewer = new Table(shellChat,SWT.NONE); 
        data = new GridData();
        data.horizontalSpan = 2;
        data.horizontalAlignment = GridData.FILL;
        data.verticalAlignment = GridData.FILL;
        data.grabExcessHorizontalSpace = true;
        chatViewer.setLayoutData(data);

        final Text chatBox = new Text(shellChat,SWT.SINGLE);
        data = new GridData();
        data.verticalAlignment = GridData.FILL;
        data.horizontalAlignment = GridData.FILL;
        data.grabExcessHorizontalSpace = true;
        chatBox.setLayoutData(data);

        Button send = new Button(shellChat,SWT.PUSH);
        send.setText("Send");

        send.addSelectionListener(new SelectionAdapter(){

            public void widgetSelected(SelectionEvent e)
            {

                String s = chatBox.getText();
                TableItem item = new TableItem(chatViewer, SWT.NONE);
                item.setText("Me: " + s);
                try {
                    chat.sendMessage(s);
                } catch (Exception e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }

                chatBox.setText("");
            }

        });










        shellChat.pack();
        shellChat.open();

        while(!shellChat.isDisposed())
        {
            if(!displayChat.readAndDispatch())
            {
                displayChat.sleep();
            }
        } 



    }


    public void updateChat(Message message)
    {
        TableItem item = new TableItem(chatViewer,SWT.NONE);
        item.setText("Them: " + message.getBody());
    }



}

当调用Chatter中的processMessage方法时，它应该与ClassView通信，它将调用updateChat，然后更改ClassView中的表对象。它似乎没有发生。该表未更改，并且没有抛出异常。我知道聊天工作正常，因为它将消息打印到控制台就好了。

有谁知道为什么updateChat似乎没有被调用？

更新

我在相关代码上运行了调试器。这是执行时调用的调试堆栈：

FutureTask $ Sync.innerRun（）行：不可用[局部变量不可用]

FutureTask.run（）行：不可用
ThreadPoolExecutor $ Worker.runTask（Runnable）行：不可用
ThreadPoolExecutor $ Worker.run（）行：不可用
Thread.run（）行：不可用[局部变量不可用]

我不确定这究竟是什么意思。提到线程是让我觉得方法调用没有与另一个线程同步的原因。

Answer 1

这是推测，但看起来你的updateChat消息只是创建了一个TableItem而没有将它添加到任何表中。

    public void updateChat(Message message)
{
    TableItem item = new TableItem(chatViewer,SWT.NONE);
    item.setText("Them: " + message.getBody());
}

Answer 2

您应该使用eclipse调试代码（猜测在使用SWT时使用此IDE）。在processMessage内设置断点并逐步执行代码。然后，您将看到是否调用updateChat。

Answer 3

我和Smack有类似的错误，在我的情况下，诀窍是真正的bug是NullPointer异常。这是我的代码：

for(PartnerMessageCallback callback : callbacks) {
   callback.processMessage(null, message);
}

从processMessage抛出了NullPointer异常，但我在StackTrace中看到以下内容：

FutureTask $ Sync.innerRun（）行：不可用[局部变量不可用]

就我而言，一个简单的try-catch解决了这个问题：

for(PartnerMessageCallback callback : callbacks) {
  try {
    callback.processMessage(null, message);
  } catch (Exception ex) {
    ex.printStackTrace();
  }
}

我希望它可以帮到你。

方法在调用时似乎没有运行

3 个答案: