qqform.java

J2ME程序设计实例教程的源码

import javax.microedition.lcdui.*;
import javax.microedition.io.*;
import java.io.*;

/**
 * 聊天交互界面，为用户提供了发送消息，接收显示消息的功能。
 */
public class QQForm extends Form implements CommandListener, Runnable {
    //
    private QQMIDlet midlet;
    private SocketConnection sconn;    //套接字连接
    private DataOutputStream dos;   //
    private DataInputStream dis;    //
    private StringItem siReceive;
    private TextField tfSender;
    private boolean stop = false;
    private Thread receiveThread;
    private Command cmdOK = new Command("发送", Command.OK, 1);
    private Command cmdCancel = new Command("断开", Command.CANCEL, 2);
    private Command cmdBack = new Command("返回", Command.BACK, 1);
    
    public QQForm(String title, SocketConnection sconn, QQMIDlet midlet) {
        super(title);
        this.sconn = sconn;
        this.midlet = midlet;
        
        try {
            dos = sconn.openDataOutputStream();
            dis = sconn.openDataInputStream();
            siReceive = new StringItem(sconn.getAddress() + "说：\n", "");
            tfSender = new TextField("请输入消息:", "", 200, TextField.ANY);
        }
        catch(IOException ioe) {
            midlet.showError(ioe.toString());
        }
        
        tfSender.setPreferredSize(getWidth(), 150);
        append(siReceive);
        append(new Spacer(this.getWidth(), 10));
        append(tfSender);
        addCommand(cmdOK);
        addCommand(cmdCancel);
        setCommandListener(this);
        
        //创建并启动接收信息线程
        receiveThread = new Thread(this);
        receiveThread.start();
    }
    
    //
    public void commandAction(Command cmd, Displayable d) {
        if(cmd == cmdOK) {  //发送信息
            //创建并启动发送信息线程。
            Thread t = new Thread(new Runnable() {
                public void run() { //发送消息线程
                    try {
                        dos.writeUTF(tfSender.getString());
                    }
                    catch(IOException ioe) {
                        handleCut();
                    }
                }
            });
            t.start();
        }
        else if(cmd == cmdCancel){
            stop = true;
            try {
                sconn.close();  //关闭连接
                dis.close();
                dos.close();
            }
            catch(IOException ioe) {
                //
            }
            midlet.backToModeList();
        }
        else if(cmd == cmdBack) {
            midlet.backToModeList();
        }
    }
    
    //消息接收线程
    public void run() {
        String s = "";
        while(!stop) {
            try {
                //如果套接字连接通道中没有数据，该方法将阻塞当前线程。
                s = dis.readUTF();   //
                siReceive.setText(s);
            }
            catch(IOException ioe) {
                handleCut();
                stop = true;
            }
        }
    }
    
    //处理断开
    private void handleCut() {
        siReceive.setText("再见！！！");
        tfSender.setConstraints(TextField.	UNEDITABLE);
        removeCommand(cmdOK);
        removeCommand(cmdCancel);
        addCommand(cmdBack);
    }
}