bookinfoscreen.java

手机游戏设计一书的源代码

/*
 *  图书信息显示界面类BookInfoScreen.java
 */

package bookshop.midlet;

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

public class BookInfoScreen
    extends Canvas
    implements CommandListener {

  String bookTitle = null;
  String bookAuthor = null;
  String bookPrice = null;

  public BookInfoScreen(String bookNo) {
    this.bookNo = bookNo;
//添加Back命令
    addCommand(new Command("Back", Command.BACK, 1));
    setCommandListener(this);
    //启动线程获取并显示图书信息
    new Thread(new HttpConnector()).start();
  }

  private void showBookInfo() {
    repaint();
  }

  /**处理命令事件 */
  public void commandAction(Command command, Displayable displayable) {
    //如果是BACK命令则将界面切换到图书编号输入界面
    if (command.getCommandType() == command.BACK) {
      BookNoScreen clientScreen = new BookNoScreen();
      Display.getDisplay(BookMIDlet.bookMIDlet).setCurrent(clientScreen);
    }
  }

  //HTTP连接器类

  class HttpConnector
      implements java.lang.Runnable {

    /**
     *  获取并显示图书信息的线程主方法
     */
    public void run() {
      getBookInfo();
      showBookInfo();
    }
  }

  /**
   * 获取图书信息的方法
   */
  public void getBookInfo() {
    try {
      HttpConnection connection = (HttpConnection) Connector.open(
          "http://localhost:7001/book/bookServlet?bookNo=" + bookNo);
      InputStream is = null;
      is = connection.openInputStream();
      DataInputStream dis = new DataInputStream(is);
      bookTitle = dis.readUTF(); // 从服务器端获取图书信息
      bookAuthor = dis.readUTF();
      bookPrice = dis.readUTF();
      dis.close();
      is.close();
      connection.close();
    }
    catch (IOException ex) {
      ex.printStackTrace();
    }

  }

  public void paint(Graphics g) {

    g.setColor(0xffffff);
    g.fillRect(0, 0, getWidth(), getHeight());
    g.setColor(0x000000);
    //显示图书信息
    if (bookTitle != null) {
      g.drawString("书名：" + bookTitle, 0, 0, Font.SIZE_MEDIUM);
      g.drawString("作者：" + bookAuthor, 0, Font.SIZE_MEDIUM + 25,
                   Font.SIZE_MEDIUM);
      g.drawString("价格：" + bookAuthor, 0, (Font.SIZE_MEDIUM + 25) * 2,
                   Font.SIZE_MEDIUM);

    }
  }

  private String bookNo = null;
}