为TextBox组件创建简单的剪贴板(Matrix-corej2me系列) (1)

    在Core J2ME Technology and MIDP一书中许多的可以在多个多行编辑组件(multiple TextBox)中共享剪贴板数据的例子。

   注意：这个例子基于MIDP与CLDC 1.0.3版
   本文得到作者John W. Muchow的允许，部分引用了Core J2ME Technology and MIDP, Sun Microsystems与Prentice Hall出版社 2002 Sun Microsystems Inc, 的内容。

源代码：

/*--------------------------------------------------
* SimpleClipBoard.java
*
* Example from the book:     Core J2ME Technology
* Copyright John W. Muchow   http://www.CoreJ2ME.com
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class SimpleClipBoard extends MIDlet implements CommandListener
{
  private Display display;            // 对显示对象的引用Reference to Display object
  private TextBox tbClip;      // 主TextBox组件Main textbox
  private Command cmExit;      // 退出命令Command to exit
  private Command cmStartMark; // 开始标记命令Command to start marking a block
  private Command cmCopy;      // 复制剪贴板命令Command to copy to clipboard 
  private Command cmPaste;     // 粘贴剪贴板命令Command to paste into textbox
  private int beginOffset = 0;  // 复制的开始索引The start index of copy
  private char[] clipBoard = null; // 剪贴板The clipboard
  private int clipBoardChars = 0;  // 记录剪贴板中的字符Number of chars in clipboard
  
  public SimpleClipBoard()
  {
    display = Display.getDisplay(this);

    // Create the Commands. Notice the priorities assigned
    cmExit = new Command("Exit", Command.EXIT, 1);
    cmStartMark = new Command("Mark", Command.SCREEN, 2);
    cmCopy = new Command("Copy", Command.SCREEN, 3);
    cmPaste = new Command("Paste", Command.SCREEN, 4);

    tbClip = new TextBox("Clip Board", "Tee to grn", 15, TextField.ANY);
    tbClip.addCommand(cmExit);
    tbClip.addCommand(cmStartMark);
    tbClip.addCommand(cmCopy);
    tbClip.addCommand(cmPaste);    
    tbClip.setCommandListener(this);