micromenu.java

J2ME程序设计实例教程的源码

import javax.microedition.lcdui.*;

/**
 * 该类描述了菜单组件。
 */
public class MicroMenu extends MicroComponent 
                        implements CommandListener {
    //
    private MicroMenuListener mmListener;       //菜单监视器
    private List list;
    private String title;
    private Command cmdSelect;
    private Command command;
    
    public MicroMenu(String title, Display display) {
        super(display);
        this.title = title;
        createModel();
        createGUI();
    }
    
    //向菜单中设置命令
    public void setCommand(Command cmd) {
        if(this.command != null) {
            list.removeCommand(this.command);
        }
        this.command = cmd;
        list.addCommand(this.command);
    }
    
    //添加菜单项
    public void addItem(String mi) {
        list.append(mi, null);
    }
    
    //设置菜单监视器
    public void setMicroMenuListener(MicroMenuListener listener) {
        mmListener = listener;
    }
    
    protected void createModel() { 
        //
    }
    
    protected void createGUI() {
        list = new List(title, List.IMPLICIT);
        cmdSelect = new Command("选择", Command.ITEM, 1);
        list.setSelectCommand(cmdSelect);
        list.setCommandListener(this);
    }
    
    protected Displayable getGUI() {
        return list;
    }
    
    protected void update() {
        //
    }
    
    public void commandAction(Command cmd, Displayable screen) {
        if(mmListener != null) {
            if(cmd == cmdSelect) {
                mmListener.transactItem(this, list.getSelectedIndex());
            }
            else if(cmd == command) {
                mmListener.transactCommand(this, cmd);
            }
        }
    }
}