selectscreen.java

一个基于j2me MIDP的迷宫游戏

/*
 * SelectScreen.java
 *
 * Created on 2005年12月2日, 下午1:06
 *
 * To change this template, choose Tools | Options and locate the template under
 * the Source Creation and Management node. Right-click the template and choose
 * Open. You can then make changes to the template in the Source Editor.
 */

package com.j2medev.maze;

import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.Gauge;
import javax.microedition.lcdui.Item;
import javax.microedition.lcdui.ItemStateListener;

/**
 * This is the screen that allows the user to modify the 
 * width of the maze walls..
 *
 * @author Carol Hamer
 */
class SelectScreen extends Form 
  implements ItemStateListener, CommandListener  {

  //----------------------------------------------------------------
  //  fields

  /**
   * The "Done" button to exit this screen and return to the maze.
   */
  private Command myExitCommand = new Command("完成", Command.EXIT, 1);

  /**
   * The gague that modifies the width of the maze walls.
   */
  private Gauge myWidthGauge;

  /**
   * The gague that displays the number of columns of the maze.
   */
  private Gauge myColumnsGauge;

  /**
   * A handle to the main game canvas.
   */
  private MazeCanvas myCanvas;

  //----------------------------------------------------------------
  //  initialization

  /**
   * Create the gagues and place them on the screen.
   */
  public SelectScreen(MazeCanvas canvas) {
    super("Size Preferences");
    addCommand(myExitCommand);
    setCommandListener(this);
    myCanvas = canvas;
    setItemStateListener(this);
    myWidthGauge = new Gauge("每一列的宽度", true, 
           myCanvas.getMaxColWidth(), 
           myCanvas.getColWidth());
    myColumnsGauge = new Gauge("迷宫的列数", false,  
             myCanvas.getMaxNumCols(), 
             myCanvas.getNumCols());
    // Warning: the setLayout method does not exist in 
    // MIDP 1.4.  If there is any chance that a target 
    // device will be using MIDP 1.4, comment out the 
    // following two lines:
    //myWidthGauge.setLayout(Item.LAYOUT_CENTER);
    //myColumnsGauge.setLayout(Item.LAYOUT_CENTER);
    append(myWidthGauge);
    append(myColumnsGauge);
  }

  //----------------------------------------------------------------
  //  implementation of ItemStateListener

  /**
   * Respond to the user changing the width.
   */
  public void itemStateChanged(Item item) {
    if(item == myWidthGauge) {
      int val = myWidthGauge.getValue();
      if(val < myCanvas.getMinColWidth()) {
  myWidthGauge.setValue(myCanvas.getMinColWidth());
      } else {
  int numCols = myCanvas.setColWidth(val);
  myColumnsGauge.setValue(numCols);
      }
    }
  }

  //----------------------------------------------------------------
  //  implementation of CommandListener

  /*
   * Respond to a command issued on this screen.
   * (either reset or exit).
   */
  public void commandAction(Command c, Displayable s) {
    if(c == myExitCommand) {
      myCanvas.newMaze();
    }
  }
}