list.java

j2me手机图书阅读器

/********************************************************************
 * 
 * 版权说明，此程序仅供学习参考。不能用于商业
 * 
 ********************************************************************/
package org.pook.ui;

import java.util.Vector;

import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;

import org.pook.ui.core.Platform;
import org.pook.ui.util.GraphicsUtil;
 

/**
 * <b>类名：List.java</b> </br> 
 * 编写日期: 2006-10-14 <br/>
 * 程序功能描述： <br/>
 * Demo: <br/>
 * Bug: <br/>
 * 
 * 程序变更日期 ：<br/> 
 * 变更作者 ：<br/> 
 * 变更说明 ：<br/>
 * 
 * @author wuhua </br> <a href="mailto:[e-mail]">[e-mail]</a>
 */
public class List extends Part {

	Image icon;
	
	Vector items;
	
	int numOfEls;
	
	int paintSize;
	
	
	int space;
	/** 开始索引 * */
	private int startIndex;
	
	public List(Image icon) {
		super(0, 21, Platform.WIDTH, Platform.HEIGHT - 41);
		this.icon = icon;
		items = new Vector();
		 
	}
	
	public void changeViewAndSize(){
		if (Platform.HEIGHT - 20 > view[HEIGHT]) {
			view[HEIGHT] = Platform.HEIGHT - 41;
			space = font.getHeight() + 2;
			paintSize  = view[HEIGHT] / space;
		}
		
	}
	
	 

	public void append(Vector items){
		if(items == null)
			return;
		this.items = items;
		this.numOfEls = items.size();
	}

	public void append(String stringItem){
		this.items.addElement(stringItem);
		this.numOfEls = items.size();
	}
	
	
	public void insert(String stringItem){
		this.items.insertElementAt(stringItem,0);
		this.numOfEls = items.size();
	}
	
	public int getSelectIndex(){
		return this.selectIndex;
	}
	
	public String getSelectString(){
		//System.out.println(this.numOfEls);
		return (String) this.items.elementAt(selectIndex+startIndex );
	}
	
	public void paint(Graphics g) {
		changeViewAndSize();
		GraphicsUtil.fillScreen(g, this.bgColor, view[X], view[Y], view[WIDTH], view[HEIGHT]);
		paintStrings(g);

	}
	
	
	private void paintStrings(Graphics g) {
	
		if (items.size() == 0)
			return;
		
		 
		int size = this.paintSize > this.numOfEls? this.numOfEls:this.paintSize + startIndex;
		
		paintSelect(g, view[Y] + space * selectIndex + 2 );
		
		g.setColor(this.fontColor);
		
		for(int i =startIndex,j=0; i< size; i++, j++){
			 
			String it = (String) items.elementAt(i);		
			
			if(this.selectIndex == j){
				it = (String) items.elementAt(selectIndex+startIndex);
				//this.select.paint(view[X], height, view[WIDTH],it.getItemHeight(),g);
			}else{
				 
			}
			GraphicsUtil.darwString(g,it, view[X] + 10, view[Y] + space *j + 2);
			// 变化的高度
			 
		}
		
		
		
		
	}

 
	private void paintSelect(Graphics g, int height) {
		g.setColor(0x909090);
		g.fillRect(view[X], height, view[WIDTH], space);
		
	}

	public void onClick(int keyCode) {
		keyUpAndDown(keyCode);
	}

	/**
	 * 内部实现按钮向上向下时候的动作,有具体类的keyPress调用.
	 * 
	 * @param keyCode
	 */
	void keyUpAndDown(int keyCode) {
		if(this.numOfEls == 0)
			return;
		switch (keyCode) {
	
		case Platform.KEY_UP: {
			selectIndex--;
			 
		 break;
			  
			 
		}
		case Platform.KEY_DOWN: {
			selectIndex++;
			 
			 break;
		}
		}
		changeSelectIndex();
	}
	
	/**
	 * 判断当前选择条是否到了底部,经过用户的选择,这些选择条会不断的变化</br> 变化的依据是当selectPosition >=
	 * viewPart[HEIGHT]*/
	private void changeSelectIndex(){
		int num = (this.paintSize < numOfEls)?paintSize:numOfEls;//取可显示的菜单项数目
	    if (selectIndex>num-1)
	    {
	        startIndex++;
	        selectIndex=(byte)(num-1);
	    }
	    
	    if (selectIndex < 0)
	    {
	        if (startIndex>0)
	        {
	            selectIndex =0;
	            startIndex--;
	        }
	        else
	        {
	            startIndex = numOfEls-num;
	            selectIndex=num-1;
	        }
	        
	    }
	    if (startIndex+ selectIndex > numOfEls -1)
	    {
	        startIndex= 0;
	        selectIndex = 0;
	    }
	}

}