maincanvas.java

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package src.com.j2meclient.citation;

import javax.microedition.lcdui.*;

public class MainCanvas extends Canvas {

    private int selected = 0;
    private int preferWidth = -1;
    private int preferHeight = -1;
    public static final int[] OPTIONS = {0,1,2,3};
    public static final String[] LABELS={"产品查询","添加库存","修改库存","删除产品"};
    public static final String iconFiles[]={"/res/icons/a.png", "/res/icons/b.png","/res/icons/c.png", "/res/icons/d.png"};
    
    Image  icons[]= new Image[iconFiles.length];

    public MainCanvas()
    {
        selected = OPTIONS[0];
		for(int m = 0;m<iconFiles.length;m++){
		    try{
				icons[m]= Image.createImage(iconFiles[m]);
			}catch(Exception e){
			}
		}
  
        Font f = Font.getDefaultFont();
        for(int i = 0;i<LABELS.length;i++){
            int temp = f.stringWidth(LABELS[i]);
            if(temp > preferWidth){
                preferWidth = temp;
            }
        }
        preferWidth  = preferWidth + 2*45;
        preferHeight = f.getHeight()+2*12;

    }



    public void paint(Graphics g)
    {
        int color = g.getColor();
        g.setColor(0xCCFFFF);
        g.fillRect(0,0,getWidth(),getHeight());
        g.setColor(color);
        
        int rectWidth = preferWidth;
        int rectHeight = preferHeight * LABELS.length;
        int x = (getWidth()-rectWidth)/2;
        int y = (getHeight()-rectHeight)/2;
        
        //g.drawRect(x,y,rectWidth,rectHeight);
        for(int i = 1;i<LABELS.length;i++){
            //g.drawLine(x,y+preferHeight*i,x+rectWidth,y+preferHeight*i);
        }
        
        for(int j = 0;j<LABELS.length;j++){
            if(selected == j){
                g.setColor(0xCCCCFF);
                g.fillRect(x+1,y+j*preferHeight+1,rectWidth-1,preferHeight-1);
                g.setColor(color);
            }
            Image img= icons[j];
            g.drawImage(img,x+15,y+j*preferHeight+9,Graphics.LEFT | Graphics.TOP);
            g.setFont(Font.getFont(Font.FACE_SYSTEM, Font.STYLE_BOLD, Font.SIZE_LARGE));
            g.drawString(LABELS[j],x+15+img.getWidth()+3,y+j*preferHeight+9,Graphics.LEFT|Graphics.TOP);
        }
    }
    
    public int getSelectedCount(){
    	int i = this.selected;
    	return i;
    }

    //keyboard listener
    public void keyPressed(int keyCode)
    {     
        int action = this.getGameAction(keyCode);
        switch(action){
            case Canvas.FIRE:
//              printLabel(selected);
            	if(selected==0){
            		selected = 0;
            	}else if(selected==1){

            		selected = 1;
            	}else if(selected==2){
            		selected = 2;
            		
            	}else if(selected==3){
            		selected = 3;
            		
            	}
                break;
            case Canvas.DOWN:
                selected = (selected+1)%4;
                break;
            case Canvas.UP:{
                if(--selected < 0){
                    selected+=4;
                }
                break;
            }
            default:
                break;
        }
        repaint();
        serviceRepaints();
    }
    

}