splashcanvas.java

Java ME手机应用开发大全一书的配套光盘上的源码

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

class SplashCanvas extends Canvas implements Runnable {
    private Image splash1, splash2, bufImage;
    private Graphics g;
    private int[] rawInt1, rawInt2;
    
    public SplashCanvas() {
        setFullScreenMode(true);
        bufImage = Image.createImage(getWidth(), getHeight());
        g = bufImage.getGraphics();
        try {
            Image img = Image.createImage("/Image/splash.png");
            splash1 = Image.createImage(img, 0, 0, 135, 88, 0);
            splash2 = Image.createImage(img, 0, 88, 135, 85, 0);
        } catch(Exception e){}
        rawInt1 = new int[splash1.getWidth() * splash1.getHeight()];
        splash1.getRGB(rawInt1, 0, splash1.getWidth(), 0, 0, splash1.getWidth(), splash1.getHeight());
        rawInt2 = new int[splash2.getWidth() * splash2.getHeight()];
        splash2.getRGB(rawInt2, 0, splash2.getWidth(), 0, 0, splash2.getWidth(), splash2.getHeight());
        Thread t = new Thread(this);
        t.start();
    }
    
    public void paint(Graphics g) {
        g.drawImage(bufImage, 0, 0, 0);
    }
    
    public void run() {
        draw(rawInt1, 0, 15, splash1, 2000);
        draw(rawInt2, 0, 15, splash2, 2000);
        Start.disposeSplash();
    }
    
    protected void keyPressed(int keyCode)
    {
        if(keyCode!=0)
            Start.disposeSplash();
    }
    
    //绘制Alpha图像
    private void draw(int[] rawInt, int alpha, int value, Image img, int sleep) {
        // rawInt为图片数组，alpha为初始图片的alpha值，value为每次增加的alpha值
        // img为原图像，sleep为停止时间
        while(alpha >= 0) {
            alpha += value;
            if(alpha >= 255) {
                try{ Thread.sleep(sleep); }catch(Exception e){}
                value = value * -1;
            } else {
                Fade(rawInt, alpha, 0xFFFFFFFF, 0xFFFFFFFF);
                Image fadeImage = Image.createRGBImage(rawInt, img.getWidth(),
                        img.getHeight(), true);
                g.setColor(0xFFFFFF);
                g.fillRect(0, 0, getWidth(), getHeight());
                g.drawImage(fadeImage, (getWidth()-fadeImage.getWidth())/2,
                        (getHeight()-fadeImage.getHeight())/2, 0);
                try{ Thread.sleep(5); }catch(Exception e){}
            }
            repaint();
            System.gc();
        }
    }
    
    public void Fade(int[] raw, int alphaValue, int maskColor, int notMaskColor) {
        int len = raw.length;
        for(int i=0; i<len; i++) {
            int a = 0;
            int color = (raw[i] & 0x00FFFFFF);   // 获得像素颜色
            if(maskColor==color)  a = 0;
            else if(notMaskColor==color)  a = 255;
            else if(alphaValue>0)  a = alphaValue;   // 设置Alpha值
            a = (a<<24);    //将Alpha值左移24位，颜色为0xAARRGGBB
            color += a;
            raw[i] = color;
        }
    }
}