public static Bitmap getTransparentBitmap(Bitmap sourceImg, int number){
        int[] argb = new int[sourceImg.getWidth() * sourceImg.getHeight()];

        sourceImg.getPixels(argb, 0, sourceImg.getWidth(), 0, 0, sourceImg

                .getWidth(), sourceImg.getHeight());// 获得图片的ARGB值

        number = number * 255 / 100;

        for (int i = 0; i < argb.length; i++) {

            argb[i] = (number << 24) | (argb[i] & 0x00FFFFFF);
        }

        sourceImg = Bitmap.createBitmap(argb, sourceImg.getWidth(), sourceImg

                .getHeight(), Bitmap.Config.ARGB_8888);

        return sourceImg;
    }

class drawCanvas extends View {  
    public drawCanvas(Context context) {  
        super(context);  
    }  
  
    @Override  
    protected void onDraw(Canvas canvas) {  
        super.onDraw(canvas);  
  
        // 取得Resource 图片的Bitmap  
        Bitmap vBitmap = BitmapFactory.decodeResource( this.getResources()  
                                                     , R.drawable.icon  
                                                     );  
  
        // 建立Paint 物件  
        Paint vPaint = new Paint();  
        vPaint .setStyle( Paint.Style.STROKE );   //空心  
        vPaint .setAlpha( 75 );   //   
  
        canvas.drawBitmap ( vBitmap , 50, 100, null );  //无透明  
        canvas.drawBitmap ( vBitmap , 50, 200, vPaint );  //有透明  
    }  
}