Android 使用Gallery实现3D相册(附效果图+Demo源码)

    protected void onSizeChanged(int w, int h, int oldw, int oldh)
    {
　　　　//重写计算旋转的中心
        mCoveflowCenter = getCenterOfCoverflow();
        super.onSizeChanged(w, h, oldw, oldh);
    }

protected boolean getChildStaticTransformation(View child, Transformation trans)
    {
　　　　 //图像的中心点和宽度
        final int childCenter = getCenterOfView(child);
        final int childWidth = child.getWidth();
        int rotationAngle = 0;

        trans.clear();
        trans.setTransformationType(Transformation.TYPE_BOTH);        // alpha 和 matrix 都变换

        if (childCenter == mCoveflowCenter)
        {   
　　　　　　  // 正中间的childView
            transformImageBitmap((ImageView) child, trans, 0);   
        }
        else
        {       
　　　　　　  // 两侧的childView
            rotationAngle = (int) ( ( (float) (mCoveflowCenter - childCenter) / childWidth ) * mMaxRotationAngle );
            if (Math.abs(rotationAngle) > mMaxRotationAngle)
            {
                rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle : mMaxRotationAngle;
            }
　　　　　　　//根据偏移角度对图片进行处理，看上去有3D的效果。
            transformImageBitmap((ImageView) child, trans, rotationAngle);
        }

        return true;
    }

public boolean createReflectedForAdapter()
    {
        final int reflectionGap = 4;
        final int Height = 200;
        int index = 0;
        for (Map<String, Object> map : list)
        {
            Integer id = (Integer) map.get("image");
            // 获取原始图片
            Bitmap originalImage = BitmapFactory.decodeResource(mContext.getResources(), id);   
            int width = originalImage.getWidth();
            int height = originalImage.getHeight();
            float scale = Height / (float)height;

            Matrix sMatrix = new Matrix();
            sMatrix.postScale(scale, scale);
            Bitmap miniBitmap = Bitmap.createBitmap(originalImage, 0, 0,
                    originalImage.getWidth(), originalImage.getHeight(), sMatrix, true);

            //是否原图片数据，节省内存
            originalImage.recycle();

            int mwidth = miniBitmap.getWidth();
            int mheight = miniBitmap.getHeight();
            Matrix matrix = new Matrix();
            // 图片矩阵变换（从低部向顶部的倒影）
            matrix.preScale(1, -1);           
            // 截取原图下半部分
            Bitmap reflectionImage = Bitmap.createBitmap(miniBitmap, 0, mheight/2, mwidth, mheight/2, matrix, false);
            // 创建倒影图片（高度为原图3/2）
            Bitmap bitmapWithReflection = Bitmap.createBitmap(mwidth, (mheight + mheight / 2), Config.ARGB_8888);   
            // 绘制倒影图（原图 + 间距 + 倒影）
            Canvas canvas = new Canvas(bitmapWithReflection);   
            // 绘制原图
            canvas.drawBitmap(miniBitmap, 0, 0, null);       
            Paint paint = new Paint();
            // 绘制原图与倒影的间距
            canvas.drawRect(0, mheight, mwidth, mheight + reflectionGap, paint);
            // 绘制倒影图
            canvas.drawBitmap(reflectionImage, 0, mheight + reflectionGap, null);   

            paint = new Paint();
            // 线性渐变效果
            LinearGradient shader = new LinearGradient(0, miniBitmap.getHeight(), 0, bitmapWithReflection.getHeight()
                    + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);
            paint.setShader(shader);   
            // 倒影遮罩效果
            paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));       
            // 绘制倒影的阴影效果
            canvas.drawRect(0, mheight, mwidth, bitmapWithReflection.getHeight() + reflectionGap, paint);       
            ImageView imageView = new ImageView(mContext);
　　　　　　  // 设置倒影图片
            imageView.setImageBitmap(bitmapWithReflection);       
            imageView.setLayoutParams(new GalleryView.LayoutParams((int)(width * scale),
                    (int)(mheight * 3 / 2.0 + reflectionGap)));
            imageView.setScaleType(ScaleType.MATRIX);
            mImages[index++] = imageView;
        }
        return true;
    }