代码:指定大小的图片

    /**

     * 从文件解析出Bitmap格式的图片

     * 

     * @param path

     * @param maxWidth

     * @param maxHeight

     * @return

     */

    public static Bitmap decodeFile(String path, int maxWidth, int maxHeight){

        BitmapFactory.Options options = new BitmapFactory.Options();

        options.inJustDecodeBounds = true;

        Bitmap image = null;

        image = BitmapFactory.decodeFile(path, options);

        double ratio = 1D;

        if (maxWidth > 0 && maxHeight <= 0) {

            // 限定宽度，高度不做限制

            ratio = Math.ceil(options.outWidth / maxWidth);

        } else if (maxHeight > 0 && maxWidth <= 0) {

            // 限定高度，不限制宽度

            ratio = Math.ceil(options.outHeight / maxHeight);

        } else if (maxWidth > 0 && maxHeight > 0) {

            // 高度和宽度都做了限制，这时候我们计算在这个限制内能容纳的最大的图片尺寸，不会使图片变形

            double _widthRatio = Math.ceil(options.outWidth / maxWidth);

            double _heightRatio = (double) Math.ceil(options.outHeight / maxHeight);

            ratio = _widthRatio > _heightRatio ? _widthRatio : _heightRatio;

        }

        if (ratio > 1) {

            options.inSampleSize = (int) ratio;

        }

        options.inSampleSize = calcScaleRatio(maxWidth, maxHeight, options.outWidth, options.outHeight);

        options.inJustDecodeBounds = false;

        options.inPreferredConfig = Bitmap.Config.RGB_565;

        image = BitmapFactory.decodeFile(path, options);

        return image;

    }