异步加载图片以及Bitmap相关处理方法

私类：

// 异步更新Image
    private class GetImageTask extends AsyncTask<String, Void, Bitmap> {

        // 覆写的方法，这个方法将在这个类的对象execute()的时候调用
        protected Bitmap doInBackground(String... urls) {
            Bitmap bmp = null;
            Bitmap newBitmap = null;
            int bmWidth, bmHeight;
            try {
                bmp = FileUtil.getBitmapByPath(urls[0]);//本地图片获得Bitmap
                bmWidth = bmp.getWidth();
                bmHeight = bmp.getHeight();

                // 图片过大就剪裁以下
                if ((bmWidth > 240) || (bmHeight > 240)) {
                    newBitmap = fileUtil.imageCropSquare(bmp);//从bitmap剪裁为正方形Bitmap
                } else {
                    newBitmap = bmp;
                }

            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return newBitmap;
        }

        @Override
        // 覆写的方法，当耗时的操作执行完之后执行，这里就是把获得的Bitmap更新到ImageView上
        protected void onPostExecute(Bitmap result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);
            imgPostPic.setImageBitmap(result);

        }

getBitmapByPath本地图片路径获得BitMap方法：

/**
     * 从本地路径获取、生成与原图同样大小的Bitmap，不作压缩
     *
     * @param path
     * @return
     */
    public static Bitmap getBitmapByPath(String path) {
        if (path == null){
            return null;
        }

        Bitmap bmTemp = null;
        if (bmTemp == null) {
            try {
                bmTemp = BitmapFactory.decodeFile(path);
            } catch (Exception e) {
                e.printStackTrace();
            } catch (Error e) {
                e.printStackTrace();
            }
        }
        return bmTemp;
    }

网络图片路径获得Bitmap的方法

/**
     * Android获取网络图片转换成Bitmap
     *
     * @return Bitmap
     */

    private static final int IO_BUFFER_SIZE = 4 * 1024;// 设置缓冲区大小

    public static Bitmap GetBitmapFromWeb(String url) {
        Bitmap bitmap = null;
        InputStream in = null;
        BufferedOutputStream out = null;
        try {
            System.out.println("GetLocalOrWebBitmap HEAD, url:" + url);
            in = new BufferedInputStream(new URL(url).openStream(),
                    IO_BUFFER_SIZE);
            final ByteArrayOutputStream dataStream = new ByteArrayOutputStream();
            out = new BufferedOutputStream(dataStream, IO_BUFFER_SIZE);
            copy(in, out);
            out.flush();
            byte[] data = dataStream.toByteArray();
            bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
            data = null;
            System.out.println("GetLocalOrWebBitmap END");
            return bitmap;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

    // 附加的copy函数
    private static void copy(InputStream in, OutputStream out)
            throws IOException {
        byte[] b = new byte[IO_BUFFER_SIZE];
        int read;
        while ((read = in.read(b)) != -1) {
            out.write(b, 0, read);
        }
    }

正方形Bitmap剪裁：

/**
     * 按正方形裁切图片

     */

    public  Bitmap imageCropSquare(Bitmap bitmap) {

        int w = bitmap.getWidth(); // 得到图片的宽，高
        int h = bitmap.getHeight();
        int wh = w > h ? h : w;// 裁切后所取的正方形区域边长
        int retX = w > h ? (w - h) / 2 : 0;//基于原图，取正方形左上角x坐标
        int retY = w > h ? 0 : (h - w) / 2;

        //下面这句是关键

        return Bitmap.createBitmap(bitmap, retX, retY, wh, wh, null, false);

    }