Android的图片压缩并上传

Android开发中上传图片很常见，一般为了节省流量会进行压缩的操作，本篇记录一下压缩和上传的方法。

图片压缩的方法 ：

import java.io.ByteArrayOutputStream;

import java.io.File;



import android.content.Context;

import android.content.Intent;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.net.Uri;

import android.os.Environment;

import android.util.Base64;



public class PictureUtil {



    /**

     * 把bitmap转换成String

     * 

     * @param filePath

     * @return

     */

    public static String bitmapToString(String filePath) {



        Bitmap bm = getSmallBitmap(filePath);



        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        bm.compress(Bitmap.CompressFormat.JPEG, 40, baos);

        byte[] b = baos.toByteArray();



        return Base64.encodeToString(b, Base64.DEFAULT);



    }



    /**

     * 根据路径获得图片并压缩返回bitmap用于显示

     * 

     * @param imagesrc

     * @return

     */

    public static Bitmap getSmallBitmap(String filePath) {

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

        options.inJustDecodeBounds = true;

        BitmapFactory.decodeFile(filePath, options);



        // Calculate inSampleSize

        options.inSampleSize = calculateInSampleSize(options, 480, 800);



        // Decode bitmap with inSampleSize set

        options.inJustDecodeBounds = false;



        return BitmapFactory.decodeFile(filePath, options);

    }



    /**

     * 计算图片的缩放值

     * 

     * @param options

     * @param reqWidth

     * @param reqHeight

     * @return

     */

    public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {

        // Raw height and width of image

        final int height = options.outHeight;

        final int width = options.outWidth;

        int inSampleSize = 1;



        if (height > reqHeight || width > reqWidth) {



            // Calculate ratios of height and width to requested height and

            // width

            final int heightRatio = Math.round((float) height / (float) reqHeight);

            final int widthRatio = Math.round((float) width / (float) reqWidth);



            // Choose the smallest ratio as inSampleSize value, this will

            // guarantee

            // a final image with both dimensions larger than or equal to the

            // requested height and width.

            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;

        }



        return inSampleSize;

    }

    

}

 

图片上传的代码：

/**

     * 将图片转成String的形式，进行上传

     *

     * @param json

     * @return 

     * @return String  

     * @author hsx

     * @time 2014-3-21上午10:47:30

     */

    public String sendPost(String json) {

        try {

            HttpURLConnection httpcon = (HttpURLConnection) ((new URL(POST_URL)

                    .openConnection()));

            httpcon.setDoOutput(true);

            httpcon.setRequestProperty("Content-Type", "application/json");

            httpcon.setRequestProperty("Accept", "application/json");

            httpcon.setRequestMethod("POST");

            httpcon.connect();



            byte[] outputBytes = json.getBytes("UTF-8");

            OutputStream os = httpcon.getOutputStream();

            os.write(outputBytes);

            os.close();

            

            int status = httpcon.getResponseCode();

            if (status != 200) {

                throw new IOException("Post failed with error code " + status);

            }

            BufferedReader br = new BufferedReader(new InputStreamReader(httpcon.getInputStream()));

            StringBuilder sb = new StringBuilder();

            String line;

            while ((line = br.readLine()) != null) {

                sb.append(line+"\n");

            }

            br.close();

          

            return sb.toString();

        } catch (IOException e) {

            e.printStackTrace();

        }

        return null;

    }

 

图片压缩的方式还有其他的形式，可以参考一下这篇文字：http://104zz.iteye.com/blog/1694762

 

完整的demo下载地址：

http://download.csdn.net/detail/abc13939746593/7076025