wemall doraemon是Android客户端程序，服务端采用wemall微信商城，不对原商城做任何修改，只需要在原商城目录下上传接口文件即可完成服务端的配置，客户端可随意定制修改。本文分享其中关于异步加载图片管理器，供技术员参考学习。

package com.inuoer.util;import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.lang.ref.SoftReference;
import java.net.HttpURLConnection;
import java.net.URL;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Map;import android.graphics.Bitmap;
import android.graphics.BitmapFactory;/*** * @author Administrator* @desc 异步加载图片管理器**/
public class LoaderImpl {//内存中的软应用缓存private Map<String, SoftReference<Bitmap>> imageCache;//是否缓存图片至本地文件private boolean cache2FileFlag = false;//缓存目录,默认是/data/data/package/cache/目录private String cachedDir;public LoaderImpl(Map<String, SoftReference<Bitmap>> imageCache){this.imageCache = imageCache;}/*** 是否缓存图片至外部文件* @param flag */public void setCache2File(boolean flag){cache2FileFlag = flag;}/*** 设置缓存图片到外部文件的路径* @param cacheDir*/public void setCachedDir(String cacheDir){this.cachedDir = cacheDir;}/*** 从网络端下载图片* @param url 网络图片的URL地址* @param cache2Memory 是否缓存(缓存在内存中)* @return bitmap 图片bitmap结构* */public Bitmap getBitmapFromUrl(String url, boolean cache2Memory){Bitmap bitmap = null;try{URL u = new URL(url);HttpURLConnection conn = (HttpURLConnection)u.openConnection();  InputStream is = conn.getInputStream();bitmap = BitmapFactory.decodeStream(is);if(cache2Memory){//1.缓存bitmap至内存软引用中imageCache.put(url, new SoftReference<Bitmap>(bitmap));if(cache2FileFlag){//2.缓存bitmap至/data/data/packageName/cache/文件夹中String fileName = getMD5Str(url);String filePath = this.cachedDir + "/" +fileName;FileOutputStream fos = new FileOutputStream(filePath);bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);}}is.close();conn.disconnect();return bitmap;}catch(IOException e){e.printStackTrace();return null;}}/*** 从内存缓存中获取bitmap* @param url* @return bitmap or null.*/public Bitmap getBitmapFromMemory(String url){Bitmap bitmap = null;if(imageCache.containsKey(url)){synchronized(imageCache){SoftReference<Bitmap> bitmapRef = imageCache.get(url);if(bitmapRef != null){bitmap = bitmapRef.get();return bitmap;}}}//从外部缓存文件读取if(cache2FileFlag){bitmap = getBitmapFromFile(url);if(bitmap != null)imageCache.put(url, new SoftReference<Bitmap>(bitmap));}return bitmap;}/*** 从外部文件缓存中获取bitmap* @param url* @return*/private Bitmap getBitmapFromFile(String url){Bitmap bitmap = null;String fileName = getMD5Str(url);if(fileName == null)return null;String filePath = cachedDir + "/" + fileName;try {FileInputStream fis = new FileInputStream(filePath);bitmap = BitmapFactory.decodeStream(fis);} catch (FileNotFoundException e) {e.printStackTrace();bitmap = null;}return bitmap;}/**  * MD5 加密  */   private static String getMD5Str(String str) {   MessageDigest messageDigest = null;   try {   messageDigest = MessageDigest.getInstance("MD5");   messageDigest.reset();   messageDigest.update(str.getBytes("UTF-8"));   } catch (NoSuchAlgorithmException e) {
//          System.out.println("NoSuchAlgorithmException caught!");   return null;} catch (UnsupportedEncodingException e) {   e.printStackTrace();return null;}   byte[] byteArray = messageDigest.digest();   StringBuffer md5StrBuff = new StringBuffer();   for (int i = 0; i < byteArray.length; i++) {               if (Integer.toHexString(0xFF & byteArray[i]).length() == 1)   md5StrBuff.append("0").append(Integer.toHexString(0xFF & byteArray[i]));   else   md5StrBuff.append(Integer.toHexString(0xFF & byteArray[i]));   }   return md5StrBuff.toString();   }  /**  * MD5 加密  private static String getMD5Str(Object...objects){StringBuilder stringBuilder=new StringBuilder();for (Object object : objects) {stringBuilder.append(object.toString());}return getMD5Str(stringBuilder.toString());}*/
}

原文详情地址：http://git.oschina.net/zzunet/wemall-doraemon/commit/e8f303df5663dc69fe47bb9623222149d40e3956

wemall doraemonAndroid app商城详情地址：http://www.koahub.com/home/product/55

wemall官网地址：http://www.wemallshop.com

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