wemall app商城源码中基于JAVA的Android异步加载图片管理器代码

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。

 

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1. package com.inuoer.util;
   
2. 
   
3. import java.io.FileInputStream;
   
4. import java.io.FileNotFoundException;
   
5. import java.io.FileOutputStream;
   
6. import java.io.IOException;
   
7. import java.io.InputStream;
   
8. import java.io.UnsupportedEncodingException;
   
9. import java.lang.ref.SoftReference;
   
10. import java.net.HttpURLConnection;
    
11. import java.net.URL;
    
12. import java.security.MessageDigest;
    
13. import java.security.NoSuchAlgorithmException;
    
14. import java.util.Map;
    
15. 
    
16. import android.graphics.Bitmap;
    
17. import android.graphics.BitmapFactory;
    
18. 
    
19. /**
    
20.  *
    
21.  * @author Administrator
    
22.  * @desc 异步加载图片管理器
    
23.  *
    
24.  */
    
25. public class LoaderImpl {
    
26.     //内存中的软应用缓存
    
27.     private Map<String, SoftReference<Bitmap>> imageCache;
    
28.     
    
29.     //是否缓存图片至本地文件
    
30.     private boolean cache2FileFlag = false;
    
31.     
    
32.     //缓存目录,默认是/data/data/package/cache/目录
    
33.     private String cachedDir;
    
34.     
    
35.     public LoaderImpl(Map<String, SoftReference<Bitmap>> imageCache){
    
36.         this.imageCache = imageCache;
    
37.     }
    
38.     
    
39.     /**
    
40.      * 是否缓存图片至外部文件
    
41.      * @param flag
    
42.      */
    
43.     public void setCache2File(boolean flag){
    
44.         cache2FileFlag = flag;
    
45.     }
    
46.     
    
47.     /**
    
48.      * 设置缓存图片到外部文件的路径
    
49.      * @param cacheDir
    
50.      */
    
51.     public void setCachedDir(String cacheDir){
    
52.         this.cachedDir = cacheDir;
    
53.     }
    
54.     
    
55.     /**
    
56.      * 从网络端下载图片
    
57.      * @param url 网络图片的URL地址
    
58.      * @param cache2Memory 是否缓存(缓存在内存中)
    
59.      * @return bitmap 图片bitmap结构
    
60.      *
    
61.      */
    
62.     public Bitmap getBitmapFromUrl(String url, boolean cache2Memory){
    
63.         Bitmap bitmap = null;
    
64.         try{
    
65.             URL u = new URL(url);
    
66.             HttpURLConnection conn = (HttpURLConnection)u.openConnection();
    
67.             InputStream is = conn.getInputStream();
    
68.             bitmap = BitmapFactory.decodeStream(is);
    
69.             
    
70.             if(cache2Memory){
    
71.                 //1.缓存bitmap至内存软引用中
    
72.                 imageCache.put(url, new SoftReference<Bitmap>(bitmap));
    
73.                 if(cache2FileFlag){
    
74.                     //2.缓存bitmap至/data/data/packageName/cache/文件夹中
    
75.                     String fileName = getMD5Str(url);
    
76.                     String filePath = this.cachedDir + "/" +fileName;
    
77.                     FileOutputStream fos = new FileOutputStream(filePath);
    
78.                     bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
    
79.                 }
    
80.             }
    
81.             
    
82.             is.close();
    
83.             conn.disconnect();
    
84.             return bitmap;
    
85.         }catch(IOException e){
    
86.             e.printStackTrace();
    
87.             return null;
    
88.         }
    
89.     }
    
90.     
    
91.     /**
    
92.      * 从内存缓存中获取bitmap
    
93.      * @param url
    
94.      * @return bitmap or null.
    
95.      */
    
96.     public Bitmap getBitmapFromMemory(String url){
    
97.         Bitmap bitmap = null;
    
98.         if(imageCache.containsKey(url)){
    
99.             synchronized(imageCache){
    
100.                 SoftReference<Bitmap> bitmapRef = imageCache.get(url);
     
101.                 if(bitmapRef != null){
     
102.                     bitmap = bitmapRef.get();
     
103.                     return bitmap;
     
104.                 }
     
105.             }
     
106.         }
     
107.         //从外部缓存文件读取
     
108.         if(cache2FileFlag){
     
109.             bitmap = getBitmapFromFile(url);
     
110.             if(bitmap != null)
     
111.                 imageCache.put(url, new SoftReference<Bitmap>(bitmap));
     
112.         }
     
113.         
     
114.         return bitmap;
     
115.     }
     
116.     
     
117.     /**
     
118.      * 从外部文件缓存中获取bitmap
     
119.      * @param url
     
120.      * @return
     
121.      */
     
122.     private Bitmap getBitmapFromFile(String url){
     
123.         Bitmap bitmap = null;
     
124.         String fileName = getMD5Str(url);
     
125.         if(fileName == null)
     
126.             return null;
     
127.         
     
128.         String filePath = cachedDir + "/" + fileName;
     
129.         
     
130.         try {
     
131.             FileInputStream fis = new FileInputStream(filePath);
     
132.             bitmap = BitmapFactory.decodeStream(fis);
     
133.         } catch (FileNotFoundException e) {
     
134.             e.printStackTrace();
     
135.             bitmap = null;
     
136.         }
     
137.         return bitmap;
     
138.     }
     
139.     
     
140.     
     
141.     /**
     
142.      * MD5 加密
     
143.      */
     
144.     private static String getMD5Str(String str) {
     
145.         MessageDigest messageDigest = null;
     
146.         try {
     
147.             messageDigest = MessageDigest.getInstance("MD5");
     
148.             messageDigest.reset();
     
149.             messageDigest.update(str.getBytes("UTF-8"));
     
150.         } catch (NoSuchAlgorithmException e) {
     
151. // System.out.println("NoSuchAlgorithmException caught!");
     
152.             return null;
     
153.         } catch (UnsupportedEncodingException e) {
     
154.             e.printStackTrace();
     
155.             return null;
     
156.         }
     
157.    
     
158.         byte[] byteArray = messageDigest.digest();
     
159.         StringBuffer md5StrBuff = new StringBuffer();
     
160.         for (int i = 0; i < byteArray.length; i++) {
     
161.             if (Integer.toHexString(0xFF & byteArray[i]).length() == 1)
     
162.                 md5StrBuff.append("0").append(Integer.toHexString(0xFF & byteArray[i]));
     
163.             else
     
164.                 md5StrBuff.append(Integer.toHexString(0xFF & byteArray[i]));
     
165.         }
     
166.    
     
167.         return md5StrBuff.toString();
     
168.     }
     
169. 
     
170.     /**
     
171.      * MD5 加密
     
172.     private static String getMD5Str(Object...objects){
     
173.         StringBuilder stringBuilder=new StringBuilder();
     
174.         for (Object object : objects) {
     
175.             stringBuilder.append(object.toString());
     
176.         }
     
177.         return getMD5Str(stringBuilder.toString());
     
178.     }*/
     
179. }

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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