图片异步下载加载代码

 1 import java.io.IOException;

 2 import java.io.InputStream;

 3 import java.util.HashMap;

 4 import java.util.Map;

 5 

 6 import org.apache.http.HttpResponse;

 7 import org.apache.http.client.ClientProtocolException;

 8 import org.apache.http.client.methods.HttpGet;

 9 import org.apache.http.impl.client.DefaultHttpClient;

10 

11 import android.graphics.drawable.Drawable;

12 import android.os.Handler;

13 import android.os.Message;

14 import android.widget.ImageView;

15 

16 public class DrawableManager {

17 

18     private final Map<String, Drawable> drawableMap;

19 

20     public DrawableManager() {

21         drawableMap = new HashMap<String, Drawable>();

22     }

23 

24     public Drawable fatchDrawable(String urlString) {

25         if (drawableMap.containsKey(urlString)) {

26             return drawableMap.get(urlString);

27         }

28         try {

29             InputStream is = fetch(urlString);

30             Drawable drawable = Drawable.createFromStream(is, "src");

31             drawableMap.put(urlString, drawable);

32             return drawable;

33         } catch (ClientProtocolException e) {

34             // TODO Auto-generated catch block

35             e.printStackTrace();

36             return null;

37         } catch (IOException e) {

38             // TODO Auto-generated catch block

39             e.printStackTrace();

40             return null;

41         }

42 

43     }

44 

45     public void fetchDrawableOnThread(final String urlString,

46             final ImageView imageView) {

47         if (drawableMap.containsKey(urlString)) {

48             imageView.setImageDrawable(drawableMap.get(urlString));

49         }

50         final Handler handler = new Handler() {

51 

52             @Override

53             public void handleMessage(Message msg) {

54                 // TODO Auto-generated method stub

55                 imageView.setImageDrawable((Drawable) msg.obj);

56             }

57         };

58 

59         Thread thread = new Thread() {

60 

61             @Override

62             public void run() {

63                 // TODO Auto-generated method stub

64                 Drawable drawable = fatchDrawable(urlString);

65                 Message msg = handler.obtainMessage(1, drawable);

66                 handler.sendMessage(msg);

67             }

68         };

69         thread.start();

70     }

71 

72     private InputStream fetch(String urlString) throws ClientProtocolException,

73             IOException {

74         DefaultHttpClient httpClient = new DefaultHttpClient();

75         HttpGet request = new HttpGet(urlString);

76         HttpResponse response = httpClient.execute(request);

77         return response.getEntity().getContent();

78 

79     }

80 }