Android listview asynchronously and dynamically loads network images

Android listview asynchronously and dynamically loads network images
See: http://blog.sina.com.cn/s/blog_62186b460100zsvb.html
Tags: Android SDK
Code snippet (5)
[Code] (1) define the maplistimageandtext class to manage the contents of controls in listviewitem
01 package com. Google. zxing. Client. Android. asyncloadimage;
02
03
04
05 public class maplistimageandtext {
06 private string imageurl;
07 private string shopname;
08 private string activitynifo;
09 private string address;
10 private string telephone;
11 private string distance;
12
13 public maplistimageandtext (string imageurl, string shopname, string activitynifo, string address, string telephone, string distance ){
14 This. imageurl = imageurl;
15 this. shopname = shopname;
16 this. activitynifo = activitynifo;
17 this. Address = address;
18 this. Telephone = telephone;
19 this. Distance = distance;
20}
21
22 Public String getimageurl (){
23 return imageurl;
24}
25
26 Public String getshopname (){
27 return shopname;
28}
29
30 Public String getactivitynifo (){
31 return activitynifo;
32}
33
34 Public String getaddress (){
35 return address;
36}
37
38 public string gettelephone (){
39 return telephone;
40}
41
42 Public String getdistance (){
43 return distance;
44}
45
46
47}
[Code] (2) Definition class maplistviewcache instantiate controls in listviewitem
01 package com. Google. zxing. Client. Android. asyncloadimage;
02
03 import com. Google. zxing. Client. Android. R;
04
05 import Android. View. view;
06 import Android. widget. imageview;
07 import Android. widget. textview;
08
09 public class maplistviewcache {
10
11 private view baseview;
12 private textview shopname;
13 private textview activitynifo;
14 private textview address;
15 private textview telephone;
16 private textview distance;
17
18 private imageview;
19
20 public maplistviewcache (view baseview ){
21 This. baseview = baseview;
22}
23
24 public textview getshopname (){
25 if (shopname = NULL ){
26 shopname = (textview) baseview. findviewbyid (R. Id. maplistviewitemshopname );
27}
28 return shopname;
29}
30
31 public textview getactivitynifo (){
32 If (activitynifo = NULL ){
33 activitynifo = (textview) baseview. findviewbyid (R. Id. maplistviewitemacti );
34}
35 return activitynifo;
36}
37
38 public textview getaddress (){
39 if (address = NULL ){
40 address = (textview) baseview. findviewbyid (R. Id. maplistviewitemaddr );
41}
42 return address;
43}
44
45 public textview gettelephone (){
46 If (telephone = NULL ){
47 Telephone = (textview) baseview. findviewbyid (R. Id. maplistviewitemtelphone );
48}
49 return telephone;
50}
51
52 public imageview getimageview (){
53 If (imageview = NULL ){
54 imageview = (imageview) baseview. findviewbyid (R. Id. maplistviewitemimage );
55}
56 return imageview;
57}
58
59 Public textview getdistance (){
60 if (distance = NULL ){
61 distance = (textview) baseview. findviewbyid (R. Id. maplistviewitemdistance );
62}
63 return distance;
64}
65
66}
[Code] (3) define the class asyncimageloader and enable the thread to download the specified Image
01 package com. Google. zxing. Client. Android. asyncloadimage;
02
03 import java. Io. ioexception;
04 import java. Io. inputstream;
05 import java. Lang. Ref. softreference;
06 import java.net. malformedurlexception;
07 import java.net. url;
08 import java. util. hashmap;
09
10 Import Android. Graphics. drawable. drawable;
11 import Android. OS. Handler;
12 Import Android. OS. message;
13
14 public class asyncimageloader {
15
16 private hashmap <string, softreference <drawable> imagecache;
17
18 public asyncimageloader (){
19 imagecache = new hashmap <string, softreference <drawable> ();
20}
21
22 public drawable loaddrawable (final string imageurl, final imagecallback ){
23 if (imagecache. containskey (imageurl )){
24 softreference <drawable> softreference = imagecache. Get (imageurl );
25 drawable = softreference. Get ();
26 if (drawable! = NULL ){
27 return drawable;
28}
29}
30 final handler = new handler (){
31 public void handlemessage (message ){
32 imagecallback. imageloaded (drawable) message. OBJ, imageurl );
33}
34 };
35 new thread (){
36 @ override
37 public void run (){
38 drawable = loadimagefromurl (imageurl );
39 imagecache. Put (imageurl, new softreference <drawable> (drawable ));
40 message = handler. obtainmessage (0, drawable );
41 handler. sendmessage (Message );
42}
43}. Start ();
44 return NULL;
45}
46
47 Public static drawable loadimagefromurl (string URL ){
48 URL m;
49 inputstream I = NULL;
50 try {
51 m = new URL (URL );
52 I = (inputstream) M. getcontent ();
53} catch (malformedurlexception E1 ){
54 e1.printstacktrace ();
55} catch (ioexception e ){
56 E. printstacktrace ();
57}
58 drawable d = drawable. createfromstream (I, "src ");
59 return D;
60}
61
62 public interface imagecallback {
63 public void imageloaded (drawable imagedrawable, string imageurl );
64}
65
66}
[Code] (4) Definition class maplistimageandtextlistadapter inherits arrayadapter
01 package com. Google. zxing. Client. Android. asyncloadimage;
02
03 import java. util. List;
04
05 import com. Google. zxing. Client. Android. R;
06
07 import com. Google. zxing. Client. Android. asyncloadimage. asyncimageloader. imagecallback;
08
09 import Android. App. activity;
10 Import Android. Graphics. drawable. drawable;
11 import Android. View. layoutinflater;
12 Import Android. View. view;
13 Import Android. View. viewgroup;
14 Import Android. widget. arrayadapter;
15 Import Android. widget. imageview;
16 Import Android. widget. listview;
17 import Android. widget. textview;
18
19 public class maplistimageandtextlistadapter extends arrayadapter <maplistimageandtext> {
20
21 private listview;
22 private asyncimageloader;
23
24 public maplistimageandtextlistadapter (activity, list <maplistimageandtext> imageandtexts, listview ){
25 super (activity, 0, imageandtexts );
26 This. listview = listview;
27 asyncimageloader = new asyncimageloader ();
28}
29
30 public view getview (INT position, view convertview, viewgroup parent ){
31 activity = (activity) getcontext ();
32
33 // inflate the views from XML
34 view rowview = convertview;
35 maplistviewcache viewcache;
36 IF (rowview = NULL ){
37 layoutinflater Inflater = activity. getlayoutinflater ();
38 rowview = Inflater. Inflate (R. layout. maplistviewitem, null );
39 viewcache = new maplistviewcache (rowview );
40 rowview. settag (viewcache );
41} else {
42 viewcache = (maplistviewcache) rowview. gettag ();
43}
44 maplistimageandtext imageandtext = getitem (position );
45
46 // load the image and set it on the imageview
47 string imageurl = imageandtext. getimageurl ();
48 imageview = viewcache. getimageview ();
49 imageview. settag (imageurl );
50 drawable cachedimage = asyncimageloader. loaddrawable (imageurl, new imagecallback (){
51
52
53 public void imageloaded (drawable imagedrawable, string imageurl ){
54 imageview imageviewbytag = (imageview) listview. findviewwithtag (imageurl );
55 if (imageviewbytag! = NULL ){
56 imageviewbytag. setimagedrawable (imagedrawable );
57}
58}
59 });
60 if (cachedimage = NULL ){
61 imageview. setimageresource (R. drawable. Refresh );
62} else {
63 imageview. setimagedrawable (cachedimage );
64}
65 // set the text on the textview
66 textview shopname = viewcache. getshopname ();
67 shopname. settext (imageandtext. getshopname ());
68
69 textview activitynifo = viewcache. getactivitynifo ();
70 activitynifo. settext (imageandtext. getactivitynifo ());
71
72 textview address = viewcache. getaddress ();
73 address. settext (imageandtext. getaddress ());
74
75 textview telephone = viewcache. gettelephone ();
76 telephone. settext (imageandtext. gettelephone ());
77
78 textview distance = viewcache. getdistance ();
79 distance. settext (imageandtext. getdistance ());
80
81 return rowview;
82}
83
84}
[Code] (5) bundling of listview and maplistimageandtextlistadapter in the main program
01 // tuangoupoints is the string obtained after parsing the data transmitted from the background
02 string [] mtuangoupoints = tuangoupoints. Split ("@");
03
04 list <maplistimageandtext> dataarray = new arraylist <maplistimageandtext> ();
05
06 for (INT I = 0; I <mtuangoupoints. length; I ++ ){
07 string [] tonepoint = mtuangoupoints [I]. Split ("#");
08
09 string shopname = string. valueof (I + 1) + tonepoint [2];
10 string activityinfo = tonepoint [1];
11 string address = tonepoint [6];
12 string telephone = tonepoint [7];
13 string imageurl = tonepoint [8];
14 string distance = tonepoint [5];
15
16 maplistimageandtext test = new maplistimageandtext (imageurl, shopname, activityinfo, address, telephone, distance );
17 dataarray. Add (test );
18}
19
20 maplistimageandtextlistadapter adapter = new maplistimageandtextlistadapter (this, dataarray, mlistview );

21 mlistview. setadapter (adapter );

From: http://www.oschina.net/code/snippet_176897_7207