Android image asynchronous loading class

Source: Internet
Author: User

Keywords: cache pool, loading queue

/*** Title: asynchronous image loading class * Description: * copyright: Copyright (c) 2012 * company: ** @ author tom_liang */package COM. zouba. DD. UI. util; import Java. io. ioexception; import Java. io. inputstream; import Java. io. serializable; import Java. lang. ref. softreference; import malformedurlexception; import URL; import Java. util. arraylist; import Java. util. hashmap; import Java. util. list; import Java. util. map; Im Port android. graphics. drawable. drawable; import android. OS. bundle; import android. OS. handler; import android. OS. message; public class dandanasynchimageloader {public static Boolean isstop = false; // whether to stop asynchronously loading the image thread private static object locker = new object (); // Synchronous lock Private Static thread loadthread = NULL; // asynchronously load the thread object Private Static Map <string, softreference <drawable> imagecache = new hashmap <string, softrefere NCE <drawable> (); // Private Static list of all image caches <asynchimage> taskqueue = new arraylist <asynchimage> (); // asynchronously load the task queue // message processor Private Static final handler = new handler () {public void handlemessage (message) {// after the current task is loaded into the image, execute callback bundle = message. getdata (); asynchimage = (asynchimage) bundle. getserializable ("handled_task"); asynchimage. getcallback (). imageloaded (drawable) Message. OBJ, asynchimage. getimgurl () ;}; static {dandanasynchimageloader. loadthread = new thread () {public void run () {While (! Dandanasynchimageloader. isstop) {synchronized (locker) {If (taskqueue. size () = 0) {try {locker. wait ();} catch (interruptedexception e) {e. printstacktrace () ;}} asynchimage temptask = taskqueue. remove (0); drawable = loadimagefromurl (temptask. getimgurl (); imagecache. put (temptask. getimgurl (), new softreference <drawable> (drawable); message = handler. obtainmessage (0, drawable); bundle = New bundle (); bundle. putserializable ("handled_task", temptask); message. setdata (bundle); handler. sendmessage (Message); locker. notifyall () ;}}}; // start asynchronous thread (network event thread) dandanasynchimageloader. loadthread. start ();}/*** the static method for loading images asynchronously. First, check whether there are previously loaded images in the cache. * If yes, return directly. No, add to asynchronous task queue for loading * @ Param imageurl URL for slice * @ Param imagecallback callback interface * @ return returns the drawable object of asynchronous images */public static drawable loaddrawable (final string I Mageurl, final imagecallback) {If (imagecache. containskey (imageurl) {softreference <drawable> softreference = imagecache. get (imageurl); drawable = softreference. get (); If (drawable! = NULL) {return drawable;} new thread () {public void run () {synchronized (locker) {If (! Taskqueue. contains (imageurl) {taskqueue. add (New asynchimage (imageurl, imagecallback);} locker. policyall ();}}}. start (); return NULL;}/*** network image loading callback interface * @ author zouba **/public interface imagecallback {public void imageloaded (drawable imagedrawable, string imageurl);}/*** description: real network image Loading Method * @ Param URL address of the network image * @ return returns the drawable object of the network image */Private Static drawable loadimagefromurl (string URL) {URL m; inputstream I = NULL; try {M = new URL (URL); I = (inputstream) M. getcontent ();} catch (malformedurlexception E1) {e1.printstacktrace ();} catch (ioexception e) {e. printstacktrace ();} drawable d = drawable. createfromstream (I, "src"); Return D ;} /*************************************** **************************************** * ****** asynchronously load the image's Java Bean, simple encapsulation of asynchronous Image Information ********************************* **************************************** * **********/static class asynchimage implements serializable {Private Static final long serialversionuid = 1l; private string imgurl; private imagecallback callback; Public asynchimage (string imgurl, imagecallback callback) {This. imgurl = imgurl; this. callback = callback;} Public String getimgurl () {return imgurl;} public void setimgurl (string imgurl) {This. imgurl = imgurl;} public imagecallback getcallback () {return callback;} public void setcallback (imagecallback callback) {This. callback = callback ;}}}

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