Use LRUCache and disklrucache to download images

LRUCache is a very useful image caching tool:

The main practice is: Slide the picture when the Bitmap cache in Lrucache<string, bitmap>, after exiting the program to cache the picture into the file. Used Disklrucache Mdisklrucache

So we have to set the address of a picture cache:

public void Setimagecache () {String strpath = null; if (Environment.getexternalstoragestate (). Equals (environment.media_mounted)) {File Sdfile =    Environment.getexternalstoragedirectory ();    strpath = Sdfile.getabsolutepath () + "/pic/";        File Cachefile = new file (strpath);        if (!cachefile.exists ()) {Cachefile.mkdir ();    }} else{String Strcachedir = This.getcachedir (). GetAbsolutePath ();    strpath = Strcachedir + "/pic/";    } setcachepath (strpath); }private void Setcachepath (String strpiccachepath) {if (Textutils.isempty (Strpiccachepath)) {return;} M_strpiccachepath = Strpiccachepath;        File Cachefile = new file (Strpiccachepath);        if (!cachefile.exists ()) {Cachefile.mkdir (); }}public string Getcachebmppath (string strurl) {if (Textutils.isempty (M_strpiccachepath) | | Textutils.isempty (strURL)) {return "";} return M_strpiccachepath + stringutil.md5encode (strurl) + mfileexname;//". bmp";} 

Then write the list of adapter:

Private class ListAdapter extends Baseadapter implements Onscrolllistener {protected list<shopdata> items = new Arra Ylist<shopdata> ();p rotected static final int fetch_image_msg = 1;private lrucache<string, bitmap> mmemorycache;protected hashset<imageview> mitemsmissingimages = new hashset<imageview> ();p rotected Imageloaderhandler mhandler;protected imageloader mimagefetcher;public static final int TIMEOUT = 30000;//  Timeout Time 30 sec private Disklrucache Mdisklrucache; Public ListAdapter () {super (); Mhandler = new Imageloaderhandler (); int maxmemory = (int) runtime.getruntime (). MaxMemory ( int mcachesize = maxmemory/8;//assigns LruCache 1/8 4MmMemoryCache = new lrucache<string, bitmap> (mcachesize) {//Must be re- Write this method to measure the size of the Bitmap @overrideprotected int sizeOf (String key, Bitmap value) {return value.getrowbytes () * Value.getheight ( );}}; try {mdisklrucache = disklrucache. Open (New File (M_strpiccachepath), Getappversion (Mainactivitytest.this) , 1, 10 * 1024 * 1024);}  catch (IOException e) {e.printstacktrace ();} }/** * Synchronizes cache records to the journal file.
 
 
 */public void Fluchcache () {if (Mdisklrucache! = null) {try {Mdisklrucache.flush ();} catch (IOException e) {e.printstackt Race ();}}} @Overridepublic int GetCount () {return items.size ();} @Overridepublic Object getItem (int position) {return items.get (position);} @Overridepublic long Getitemid (int position) {return position;} @Overridepublic view GetView (int position, view Convertview, ViewGroup parent) {Shopdatatag tag = new Shopdatatag (); if (CO Nvertview = = null) {Convertview = minflater.inflate (R.layout.listitem, null); tag.name = (TextView) Convertview.findviewbyid (r.id.name); tag.shopinfo = (TextView) Convertview.findviewbyid (r.id.info); Tag.icon = ( ImageView) Convertview.findviewbyid (R.id.image_icon); Convertview.settag (tag);} else {tag = (Shopdatatag) Convertview.gettag ();} TextView name = Tag.name; TextView info = Tag.shopinfo;imageview ImageView = Tag.icon; Shopdata data = items.get (position); Name.settext (data.name); Info.settext (Data.info); Imageview.settag (Data.url); Setcontactphoto (Data.url, ImageView); return convertview;} protected void Setcontactphoto (String url,imageview viewtouse) {if (Textutils.isempty (URL)) { Viewtouse.setimageresource (R.drawable.avatar);}  else{//first See Mmemorycache can not get bitmapbitmap bitmap = mmemorycache.get (URL); if (bitmap! = null) {Viewtouse.setimagebitmap (bitmap);} else {Snapshot Snapshot = null; FileDescriptor filedescriptor = null; FileInputStream FileInputStream = null;try {//Because Mdisklrucache will use key as the file name. So the URL is converted through MD5 to keyfinal String key = Hashkeyfordisk (URL); snapShot = Mdisklrucache.get (key);//Assuming snapShot is empty, Just can't find the corresponding file if (SnapShot = = null) {//here to download fetchimage (viewtouse);} Else{fileinputstream = (fileinputstream) snapshot.getinputstream (0); filedescriptor = Fileinputstream.getfd (); if ( FileDescriptor = null) {bitmap = Bitmapfactory.decodefiledescriptor (FileDescriptor);} Suppose parsing a file into bitmap failed. Download again if (! Textutils.isempty (URL) && bitmap! = null) {mmemorycache.put (URL, bitmap); Viewtouse.setimagebitmap (bitmap);} Else{fetchimage (Viewtouse);}}} catch (IOException ex) {ex.printstacktrace ();}  Finally{if (FileDescriptor = = NULL && FileInputStream! = null) {try {fileinputstream.close ();} catch (IOException e) {}}}}} private void Fetchimage (ImageView viewtouse) {viewtouse.setimageresource (R.drawable.avatar); Mitemsmissingimages.add (Viewtouse); if (mscrollstate! = onscrolllistener.scroll_state_fling) {sendFetchImageMessage (Viewtouse);}} public string <strong>hashKeyForDisk</strong> (string key) {convert key to MD5 file return Stringutil.md5encode (key) ;} Image Downloaderprivate Class Imageloaderhandler extends Handler {@Overridepublic void handlemessage (Message message) {if (isfinishing ()) {return;} Switch (message.what) {case fetch_image_msg: {final ImageView ImageView = (ImageView) message.obj;if (ImageView = = null) { break;} Final String url = (String) imageview.gettag (); if (Textutils.isempty (URL)) {break;} Bitmap map = getbitmapfrommemcache (URL); if (map = = null) {break;} Synchronized (ImageView) {final String Myurl = (String) Imageview.gettag ()if (textutils.equals (URL, myurl)) {imageview.setimagebitmap (map); Mitemsmissingimages.remove (ImageView);} else {}} Break;}}} public void clearimagefecthing () {removemessages (fetch_image_msg);}} Private class Imageloader implements Runnable {string url;private ImageView mimageview;public imageloader (string URL, Ima Geview imageView) {this.url = Url;this.mimageview = ImageView;} public void Run () {if (isfinishing ()) {return;} if (thread.interrupted ()) {return;} FileDescriptor filedescriptor = null; FileInputStream fileinputstream = null; Snapshot Snapshot = null;try {final String key = Hashkeyfordisk (URL); Snapshot = Mdisklrucache.get (key); if (Snapshot = = nul L) {//if the corresponding cache is not found, prepare to request data from the network. and writes the cache disklrucache.editor Editor = Mdisklrucache.edit (key); if (Editor! = null) {OutputStream OutputStream = Editor.newoutputstream (0); Boolean flag = Downloadimage (URL, outputstream), if (flag) {Editor.commit ();} else { Editor.abort ();}} After the cache is written, look again for the corresponding cache of key snapshot = Mdisklrucache.get (key);} This should delete the appropriate file if (SnapshoT! = null) {FileInputStream = (fileinputstream) snapshot.getinputstream (0); filedescriptor = Fileinputstream.getfd ();} Parses the cached data into a Bitmap object bitmap bitmap = null;if (filedescriptor! = null) {bitmap = Bitmapfactory.decodefiledescriptor ( FileDescriptor);} if (bitmap! = null) {//Bitmap object is added to the memory cache where Mmemorycache.put (URL, bitmap);}} catch (IOException e) {e.printstacktrace ();} finally {if (FileDescriptor = = NULL && FileInputStream! = null) {try {Fileinputstream.close ();} catch (IOException e) {}}}if (thread.interrupted ()) {return;} Message msg = new Message (); msg.what = Fetch_image_msg;msg.obj = Mimageview;mhandler.sendmessage (msg);}}  Public Bitmap Getbitmapfrommemcache (String key) {return mmemorycache.get (key); public boolean downloadimage (String strurl,outputstream fos) {URL getUrl = null; Bitmap Bitmap = null; Bufferedoutputstream out = null; Bufferedinputstream in = null;try {getUrl = new URL (strURL),} catch (Malformedurlexception ex) {LOG.E ("Httputil", "Get Mal Formedurl ", ex); return false;} InputStream input = null; HttpURLConnection conn = null;try {conn = (httpurlconnection) geturl.openconnection (); Conn.setconnecttimeout (TIMEOUT) ; Conn.setreadtimeout (TIMEOUT); Conn.setdoinput (true); Conn.connect (); input = Conn.getinputstream (); in = new Bufferedinputstream (Input, 8 * 1024x768); out = new Bufferedoutputstream (FOS, 8 * 1024x768), int b;while ((b = In.read ())! =-1) {OU T.write (b);} return true;} catch (Exception ex) {LOG.E ("Httputil", "Downloadimage", Ex),} catch (OutOfMemoryError ex) {ex.printstacktrace ();} Finally {try {if (out! = null) {out.close (); out = null;} if (in! = null) {in.close (); in = null;} IF (conn! = null) {conn.disconnect (); conn = null;}} catch (Exception ex) {LOG.E ("Httputil", "Downloadimage finally", Ex);}} return false;} Private Boolean GetResponse (InputStream input, OutputStream OS, byte[] data) throws ioexception{if (input = = NULL | | os = = null | | data = = NULL) {return false;} int i = 0;while ((i = input.read (data))! =-1) {os.write (data, 0, I); Os.flush ();} Os.flush (); return true;} private void Processmissingimageitems (Abslistview view) {for (ImageView iv:mitemsmissingimages) { Sendfetchimagemessage (iv);}} protected void Sendfetchimagemessage (ImageView view) {final String url = (String) view.gettag (); if (Textutils.isempty ( URL)) {return;} Mimagefetcher = new Imageloader (URL, view); synchronized (mainactivitytest.this) {if (Simagefetchthreadpool = = null) { Simagefetchthreadpool = Executors.newfixedthreadpool (3);} Simagefetchthreadpool.execute (Mimagefetcher);}} public void clearimagefetching () {synchronized (mainactivitytest.this) {if (Simagefetchthreadpool! = null) { Simagefetchthreadpool.shutdownnow (); simagefetchthreadpool = null;}} Mhandler.clearimagefecthing ();} public void Clearmessages () {if (Mhandler! = null) {try {mhandler.removecallbacksandmessages (null);} catch ( java.lang.Throwable th) {}mhandler = null;}} @Overridepublic void onscrollstatechanged (abslistview view, int scrollstate) {mscrollstate = Scrollstate;if ( Scrollstate = = Onscrolllistener.scroll_state_fling) {clearimagefetching ();} else {processmissingimageitems (view);}} @Overridepublic void Onscroll (abslistview view, int firstvisibleitem, int visibleitemcount, int totalitemcount) {}} Private class Shopdatatag {TextView name; TextView shopinfo;imageview icon;}

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Code: http://download.csdn.net/detail/baidu_nod/7777137

Use LRUCache and disklrucache to download images