Android Development using the handler package download Picture Tool class

If every download of a picture, you have to rewrite the HTTP protocol, multi-threaded start and handler information transfer is too troublesome, we directly encapsulate a tool class, so that we can be called at any time in development.

(1) Adding permissions in the manifest file

  <uses-permission android:name= "Android.permission.INTERNET"/>

(2) Editing Tool classes

Package Com.example.g05_handler;import Java.io.ioexception;import Org.apache.http.httpresponse;import Org.apache.http.client.clientprotocolexception;import Org.apache.http.client.httpclient;import Org.apache.http.client.methods.httpget;import Org.apache.http.impl.client.defaulthttpclient;import Org.apache.http.util.entityutils;import Android.annotation.suppresslint;import Android.app.ProgressDialog;import Android.content.context;import Android.os.handler;import Android.os.message;import Android.util.Log;public class  DownLoad {private ProgressDialog dialog;public DownLoad (Context context) {//TODO auto-generated Constructor Stubdialog = New ProgressDialog (context);d ialog.settitle ("hint");d ialog.setmessage ("desperate Loading");}  @SuppressLint ("Handlerleak") public void-down (final String path, final Downloadcallback callback) {final Handler Handler = New Handler () {@Overridepublic void Handlemessage (Message msg) {//TODO auto-generated method Stubsuper.handlemessage (MS g); byte[] result = (byte[]) msg.obj;Callback.download (result); if (msg.what = = 1) {Dialog.dismiss ();}}}; Class MyThread implements Runnable {@Overridepublic void Run () {//TODO auto-generated method Stubhttpclient client = new Defaulthttpclient (); HttpGet httpget = new HttpGet (path); try {HttpResponse HttpResponse = Client.execute (HttpGet); LOG.I ("TAG", "------>" + httpresponse.getstatusline (). Getstatuscode ()); if (Httpresponse.getstatusline (). Getstatuscode () = = () {byte[] result = Entityutils.tobytearray (httpresponse.getentity ()); Message message = Message.obtain (); message.obj = Result;message.what = 1;handler.sendmessage (message);}} catch (Clientprotocolexception e) {//Todo auto-generated catch Blocke.printstacktrace ();} catch (IOException e) {//TODO Auto-generated catch Blocke.printstacktrace ();} Finally {if (client! = null) {Client.getconnectionmanager (). shutdown ();}}};} New Thread (New MyThread ()). Start ();d ialog.show ();} Public interface Downloadcallback {public void download (byte[] data);}}

(3) Call the tool class

Package Com.example.g05_handler;import Com.example.g05_handler. Download.downloadcallback;import Android.os.bundle;import Android.app.activity;import Android.graphics.Bitmap; Import Android.graphics.bitmapfactory;import Android.view.menu;import Android.view.view;import Android.widget.button;import Android.widget.imageview;public class Mainactivity extends Activity {private Button Butto    N    Private ImageView ImageView; Private final String path= "http://avatar.csdn.net/D/7/5/1_u013900875.jpg"; @Overrideprotected void OnCreate (Bundle Savedinstancestate) {super.oncreate (savedinstancestate); Setcontentview (R.layout.activity_main); button= (Button) This.findviewbyid (R.id.button1); imageview= (ImageView) This.findviewbyid (R.ID.IMAGEVIEW1); Button.setonclicklistener (New View.onclicklistener () {@Overridepublic void OnClick (View v) {//TODO auto-generated Method Stubdownload download=new downLoad (mainactivity.this);d ownload.down (Path, new Downloadcallback () {@ overridepublic void Download (byte[] DatA) {//TODO auto-generated method Stubbitmap bitmap=bitmapfactory.decodebytearray (data, 0, data.length); Imageview.setimagebitmap (bitmap);});}); @Overridepublic boolean Oncreateoptionsmenu (Menu menu) {//Inflate the menu; This adds items to the action bar if it is PR Esent.getmenuinflater (). Inflate (R.menu.main, menu); return true;}}