Use Intentservice to perform background tasks in Android

Intentservice provides a way to perform tasks in a background thread and is suitable for working with long-performing background tasks.

Advantages:

(1) Intentservice runs in a separate thread and does not block the UI thread

(2) Intentservice not affected by life cycle

Disadvantages:

(1) You cannot interact directly with the UI, you can use broadcast

(2) Sequential execution of a request, the second request can only be executed after the first request has been executed

(3) The request cannot be interrupted

Steps to use Intentservice:

(1) Start service through StartService in activity and pass parameters.

(2) Receive parameters in the service, do time-consuming processing, processing complete, send Broadcat, and transfer the results of processing

(3) The activity registers Broadcastreceiver, listens to the broadcast, updates the UI.

See an example:

public class Mainactivity extends Activity {@Overrideprotected void onCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate); Setcontentview (R.layout.activity_main); Button btn = (button) This.findviewbyid (R.ID.BTN); Btn.setonclicklistener (new View.onclicklistener () {@Overridepublic void OnClick (View v) {//Start service via StartService and pass parameters. Intent mserviceintent = new Intent (mainactivity.this,rsspullservice.class); Mserviceintent.setdata (Uri.parse ("http ://www.baidu.com/")); MainActivity.this.startService (mserviceintent);}});        /register Broadcastreceiver, monitor broadcast intentfilter statusintentfilter = new Intentfilter (constants.broadcast_action); Sets the filter ' s category to DEFAULT statusintentfilter.addcategory (intent.category_default);D ownloadstaterecei Ver mdownloadstatereceiver = new Downloadstatereceiver ();//registers the Downloadstatereceiver and its intent Filtersloc Albroadcastmanager.getinstance (This). Registerreceiver (Mdownloadstatereceiver, statusintentfilter);} Private CLDownloadstatereceiver extends Broadcastreceiver {@Overridepublic void OnReceive (context context, Intent Intent) { String data = Intent.getstringextra (Constants.extended_data); LOG.E ("Test", data); Toast.maketext (context, data, Toast.length_short). Show ();}}}

public class Rsspullservice extends Intentservice {public rsspullservice () {Super ("Rsspullservice");} @Overrideprotected void Onhandleintent (Intent workintent) {//Receive parameters, do time-consuming processing, processing complete, send broadcatstring localurlstring = Workintent.getdatastring ();    String data = Download (localurlstring), Intent localintent = new Intent (constants.broadcast_action);    Puts the status into the Intentlocalintent.putextra (Constants.extended_data, DATA);    Broadcasts the Intent to receivers in this app. Localbroadcastmanager.getinstance (This). Sendbroadcast (localintent);} private string Download (String localurlstring) {try{url url = new URL (localurlstring); HttpURLConnection conn = (httpurlconnection) url.openconnection (); InputStream in = Conn.getinputstream (); Bytearrayoutputstream out = new Bytearrayoutputstream (); byte[] buff = new Byte[1024];int len = 0;while (len = in.read (Buff ))! =-1) {out.write (Buff,0,len);} In.close (); return new String (Out.tobytearray ());} catch (Exception e) {e.printstacktrace (); return "";}}} 

public class Constants {//defines a custom Intent actionpublic static final String broadcast_action = "Com.example.androi D.threadsample.broadcast ";//defines the key for the status ' Extra ' in an intentpublic static final String extended_data_s Tatus = "Com.example.android.threadsample.STATUS";p ublic static final String extended_data = " Com.example.android.threadsample.DATA ";}

Androidmanifest.xml:

<manifest xmlns:android= "http://schemas.android.com/apk/res/android" package= "        Com.example.android.intentservicedemo "android:versioncode=" 1 "android:versionname=" 1.0 "> <uses-sdk  android:minsdkversion= "android:targetsdkversion="/> <!--Requires this permission to download RSS  Data from Picasa---<uses-permission android:name= "Android.permission.INTERNET"/> <!--defines    The application. --<application android:icon= "@drawable/icon" android:label= "@string/app_name" > <acti Vity android:name= "com.example.android.intentservicedemo.MainActivity" android:label= "@string/activi                Ty_title "> <intent-filter> <action android:name=" Android.intent.action.MAIN "/>        <category android:name= "Android.intent.category.LAUNCHER"/> </intent-filter>        </activity> <!--    No Intent filters is specified, so android:exported defaults to "false".        The service is a available to this app. --<service android:name= "Com.example.android.intentservicedemo.RSSPullService" Androi D:exported= "false"/> </application></manifest>

Reference: http://developer.android.com/training/run-background-service/index.html

Use Intentservice to perform background tasks in Android