Android uses Asynctask to implement multithreaded downloads _android

The example in this article describes how Android uses Asynctask to implement multithreaded downloads. Share to everyone for your reference, specific as follows:

public class Mainactivity extends activity implements Onclicklistener {private Button btn1, btn2, btn3;
  Private ProgressBar progressBar1, ProgressBar2, PROGRESSBAR3;
  Private ImageView Img1, Img2, IMG3;
  private static final String Img_uri = "Yun_qi_img/logo.gif";
    @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);
    Setcontentview (R.layout.activity_main);
    Initview ();
  Initlistener ();
    }/** * Initialize listener */private void Initlistener () {Btn1.setonclicklistener (this);
    Btn2.setonclicklistener (this);
  Btn3.setonclicklistener (this);
    /** * * Initialization control/private void Initview () {btn1 = (Button) Findviewbyid (R.ID.BTN1);
    BTN2 = (Button) Findviewbyid (R.ID.BTN2);
    Btn3 = (Button) Findviewbyid (R.ID.BTN3);
    ProgressBar1 = (ProgressBar) Findviewbyid (R.ID.PROGRESSBAR1);
    ProgressBar2 = (ProgressBar) Findviewbyid (R.ID.PROGRESSBAR2); ProgressBar3 = (ProgressBar) Findviewbyid (R.ID.PROGRESSBAR3);
    IMG1 = (ImageView) Findviewbyid (R.ID.IMG1);
    Img2 = (ImageView) Findviewbyid (R.ID.IMG2);
  IMG3 = (ImageView) Findviewbyid (R.ID.IMG3);  @Override public boolean Oncreateoptionsmenu (Menu menu) {//Inflate the menu; This adds items to the action Bar
    If it is present.
    Getmenuinflater (). Inflate (R.menu.main, menu);
  return true;
    @Override public void OnClick (View arg0) {//click button simulate download mydownloadasy down = new Mydownloadasy ();
  Down.execute (Img_uri, Arg0.getid () + "");
   /** * 1.Params, the parameter type passed to the background task. * 2.Progress, background calculates the type of progressive unit (Progress units) during the execution process. (that is, a few percent of the background program has been executed.)
   * * 3.Result, the background to perform the type of returned results.
    * * Class Mydownloadasy extends Asynctask<string, Integer, bitmap> {private static final String TAG = "Asy";
    private int clickbtn = 0;
    private void I (String object) {log.i (TAG, object); @Override protected void OnPreExecute () {//TODO auto-generated method stub supEr.onpreexecute ();
      I ("Ready to run a thread"); 
    Progressbar1.setprogress (0),//progress bar Reset Progressbar2.setprogress (0),//progress bar Reset progressbar3.setprogress (0);//progress bar Reset
      @Override protected Bitmap doinbackground (String ... arg0) {switch (Integer.parseint (arg0[1))) {
        Case R.ID.BTN1:CLICKBTN = 1;
      Break
        Case R.ID.BTN2:CLICKBTN = 2;
      Break
        Case R.ID.BTN3:CLICKBTN = 3;
      Break
      Default:break;
      I ("Performing in the background");
      Publishprogress (0);
      Download Photo HttpClient HC = new Defaulthttpclient ();
      Wait for 2s sleepwait ();
      Publishprogress (50);
      HttpGet hg = new HttpGet (arg0[0]);//Get JB51 logo final Bitmap BM;
        try {HttpResponse hr = Hc.execute (Hg);
      BM = Bitmapfactory.decodestream (Hr.getentity (). getcontent ());
      catch (Exception e) {return null;
      } sleepwait ();
      Publishprogress (100); Mimageview.setimagEbitmap (result);
    Cannot operate UI return bm in background threads;
      /** * wait for 2s clock/private void sleepwait () {try {thread.sleep (2000);
      catch (Interruptedexception E1) {//TODO auto-generated catch block E1.printstacktrace ();
      } protected void Onprogressupdate (Integer ... values) {//Dynamic update I ("Progress Update");
      Switch (CLICKBTN) {case 1:progressbar1.setprogress (values[0]);//Update progress bar progress break;
      Case 2:progressbar2.setprogress (values[0]);//Update progress bar progress break;
      Case 3:progressbar3.setprogress (values[0]);//Update progress bar progress break;
      Default:break; } protected void OnPostExecute (Bitmap result) {//TODO auto-generated method stub Super.onpostexecu
      TE (result);
      I ("Thread execution Complete");
        if (result!= null) {i ("Download picture succeeded");
          Switch (CLICKBTN) {case 1:img1.setimagebitmap (result);
        Break Case 2:img2.setimagebitmap (result);
        Break
          Case 3:img3.setimagebitmap (Result);
        Break
        Default:break;
      } else {i ("Download picture failed"); } @Override protected void oncancelled () {//TODO auto-generated method Stub super.oncancelled (
      );
      I ("Cancel the thread");
      Switch (CLICKBTN) {case 1:progressbar1.setprogress (0);//progress bar reset break;
      Case 2:progressbar2.setprogress (0);//progress bar reset break;
      Case 3:progressbar3.setprogress (0);//progress bar reset break;
      Default:break;

 }
    }
  }
}

XML:

<relativelayout xmlns:android= "http://schemas.android.com/apk/res/android" xmlns:tools= "http:// Schemas.android.com/tools "android:layout_width=" match_parent "android:layout_height=" Match_parent "Android: paddingbottom= "@dimen/activity_vertical_margin" android:paddingleft= "@dimen/activity_horizontal_margin" Android: paddingright= "@dimen/activity_horizontal_margin" android:paddingtop= "@dimen/activity_vertical_margin" tools: Context= ". Mainactivity "> <tablelayout android:layout_width=" fill_parent "android:layout_height=" an Droid:layout_centerhorizontal= "true" > <TableRow> <button android:id= "@+id/btn1" and roid:text= "@string/btn1" "/> <progressbar android:id=" @+id/progressbar1 "style="? android:attr/p
      Rogressbarstylehorizontal "android:layout_width=" fill_parent "android:layout_height=" Wrap_content "/>" <imageview android:id= "@+id/img1" aNdroid:layout_width= "Wrap_content" android:layout_height= "wrap_content" android:contentdescription= "@id/im
        G1 "android:src=" @drawable/ic_launcher "/> </TableRow> <TableRow> <button Android:id= "@+id/btn2" android:text= "@string/btn2"/> <progressbar android:id= "@+id/progressba R2 "style=" "Android:attr/progressbarstylehorizontal" android:layout_width= "Fill_parent" Android:la yout_height= "Wrap_content"/> <imageview android:id= "@+id/img2" android:layout_width= Tent "android:layout_height=" Wrap_content "android:contentdescription=" @id/img2 "android:src=" @dra
        Wable/ic_launcher "/> </TableRow> <TableRow> <button android:id=" @+id/btn3 " android:text= "@string/btn3" "/> <progressbar android:id=" @+id/progressbar3 "style="? android:a Ttr/progressbarstylehoriZontal "android:layout_width=" fill_parent "android:layout_height=" wrap_content "/> <ImageView
        Android:id= "@+id/img3" android:layout_width= "wrap_content" android:layout_height= "Wrap_content" android:contentdescription= "@id/img3" android:src= "@drawable/ic_launcher"/> </TableRow> <

 /tablelayout> </RelativeLayout>

Androidmanifast:

<?xml version= "1.0" encoding= "Utf-8"?> <manifest xmlns:android= "http://schemas.android.com/apk/res/"
    Android "package=" Com.xunfang.asynctackdemo "android:versioncode=" 1 "android:versionname=" 1.0 "> <uses-sdk android:minsdkversion= "android:targetsdkversion="/> <!--permissions to access the network--> <uses-permission Andro
    Id:name= "Android.permission.INTERNET" > </uses-permission> <application android:allowbackup= "true" android:icon= "@drawable/ic_launcher" android:label= "@string/app_name" android:theme= "@style/apptheme" > &L T;activity android:name= "com.xunfang.asynctackdemo.MainActivity" android:label= "@string/app_name" > & lt;intent-filter> <action android:name= "Android.intent.action.MAIN"/> <category "Android.intent.category.LAUNCHER"/> </intent-filter> </activity> </application> </ma

 Nifest>

For more information on Android-related content readers can view the site topics: "Android Debugging techniques and common problems solution summary", "Android Development introduction and Advanced Course", "Android Multimedia operating skills Summary (audio, video, recording, etc.)", " Android Basic Components Usage Summary, Android View tips Summary, Android layout layout tips and Android Control usage summary

I hope this article will help you with the Android program.