When the android handler starts to download text content from the network, the following prompt is displayed: progressbar-circular progress bar.

After reading a lot of examples of downloading text, I thought it was not easy to understand. I wrote a simple and easy-to-understand code.

Package COM. example. demodownload; import android. app. activity; import android. app. progressdialog; import android. OS. bundle; import android. OS. handler; import android. OS. message; import android. view. view; import android. view. view. onclicklistener; import android. widget. button; import android. widget. textview; public class mainactivity extends activity {private button; private textview show; private string STR; private progressdialog mypdialog; @ overridepublic void oncreate (bundle savedinstancestate) {super. oncreate (savedinstancestate); setcontentview (R. layout. activity_main); button = (button) findviewbyid (R. id. button1); show = (textview) findviewbyid (R. id. textview1); button. setonclicklistener (New onclicklistener () {public void onclick (view v) {downloadthread thread = new downloadthread (); thread. start ();} }); Mypdialog = new progressdialog (this); // instantiate mypdialog. setprogressstyle (progressdialog. style_spinner); // you can specify the progress bar style. The style is circular and the mypdialog is rotated. settitle ("login"); // set progressdialog title mypdialog. setmessage ("downloading... please wait"); // sets the progressdialog prompt message mypdialog. setindeterminate (false); // sets progressdialogmypdialog. setcancelable (true); // set progressdialog // whether the ssdialog can be canceled by pressing the return button} handler = new handler () {@ overridepublic void Han Dlemessage (Message MSG) {Switch (MSG. what) {Case 1: // start the download mark mypdialog. show (); // Let progressdialog display break; Case 2: // The end download mark mypdialog. cancel (); show. settext (STR); break ;}}; private class downloadthread extends thread {@ overridepublic void run () {message MSG = new message (); MSG. what = 1; // start the download mark 1handler. sendmessage (MSG); httpdownloader HTTP = new httpdownloader (); STR = http. download ("http://m.weather.com. CN/data/101010100.html "); MSG = new message (); // This is required; otherwise, an error is returned. Because MSG. What is generally final type MSG. What = 2; handler. sendmessage (MSG );}}}

The layout file is not pasted, mainly a button and a button. Paste the Download text class

Package COM. example. demodownload; import Java. io. bufferedreader; import Java. io. ioexception; import Java. io. inputstreamreader; import java.net. httpurlconnection; import java.net. URL; public class httpdownloader {// download the file based on the URL, provided that the content in the file is text, and the return value of the function is the content in the text. // 1. create a URL object // 2. create an httpurlconnection object through a URL object // 3. obtain inputstream // 4. read Private URL from inputstream; Public String download (string urlstr) {strin Gbuffer sb = new stringbuffer (); string line = NULL; bufferedreader buffer = NULL; try {url = new URL (urlstr); httpurlconnection urlconn = (httpurlconnection) URL. openconnection (); buffer = new bufferedreader (New inputstreamreader (urlconn. getinputstream (); While (line = buffer. readline ())! = NULL) {sb. append (line) ;}} catch (exception e) {e. printstacktrace () ;}finally {try {If (buffer! = NULL) {buffer. close () ;}else {return "error" ;}} catch (ioexception e) {e. printstacktrace () ;}} return sb. tostring ();}}

By the way, do not forget to configure network permissions.

What surprised me is that the manifest. xml file is written correctly.

    <uses-sdk android:minSdkVersion="8" />    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />    <uses-permission android:name="android.permission.READ_PHONE_STATE" />    <uses-permission android:name="android.permission.INTERNET" />

If it is written as below, an error will be reported because the buffer is empty during the download. If you have searched the internet for a long time and do not know what is going on, which of the following knows what is going on, you can leave a message. Thank you first.

  <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="15" />    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />    <uses-permission android:name="android.permission.READ_PHONE_STATE" />    <uses-permission android:name="android.permission.INTERNET" />

Now, when you download a file or parse network resources, you can give the user a friendly interactive interface to wait. Of course, you can set the download process. This progressbar is just a prompt, there is no progress. You can use another progressbar to kindly prompt the download progress. I will post it later.