Question

i have maybe a stupid/strange question

i am new to android and java and i need some advice to understand the methods of android and how to use them

i have a main activity class that looks like this

extends  Activity implements OnClickListener{

     private static final String TAG = "ServicesDemo";
     public String myimageURL;
     private EditText Lyrics;
    private ImageView AlbumPic;
    private Button play,  stop;
    private TextView Artist, Song, Album, News, Lyric;
    private UpdateTimeTask m_updateTime;
    private Handler m_handler;
    Parser data;
    /** The delay in milliseconds between updates. */
    private final int DELAY = 20000;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Artist =(TextView)findViewById(R.id.tvArtist);
        Song  =(TextView)findViewById(R.id.tvSongTitle);
        Album =(TextView)findViewById(R.id.tvAlbum);
        play = (Button) findViewById(R.id.play);
        stop = (Button) findViewById(R.id.stop);
        Lyrics = (EditText) findViewById(R.id.tvLyrics);
        News = (TextView)findViewById(R.id.tvAnouncement);
        AlbumPic = (ImageView) findViewById(R.id.AlbumPic);



        play.setOnClickListener(this);
        stop.setOnClickListener(this);



        m_updateTime = new UpdateTimeTask();

        m_handler = new Handler();
        m_handler.post(m_updateTime);
    }

    private class UpdateTimeTask implements Runnable {
        public void run() {


            try {

                SAXParserFactory saxPF = SAXParserFactory.newInstance();
                SAXParser saxP = saxPF.newSAXParser();
                XMLReader xmlR = saxP.getXMLReader();


                URL url = new URL("http://www.mysite.com/AndroidTest.php"); 
                XMLHandler myXMLHandler = new XMLHandler();
                xmlR.setContentHandler(myXMLHandler);
                xmlR.parse(new InputSource(url.openStream()));

            } catch (Exception e) {
                System.out.println(e);
            }
            data = XMLHandler.data;



            for (int i = 0; i < data.getTitle().size(); i++) {

           Lyrics.setText(data.getLyric().get(i));
                 myimageURL = data.getPic().get(i);

            Song.setText("Title = "+data.getTitle().get(i));


            Artist.setText("Artist = "+data.getArtist().get(i));


            Album.setText("Album = "+data.getAlbum().get(i)); 






 }

 downloadFile(myimageURL );

}

Bitmap bmImg;
void downloadFile(String fileUrl) {
 URL myFileUrl = null;
 try {
    myFileUrl = new URL(fileUrl);
 } catch (MalformedURLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
 }
 try {
    HttpURLConnection conn = (HttpURLConnection) myFileUrl
          .openConnection();
    conn.setDoInput(true);
    conn.connect();
    InputStream is = conn.getInputStream();

    bmImg = BitmapFactory.decodeStream(is);
    AlbumPic.setImageBitmap(bmImg);
 } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
 }
 m_handler.postDelayed(m_updateTime, DELAY);
 AlbumPic.clearAnimation();
}

}

the code works ok

as you can see i use a timer and a service

the service code is written in a different class called “my_service”
the timer code is written in the main class

my question is should i put the timer code which i have now in the main class in a separate class for example “timer class”

and then call it from the main class just like i did for the for the service

or is it ok just like it is now

and because the xml is on a internet server should i use asynctask?

did i understood it right that the asynctask only runs once so if i use a asynctask i have to use it in combination with a timer to keep the UI updated

thanks

p.s. is a “thread” the same as a “class”

Answer 1

I’d leave the timer code it in there, unless you wanted to some major refactoring.

The reason for this being that you access a number of private members of your main activity in the UpdateTimeTask. Break this out into a separate file, and you will no longer have access to these members in their current state.

If you’re up for some refactoring, you might be able to make an AsyncTask work. They are used when you want to perform a single task (rather than something like polling), which you’re doing. If you find the AsyncTask to be causing problems, then use a handler to communicate with the UI.

Finally, threads are not the same as classes in Java. A class represents a set of characteristics and commands for a particular object, whereas a thread represents a path of execution. Class objects are the things that are used to perform actions, whereas threads are certain collections of actions.