如何从线程返回值

Question

我在一个新线程（实现可运行的类，如下所示）中拉入一个 rss 提要，我想使用从 rss 提要中获得的字符串并将它们返回给主类。主类只是像这样运行线程

new Thread(new RssParse()).start();

我很难找到将这些从 xml 中剪切出来的字符串返回给主类的方法。感谢任何帮助。

public class RssParse implements Runnable  {

            private static final String MY_DEBUG_TAG = "pfaff";


            public void run(){

            System.out.println("1");
            URL iotd;
            try{

                iotd = new URL("http://www.nasa.gov/rss/image_of_the_day.rss");//set URl
                BufferedReader in;//new BufferedReader
                in = new BufferedReader(new InputStreamReader(iotd.openStream()));//get rss

                XmlPullParserFactory factory;
                factory = XmlPullParserFactory.newInstance();//new factory


                factory.setNamespaceAware(true);
                XmlPullParser xpp;
                xpp = factory.newPullParser();
                xpp.setInput(in);


                int eventType;
                eventType = xpp.getEventType();

                System.out.println(eventType+"!!!!!!!!!!!!!!!!");

            while(eventType!=XmlPullParser.END_DOCUMENT){

                switch(eventType){

                case XmlPullParser.START_DOCUMENT:
                    break;
                case XmlPullParser.START_TAG:
                    String tagName=xpp.getName();
                    System.out.println(tagName+" "+xpp.getDepth());
                    if(tagName.equals("title")&& xpp.getDepth()==4){//depth is specific to this certain rss feed, there are multiple tags with the same names
                        String title=xpp.nextText();// I want to return title and a few other strings but can't figure out how to do this when dealing with threads.
                        System.out.println(title);
                    }

                    break;

                }
                eventType=xpp.next();
            }//switch


                in.close();//close BufferedReader
            } catch (MalformedURLException e){
                e.printStackTrace();
            }catch(XmlPullParserException e1){
                e1.printStackTrace();
            }catch(IOException e2){
                e2.printStackTrace();
            }           
      }//method


}//class

Answer 1

我想推荐AsyncTask。您必须在子类中覆盖 AsyncTask 的 doInBackground(Params...) 和 onPostExecute(Result)。

教程：Android Threads, Handlers and AsyncTask - Tutorial

Answer 2

您可以使用处理程序将其发布到主线程

 Runnable runnable = new Runnable() 
 {
  @Override
  public void run() {
   for (int i = 0; i <= 10; i++) {
    handler.post(new Runnable() {
        @Override
            public void run() {
                progress.setProgress(value);
            }
        });
    }
}

};