Question

所以，我已经为即将发布的新体育应用程序构建了一个Ok RSS阅读器。它将读取各种体育网站的提要并显示它们。我遇到的问题是，在需要互联网连接的活动开始时，Feed会立即加载。

如果互联网连接中断或存在延迟，应用有时会挂起和/或强制关闭我。我需要暂停屏幕，直到从各种XML Feed中提取了Feed内容。

当您点击新的新闻类别时，许多新闻应用和其他RSS阅读器都会这样做。你会得到一个动画“更新”或“加载”对话。这是我目前的代码。

public class MyActivity extends ListActivity implements OnClickListener {

    Button btn1;
    Button btn2;
    Button btn3;
    Button btn4;

    WebView webview;

    TextView feedTitle;
    TextView feedDescribtion;
    TextView feedPubdate;
    TextView feedLink;

private RSSFeed myRssFeed = null;

public class MyCustomAdapter extends ArrayAdapter<RSSItem> {

 public MyCustomAdapter(Context context, int textViewResourceId,
   List<RSSItem> list) {
  super(context, textViewResourceId, list);
 }

 @Override
 public View getView(int position, View convertView, ViewGroup parent) {
  // TODO Auto-generated method stub
  //return super.getView(position, convertView, parent);

  View row = convertView;

  if(row==null){
   LayoutInflater inflater=getLayoutInflater();
   row=inflater.inflate(R.layout.row, parent, false);
  }

  TextView listTitle=(TextView)row.findViewById(R.id.listtitle);
  listTitle.setText(myRssFeed.getList().get(position).getTitle());
  TextView listTitle2=(TextView)row.findViewById(R.id.listtitle2);
  listTitle2.setText(myRssFeed.getTitle());
  TextView listPubdate=(TextView)row.findViewById(R.id.listpubdate);
  String str = (myRssFeed.getList().get(position).getPubdate());


  SimpleDateFormat inputFormatter = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z"); //please notice the    capital M
  SimpleDateFormat outputFormatter = new SimpleDateFormat("MM/dd/yyyy");

  try {
      Date date = inputFormatter.parse(str);
      String text = outputFormatter.format(date);
      listPubdate.setText(text);
  } catch (ParseException e ) {
      e.printStackTrace();
  }


  return row;
 }
}

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

      btn1 = (Button) findViewById(R.id.hawknation_button);
      btn1.setOnClickListener(this);

      btn2 = (Button) findViewById(R.id.hawkcentral_button);
      btn2 .setOnClickListener(this);

      btn3 = (Button) findViewById(R.id.hawkeyesports_button);
      btn3 .setOnClickListener(this);

      espn = (Button) findViewById(R.id.espn_button);

      feedTitle = (TextView)findViewById(R.id.feedtitle);
      feedDescribtion = (TextView)findViewById(R.id.feeddescribtion);
      feedPubdate = (TextView)findViewById(R.id.feedpubDate);
      feedLink = (TextView)findViewById(R.id.feedlink);

           readRss();
       }

       private void readRss(){

      feedTitle.setText("--- wait ---");
      feedDescribtion.setText("");
      feedPubdate.setText("");
      feedLink.setText("");
      setListAdapter(null);

      Toast.makeText(this, "Reading RSS, Please wait.", Toast.LENGTH_LONG).show();


       try {
          URL rssUrl = new URL("http://www.sports.com/feed");
          SAXParserFactory mySAXParserFactory = SAXParserFactory.newInstance();
          SAXParser mySAXParser = mySAXParserFactory.newSAXParser();
          XMLReader myXMLReader = mySAXParser.getXMLReader();
          RSSHandler myRSSHandler = new RSSHandler();
          myXMLReader.setContentHandler(myRSSHandler);
          InputSource myInputSource = new InputSource(rssUrl.openStream());
          myXMLReader.parse(myInputSource);

          myRssFeed = myRSSHandler.getFeed();

         } catch (MalformedURLException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
         } catch (ParserConfigurationException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
         } catch (SAXException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
         } catch (IOException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
         }

         if (myRssFeed!=null)
         {
          TextView feedTitle = (TextView)findViewById(R.id.feedtitle);
          TextView feedDescribtion = (TextView)findViewById(R.id.feeddescribtion);
          TextView feedPubdate = (TextView)findViewById(R.id.feedpubDate);
          TextView feedLink = (TextView)findViewById(R.id.feedlink);
          feedTitle.setText(myRssFeed.getTitle());
          feedDescribtion.setText(myRssFeed.getDescription());
          feedPubdate.setText(myRssFeed.getPubdate());
          feedLink.setText(myRssFeed.getLink());

          MyCustomAdapter adapter =
           new MyCustomAdapter(this, R.layout.row, myRssFeed.getList());
          setListAdapter(adapter);
         }
         }       


@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
 // TODO Auto-generated method stub
 Intent intent = new Intent(this,HawkCentralDetails.class);
 Bundle bundle = new Bundle();
 bundle.putString("keyTitle", myRssFeed.getItem(position).getTitle());
 bundle.putString("keyDescription", myRssFeed.getItem(position).getDescription());
 bundle.putString("keyLink", myRssFeed.getItem(position).getLink());
 bundle.putString("keyPubdate", myRssFeed.getItem(position).getPubdate());
 intent.putExtras(bundle);
      startActivity(intent);
}

Answer 1

您应该尝试使用 AsyncTask ，这将有助于按照以下链接

http://developer.android.com/reference/android/os/AsyncTask.html

使用AsyncTask，您可以在后台加载数据，并在加载时显示，直到您可以显示ProgressDialog

Answer 2

你需要在单独的线程中调用readRSS（），因为oncreate会对时间进行限制。您可以使用线程来获取rs并通过将其放入UI线程或使用异步任务来更新UI

指 http://developer.android.com/resources/articles/painless-threading.html

Answer 3

您可以使用asynctask或使用以下代码使用消息队列来确保仅在从Web请求完全加载内容时向用户显示内容，并且由于其在单独的线程中运行，因此GUI不会暂停以及： InputSource myInputSource;

public void sampleFunction()
    {


        progressDialog = ProgressDialog.show(this, "", "Getting data...");
        new Thread() {
            public void run() {
                try {
                    //do the web request to get the feeds
                   myInputSource = new InputSource(rssUrl.openStream());
                }catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                messageHandler.sendEmptyMessage(0);
                //              messageHandler.sendEmptyMessage(0);
            }
        }.start();
    }
}


//inside the handler set the string array retrieved from the WS in sampleFunction to the adapter
private Handler messageHandler = new Handler() {

        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            //here write the code to parse the value stored in myInputSource 

        }
    };

Android：实施暂停，直到从网站提取RSS Feed

3 个答案: