我正在尝试实现RSS阅读器，但我不断收到RuntimeException。
这是我的.java文件的代码：
public class TopRatedFragment extends Fragment {
Context context;
ListView listView;
List<String> headlines;
List<String> links;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_top_rated,
container, false);
context = getActivity().getApplicationContext();
listView = (ListView) rootView.findViewById(R.id.list);
new RssFeed1().execute();
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapter, View view, int pos,
long id) {
Log.d("ListView", String.valueOf(pos));
Uri uri = Uri.parse((String) links.get(pos));
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);
}
});
return rootView;
}
private class RssFeed1 extends AsyncTask<Void, Void, List<String>> {
@Override
protected List<String> doInBackground(Void... params) {
// Initializing instance variables
headlines = new ArrayList<String>();
links = new ArrayList<String>();
try {
URL url = new URL("http://feeds.pcworld.com/pcworld/latestnews");
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
factory.setNamespaceAware(false);
XmlPullParser xpp = factory.newPullParser();
// We will get the XML from an input stream
xpp.setInput(getInputStream(url), "UTF_8");
/* We will parse the XML content looking for the "<title>" tag which appears inside the "<item>" tag.
* However, we should take in consideration that the rss feed name also is enclosed in a "<title>" tag.
* As we know, every feed begins with these lines: "<channel><title>Feed_Name</title>...."
* so we should skip the "<title>" tag which is a child of "<channel>" tag,
* and take in consideration only "<title>" tag which is a child of "<item>"
*
* In order to achieve this, we will make use of a boolean variable.
*/
boolean insideItem = false;
// Returns the type of current event: START_TAG, END_TAG, etc..
int eventType = xpp.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT) {
if (eventType == XmlPullParser.START_TAG) {
if (xpp.getName().equalsIgnoreCase("item")) {
insideItem = true;
} else if (xpp.getName().equalsIgnoreCase("title")) {
if (insideItem)
headlines.add(xpp.nextText()); //extract the headline
} else if (xpp.getName().equalsIgnoreCase("link")) {
if (insideItem)
links.add(xpp.nextText()); //extract the link of article
}
}else if(eventType==XmlPullParser.END_TAG && xpp.getName().equalsIgnoreCase("item")){
insideItem=false;
}
eventType = xpp.next(); //move to next element
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (XmlPullParserException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
// Binding data
// ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
// R.layout.fragment_top_rated, headlines);
return headlines;
// Populate list view with ArrayAdapter
// ListView listView = (ListView) findViewById(R.id.list);
// listView.setAdapter(adapter);
}
@Override
protected void onPostExecute(List<String> hList) {
if (hList == null) {
Log.v("MyTabNavigation", "hList is null");
} else {
ArrayAdapter<String> adapter = new ArrayAdapter<String>(
context, R.layout.top_rated_textview, hList);
listView.setAdapter(adapter);
}
}
public InputStream getInputStream(URL url) {
try {
return url.openConnection().getInputStream();
} catch (IOException e) {
return null;
}
}
}
}
这是我的堆栈跟踪：
08-12 06:20:54.470: E/AndroidRuntime(2925): FATAL EXCEPTION: AsyncTask #1
08-12 06:20:54.470: E/AndroidRuntime(2925): java.lang.RuntimeException: An error occured while executing doInBackground()
08-12 06:20:54.470: E/AndroidRuntime(2925): at android.os.AsyncTask$3.done(AsyncTask.java:299)
08-12 06:20:54.470: E/AndroidRuntime(2925): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
08-12 06:20:54.470: E/AndroidRuntime(2925): at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
08-12 06:20:54.470: E/AndroidRuntime(2925): at java.util.concurrent.FutureTask.run(FutureTask.java:239)
08-12 06:20:54.470: E/AndroidRuntime(2925): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
08-12 06:20:54.470: E/AndroidRuntime(2925): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
08-12 06:20:54.470: E/AndroidRuntime(2925): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
08-12 06:20:54.470: E/AndroidRuntime(2925): at java.lang.Thread.run(Thread.java:841)
08-12 06:20:54.470: E/AndroidRuntime(2925): Caused by: java.lang.IllegalArgumentException: is == null
08-12 06:20:54.470: E/AndroidRuntime(2925): at org.kxml2.io.KXmlParser.setInput(KXmlParser.java:1615)
08-12 06:20:54.470: E/AndroidRuntime(2925): at com.idsil.rssfeedsample.TopRatedFragment$RssFeed1.doInBackground(TopRatedFragment.java:78)
08-12 06:20:54.470: E/AndroidRuntime(2925): at com.idsil.rssfeedsample.TopRatedFragment$RssFeed1.doInBackground(TopRatedFragment.java:1)
08-12 06:20:54.470: E/AndroidRuntime(2925): at android.os.AsyncTask$2.call(AsyncTask.java:287)
08-12 06:20:54.470: E/AndroidRuntime(2925): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
08-12 06:20:54.470: E/AndroidRuntime(2925): ... 4 more
我使用了两个在网上找到的教程。 以下是链接：
这是使用ActionBar教程的UI链接：
http://www.androidhive.info/2013/10/android-tab-layout-with-swipeable-views-1/
这是RSS阅读器：
http://androidresearch.wordpress.com/2012/01/21/creating-a-simple-rss-application-in-android/
请非常感谢任何帮助。
谢谢。
答案 0 :(得分：0)
在我看来，这个问题是由连接错误引起的。网站已关闭，某些内容干扰了连接，或者您没有正确连接。
我建议使用此RSS库来简化操作： https://github.com/Pkmmte/PkRSS