问题
I am trying to parse rss feed in honeycomb 3.0 but it gives error as follows.
ERROR/AndroidNews::PullFeedParser(444): android.os.NetworkOnMainThreadException
I tried same code in android lower version it works but it doesn't work in Honeycomb. Please suggest some help
This is in main activity
try{
FeedParser parser = new XmlPullFeedParser(feedUrl);
messages = parser.parse();
titles = new ArrayList<String>(messages.size());
String description ="";//= new ArrayList<String>(messages.size());
for (Message msg : messages){
description = msg.getDescription().toString();
Log.v("Desc", description);
titles.add(description);
}
} catch (Throwable t){
Log.e("AndroidNews",t.getMessage(),t);
}
I am using XmlPullFeedParser which extends BaseFeedParser
public class XmlPullFeedParser extends BaseFeedParser {
public XmlPullFeedParser(String feedUrl) {
super(feedUrl);
}
public List<Message> parse() {
List<Message> messages = null;
XmlPullParser parser = Xml.newPullParser();
try {
// auto-detect the encoding from the stream
parser.setInput(this.getInputStream(), null);
int eventType = parser.getEventType();
Message currentMessage = null;
boolean done = false;
while (eventType != XmlPullParser.END_DOCUMENT && !done){
String name = null;
switch (eventType){
case XmlPullParser.START_DOCUMENT:
messages = new ArrayList<Message>();
break;
case XmlPullParser.START_TAG:
name = parser.getName();
if (name.equalsIgnoreCase(ITEM)){
currentMessage = new Message();
} else if (currentMessage != null){
if (name.equalsIgnoreCase(LINK)){
currentMessage.setLink(parser.nextText());
} else if (name.equalsIgnoreCase(DESCRIPTION)){
currentMessage.setDescription(parser.nextText());
} else if (name.equalsIgnoreCase(PUB_DATE)){
currentMessage.setDate(parser.nextText());
} else if (name.equalsIgnoreCase(TITLE)){
currentMessage.setTitle(parser.nextText());
}
}
break;
case XmlPullParser.END_TAG:
name = parser.getName();
if (name.equalsIgnoreCase(ITEM) && currentMessage != null){
messages.add(currentMessage);
} else if (name.equalsIgnoreCase(CHANNEL)){
done = true;
}
break;
}
eventType = parser.next();
}
} catch (Exception e) {
Log.e("AndroidNews::PullFeedParser", e.getMessage(), e);
throw new RuntimeException(e);
}
return messages;
}
}
This is BaseFeedParser:
public class BaseFeedParser implements FeedParser {
// names of the XML tags
static final String CHANNEL = "channel";
static final String PUB_DATE = "pubDate";
static final String DESCRIPTION = "description";
static final String LINK = "link";
static final String TITLE = "title";
static final String ITEM = "item";
static final String BODY = "body";
private final URL feedUrl;
protected BaseFeedParser(String feedUrl){
try {
this.feedUrl = new URL(feedUrl);
} catch (MalformedURLException e) {
throw new RuntimeException(e);
}
}
protected InputStream getInputStream() {
try {
return feedUrl.openConnection().getInputStream();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public List<Message> parse() {
// TODO Auto-generated method stub
return null;
}
}
This is FeedParser:
public interface FeedParser {
List<Message> parse();
}
This is message class:
public class Message implements Comparable<Message>{
static SimpleDateFormat FORMATTER =
new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z");
private String title;
private URL link;
private String description;
private Date date;
private String body;
public String getTitle() {
return title;
}
public String getBody() {
return body;
}
public void setTitle(String title) {
this.title = title.trim();
}
// getters and setters omitted for brevity
public URL getLink() {
return link;
}
public void setLink(String link) {
try {
this.link = new URL(link);
} catch (MalformedURLException e) {
throw new RuntimeException(e);
}
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description.trim();
}
public String getDate() {
return FORMATTER.format(this.date);
}
public void setDate(String date) {
// pad the date if necessary
while (!date.endsWith("00")){
date += "0";
}
try {
this.date = FORMATTER.parse(date.trim());
} catch (ParseException e) {
throw new RuntimeException(e);
}
}
public Message copy(){
Message copy = new Message();
copy.title = title;
copy.link = link;
copy.description = description;
copy.date = date;
copy.body = body;
return copy;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("Title: ");
sb.append(title);
sb.append("Body: ");
sb.append(body);
sb.append('\n');
sb.append("Date: ");
sb.append(this.getDate());
sb.append('\n');
sb.append("Link: ");
sb.append(link);
sb.append('\n');
sb.append("Description: ");
sb.append(description);
return sb.toString();
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((date == null) ? 0 : date.hashCode());
result = prime * result
+ ((description == null) ? 0 : description.hashCode());
result = prime * result + ((link == null) ? 0 : link.hashCode());
result = prime * result + ((title == null) ? 0 : title.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Message other = (Message) obj;
if (date == null) {
if (other.date != null)
return false;
} else if (!date.equals(other.date))
return false;
if (description == null) {
if (other.description != null)
return false;
} else if (!description.equals(other.description))
return false;
if (link == null) {
if (other.link != null)
return false;
} else if (!link.equals(other.link))
return false;
if (title == null) {
if (other.title != null)
return false;
} else if (!title.equals(other.title)){
return false;
} else if (!body.equals(other.body))
return false;
return true;
}
public int compareTo(Message another) {
if (another == null) return 1;
// sort descending, most recent first
return another.date.compareTo(date);
}
}
回答1:
The error message here pretty much tells you what is going on -- you are trying to access the network on tthe main thread. You really shouldn't do that on any version of android, because it can (read: will) cause your UI to hang while the connection is processing.
There are ways to turn the error off, but I won't get into tthem: you shouodnt do it.
instead, you want to do this work in aa background thread and post a minimal handler back to the UI thread. I don't have an example handy (on my tablet now) but let me know if you cannot find one.
..edit.. OK, here's a simple example. This requires an activity with a text view (id "text") and, of course, INTERNET permissions. Let me know if you have any questions!
public class MainActivity extends Activity {
private TextView mTextView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mTextView = (TextView) findViewById(R.id.text);
// start our call in a new thread
(new Thread(new Runnable() {
@Override
public void run() {
fetchPage();
}
})).start();
}
private void fetchPage() {
try {
URL url = new URL("http://stackoverflow.com/feeds");
HttpURLConnection c = (HttpURLConnection) url.openConnection();
c.setRequestMethod("GET");
c.setDoOutput(true);
c.connect();
ByteArrayOutputStream bos = new ByteArrayOutputStream();
InputStream is = c.getInputStream();
byte[] buffer = new byte[1024];
int len1 = 0;
while ((len1 = is.read(buffer)) != -1) {
bos.write(buffer, 0, len1);
}
bos.close();
is.close();
// Remember, all UI things must occur back on the UI thread!
final String text = bos.toString();
this.runOnUiThread(new Runnable() {
@Override
public void run() {
mTextView.setText(text);
}
});
} catch (final IOException ioe) {
this.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this, ioe.getMessage(), Toast.LENGTH_LONG).show();
}
});
}
}
thanks, --randy
来源:https://stackoverflow.com/questions/6275681/android-3-0-honeycomb-problem-in-parsing-rss-feed