【发布时间】：2015-08-15 13:20:42
【问题描述】：
我正在制作一个 Android 应用程序，我想在其中向用户显示他们的作者当天的随机报价。为此，我使用了他们所说的 Quote API。我正在尝试解析这个http://api.theysaidso.com/qod.xml 文件，以便我可以在我的代码中使用他们的作者当天的报价。但由于某种原因，我的 onPostExecute 中的结果参数为空。所以我猜 XML 没有正确解析，或者我没有在我的 ArrayList 中放入正确的值，这是 xmlParser.parse(inputStream) 方法的结果？或者是什么原因导致我的 ArrayList 结果仍然为空？
XML 解析器：
public class XMLParser {
private static final String ns = null;
public List parse(InputStream in) throws XmlPullParserException, IOException {
try {
XmlPullParser parser = Xml.newPullParser();
parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
parser.setInput(in, null);
parser.nextTag();
return readResponse(parser);
} finally {
in.close();
}
}
private List readResponse(XmlPullParser parser) throws XmlPullParserException, IOException {
List quotes = new ArrayList();
parser.require(XmlPullParser.START_TAG, ns, "response");
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
// Starts by looking for the entry tag
if (name.equals("quotes")) {
quotes.add(readEntry(parser));
} else {
skip(parser);
}
}
return quotes;
}
public static class Quote{
public final String quote;
public final String author;
private Quote(String quote, String author) {
this.quote = quote;
this.author = author;
}
}
// Parses the contents of an entry. If it encounters a title, summary, or link tag, hands them off
// to their respective "read" methods for processing. Otherwise, skips the tag.
private Quote readEntry(XmlPullParser parser) throws XmlPullParserException, IOException {
parser.require(XmlPullParser.START_TAG, ns, "quotes");
String quote = null;
String author = null;
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
if (name.equals("quote")) {
quote = readQuote(parser);
} else if (name.equals("author")) {
author = readAuthor(parser);
} else {
skip(parser);
}
}
return new Quote(quote, author);
}
// Processes quote tags in the feed.
private String readQuote(XmlPullParser parser) throws IOException, XmlPullParserException {
parser.require(XmlPullParser.START_TAG, ns, "quote");
String quote = readText(parser);
parser.require(XmlPullParser.END_TAG, ns, "quote");
return quote;
}
// Processes author tags in the feed.
private String readAuthor(XmlPullParser parser) throws IOException, XmlPullParserException {
parser.require(XmlPullParser.START_TAG, ns, "author");
String author = readText(parser);
parser.require(XmlPullParser.END_TAG, ns, "author");
return author;
}
// For the tags quote and author, extracts their text values.
private String readText(XmlPullParser parser) throws IOException, XmlPullParserException {
String result = "";
if (parser.next() == XmlPullParser.TEXT) {
result = parser.getText();
parser.nextTag();
}
return result;
}
private void skip(XmlPullParser parser) throws XmlPullParserException, IOException {
if (parser.getEventType() != XmlPullParser.START_TAG) {
throw new IllegalStateException();
}
int depth = 1;
while (depth != 0) {
switch (parser.next()) {
case XmlPullParser.END_TAG:
depth--;
break;
case XmlPullParser.START_TAG:
depth++;
break;
}
}
}
}
我的活动
String url="http://api.theysaidso.com/qod.xml";
setContentView(R.layout.activity_quotes);
new DownloadXML().execute(url);
private class DownloadXML extends AsyncTask<String,Void,ArrayList> {
@Override
protected ArrayList doInBackground(String... url) {
ArrayList lijstQuote = new ArrayList();
try {
InputStream inputStream = new URL(url[0]).openStream();
XMLParser xmlParser = new XMLParser();
lijstQuote =(ArrayList) xmlParser.parse(inputStream);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (XmlPullParserException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return lijstQuote;
}
protected void onPostExecute(ArrayList result) {
if (!result.isEmpty()) {
XMLParser.Quote contents = (XMLParser.Quote) result.get(0);
TextView quoteTekst = (TextView) findViewById(R.id.quote);
quoteTekst.setText(contents.quote);
TextView authorTekst = (TextView) findViewById(R.id.author);
authorTekst.setText(contents.author);
}
else
{
TextView quoteTekst = (TextView) findViewById(R.id.quote);
quoteTekst.setText(R.string.outOfQuotes);
TextView authorTekst = (TextView) findViewById(R.id.author);
authorTekst.setText(R.string.authorOutOfQuotes);
}
}
}
【问题讨论】：