我目前正在使用 XMLPullParser 来解析来自火车站 API 的页面。我正在使用 Async 任务执行此操作，以跟上较新版本的 android。
目前我已将 XML 字符串硬编码到类中，结果显示在列表视图中。
但是，我无法附加 baseURL 以将用户输入的查询添加到它的末尾。在使用以下代码使用异步任务之前，我没有遇到任何问题：
public void StationDetails(){
//--- Search button ---
Button btnSearch = (Button) findViewById(R.id.btnSearch);
btnSearch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//--- EditText View ---
EditText input = (EditText) findViewById(R.id.inputStation);
StringBuilder URL = new StringBuilder(baseURL);
URL.append(input);
String fullURL = URL.toString();
}
});
}
但我无法将其与异步方法联系起来。我似乎在网上找不到任何东西，非常感谢任何人在这件事上的帮助。
这是带有硬编码字符串的类：
public class Realtime extends Activity {
// Irish Rail Site URL
private static final String baseURL = "http://api.irishrail.ie/realtime/realtime.asmx/getStationDataByNameXML?StationDesc=Malahide";
// XML TAG Name
private static final String TAG_ITEM = "objStationData";
private static final String TAG_ORIGIN = "Origin";
private static final String TAG_DEST = "Destination";
private static final String TAG_SCHARR = "Scharrival";
private static final String TAG_EXPARR = "Exparrival";
private static final String TAG_DIRECT = "Direction";
private static final String TAG_STAT = "Status";
private static final String TAG_TRAINTYPE = "Traintype";
private RealtimeListviewAdapter mAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.stations_realtime_layout);
ListView listView = (ListView) findViewById(R.id.listview);
mAdapter = new RealtimeListviewAdapter(this);
// set adapter
listView.setAdapter(mAdapter);
// use AsyncTask to parse the URL data
ParseTask task = new ParseTask(this);
task.execute(baseURL);
// --- Register the list view for long press menu options
registerForContextMenu(listView);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private class ParseTask extends
AsyncTask<String, Void, ArrayList<StationDetails>> {
private ProgressDialog dialog;
public ParseTask(Context c) {
dialog = new ProgressDialog(c);
}
@Override
protected void onPreExecute() {
dialog.setMessage("Loading Station Info...");
dialog.show();
}
@Override
protected ArrayList<StationDetails> doInBackground(String... params) {
String strUrl = params[0];
HttpURLConnection httpConnection = null;
InputStream is = null;
try {
URL url = new URL(strUrl);
httpConnection = (HttpURLConnection) url.openConnection();
httpConnection.setRequestMethod("GET");
httpConnection.setConnectTimeout(10000);
httpConnection.setReadTimeout(10000);
httpConnection.connect();
int responseCode = httpConnection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
is = httpConnection.getInputStream();
return parseNews(is);
}
} catch (Exception e) {
// TODO
} finally {
if (is != null) {
try {
is.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (httpConnection != null) {
httpConnection.disconnect();
httpConnection = null;
}
}
return null;
}
@Override
protected void onPostExecute(ArrayList<StationDetails> result) {
// set the result
mAdapter.setData(result);
// notify to refresh
mAdapter.notifyDataSetChanged();
// Close the progress dialog
if (dialog.isShowing()) {
dialog.dismiss();
}
}
}
private ArrayList<StationDetails> parseNews(InputStream in)
throws XmlPullParserException, IOException {
ArrayList<StationDetails> newsList = new ArrayList<StationDetails>();
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
XmlPullParser pullParser = factory.newPullParser();
pullParser.setInput(in, "UTF-8");
int eventType = pullParser.getEventType();
StationDetails item = null;
while (eventType != XmlPullParser.END_DOCUMENT) {
String tagName;
if (eventType == XmlPullParser.START_TAG) {
tagName = pullParser.getName();
if (tagName.equals(TAG_ITEM)) {
item = new StationDetails();
} else if (tagName.equals(TAG_ORIGIN)) {
if (item != null) {
item.mOrigin = pullParser.nextText();
}
} else if (tagName.equals(TAG_DEST)) {
if (item != null) {
item.mDestination = pullParser.nextText();
}
} else if (tagName.equals(TAG_SCHARR)) {
if (item != null) {
item.mSchArrival = pullParser.nextText();
}
} else if (tagName.equals(TAG_EXPARR)) {
if (item != null) {
item.mExpArrival = pullParser.nextText();
}
} else if (tagName.equals(TAG_DIRECT)) {
if (item != null) {
item.mDirection = pullParser.nextText();
}
} else if (tagName.equals(TAG_STAT)) {
if (item != null) {
item.mStatus = pullParser.nextText();
}
}
} else if (eventType == XmlPullParser.END_TAG) {
tagName = pullParser.getName();
if (tagName.equals(TAG_ITEM)) {
newsList.add(item);
item = null;
}
}
eventType = pullParser.next();
}
return newsList;
}
编辑更新
好的，我将 fullURL 的 stringbuilder 放在按钮的 onClickListener 中。现在我想要的是在单击按钮时执行任务。我将 parsetask 任务、.excute 等移到了这个 clickListener 中。然而，这给了我一个错误，说实时的 View.OnClickListener 是未定义的，我遵循快速修复，但是当运行 porject 时，我在 logcat 中得到一个错误，说不能转换为 android.content.Context。
这是快速修复后代码现在的样子的片段
searchBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Append user input to baseURL
StringBuilder URL = new StringBuilder(baseURL);
URL.append(userInput);
String fullURL = URL.toString();
// use AsyncTask to parse the URL data
ParseTask task = new ParseTask(this);
task.execute(fullURL);
}
});
public ParseTask(OnClickListener onClickListener) {
dialog = new ProgressDialog((Context) onClickListener);
}
和我的日志：
我仍然无法弄清楚这一点，任何人的帮助都会非常受欢迎