Question

我相对较新的Android并使用在线API。我有两个活动。第一个活动是显示搜索结果列表并将它们放入ListView。这不是问题。我正在尝试从此ListView中选择一个项目并将其传递给下一个活动，并使用所选项目中的信息在此新活动中填充另一个ListView。这就是问题所在。第二个活动永远不会加载。让第二项活动奏效的好方法是什么？我一直在做研究而没有得到预期的结果。下面是两个活动和帮助程序类的代码。谢谢

第一项活动

import helper.ArtistCalendarHelper;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import services.XMLParser;

import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;

public class ArtistsSearchActivity extends ListActivity {

public static final String TAG = "ArtistsSearchActivity";
public static final String INTENT_EXTRAS_XML = "XML";

static final String KEY_ARTISTS = "artist";
static final String KEY_ID = "id";
static final String KEY_DISPLAY_NAME = "displayName";
static final String KEY_URI = "uri";
static final String KEY_ON_TOUR_UNTIL = "onTourUntil";
String onTourUntil ;
String displayName;
String identification;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_artists_search);

    String xml = getIntent().getStringExtra(HomeActivity.INTENT_EXTRAS_XML);

    List<HashMap<String, String>> menuItems = new ArrayList<HashMap<String, String>>();

    addArtistsToHashmap(menuItems, xml);
    addItemsToList(menuItems);
}

private void addItemsToList(List<HashMap<String, String>> menuItems) {
    ListAdapter adapter = new SimpleAdapter(this, menuItems,
            R.layout.list_item_artist_search, new String[] { KEY_ID, KEY_DISPLAY_NAME,
                    KEY_URI, KEY_ON_TOUR_UNTIL }, new int[] { R.id.tvId,
                    R.id.tvDisplayName, R.id.tvUri, R.id.tvOnTourUntil });

    setListAdapter(adapter);
}

private void addArtistsToHashmap(List<HashMap<String, String>> menuItems,
        String xml) {
    XMLParser parser = new XMLParser();

    Document doc = parser.getDomElement(xml);

    NodeList nl = doc.getElementsByTagName(KEY_ARTISTS);
    for (int i = 0; i < nl.getLength(); i++) {
        HashMap<String, String> map = new HashMap<String, String>();
        Element e = (Element) nl.item(i);

        map.put(KEY_ID, e.getAttribute(KEY_ID));
        map.put(KEY_DISPLAY_NAME, e.getAttribute(KEY_DISPLAY_NAME));
        map.put(KEY_URI, e.getAttribute(KEY_URI));
        map.put(KEY_ON_TOUR_UNTIL, e.getAttribute(KEY_ON_TOUR_UNTIL));

        menuItems.add(map);
    }

// selecting single ListView item
        ListView lv = getListView();

        lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // getting values from selected ListItem
                displayName = ((TextView) view.findViewById(R.id.tvDisplayName)).getText().toString();
                onTourUntil = ((TextView) view.findViewById(R.id.tvOnTourUntil)).getText().toString();
                identification = ((TextView) view.findViewById(R.id.tvId)).getText().toString();

                new AsyncDownload().execute(identification);
            }
        });
}

private class AsyncDownload extends AsyncTask<String, String, String> {

    ProgressDialog pDialog;

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(ArtistsSearchActivity.this);
        pDialog.setMessage("Please Wait...");

        pDialog.setCancelable(false);
        pDialog.show();
    }

    @Override
    protected String doInBackground(String... params) {

        Log.v(TAG, "query is" +  params[0]);
        String result = new ArtistCalendarHelper().getXml(params[0]);
        return result;
    }

    @Override
    protected void onCancelled() {
        super.onCancelled();
        pDialog.dismiss();
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        pDialog.dismiss();
        Log.v(TAG, "result=" + result);
        Intent intent = new Intent();
        intent.setClass(ArtistsSearchActivity.this, SingleArtistActivity.class);
        intent.putExtra(KEY_DISPLAY_NAME, displayName);
        intent.putExtra(KEY_ID, identification);
        intent.putExtra(KEY_ON_TOUR_UNTIL, onTourUntil);
        intent.putExtra(INTENT_EXTRAS_XML, result);
        startActivity(intent);
    }
}
}

第二项活动

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import services.XMLParser;

import android.os.Bundle;
import android.app.Activity;
import android.app.ListActivity;
import android.content.Intent;
import android.widget.ListAdapter;
import android.widget.SimpleAdapter;
import android.widget.TextView;


public class SingleArtistActivity extends ListActivity {

public static final String TAG = "SingleArtistActivity";
public static final String INTENT_EXTRAS_XML = "XML";

static final String KEY_VENUE = "event";
static final String KEY_VENUE_NAME = "displayName";

    static final String KEY_DISPLAY_NAME = "displayName";
    static final String KEY_ON_TOUR_UNTIL = "onTourUntil";
    static final String KEY_ID = "id";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_single_artist);

        // getting intent data
        Intent in = getIntent();

        // Get XML values from previous intent
        String displayName = in.getStringExtra(KEY_DISPLAY_NAME);
        String onTourUntil = in.getStringExtra(KEY_ON_TOUR_UNTIL);
        String id = in.getStringExtra(KEY_ID);

        // Displaying all values on the screen
        TextView lblDisplayName = (TextView) findViewById(R.id.display_name_label);
        TextView lblOnTourUntil = (TextView) findViewById(R.id.on_tour_until_label);
        TextView lblID = (TextView) findViewById(R.id.id_label);

        lblDisplayName.setText(displayName);
        lblOnTourUntil.setText(onTourUntil);
        lblID.setText(id);

        String xml = getIntent().getStringExtra(HomeActivity.INTENT_EXTRAS_XML);

        List<HashMap<String, String>> menuItems = new ArrayList<HashMap<String, String>>();


        addItemsToList(menuItems);   
        addCalendarToHashmap(menuItems, xml);
    }

    private void addItemsToList(List<HashMap<String, String>> menuItems) {
        ListAdapter adapter = new SimpleAdapter(this, menuItems,
                R.layout.list_item_artist_calendar, new String[] { KEY_VENUE_NAME }, new int[] { R.id.calendarDisplayName });

        setListAdapter(adapter);
    }

    private void addCalendarToHashmap(List<HashMap<String, String>> menuItems,
            String xml) {
        XMLParser parser = new XMLParser();

        Document doc = parser.getDomElement(xml);

        NodeList nl = doc.getElementsByTagName(KEY_VENUE);
        for (int i = 0; i < nl.getLength(); i++) {
            HashMap<String, String> map = new HashMap<String, String>();
            Element e = (Element) nl.item(i);

            map.put(KEY_VENUE_NAME, e.getAttribute(KEY_VENUE_NAME));

            menuItems.add(map);
        }
    }
}

我的助手班

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import android.util.Log;

public class LocationCalendarHelper {
private static final String TAG = "LocationCalendarHelper";
private static final String SONGKICK_URL = "http://api.songkick.com/api/3.0/metro_areas/";
private static final String API_KEY = "yIekMi1hQzcFheKc";

public String getXml(String searchQuery) {

    HttpClient httpclient = new DefaultHttpClient();

    String getParameters = "";
    try {
        getParameters =  URLEncoder.encode(searchQuery, "UTF-8")
                + "/calendar.xml?apikey=" + URLEncoder.encode(API_KEY, "UTF-8");
    } catch (UnsupportedEncodingException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }

    String url = SONGKICK_URL + getParameters;
    // Prepare a request object
    HttpGet httpget = new HttpGet(url);

    // Execute the request
    HttpResponse response;
    try {
        response = httpclient.execute(httpget);
        // Examine the response status
        Log.i(TAG, response.getStatusLine().toString());

        // Get hold of the response entity
        HttpEntity entity = response.getEntity();
        // If the response does not enclose an entity, there is no need
        // to worry about connection release

        if (entity != null) {

            // A Simple JSON Response Read
            InputStream instream = entity.getContent();
            String result = convertStreamToString(instream);

            // now you have the string representation of the HTML request
            instream.close();
            return result;
        }

    } catch (Exception e) {

        e.printStackTrace();
        return null;
    }
    return null;
}

private static String convertStreamToString(InputStream is) {

    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb = new StringBuilder();

    String line = null;
    try {
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return sb.toString();
}

}

我的日志cat错误。它以一堆xml开头，因此活动将提取信息然后以错误结束

05-10 07:09:41.587: V/ArtistsSearchActivity(796):           <identifier mbid="eb558587-e7a1-4f2b-9fda-b6ff5e137ed1" href="http://api.songkick.com/api/3.0/artists/mbid:eb558587-e7a1-4f2b-9fda-b6ff5e137ed1.xml"/>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):         </artist>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):       </performance>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):       <performance billingIndex="3" displayName="Love And Death" billing="support" id="32720419">
05-10 07:09:41.587: V/ArtistsSearchActivity(796):         <artist displayName="Love And Death" uri="http://www.songkick.com/artists/286472-love-and-death?utm_source=19089&amp;utm_medium=partner" id="286472">
05-10 07:09:41.587: V/ArtistsSearchActivity(796):           <identifier mbid="27796970-8f7a-4196-9f7d-87f091af4412" href="http://api.songkick.com/api/3.0/artists/mbid:27796970-8f7a-4196-9f7d-87f091af4412.xml"/>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):           <identifier mbid="c29b667e-9895-41d2-b5a5-1817050ce0bc" href="http://api.songkick.com/api/3.0/artists/mbid:c29b667e-9895-41d2-b5a5-1817050ce0bc.xml"/>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):         </artist>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):       </performance>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):       <venue displayName="Rostraver Ice Garden Arena" lat="40.1981235" lng="-79.8294916" uri="http://www.songkick.com/venues/51599-rostraver-ice-garden-arena?utm_source=19089&amp;utm_medium=partner" id="51599">
05-10 07:09:41.587: V/ArtistsSearchActivity(796):         <metroArea displayName="Belle Vernon" uri="http://www.songkick.com/metro_areas/56020-us-belle-vernon?utm_source=19089&amp;utm_medium=partner" id="56020">
05-10 07:09:41.587: V/ArtistsSearchActivity(796):           <state displayName="PA"/>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):           <country displayName="US"/>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):         </metroArea>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):       </venue>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):       <start time="19:30:00" datetime="2013-05-15T19:30:00-0500" date="2013-05-15"/>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):       <location lat="40.1981235" lng="-79.8294916" city="Belle Vernon, PA, US"/>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):     </event>
05-10 07:09:41.587: V/ArtistsSearchActivity(796):     <event type="Festival" status="ok" displayName="Rock on the Range 2013" uri="http://www.songkick.com/festivals/8261/id/14745014-rock-on-the-range-2013?utm_source=19089&amp;utm_medium=partner" popularity="0
05-10 07:09:41.637: I/Choreographer(796): Skipped 49 frames!  The application may be doing too much work on its main thread.
05-10 07:09:43.807: E/Trace(871): error opening trace file: No such file or directory (2)
05-10 07:09:45.357: E/Trace(910): error opening trace file: No such file or directory (2)
05-10 07:09:45.687: E/Trace(923): error opening trace file: No such file or directory (2)
05-10 07:09:46.307: E/Trace(936): error opening trace file: No such file or directory (2)
05-10 07:09:47.167: E/Trace(949): error opening trace file: No such file or directory (2)
05-10 07:09:48.337: E/Trace(975): error opening trace file: No such file or directory (2)

我有更新。上面的代码有效！我将把它留给那些需要它的人。我遇到的问题是，如果xml字符串太长，搜索会超时。那么如何让Android有更多时间进行搜索？

Answer 1

  private void addItemsToList(List<HashMap<String, String>> menuItems) {
       ListAdapter adapter = new SimpleAdapter(this, menuItems,
            R.layout.list_item_artist_calendar, new String[] { KEY_VENUE_NAME }, new  int[] { R.id.calendarDisplayName });

       setListAdapter(adapter);
       adapter.notifyDataSetChanged();


  }

Android - 多级列表视图

1 个答案: