android - arraylist> 不工作

Question

我想知道，这两天我做错了什么。我启动以下 AsyncTask GetLocationsAsync.java 以将 HttpPost 发送到服务器上的 PHP 文件，

public class GetLocationsAsyncTask extends AsyncTask<Map<String, String>, Object, ArrayList<HashMap<String, String>>>
{
public static final String USER_CURRENT_LAT = "user_current_lat";
public static final String USER_CURRENT_LONG = "user_current_long";
public static final String USER_CURRENT_ADDRESS = "user_current_address";
private Exception exception;
private ProgressDialog progressDialog;
private Context MainContext;
private GoogleMap mMap;
private MapActivity activity;

public GetLocationsAsyncTask(MapActivity activity, Context con)
{
    super();
    this.activity = activity;
    this.MainContext = con;

}

public void onPreExecute()
{
    progressDialog = new ProgressDialog(MainContext);
    progressDialog.setMessage("Loading....");
    progressDialog.show();
}

@Override
public void onPostExecute(ArrayList<HashMap<String, String>> result)
{
    progressDialog.dismiss();
    if (exception == null)
    {
        activity.loadLocations(result);
    }
    else
    {
        processException();
    }
 }

@Override
protected ArrayList<HashMap<String, String>> doInBackground(Map<String, String>... params)
{
    Map<String, String> paramMap = params[0];
    try
    {
        double PLat = Double.valueOf(paramMap.get(USER_CURRENT_LAT));
        double PLong = Double.valueOf(paramMap.get(USER_CURRENT_LONG));
        String Addr = new String(paramMap.get(USER_CURRENT_ADDRESS));
        Locq5ionsParser Lp = new LocationsParser();
        Document doc = Pp.getDocument(Addr, PLat, PLong, "Bar");
        ArrayList<HashMap<String, String>>LocationPoints = Lp.getDirection(doc);
        return LocationPoints;
    }
    catch (Exception e)
    {
        exception = e;
        Log.d("GetLocations", e.getMessage());
        return null;
    }
 }

private void processException()
{
    Toast.makeText(MainContext, "Fehler beim Auslesen der XML", Toast.LENGTH_LONG).show();
    Log.d("GetLocationAsync", exception.getLocalizedMessage());
 }



}


public class LocationParser {
public LocationParser() {
}

public Document getDocument(String addr, double latitude, double longitude, String type) {
        String url = "http://**********/xmlphpshow.php";

 try {
     HttpClient httpClient = new DefaultHttpClient();
     HttpContext localContext = new BasicHttpContext();
     HttpPost httpPost = new HttpPost(url);
     ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>(4);
     postParameters.add(new BasicNameValuePair("Addresse", addr
             .toString()));
     postParameters.add(new BasicNameValuePair("latitude", String.valueOf(latitude)
             .toString()));
     postParameters.add(new BasicNameValuePair("longitude", String.valueOf(longitude)
             .toString()));
     postParameters.add(new BasicNameValuePair("type", "Bar"
             .toString()));
     httpPost.setEntity(new UrlEncodedFormEntity(postParameters));
     HttpResponse response = httpClient.execute(httpPost, localContext);
     InputStream in = response.getEntity().getContent();
     DocumentBuilder builder = DocumentBuilderFactory.newInstance()
                     .newDocumentBuilder();
     Document doc = builder.parse(in);
     return doc;
 } catch (Exception e) {
 Log.d("LocationParser", e.getMessage());
     e.printStackTrace();
     return null;
}

}


public ArrayList<HashMap<String, String>> getDirection(Document DirektDoc) {

ArrayList<HashMap<String, String>> LocationItems = new ArrayList<HashMap<String, String>>();
NodeList nl, nl2, nl3;
  // getting XML
 if (DirektDoc.equals(null)){
        Log.d("Dokument", "doc ist leer");
        return null;
     }
     try{
nl = DirektDoc.getElementsByTagName("marker");
     }catch(Exception e){
            Log.d("TagName Markers", e.getMessage());
            return null;
         }


// looping through all item nodes <item>
HashMap<String, String> map = new HashMap<String, String>();
for (int i = 0; i < nl.getLength(); i++) {
    // creating new HashMap
   try{ 
   Node node1  = nl.item(i);
   nl3 = node1.getChildNodes();
   Node AddrNode = nl3.item(getNodeIndex(nl3, "address"));
   String PAddr = AddrNode.getTextContent();

   //the Log shows that the addresses of each marker item was read correctly 
   Log.d("LocationParser","Adresse :" + PAddr);



   map.put("Addresse", PAddr);
   Node latNode = nl3.item(getNodeIndex(nl3, "lat"));
   String lat = latNode.getTextContent();
   map.put("latitude", lat);
   Node lngNode = nl3.item(getNodeIndex(nl3, "lng"));
   String lng = lngNode.getTextContent();
   map.put("longitude", lng);
   Node typeNode = nl3.item(getNodeIndex(nl3, "type"));
   String LocType = typeNode.getTextContent();
   map.put("Type", LocType);
   Node timeNode = nl3.item(getNodeIndex(nl3, "tstamp"));
   String timeString = timeNode.getTextContent();
   map.put("TimeStamp", timeString);


           LocationItems.add(map);
   }catch(Exception e){
       Log.d("LocationParser", e.getMessage());
   }
}

return LocationItems;
}


private int getNodeIndex(NodeList NodeInl, String nodename) {
for (int i = 0; i < NodeInl.getLength(); i++) {
     if (NodeInl.item(i).getNodeName().equals(nodename)){
         return i;
}

}
return -1;
}
}

当我现在尝试读取 ArrayList 中的 Hashmap 值并在我的 GoogleMap 上创建一个标记时，只有一个标记可见。

public class MapActivity {
public GoogleMap googleMap;
public MapFragment mapfrag;
public Context MapContext;
public Document dc;
public MarkerOptions startMarker, ParkMarker;
public MapActivity(MapFragment gmapfrag, Context con){
    this.mapfrag = gmapfrag;
    this.googleMap = mapfrag.getMap();
    this.MapContext = con;
}
 public void initilizeMap() {
        try {
            googleMap.clear();
            googleMap.getUiSettings().setRotateGesturesEnabled(true);
            googleMap.getUiSettings().setCompassEnabled(true);


            if (googleMap == null) {
                Toast.makeText(MapContext, "Karte konnte nicht erstellt werden. Versuchen 
            sie es zu einem Späteren Zeitpunkt erneut.", Toast.LENGTH_SHORT).show();
            }               
        }catch(Exception e){
            Toast.makeText(MapContext, "Karte konnte nicht erstellt werden. Versuchen 
       sie es zu einem Späteren Zeitpunkt erneut.", Toast.LENGTH_SHORT).show();
        }
        return;
    }
 public void loadMarkers(double Mylati, double Mylongi, String aDdR){
     googleMap.clear();
     startMarker = new MarkerOptions().position(new 
     LatLng(Mylati,Mylongi)).title("Aktuelle Position");
     startMarker.icon(BitmapDescriptorFactory.fromResource(R.drawable.start_icon));
     googleMap.addMarker(startMarker);
     Map<String, String> map = new HashMap<String, String>();
     map.put(GetLocationsAsyncTask.USER_CURRENT_LAT, String.valueOf(Mylati));
     map.put(GetLocationsAsyncTask.USER_CURRENT_LONG, String.valueOf(Mylongi));
     map.put(GetLocationsAsyncTask.USER_CURRENT_ADDRESS, String.valueOf(aDdR));
     GetLocationsAsyncTask asyncTask = new GetLocationsAsyncTask(this, MapContext);
     asyncTask.execute(map);
     //setCamView(Mylati, Mylongi);
     return;
 }
 public void loadLocations(ArrayList<HashMap<String, String>> directionPoints){
     for(int i = 0 ; i < directionPoints.size() ; i++){

         String LocAddress = directionPoints.get(i).get("Addresse");
         double LocLat = Double.parseDouble(directionPoints.get(i).get("latitude"));
         double LocLng =  
                     Double.parseDouble(directionPoints.get(i).get("longitude"));
         String LocType = directionPoints.get(i).get("Type");
         Log.d("MapActivit", "directionPoints.size beträgt: "+   
                     directionPoints.size() + LocAddress + String.valueOf(i));
         String LocTime = directionPoints.get(i).get("TimeStamp");


        googleMap.addMarker( new MarkerOptions().position(new LatLng(LocLat,LocLng)).icon(BitmapDescriptorFactory.fromResource(R.drawable.marker_icon)));
     }
     return;

 }
 public void setCamView(double camLat, double camLong){
     CameraPosition cameraPosition = new CameraPosition.Builder().target(
     new LatLng(camLat, camLong)).zoom(12).build();
     LatLng Startposition = new LatLng(camLat, camLong);
     googleMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
     return;
 }
    }

生成的 XML 文件如下所示:


<markers>
<marker>
<address>1908 Pike pl, Seattle, WA</address>
<lat>47.610126</lat>
<lng>-122.342834</lng>
<type>Bar</type>
<tstamp>2013-12-25 00:43:50</tstamp>
</marker>
<marker>
<address>1416 E Olive Way, Seattle, WA</address>
<lat>47.617214</lat>
<lng>-122.326584</lng>
<type>Bar</type>
<tstamp>2013-12-25 00:43:50</tstamp>
</marker>
<marker>
<address>2234 2nd Ave, Seattle, WA</address>
<lat>47.613976</lat>
<lng>-122.345467</lng>
<type>Restaurant</type>
<tstamp>2013-12-25 00:43:50</tstamp>
</marker>
<marker>
<address>1301 Alaskan Way, Seattle, WA</address>
<lat>47.605961</lat>
<lng>-122.340363</lng>
<type>Bar</type>
<tstamp>2013-12-25 00:43:50</tstamp>
</marker>
<marker>
<address>1225 1st Ave, Seattle, WA</address>
<lat>47.606365</lat>
<lng>-122.337654</lng>
<type>Bar</type>
<tstamp>2013-12-25 00:43:50</tstamp>
</marker>
</markers>

有人能帮帮我吗？我的代码有什么问题？

编辑:

问题在 gaurav5430 和 Ivan 的帮助下得以解决。请在下面查看他们的回答。

Answer 1

方法中

public ArrayList<HashMap<String, String>> getDirection(Document DirektDoc) {
....
HashMap<String, String> map = new HashMap<String, String>();
for (int i = 0; i < nl.getLength(); i++) {
// creating new HashMap
    try{ 

       ....

       LocationItems.add(map);
   }catch(Exception e){
       Log.d("LocationParser", e.getMessage());
   }
}

您始终操作一个 hashmap 实例并将该实例添加到 List 中。所以你需要像这样将 HashMap 的创建移动到循环中:

   public ArrayList<HashMap<String, String>> getDirection(Document DirektDoc) {
   ....

   for (int i = 0; i < nl.getLength(); i++) {
    HashMap<String, String> map = new HashMap<String, String>();
   // creating new HashMap
    try{ 

       ....

       LocationItems.add(map);
   }catch(Exception e){
       Log.d("LocationParser", e.getMessage());
   }