3

我有一个地图视图，它确定 ASyncTask 中的用户位置，然后在地图上的某些位置添加一些标记。找到位置后，我似乎无法更新地图。在运行 onPostExecute 之前是否有任何可能的方法来等待找到该位置。我尝试在 MainMapView 类中包含位置侦听器而不使用 ASyncTask。这会更新地图，但会使地图变得非常缓慢和滞后。我认为这是因为每次找到新位置时地图都会更新。任何帮助深表感谢。

import android.os.Bundle;
import android.os.AsyncTask;
import android.os.Looper;
import android.util.Log;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;

import java.io.IOException;
import java.util.List;
import java.util.Locale;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapController;
import com.google.android.maps.Overlay;
import com.google.android.maps.OverlayItem;


public class MainMapView extends MapActivity{

    private Location currentLocation;
    private String serviceName;
    private MapController mapController;
    private List<Overlay> mapOverlays;
    private ItemizedOverlay itemizedoverlay;
    private LocationManager locationManager;
    private HealthCarePractice[] practices;

    @Override
    protected boolean isRouteDisplayed() {
        return false;
    }

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

        Bundle retItem = getIntent().getExtras();
        serviceName = retItem.getString("serviceName");
        //Log.e("This One", serviceName);

        MapView mapView = (MapView) findViewById(R.id.mapview);
        mapView.setBuiltInZoomControls(true);
        //mapView.setSatellite(true);
        mapController = mapView.getController(); 

        mapOverlays = mapView.getOverlays();
        Drawable drawable = this.getResources().getDrawable(R.drawable.androidmarker);
        itemizedoverlay = new ItemizedOverlay(drawable, this);

        Context context = this;

        MainMapViewTask task = new MainMapViewTask();
        task.execute(context);

    }

    public class MainMapViewTask extends AsyncTask<Context, Integer, Void>
    {
        Context localContext;

        @Override
        protected Void doInBackground(Context... params) {
            localContext = params[0];
            // Aquire a reference to the system Location Manager
            locationManager = (LocationManager) localContext.getSystemService(Context.LOCATION_SERVICE);

            // Define a listener that responds to location updates
            LocationListener locationListener = new LocationListener() {
                public void onLocationChanged(Location location) {
                    // Called when a new location is found by the network location provider.
                    if (location != null)
                    {
                        currentLocation = location;
                        locationManager.removeUpdates(this);
                        locationManager = null;
                        Geocoder geocoder = new Geocoder(MainMapView.this, Locale.getDefault());  

                        List<Address> list;

                        if(currentLocation == null)
                        {
                            Log.e("Message", "Location not found");
                        }else{
                            try {
                                list = geocoder.getFromLocation(
                                currentLocation.getLatitude(), currentLocation.getLongitude(), 1);
                                if (list != null && list.size() > 0) {
                                    android.location.Address address = list.get(0);
                                    //Log.e("Post Code", address.getPostalCode());
                                    String poCode = address.getPostalCode();
                                    if (poCode != null)
                                    {
                                        //Log.e("Post Code", address.getPostalCode());
                                        String searchString = buildSearchString(serviceName, poCode.replaceAll(" ", ""));
                                        //Log.e("posplit", poCode.split(" ")[0]);
                                        Log.e("Search String", searchString);
                                        RemoteData remoteData = new RemoteData("Location", searchString);
                                        practices = remoteData.getPractices();
                                    }
                                }
                            } catch (IOException e) {
                                e.printStackTrace();
                            }
                        }
                    }

                }

                public void onStatusChanged(String provider, int status, Bundle extras) {}

                public void onProviderEnabled(String provider) {}

                public void onProviderDisabled(String provider) {}
              };

            Looper.myLooper();
            Looper.prepare();
            locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            if(currentLocation != null)
            {
                GeoPoint currentPoint = new GeoPoint((int)(currentLocation.getLatitude()*1000000), (int)(currentLocation.getLongitude()*1000000));
                mapController.setCenter(currentPoint);
                mapController.setZoom(15);
                for(int i=0; i< practices.length; i++)
                {
                    int latitude = (int)(practices[i].getLatitude()*1000000);
                    int longitude = (int)(practices[i].getLongitude()*1000000);
                    currentPoint = new GeoPoint(latitude, longitude);
                    mapController.setCenter(currentPoint);
                    mapController.setZoom(15);
                    String[] addressLines = practices[i].getAddress().getAddressLines();
                    StringBuilder sb = new StringBuilder();
                    for(int y=0; y<addressLines.length; y++)
                    {
                        sb.append(addressLines[y]);
                        sb.append('\n');
                    }
                    sb.append(practices[i].getAddress().getPostcode());
                    sb.append('\n');
                    sb.append("Telephone: ");
                    sb.append(practices[i].getTelephone());
                    OverlayItem currentOverlayItem = new OverlayItem(currentPoint,practices[i].getTitle(),sb.toString());
                    itemizedoverlay.addOverlay(currentOverlayItem);
                    mapOverlays.add(itemizedoverlay);
                }
            }
        }

    }
}

作为更新，以下代码可以工作，但地图非常滞后，当用户尝试通过拖动到新位置来与地图交互时会出现延迟

import android.os.Bundle;
import android.os.AsyncTask;
import android.os.Looper;
import android.util.Log;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;

import java.io.IOException;
import java.util.List;
import java.util.Locale;


import android.content.Context;
import android.graphics.drawable.Drawable;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapController;
import com.google.android.maps.Overlay;
import com.google.android.maps.OverlayItem;


public class MainMapView extends MapActivity{

    private Location currentLocation;
    private String serviceName;
    private MapController mapController;
    private List<Overlay> mapOverlays;
    private ItemizedOverlay itemizedoverlay;
    private LocationManager locationManager;
    private HealthCarePractice[] practices;
    private boolean mapDrawn = false;

    @Override
    protected boolean isRouteDisplayed() {
        return false;
    }

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

        Bundle retItem = getIntent().getExtras();
        serviceName = retItem.getString("serviceName");
        //Log.e("This One", serviceName);

        MapView mapView = (MapView) findViewById(R.id.mapview);
        mapView.setBuiltInZoomControls(true);
        //mapView.setSatellite(true);
        mapController = mapView.getController(); 

        mapOverlays = mapView.getOverlays();
        Drawable drawable = this.getResources().getDrawable(R.drawable.androidmarker);
        itemizedoverlay = new ItemizedOverlay(drawable, this);

        Context context = this;

        /*
        MainMapViewTask task = new MainMapViewTask();
        task.execute(context);
        */

        locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);

        // Define a listener that responds to location updates
        LocationListener locationListener = new LocationListener() {
            public void onLocationChanged(Location location) {
                // Called when a new location is found by the network location provider.
                if (location != null)
                {
                    currentLocation = location;
                    locationManager.removeUpdates(this);
                    locationManager = null;
                    Geocoder geocoder = new Geocoder(MainMapView.this, Locale.getDefault());  

                    List<Address> list;

                    if(currentLocation == null)
                    {
                        Log.e("Message", "Location not found");
                    }else{
                        try {
                            list = geocoder.getFromLocation(
                            currentLocation.getLatitude(), currentLocation.getLongitude(), 1);
                            if (list != null && list.size() > 0) {
                                android.location.Address address = list.get(0);
                                //Log.e("Post Code", address.getPostalCode());
                                String poCode = address.getPostalCode();
                                if (poCode != null)
                                {
                                    //Log.e("Post Code", address.getPostalCode());
                                    String searchString = buildSearchString(serviceName, poCode.replaceAll(" ", ""));
                                    //Log.e("posplit", poCode.split(" ")[0]);
                                    Log.e("Search String", searchString);
                                    RemoteData remoteData = new RemoteData("Location", searchString);
                                    practices = remoteData.getPractices();
                                    if(!mapDrawn)
                                    {
                                        mapDrawn = true;
                                        if(currentLocation != null)
                                        {
                                            GeoPoint currentPoint = new GeoPoint((int)(currentLocation.getLatitude()*1000000), (int)(currentLocation.getLongitude()*1000000));
                                            mapController.setCenter(currentPoint);
                                            mapController.setZoom(15);
                                            for(int i=0; i< practices.length; i++)
                                            {
                                                int latitude = (int)(practices[i].getLatitude()*1000000);
                                                int longitude = (int)(practices[i].getLongitude()*1000000);
                                                currentPoint = new GeoPoint(latitude, longitude);
                                                mapController.setCenter(currentPoint);
                                                mapController.setZoom(15);
                                                String[] addressLines = practices[i].getAddress().getAddressLines();
                                                StringBuilder sb = new StringBuilder();
                                                for(int y=0; y<addressLines.length; y++)
                                                {
                                                    sb.append(addressLines[y]);
                                                    sb.append('\n');
                                                }
                                                sb.append(practices[i].getAddress().getPostcode());
                                                sb.append('\n');
                                                sb.append("Telephone: ");
                                                sb.append(practices[i].getTelephone());
                                                OverlayItem currentOverlayItem = new OverlayItem(currentPoint,practices[i].getTitle(),sb.toString());
                                                itemizedoverlay.addOverlay(currentOverlayItem);
                                                mapOverlays.add(itemizedoverlay);
                                            }
                                        }
                                    }
                                }
                            }
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }

            }

            public void onStatusChanged(String provider, int status, Bundle extras) {}

            public void onProviderEnabled(String provider) {}

            public void onProviderDisabled(String provider) {}
          };

        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);

    }
4

1 回答 1

0

我只是注意到地图由于为每个标记创建了阴影而滞后，我不知道为什么会这样，但是使用 OverlayItem 类中的以下代码删除标记的阴影已经解决了我的问题。

@Override
public void draw(Canvas canvas, MapView mapView, boolean shadow)
{
    if(!shadow)
    {
        super.draw(canvas, mapView, false);
    }
}

必须注意的是，标记的阴影非常不合适。如果有人有解决方案来合并位于正确位置的阴影，请告诉我。问候库什

于 2012-05-25T23:45:24.420 回答