我有一个地图视图，用于确定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等待找到该位置。我尝试在不使用ASyncTask的情况下在MainMapView类中包含位置监听器。这会更新地图，但会使地图变得非常缓慢且滞后。我认为这是因为每次找到新位置时地图都会更新。非常感谢任何帮助。
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，以下代码有效但地图非常滞后，当用户尝试通过拖动到新位置与地图交互时会有延迟
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);
}
答案 0 :(得分：0)
我刚注意到地图因为为每个标记创建了阴影而滞后，我不知道为什么会这样做，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。如果有人有一个解决方案，以纳入正确位置的阴影，请告诉我。关心库什