我正在尝试将融合的经度/经度坐标转换为街道地址，根据教程here.
一切都很好，直到这一行（线在最后）：
（new GetAddressTask（this））。execute（mLocation）;
它说的是什么
"The constructor LocationServices.GetAddressTask(LocationServices.GetAddressTask) is undefined."
我一般都是Java编程/ Android的新手，所以如果你能帮助我用非常棒的语言来帮助我。 这是代码：
import java.io.IOException;
import java.util.List;
import java.util.Locale;
import android.content.Context;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.View;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient;
import com.google.android.gms.location.LocationClient;
public class LocationServices extends FragmentActivity implements
GooglePlayServicesClient.ConnectionCallbacks,
GooglePlayServicesClient.OnConnectionFailedListener {
private LocationClient mLocationClient;
Location mCurrentLocation;
private TextView mAddress;
private ProgressBar mActivityIndicator;
/*
* Called by Location Services when the request to connect the
* client finishes successfully. At this point, you can
* request the current location or start periodic updates
*/
@Override
public void onConnected(Bundle dataBundle) {
// Display the connection status
mCurrentLocation = mLocationClient.getLastLocation();
Toast.makeText(this, "Your location is " + mCurrentLocation, Toast.LENGTH_LONG).show();
}
/*
* Called by Location Services if the connection to the
* location client drops because of an error.
*/
@Override
public void onDisconnected() {
// Display the connection status
Toast.makeText(this, "Disconnected. Please re-connect.",
Toast.LENGTH_SHORT).show();
}
@Override
public void onConnectionFailed(ConnectionResult arg0) {
// TODO Auto-generated method stub
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_location_services);
/*
* Create a new location client, using the enclosing class to
* handle callbacks.
*/
mLocationClient = new LocationClient(this, this, this);
mAddress = (TextView) findViewById(R.id.address);
mActivityIndicator = (ProgressBar) findViewById(R.id.address_progress);
}
/*
* Called when the Activity becomes visible.
*/
@Override
protected void onStart() {
super.onStart();
// Connect the client.
mLocationClient.connect();
}
/*
* Called when the Activity is no longer visible.
*/
@Override
protected void onStop() {
// Disconnecting the client invalidates it.
mLocationClient.disconnect();
super.onStop();
}
//////////////////////////////////////////////////////////////////////////////////////////////
/**
* A subclass of AsyncTask that calls getFromLocation() in the
* background. The class definition has these generic types:
* Location - A Location object containing
* the current location.
* Void - indicates that progress units are not used
* String - An address passed to onPostExecute()
*/
private class GetAddressTask extends
AsyncTask<Location, Void, String> {
Context mContext;
public GetAddressTask(Context context) {
super();
mContext = context;
}
/**
* Get a Geocoder instance, get the latitude and longitude
* look up the address, and return it
*
* @params params One or more Location objects
* @return A string containing the address of the current
* location, or an empty string if no address can be found,
* or an error message
*/
@Override
protected String doInBackground(Location...params) {
Geocoder geocoder =
new Geocoder(mContext, Locale.getDefault());
// Get the current location from the input parameter list
Location loc = params[0];
// Create a list to contain the result address
List<Address> addresses = null;
try {
/*
* Return 1 address.
*/
addresses = geocoder.getFromLocation(loc.getLatitude(),
loc.getLongitude(), 1);
} catch (IOException e1) {
Log.e("LocationSampleActivity",
"IO Exception in getFromLocation()");
e1.printStackTrace();
return ("IO Exception trying to get address");
} catch (IllegalArgumentException e2) {
// Error message to post in the log
String errorString = "Illegal arguments " +
Double.toString(loc.getLatitude()) +
" , " +
Double.toString(loc.getLongitude()) +
" passed to address service";
Log.e("LocationSampleActivity", errorString);
e2.printStackTrace();
return errorString;
}
// If the reverse geocode returned an address
if (addresses != null && addresses.size() > 0) {
// Get the first address
Address address = addresses.get(0);
/*
* Format the first line of address (if available),
* city, and country name.
*/
String addressText = String.format(
"%s, %s, %s",
// If there's a street address, add it
address.getMaxAddressLineIndex() > 0 ?
address.getAddressLine(0) : "",
// Locality is usually a city
address.getLocality(),
// The country of the address
address.getCountryName());
// Return the text
return addressText;
} else {
return "No address found";
}
}
/**
* A method that's called once doInBackground() completes. Turn
* off the indeterminate activity indicator and set
* the text of the UI element that shows the address. If the
* lookup failed, display the error message.
*/
protected void onPostExecute (String address) {
// Set activity indicator visibility to "gone"
mActivityIndicator.setVisibility(View.GONE);
// Display the results of the lookup.
mAddress.setText(address);
}
public void getAddress(View v) {
// Ensure that a Geocoder services is available
mActivityIndicator.setVisibility(View.VISIBLE);
(new GetAddressTask(this)).execute(mLocation);
}
}
}
答案 0 :(得分：0)
因为this指向GetAddressTask对象而非Activity对象。
使用LocationServices.this之类的：
(new GetAddressTask(LocationServices.this)).execute(mLocation);