如何获得谷歌地图的屏幕中心位置？

Question

我想用静态标记创建一个地图，以便始终显示屏幕中心的位置。我在布局中创建了一个标记，中间有可绘制的图像。 现在我需要获取中心位置坐标并将它们转换为地址。然后在文本视图中显示所选位置作为我选择的位置。 需要帮助

Answer 1

您可以通过在GoogleMap变量实例上调用此函数随时获取地图的中心点

<?xml version="1.0" encoding="utf-8"?>
xmlns:i="http://www.w3.org/2001/XMLSchema-instance"

现在，如果你想在每次改变地图时获得中心点，那么你需要实现mMap.getCameraPosition().target 监听器并调用上面的行来获得新的中心点。

Answer 2

protected void userLocationMap() {

        mapFragment = ((SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map));
        googleMap = mapFragment.getMap();
        int status = GooglePlayServicesUtil
                .isGooglePlayServicesAvailable(getBaseContext());

        if (status != ConnectionResult.SUCCESS) { 
///if play services are not available
            int requestCode = 10;
            Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this,
                    requestCode);
            dialog.show();

        } else {

            // Enabling MyLocation Layer of Google Map
            googleMap.setMyLocationEnabled(true);

            // Creating a LatLng object for the current location
            LatLng latLng = new LatLng(latitude, longitude);
            // Showing the current location in Google Map
            googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
            // Zoom in the Google Map
            googleMap.animateCamera(CameraUpdateFactory.zoomTo(15));
            Log.i("latitude", "==========" + latitude);
////locationTextView holds the address string
            locationTextView.setText(getCompleteAdressString(latitude, longitude));

            // create marker
            MarkerOptions marker = new MarkerOptions().position(
                    new LatLng(latitude, longitude)).title("My Location");
            // adding marker
            googleMap.addMarker(marker);
        }
    }

并且getcompleteAdress方法是::::: ==＆gt;

private String getCompleteAddressString(double LATITUDE, double LONGITUDE) {

        String strAdd = "";

        Geocoder geocoder = new Geocoder(this, Locale.getDefault());
        try {
            List<Address> addresses = geocoder.getFromLocation(LATITUDE,
                    LONGITUDE, 1);

            if (addresses != null) {

                Address returnedAddress = addresses.get(0);

                StringBuilder strReturnedAddress = new StringBuilder("");

                for (int i = 0; i < returnedAddress.getMaxAddressLineIndex(); i++) {

                    strReturnedAddress
                            .append(returnedAddress.getAddressLine(i)).append(
                                    ",");
                }

                strAdd = strReturnedAddress.toString();

                Log.w("My Current loction address",
                        "" + strReturnedAddress.toString());
            } else {
                Log.w("My Current loction address", "No Address returned!");
            }
        } catch (Exception e) {
            e.printStackTrace();
            Log.w("My Current loction address", "Canont get Address!");
        }
        return strAdd;
    }

根据====＆gt;点击次数更改位置

 googleMap.setOnMapClickListener(new OnMapClickListener() {

            @Override
            public void onMapClick(LatLng point) {
                Log.d("Map","Map clicked");
                marker.remove();
                double latitude = latLng.latitude;
                double longitude = latLng.longitude;
locationTextView.setText(getCompleteAdressString(latitude,longitude ));
                drawMarker(point);
            }
        });

Answer 3

我已设法为我当前的位置创建地图。但它只给我位置的坐标一次，我需要在移动到其他位置时获取位置。发布我的代码

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

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnCameraChangeListener;
import com.google.android.gms.maps.GoogleMap.OnMapClickListener;
import com.google.android.gms.maps.GoogleMap.OnMapLongClickListener;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.CameraPosition;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.maps.GeoPoint;

import android.app.ActionBar;
import android.app.Activity;
import android.app.Dialog;
import android.graphics.Canvas;
import android.location.Address;
import android.location.Criteria;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;


public class MapLocation extends FragmentActivity implements LocationListener {

    GoogleMap googleMap;
    MarkerOptions markerOptions;
    LatLng latLng;

    ImageView icon;
    TextView selected;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_map);

        icon = (ImageView)findViewById(R.id.icon_baby);
        icon.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                finish();

            }
        });


     // Getting Google Play availability status
        int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext());

        // Showing status
        if(status!=ConnectionResult.SUCCESS){ // Google Play Services are not available

            int requestCode = 10;
            Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode);
            dialog.show();

        }else { // Google Play Services are available

            // Getting reference to the SupportMapFragment of activity_main.xml
            SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);

            // Getting GoogleMap object from the fragment
            googleMap = fm.getMap();

            // Enabling MyLocation Layer of Google Map
            googleMap.setMyLocationEnabled(true);

            // Getting LocationManager object from System Service LOCATION_SERVICE
            LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

            // Creating a criteria object to retrieve provider
            Criteria criteria = new Criteria();

            // Getting the name of the best provider
            String provider = locationManager.getBestProvider(criteria, true);

            // Getting Current Location
            Location location = locationManager.getLastKnownLocation(provider);

            if(location!=null){
                onLocationChanged(location);
            }
            locationManager.requestLocationUpdates(provider, 20000, 0, this);
        }
    }
    //@Override
    public void onLocationChanged(Location location) {

        TextView tvLocation = (TextView) findViewById(R.id.selected_location);

        // Getting latitude of the current location
        double latitude = location.getLatitude();

        // Getting longitude of the current location
        double longitude = location.getLongitude();

        // Creating a LatLng object for the current location
        LatLng latLng = new LatLng(latitude, longitude);

        // Showing the current location in Google Map
        googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));

        // Zoom in the Google Map
        googleMap.animateCamera(CameraUpdateFactory.zoomTo(15));

        // Setting latitude and longitude in the TextView tv_location
        tvLocation.setText("Latitude:" +  latitude  + ", Longitude:"+ longitude );
    }
    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub

    }
    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub

    }
    @Override
    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub

    }
    }

Answer 4

这将提供中心屏幕lat和lang

LatLng centerLatLang = 
mMap.getProjection().getVisibleRegion().latLngBounds.getCenter();