How to display my location on Google Maps for Andr

问题:

I've looked high and low for an answer on this, and no one, in any forum question has been able to help. I've searched through the tutorials. The API Guide says:

The My Location button appears in the top right corner of the screen only when the My Location layer is enabled.

So I've been looking for this My Location layer and have been unable to find anything. How do I show my location on a Google Map?

回答1:

The API Guide has it all wrong (really Google?). With Maps v2 you do not need to enable a layer to show yourself, there is a simple call to the GoogleMaps instance you created with your map.

Google Documentation

The actual documentation that Google provides gives you your answer. Call

// map is a GoogleMap object
map.setMyLocationEnabled(true);

and watch the magic happen.

回答2:

Java code:

public class MapActivity extends FragmentActivity implements LocationListener  {

    GoogleMap googleMap;
    LatLng myPosition;

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

        // 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) {
            // 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);

            myPosition = new LatLng(latitude, longitude);

            googleMap.addMarker(new MarkerOptions().position(myPosition).title("Start"));
        }
    }
}

activity_map.xml:

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:map="http://schemas.android.com/apk/res-auto"
  android:id="@+id/map"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  class="com.google.android.gms.maps.SupportMapFragment"/>

You will get your current location in a blue circle.

回答3:

From android 6.0 you need to check for user permission, if you want to use GoogleMap.setMyLocationEnabled(true) you will get Call requires permission which may be rejected by user error

if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
            == PackageManager.PERMISSION_GRANTED) {
   mMap.setMyLocationEnabled(true);
} else {
// Show rationale and request permission.
}

if you want to read more, check google map docs

回答4:

To show the "My Location" button you have to call

map.getUiSettings().setMyLocationButtonEnabled(true);

on your GoogleMap object.

回答5:

Call GoogleMap.setMyLocationEnabled(true) in your Activity, and add this 2 lines code in the Manifest:

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />