Android Google Maps API位置

Question

I've googled around a bit, and still can't find a definite answer to this.

What is the current "best" or "recommended" way of using Google Maps in Android?

I want my application to use the blue dot that automatically keeps track of the user's location, much like the Maps app does when you click on the "my location" button. Some of this functionality seems to come built in just by using the map, however, I'm unsure how to extract the Location from this, as I've read .getMyLocation() is deprecated?

What is the best way to do this?

Answer 1

I am using this code:

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


            Criteria criteria = new Criteria();

            String provider = locationManager.getBestProvider(criteria, true);

            Location myLocation = locationManager.getLastKnownLocation(provider);

            map.setMapType(GoogleMap.MAP_TYPE_NORMAL);

            double latitude = myLocation.getLatitude();
            double longitude = myLocation.getLongitude();

            LatLng latLng = new LatLng(latitude, longitude);


            map.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 10));

Answer 2

You can show the user's current location with the blue dot by enabling the My Location layer. Simply call the following method and the blue dot showing the user's current location will be displayed on the map:

mMap.setMyLocationEnabled(true);

To get location updates you should setup a LocationListener using a LocationClient . When you implement the LocationListener interface you will override the onLocationChanged method which will provide you with location updates. When you request location updates using a LocationClient you create a LocationRequest to specify how frequently you want location updates.

There is an excellent tutorial at the Android Developers site for making you app location aware.

Answer 3

You have to work with Location Listener. It will solve all you want. Use this code. I tried to explain all things in comments.

import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient.ConnectionCallbacks;
import com.google.android.gms.common.GooglePlayServicesClient.OnConnectionFailedListener;
import com.google.android.gms.location.LocationClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.CameraPosition;
import com.google.android.gms.maps.model.LatLng;

public class YourActivity extends FragmentActivity implements 
LocationListener, ConnectionCallbacks, OnConnectionFailedListener{

    private GoogleMap mMap;
    private LocationClient mLocationClient;
    private static final LocationRequest REQUEST = LocationRequest.create()
            .setInterval(1000)         // 1 second - interval between requests
            .setFastestInterval(16)    // 60fps
            .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);

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

    }

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
        setUpLocationClientIfNeeded();
        //.. and connect to client
        mLocationClient.connect();

    }

    @Override
    public void onPause() {
        super.onPause();
        // if you was connected to client you have to disconnect
        if (mLocationClient != null) {
            mLocationClient.disconnect();
        }
    }

    private void setUpMapIfNeeded() {
        // if map did not install yet
        if (mMap == null) {
            // install it from fragment
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getMap();
            // if installation success
            if (mMap != null) {
                // init all settings of map
                init();
            }
        }
    }

    //if client was not created - create it
    private void setUpLocationClientIfNeeded() {
        if (mLocationClient == null) {
            mLocationClient = new LocationClient(
                    getApplicationContext(),
                    this, 
                    this);
        }
    }

    private void init() {
        // settings of your map
        mMap.setBuildingsEnabled(true);
        mMap.setMyLocationEnabled(true);
        mMap.getUiSettings().setCompassEnabled(true);
        mMap.getUiSettings().setMyLocationButtonEnabled(true);

    }

    // when you get your current location - set it on center of screen
    @Override
    public void onLocationChanged(Location location) {

        CameraPosition cameraPosition = new CameraPosition.Builder()
        .target(new LatLng(location.getLatitude(), location.getLongitude())).zoom(9).bearing(0).tilt(0).build();
        CameraUpdate cameraUpdate = CameraUpdateFactory
        .newCameraPosition(cameraPosition);
        mMap.animateCamera(cameraUpdate);

        //Be careful, if want to show current location only once(after starting map) use this line
        //but you don't need it in your task!
        mLocationClient.removeLocationUpdates(this);
    }

    // after connection to client we will get new location from LocationListener 
    //with settings of LocationRequest
    @Override
    public void onConnected(Bundle arg0) {
        mLocationClient.requestLocationUpdates(
                REQUEST, //settings for this request described in "LocationRequest REQUEST" at the beginning
                this);
    }

    @Override
    public void onDisconnected() {

    }

    @Override
    public void onConnectionFailed(ConnectionResult arg0) {

    }
}

Answer 4

I was looking for it last 2 days.
Answering your question:

What is the current "best" or "recommended" way of using Google Maps in Android?

Today you have 2 options:

1. Use new/latest Location Service API (like google recommend). But there is a "little" problem: The official guide Location APIs is outdate. I mean, if you follow their tutorial Making Your App Location-Aware you will find that they are using LocationClient which is deprecated. After 2 days looking for the "new" way to do it I found this nice answer Android LocationClient class is deprecated but used in documentation .
   
   
2. Use LocationManager . This second one is the most used. You can find how to use it here and here .
   

As far as I have seen both works fine but if you ask to me which one I will use, I will choose the one Google recommend: #1.

Here is what they say about it:

The Google Location Services API, part of Google Play Services, provides a more powerful, high-level framework that automatically handles location providers, user movement, and location accuracy. It also handles location update scheduling based on power consumption parameters you provide. In most cases, you'll get better battery performance, as well as more appropriate accuracy, by using the Location Services API.