How to retrieve current device location & show it

问题:

I'm developing a android app with google maps. Currently I'm able to view the map inside my app, but I don't know how to view the current location on the app.

Here is my code:

public class MapsFragment extends Fragment{
        MapView m;

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, 
                Bundle savedInstanceState) {
            // inflat and return the layout
            View v = inflater.inflate(R.layout.map_near_me, container, false);
            m = (MapView) v.findViewById(R.id.map);
            m.onCreate(savedInstanceState);
            return v;
        }
}

Edited: And the xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <com.google.android.gms.maps.MapView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/map" />

</LinearLayout>

This code works fine and I got to know 'setmylocationenabled' can help to enable in FragmentActivity, but unfortunately I have to use the type as 'Fragment'. And I'm using google api v2. Please someone help with this.

回答1:

How about using the newly introduced fused location provider as referenced from: http://developer.android.com/training/location/retrieve-current.html

public static class XYZ extends Fragment
            implements
                GooglePlayServicesClient.ConnectionCallbacks,
                GooglePlayServicesClient.OnConnectionFailedListener,
                LocationListener {
        GoogleMap map;
        LatLng latlng;
        private LocationRequest lr;
        private LocationClient lc;
        MapFragment mapFragment;
        ImageView iv;
        private static View view;

        public XYZ() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {

            if (view != null) {
                ViewGroup parent = (ViewGroup) view.getParent();
                if (parent != null)
                    parent.removeView(view);
            }

            try {
                view = inflater.inflate(R.layout.XYZ, container,
                        false);

                mapFragment = ((MapFragment) this.getActivity()
                        .getFragmentManager().findFragmentById(R.id.map));
                iv = (ImageView) view.findViewById(R.id.iv);

                map = mapFragment.getMap();
                map.getUiSettings().setAllGesturesEnabled(false);
                map.getUiSettings().setMyLocationButtonEnabled(false);
                map.setMyLocationEnabled(true);
                map.getUiSettings().setZoomControlsEnabled(false);

                MapsInitializer.initialize(this.getActivity());
            } catch (GooglePlayServicesNotAvailableException e) {
                Toast.makeText(getActivity(), "Google Play Services missing !",
                        Toast.LENGTH_LONG).show();
            } catch (InflateException e) {
                Toast.makeText(getActivity(), "Problems inflating the view !",
                        Toast.LENGTH_LONG).show();
            } catch (NullPointerException e) {
                Toast.makeText(getActivity(), "Google Play Services missing !",
                        Toast.LENGTH_LONG).show();
            }

            return view;
        }
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            lr = LocationRequest.create();
            lr.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
            lc = new LocationClient(this.getActivity().getApplicationContext(),
                    this, this);
            lc.connect();
        }

        @Override
        public void onLocationChanged(Location l2) {
            CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(
                    new LatLng(l2.getLatitude(), l2.getLongitude()), 15);
            map.animateCamera(cameraUpdate);
        }

        @Override
        public void onConnectionFailed(ConnectionResult arg0) {

        }

        @Override
        public void onConnected(Bundle connectionHint) {
            lc.requestLocationUpdates(lr, this);

        }

        @Override
        public void onDisconnected() {

        }
    }

With the XML as:

      <?xml version="1.0" encoding="utf-8"?>
      <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_marginBottom="4dp"
                android:layout_weight="1" >

                    <fragment
                        android:id="@+id/map"
                        android:name="com.google.android.gms.maps.MapFragment"
                        android:layout_width="match_parent"
                        android:layout_height="match_parent"
                        />

                    <ImageView
                        android:id="@+id/iv"
                        android:layout_width="match_parent"
                        android:layout_height="match_parent"
                        android:background="@android:color/transparent" />

            </RelativeLayout>

You may get a blank map if you don't have all the requirements, https://developers.google.com/maps/documentation/android/start

1. Get Play services on your project by following this post https://blog-emildesign.rhcloud.com/?p=435

2. Then get an api key: https://blog-emildesign.rhcloud.com/?p=403

3. Add the permissions to you manifest,

      <uses-permission android:name="your.application.package.permission.MAPS_RECEIVE"/>
      <uses-permission android:name="android.permission.INTERNET" />
      <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
      <uses-permission    android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/>
      <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
      <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
   

4. To test the map application you need to have a real device, if not then push play services to emulator via adb, read this post to learn how to install play services via adb https://stackoverflow.com/a/13869332/826657

5. After all steps above, clean your project, uninstall the previous .apk from emulator, and run the project.

回答2:

You can enable your location just add this code in your class

 GoogleMap.setMyLocationEnabled(true);

回答3:

Here is the Link explains all the things you need

https://developers.google.com/maps/documentation/android/map

To set location on Map, you need to use below class

LatLong objLatLng=new LatLong(lat,longi);
yourMapObject.moveCamera(CameraUpdateFactory.newLatLngZoom(objLatLng, 20));
yourMapObject.animateCamera(CameraUpdateFactory.zoomTo(18), 2000, null);

Hope this will help you.

回答4:

You should init your Map v2 like this:

m = (MapView) v.findViewById(R.id.map);
GoogleMap mMap = m.getMap();

Now you can use mMap.setMyLocationEnabled(true);

回答5:

Use LocationListener:

       GPSTracker objGPSTracker = new GPSTracker(mContext);
            objGPSTracker.stopUsingGPS();
            objGPSTracker.getLocation();

This is class for GPSTracker

public class GPSTracker extends Service implements LocationListener {

    private final Context mContext;

    // flag for GPS status
    boolean isGPSEnabled = false;

    // flag for network status
    boolean isNetworkEnabled = false;

    // flag for GPS status
    boolean canGetLocation = false;
    //
    Location location; // location
    double latitude; // latitude
    double longitude; // longitude

    // The minimum distance to change Updates in meters
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 50; // 10 meters

    // The minimum time between updates in milliseconds
    private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute

    // Declaring a Location Manager
    protected LocationManager locationManager;

    public GPSTracker(Context context) {
        this.mContext = context;
        //getLocation();
    }

    public Location getLocation() {
        try {
            locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE);

            // getting GPS status
            isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);

            // getting network status
            isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);

            if (!isGPSEnabled && !isNetworkEnabled) {
                // no network provider is enabled
            } else {
                this.canGetLocation = true;
                if (isNetworkEnabled) {
                    locationManager.requestLocationUpdates(
                            LocationManager.NETWORK_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    Log.d("Network", "Network");
                    if (locationManager != null) {
                        location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                        if (location != null) {
                            Constant.mLocation = location;
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
                        }
                    }
                }
                // if GPS Enabled get lat/long using GPS Services
                if (isGPSEnabled) {
                    if (location == null) {
                        locationManager.requestLocationUpdates(
                                LocationManager.GPS_PROVIDER,
                                MIN_TIME_BW_UPDATES,
                                MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                        Log.d("GPS Enabled", "GPS Enabled");
                        if (locationManager != null) {
                            location = locationManager
                                    .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                            Constant.mLocation = location;
                            if (location != null) {
                                latitude = location.getLatitude();
                                longitude = location.getLongitude();
                            }
                        }
                    }
                }

            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        return location;
    }

    /**
     * Stop using GPS listener Calling this function will stop using GPS in your
     * app
     * */
    public void stopUsingGPS() {
        if (locationManager != null) {
            locationManager.removeUpdates(GPSTracker.this);
        }
    }

    /**
     * Function to get latitude
     * */
    public double getLatitude() {
        if (location != null) {
            latitude = location.getLatitude();
        }

        // return latitude
        return latitude;
    }

    /**
     * Function to get longitude
     * */
    public double getLongitude() {
        if (location != null) {
            longitude = location.getLongitude();
        }

        // return longitude
        return longitude;
    }

    /**
     * Function to check GPS/wifi enabled
     * 
     * @return boolean
     * */
    public boolean canGetLocation() {
        return this.canGetLocation;
    }

    /**
     * Function to show settings alert dialog On pressing Settings button will
     * lauch Settings Options
     * */
    public void showSettingsAlert() {
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

        // Setting Dialog Title
        alertDialog.setTitle("GPS settings");

        // Setting Dialog Message
        alertDialog
                .setMessage("GPS is not enabled. Do you want to go to settings menu?");

        // On pressing Settings button
        alertDialog.setPositiveButton("Settings",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        Intent intent = new Intent(
                                Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                        mContext.startActivity(intent);
                    }
                });

        // on pressing cancel button
        alertDialog.setNegativeButton("Cancel",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });

        // Showing Alert Message
        alertDialog.show();
    }

    public void onLocationChanged(Location location) {
        Constant.mLocation = location;

    }

    public void onProviderDisabled(String provider) {
    }

    public void onProviderEnabled(String provider) {
    }

    public void onStatusChanged(String provider, int status, Bundle extras) {
    }

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

}