180905(수) - Google Maps (Select Current Place)

Google Maps

Select Current Place

- Using Map SDK, Places SDK, fused location provider

Note : require Google Play services version 11.2.0 or later

Sample code

package com.example.currentplacedetailsonmap;

import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.location.Location;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.TextView;

import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.location.places.GeoDataClient;
import com.google.android.gms.location.places.PlaceDetectionClient;
import com.google.android.gms.location.places.PlaceLikelihood;
import com.google.android.gms.location.places.PlaceLikelihoodBufferResponse;
import com.google.android.gms.location.places.Places;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
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.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;

/**
 * An activity that displays a map showing the place at the device's current location.
 */
public class MapsActivityCurrentPlace extends AppCompatActivity
        implements OnMapReadyCallback {

    private static final String TAG = MapsActivityCurrentPlace.class.getSimpleName();
    private GoogleMap mMap;
    private CameraPosition mCameraPosition;

    // The entry points to the Places API.
    private GeoDataClient mGeoDataClient;
    private PlaceDetectionClient mPlaceDetectionClient;

    // The entry point to the Fused Location Provider.
    private FusedLocationProviderClient mFusedLocationProviderClient;

    // A default location (Sydney, Australia) and default zoom to use when location permission is
    // not granted.
    private final LatLng mDefaultLocation = new LatLng(-33.8523341, 151.2106085);
    private static final int DEFAULT_ZOOM = 15;
    private static final int PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1;
    private boolean mLocationPermissionGranted;

    // The geographical location where the device is currently located. That is, the last-known
    // location retrieved by the Fused Location Provider.
    private Location mLastKnownLocation;

    // Keys for storing activity state.
    private static final String KEY_CAMERA_POSITION = "camera_position";
    private static final String KEY_LOCATION = "location";

    // Used for selecting the current place.
    private static final int M_MAX_ENTRIES = 5;
    private String[] mLikelyPlaceNames;
    private String[] mLikelyPlaceAddresses;
    private String[] mLikelyPlaceAttributions;
    private LatLng[] mLikelyPlaceLatLngs;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Retrieve location and camera position from saved instance state.
        if (savedInstanceState != null) {
            mLastKnownLocation = savedInstanceState.getParcelable(KEY_LOCATION);
            mCameraPosition = savedInstanceState.getParcelable(KEY_CAMERA_POSITION);
        }

        // Retrieve the content view that renders the map.
        setContentView(R.layout.activity_maps);

        // Construct a GeoDataClient.
        mGeoDataClient = Places.getGeoDataClient(this, null);

        // Construct a PlaceDetectionClient.
        mPlaceDetectionClient = Places.getPlaceDetectionClient(this, null);

        // Construct a FusedLocationProviderClient.
        mFusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);

        // Build the map.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

    }

    /**
     * Saves the state of the map when the activity is paused.
     */
    @Override
    protected void onSaveInstanceState(Bundle outState) {
        if (mMap != null) {
            outState.putParcelable(KEY_CAMERA_POSITION, mMap.getCameraPosition());
            outState.putParcelable(KEY_LOCATION, mLastKnownLocation);
            super.onSaveInstanceState(outState);
        }
    }

    /**
     * Sets up the options menu.
     * @param menu The options menu.
     * @return Boolean.
     */
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.current_place_menu, menu);
        return true;
    }

    /**
     * Handles a click on the menu option to get a place.
     * @param item The menu item to handle.
     * @return Boolean.
     */
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == R.id.option_get_place) {
            showCurrentPlace();
        }
        return true;
    }

    /**
     * Manipulates the map when it's available.
     * This callback is triggered when the map is ready to be used.
     */
    @Override
    public void onMapReady(GoogleMap map) {
        mMap = map;

        // Use a custom info window adapter to handle multiple lines of text in the
        // info window contents.
        mMap.setInfoWindowAdapter(new GoogleMap.InfoWindowAdapter() {

            @Override
            // Return null here, so that getInfoContents() is called next.
            public View getInfoWindow(Marker arg0) {
                return null;
            }

            @Override
            public View getInfoContents(Marker marker) {
                // Inflate the layouts for the info window, title and snippet.
                View infoWindow = getLayoutInflater().inflate(R.layout.custom_info_contents,
                        (FrameLayout) findViewById(R.id.map), false);

                TextView title = ((TextView) infoWindow.findViewById(R.id.title));
                title.setText(marker.getTitle());

                TextView snippet = ((TextView) infoWindow.findViewById(R.id.snippet));
                snippet.setText(marker.getSnippet());

                return infoWindow;
            }
        });

        // Prompt the user for permission.
        getLocationPermission();

        // Turn on the My Location layer and the related control on the map.
        updateLocationUI();

        // Get the current location of the device and set the position of the map.
        getDeviceLocation();
    }

    /**
     * Gets the current location of the device, and positions the map's camera.
     */
    private void getDeviceLocation() {
        /*
         * Get the best and most recent location of the device, which may be null in rare
         * cases when a location is not available.
         */
        try {
            if (mLocationPermissionGranted) {
                Task<Location> locationResult = mFusedLocationProviderClient.getLastLocation();
                locationResult.addOnCompleteListener(this, new OnCompleteListener<Location>() {
                    @Override
                    public void onComplete(@NonNull Task<Location> task) {
                        if (task.isSuccessful()) {
                            // Set the map's camera position to the current location of the device.
                            mLastKnownLocation = task.getResult();
                            mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(
                                    new LatLng(mLastKnownLocation.getLatitude(),
                                            mLastKnownLocation.getLongitude()), DEFAULT_ZOOM));
                        } else {
                            Log.d(TAG, "Current location is null. Using defaults.");
                            Log.e(TAG, "Exception: %s", task.getException());
                            mMap.moveCamera(CameraUpdateFactory
                                    .newLatLngZoom(mDefaultLocation, DEFAULT_ZOOM));
                            mMap.getUiSettings().setMyLocationButtonEnabled(false);
                        }
                    }
                });
            }
        } catch (SecurityException e)  {
            Log.e("Exception: %s", e.getMessage());
        }
    }


    /**
     * Prompts the user for permission to use the device location.
     */
    private void getLocationPermission() {
        /*
         * Request location permission, so that we can get the location of the
         * device. The result of the permission request is handled by a callback,
         * onRequestPermissionsResult.
         */
        if (ContextCompat.checkSelfPermission(this.getApplicationContext(),
                android.Manifest.permission.ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            mLocationPermissionGranted = true;
        } else {
            ActivityCompat.requestPermissions(this,
                    new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
                    PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);
        }
    }

    /**
     * Handles the result of the request for location permissions.
     */
    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           @NonNull String permissions[],
                                           @NonNull int[] grantResults) {
        mLocationPermissionGranted = false;
        switch (requestCode) {
            case PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    mLocationPermissionGranted = true;
                }
            }
        }
        updateLocationUI();
    }

    /**
     * Prompts the user to select the current place from a list of likely places, and shows the
     * current place on the map - provided the user has granted location permission.
     */
    private void showCurrentPlace() {
        if (mMap == null) {
            return;
        }

        if (mLocationPermissionGranted) {
            // Get the likely places - that is, the businesses and other points of interest that
            // are the best match for the device's current location.
            @SuppressWarnings("MissingPermission") final
            Task<PlaceLikelihoodBufferResponse> placeResult =
                    mPlaceDetectionClient.getCurrentPlace(null);
            placeResult.addOnCompleteListener
                    (new OnCompleteListener<PlaceLikelihoodBufferResponse>() {
                        @Override
                        public void onComplete(@NonNull Task<PlaceLikelihoodBufferResponse> task) {
                            if (task.isSuccessful() && task.getResult() != null) {
                                PlaceLikelihoodBufferResponse likelyPlaces = task.getResult();

                                // Set the count, handling cases where less than 5 entries are returned.
                                int count;
                                if (likelyPlaces.getCount() < M_MAX_ENTRIES) {
                                    count = likelyPlaces.getCount();
                                } else {
                                    count = M_MAX_ENTRIES;
                                }

                                int i = 0;
                                mLikelyPlaceNames = new String[count];
                                mLikelyPlaceAddresses = new String[count];
                                mLikelyPlaceAttributions = new String[count];
                                mLikelyPlaceLatLngs = new LatLng[count];

                                for (PlaceLikelihood placeLikelihood : likelyPlaces) {
                                    // Build a list of likely places to show the user.
                                    mLikelyPlaceNames[i] = (String) placeLikelihood.getPlace().getName();
                                    mLikelyPlaceAddresses[i] = (String) placeLikelihood.getPlace()
                                            .getAddress();
                                    mLikelyPlaceAttributions[i] = (String) placeLikelihood.getPlace()
                                            .getAttributions();
                                    mLikelyPlaceLatLngs[i] = placeLikelihood.getPlace().getLatLng();

                                    i++;
                                    if (i > (count - 1)) {
                                        break;
                                    }
                                }

                                // Release the place likelihood buffer, to avoid memory leaks.
                                likelyPlaces.release();

                                // Show a dialog offering the user the list of likely places, and add a
                                // marker at the selected place.
                                openPlacesDialog();

                            } else {
                                Log.e(TAG, "Exception: %s", task.getException());
                            }
                        }
                    });
        } else {
            // The user has not granted permission.
            Log.i(TAG, "The user did not grant location permission.");

            // Add a default marker, because the user hasn't selected a place.
            mMap.addMarker(new MarkerOptions()
                    .title(getString(R.string.default_info_title))
                    .position(mDefaultLocation)
                    .snippet(getString(R.string.default_info_snippet)));

            // Prompt the user for permission.
            getLocationPermission();
        }
    }

    /**
     * Displays a form allowing the user to select a place from a list of likely places.
     */
    private void openPlacesDialog() {
        // Ask the user to choose the place where they are now.
        DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // The "which" argument contains the position of the selected item.
                LatLng markerLatLng = mLikelyPlaceLatLngs[which];
                String markerSnippet = mLikelyPlaceAddresses[which];
                if (mLikelyPlaceAttributions[which] != null) {
                    markerSnippet = markerSnippet + "\n" + mLikelyPlaceAttributions[which];
                }

                // Add a marker for the selected place, with an info window
                // showing information about that place.
                mMap.addMarker(new MarkerOptions()
                        .title(mLikelyPlaceNames[which])
                        .position(markerLatLng)
                        .snippet(markerSnippet));

                // Position the map's camera at the location of the marker.
                mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(markerLatLng,
                        DEFAULT_ZOOM));
            }
        };

        // Display the dialog.
        AlertDialog dialog = new AlertDialog.Builder(this)
                .setTitle(R.string.pick_place)
                .setItems(mLikelyPlaceNames, listener)
                .show();
    }

    /**
     * Updates the map's UI settings based on whether the user has granted location permission.
     */
    private void updateLocationUI() {
        if (mMap == null) {
            return;
        }
        try {
            if (mLocationPermissionGranted) {
                mMap.setMyLocationEnabled(true);
                mMap.getUiSettings().setMyLocationButtonEnabled(true);
            } else {
                mMap.setMyLocationEnabled(false);
                mMap.getUiSettings().setMyLocationButtonEnabled(false);
                mLastKnownLocation = null;
                getLocationPermission();
            }
        } catch (SecurityException e)  {
            Log.e("Exception: %s", e.getMessage());
        }
    }
}

Instantiate the Places API clients

- 다음 interfaces는 Places SDK 의 primary entry points를 제공

・ GeoDataClient 

Google's database of local place and business information

・ PlaceDetectionClient 

quick access to device's current place & particular place에서의 device location을 report 할 수 있는 opportunity 제공

- LocationServices 은 Android location services를 위한 main entry point 제공

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

    // Construct a GeoDataClient.
    mGeoDataClient = Places.getGeoDataClient(this, null);

    // Construct a PlaceDetectionClient.
    mPlaceDetectionClient = Places.getPlaceDetectionClient(this, null);

    // Construct a FusedLocationProviderClient.
    mFusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
}

(아 static method 너무 싫어)

Request location permission

- determine the location & tap the My Location button on them map 을 위해서 permission 필요

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.currentplacedetailsonmap">
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
</manifest>

private void getLocationPermission() {
    /*
     * Request location permission, so that we can get the location of the
     * device. The result of the permission request is handled by a callback,
     * onRequestPermissionsResult.
     */
    if (ContextCompat.checkSelfPermission(this.getApplicationContext(),
            android.Manifest.permission.ACCESS_FINE_LOCATION)
            == PackageManager.PERMISSION_GRANTED) {
        mLocationPermissionGranted = true;
    } else {
        ActivityCompat.requestPermissions(this,
                new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
                PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);
    }
}

@Override
public void onRequestPermissionsResult(int requestCode,
                                       @NonNull String permissions[],
                                       @NonNull int[] grantResults) {
    mLocationPermissionGranted = false;
    switch (requestCode) {
        case PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                mLocationPermissionGranted = true;
            }
        }
    }
    updateLocationUI();
}

Add a map 

public void onMapReady(GoogleMap map) {
    mMap = map;

    // Do other setup activities here too, as described elsewhere in this tutorial.

    // Turn on the My Location layer and the related control on the map.
    updateLocationUI();

    // Get the current location of the device and set the position of the map.
    getDeviceLocation();
}

private void updateLocationUI() {
    if (mMap == null) {
        return;
    }
    try {
        if (mLocationPermissionGranted) {
            mMap.setMyLocationEnabled(true);
            mMap.getUiSettings().setMyLocationButtonEnabled(true);
        } else {
            mMap.setMyLocationEnabled(false);
            mMap.getUiSettings().setMyLocationButtonEnabled(false);
            mLastKnownLocation = null;
            getLocationPermission();
        }
    } catch (SecurityException e)  {
        Log.e("Exception: %s", e.getMessage());
    }
}

Get the location of the Android device and position the map

- fused location provider를 사용하면, device's last-known location을 find한다.

- fused location provider 

private void getDeviceLocation() {
    /*
     * Get the best and most recent location of the device, which may be null in rare
     * cases when a location is not available.
     */
    try {
        if (mLocationPermissionGranted) {
            Task locationResult = mFusedLocationProviderClient.getLastLocation();
            locationResult.addOnCompleteListener(this, new OnCompleteListener() {
                @Override
                public void onComplete(@NonNull Task task) {
                    if (task.isSuccessful()) {
                        // Set the map's camera position to the current location of the device.
                        mLastKnownLocation = task.getResult();
                        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(
                                new LatLng(mLastKnownLocation.getLatitude(),
                                        mLastKnownLocation.getLongitude()), DEFAULT_ZOOM));
                    } else {
                        Log.d(TAG, "Current location is null. Using defaults.");
                        Log.e(TAG, "Exception: %s", task.getException());
                        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(mDefaultLocation, DEFAULT_ZOOM));
                        mMap.getUiSettings().setMyLocationButtonEnabled(false);
                    }
                }
            });
        }
    } catch(SecurityException e)  {
        Log.e("Exception: %s", e.getMessage());
    }
}

Get the current place

- Places SDK를 사용하면 device's current location의 likely places를 얻을 수 있다.

- place is a business or other point of interest

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getItemId() == R.id.option_get_place) {
        showCurrentPlace();
    }
    return true;
}

private void showCurrentPlace() {
    if (mMap == null) {
        return;
    }

    if (mLocationPermissionGranted) {
        // Get the likely places - that is, the businesses and other points of interest that
        // are the best match for the device's current location.
        @SuppressWarnings("MissingPermission") final
        Task<PlaceLikelihoodBufferResponse> placeResult =
                mPlaceDetectionClient.getCurrentPlace(null);
        placeResult.addOnCompleteListener
                (new OnCompleteListener<PlaceLikelihoodBufferResponse>() {
                    @Override
                    public void onComplete(@NonNull Task<PlaceLikelihoodBufferResponse> task) {
                        if (task.isSuccessful() && task.getResult() != null) {
                            PlaceLikelihoodBufferResponse likelyPlaces = task.getResult();

                            // Set the count, handling cases where less than 5 entries are returned.
                            int count;
                            if (likelyPlaces.getCount() < M_MAX_ENTRIES) {
                                count = likelyPlaces.getCount();
                            } else {
                                count = M_MAX_ENTRIES;
                            }

                            int i = 0;
                            mLikelyPlaceNames = new String[count];
                            mLikelyPlaceAddresses = new String[count];
                            mLikelyPlaceAttributions = new String[count];
                            mLikelyPlaceLatLngs = new LatLng[count];

                            for (PlaceLikelihood placeLikelihood : likelyPlaces) {
                                // Build a list of likely places to show the user.
                                mLikelyPlaceNames[i] = (String) placeLikelihood.getPlace().getName();
                                mLikelyPlaceAddresses[i] = (String) placeLikelihood.getPlace()
                                        .getAddress();
                                mLikelyPlaceAttributions[i] = (String) placeLikelihood.getPlace()
                                        .getAttributions();
                                mLikelyPlaceLatLngs[i] = placeLikelihood.getPlace().getLatLng();

                                i++;
                                if (i > (count - 1)) {
                                    break;
                                }
                            }

                            // Release the place likelihood buffer, to avoid memory leaks.
                            likelyPlaces.release();

                            // Show a dialog offering the user the list of likely places, and add a
                            // marker at the selected place.
                            openPlacesDialog();

                        } else {
                            Log.e(TAG, "Exception: %s", task.getException());
                        }
                    }
                });
    } else {
        // The user has not granted permission.
        Log.i(TAG, "The user did not grant location permission.");

        // Add a default marker, because the user hasn't selected a place.
        mMap.addMarker(new MarkerOptions()
                .title(getString(R.string.default_info_title))
                .position(mDefaultLocation)
                .snippet(getString(R.string.default_info_snippet)));

        // Prompt the user for permission.
        getLocationPermission();
    }
}

private void openPlacesDialog() {
    // Ask the user to choose the place where they are now.
    DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            // The "which" argument contains the position of the selected item.
            LatLng markerLatLng = mLikelyPlaceLatLngs[which];
            String markerSnippet = mLikelyPlaceAddresses[which];
            if (mLikelyPlaceAttributions[which] != null) {
                markerSnippet = markerSnippet + "\n" + mLikelyPlaceAttributions[which];
            }

            // Add a marker for the selected place, with an info window
            // showing information about that place.
            mMap.addMarker(new MarkerOptions()
                    .title(mLikelyPlaceNames[which])
                    .position(markerLatLng)
                    .snippet(markerSnippet));

            // Position the map's camera at the location of the marker.
            mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(markerLatLng,
                    DEFAULT_ZOOM));
        }
    };

    // Display the dialog.
    AlertDialog dialog = new AlertDialog.Builder(this)
            .setTitle(R.string.pick_place)
            .setItems(mLikelyPlaceNames, listener)
            .show();
}

info window layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layoutDirection="locale"
    android:orientation="vertical">
    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:textColor="#ff000000"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/snippet"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textColor="#ff7f7f7f" />
</LinearLayout>

@Override
public void onMapReady(GoogleMap map) {
    // Do other setup activities here too, as described elsewhere in this tutorial.
    mMap.setInfoWindowAdapter(new GoogleMap.InfoWindowAdapter() {

    @Override
    // Return null here, so that getInfoContents() is called next.
    public View getInfoWindow(Marker arg0) {
        return null;
    }

    @Override
    public View getInfoContents(Marker marker) {
        // Inflate the layouts for the info window, title and snippet.
        View infoWindow = getLayoutInflater().inflate(R.layout.custom_info_contents, null);

        TextView title = ((TextView) infoWindow.findViewById(R.id.title));
        title.setText(marker.getTitle());

        TextView snippet = ((TextView) infoWindow.findViewById(R.id.snippet));
        snippet.setText(marker.getSnippet());

        return infoWindow;
      }
    });
}

Save the map's state

- save map's camera position and device location

- configuration change일 때, destroy and rebuilds map activity -> smooth user experience를 위해서 map's state 를 저장하는것이 필요함

- onSaveInstanceState() saved the state when activity pauses

private static final String KEY_CAMERA_POSITION = "camera_position";
private static final String KEY_LOCATION = "location";

@Override
protected void onSaveInstanceState(Bundle outState) {
    if (mMap != null) {
        outState.putParcelable(KEY_CAMERA_POSITION, mMap.getCameraPosition());
        outState.putParcelable(KEY_LOCATION, mLastKnownLocation);
        super.onSaveInstanceState(outState);
    }
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null) {
        mCurrentLocation = savedInstanceState.getParcelable(KEY_LOCATION);
        mCameraPosition = savedInstanceState.getParcelable(KEY_CAMERA_POSITION);
    }
    ...
}