问题：
如何使用从服务中检索到的纬度和经度并在地图上显示它们？
宰父霖
我定义了一个服务（即LocationService）,它为我提供用户当前的纬度和经度,作为my_activity的意向性附加。现在，我想用它们在地图上显示当前的位置（使用谷歌地图）。我在mmap.AnimateCamera和mmap.MoveCamera方法中传递了这些latlng，但它们没有显示任何标记或放大到当前位置。如果我做错了什么，请告诉我。
LocationService和my MainActivity的代码粘贴在下面：
LocationServices.java
public class LocationServicesForLocationUpdates extends Service implements LocationListener,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener{
private static final String TAG = LocationServicesForLocationUpdates.class.getSimpleName();
public static final String ACTION_LOCATION_BROADCAST
= LocationServicesForLocationUpdates.class.getName() + "LocationBroadcast";
public static final String EXTRA_LATITUDE = "extra_latitude";
public static final String EXTRA_LONGITUDE = "extra_longitude";
private GoogleApiClient mLocationClient;
private LocationRequest mLocationRequest = new LocationRequest();
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
mLocationClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
mLocationRequest.setInterval(5000);
mLocationRequest.setFastestInterval(3000);
mLocationClient.connect();
// return super.onStartCommand(intent, flags, startId);
return START_STICKY;
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
/*
* LOCATION CALLBACKS
*/
@Override
public void onConnected(Bundle dataBundle) {
if (ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
&& ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
Log.d(TAG, "== Error On onConnected() Permission not granted");
//Permission not granted by user so cancel the further execution.
return;
}
LocationServices.FusedLocationApi.requestLocationUpdates(mLocationClient, mLocationRequest ,this);
Log.d(TAG, "Connected to Google API");
}
//to get the location change
@Override
public void onLocationChanged(Location location) {
Log.d(TAG, "Location changed");
if (location != null) {
Log.d(TAG, "== location != null");
//Send result to activities
sendMessageToUI(String.valueOf(location.getLatitude()), String.valueOf(location.getLongitude()));
}
}
private void sendMessageToUI(String lat, String lng) {
Log.d(TAG, "Sending info...");
Intent intent = new Intent(ACTION_LOCATION_BROADCAST);
intent.putExtra(EXTRA_LATITUDE, lat);
intent.putExtra(EXTRA_LONGITUDE, lng);
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
}
新建Mainactivity.java
public class MainActivity extends AppCompatActivity implements OnMapReadyCallback{
private TextView mLatlngTxtVu , mAddressTxtVu;
private boolean mAlreadyStartedService;
private static final String TAG = ParentHomeActivity.class.getSimpleName();
private static final int REQUEST_PERMISSIONS_REQUEST_CODE = 34;
private GoogleMap mGoogleMap;
Double mlattitude , mlongitude;
Marker mCurrentMarker;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_parent_home);
Log.d(TAG, "onCreate: Called");
mLatlngTxtVu = (TextView) findViewById(R.id.latlng_txtview);
mAddressTxtVu = (TextView) findViewById(R.id.address_txtvu);
LocalBroadcastManager.getInstance(this).registerReceiver(
new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
mlattitude = Double.parseDouble(intent.getStringExtra(LocationServicesForLocationUpdates.EXTRA_LATITUDE));
mlongitude = Double.parseDouble(intent.getStringExtra(LocationServicesForLocationUpdates.EXTRA_LONGITUDE));
Log.d("latlng", "onReceive: " + mlongitude + mlattitude);
if (mlattitude != null && mlongitude != null) {
mLatlngTxtVu.setText("Latitude : " + mlattitude + "Longitude: " + mlongitude);
}
}
}, new IntentFilter(LocationServicesForLocationUpdates.ACTION_LOCATION_BROADCAST)
);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.main_map);
mapFragment.getMapAsync(MainActivity.this);
}
@Override
protected void onResume() {
super.onResume();
checkGooglePlayServices();
}
@Override
public void onMapReady(GoogleMap googleMap) {
mGoogleMap = googleMap ;
Log.d(TAG, "onMapReady: called");
Log.d("coord", mlattitude + " " + mlongitude);
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
mGoogleMap.setMyLocationEnabled(true);
mGoogleMap.getUiSettings().setMyLocationButtonEnabled(true);
mGoogleMap.getUiSettings().setMapToolbarEnabled(false);
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(new LatLng(mlattitude, mlongitude)) // Sets the center of the map to location user
.zoom(14) // Sets the zoom
.bearing(0) // Sets the orientation of the camera to east
.tilt(90) // Sets the tilt of the camera to 30 degrees
.build(); // Creates a CameraPosition from the builder
mGoogleMap.moveCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
LatLng latLng = new LatLng(mlattitude , mlongitude);
mGoogleMap.addMarker(new MarkerOptions().position(latLng).title("YOU"));
// mGoogleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
/* CameraPosition cameraPosition = new CameraPosition.Builder()
.target(new LatLng(mlattitude, mlongitude)) // Sets the center of the map to location user
.zoom(17) // Sets the zoom
.bearing(90) // Sets the orientation of the camera to east
.tilt(40) // Sets the tilt of the camera to 30 degrees
.build(); // Creates a CameraPosition from the builder
mGoogleMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));*/
}
private void checkGooglePlayServices() {
//Check whether this user has installed Google play service which is being used by Location updates.
if (isGooglePlayServicesAvailable()) {
//Passing null to indicate that it is executing for the first time.
checkAndPromptForInternetConnection(null);
} else {
Toast.makeText(getApplicationContext(), "Play services Not Available", Toast.LENGTH_LONG).show();
}
}
private boolean checkAndPromptForInternetConnection(DialogInterface dialog) {
ConnectivityManager connectivityManager
= (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
if (activeNetworkInfo == null || !activeNetworkInfo.isConnected()) {
promptInternetConnect();
return false;
}
if (dialog != null) {
dialog.dismiss();
}
//Yes there is active internet connection. Next check Location is granted by user or not.
if (checkPermissions()) { //Yes permissions are granted by the user. Go to the next step.
startedLocationServices();
} else { //No user has not granted the permissions yet. Request now.
requestPermissions();
}
return true;
}
/**
* Step 3: Start the Location Monitor Service
*/
private void startedLocationServices() {
//And it will be keep running until you close the entire application from task manager.
//This method will executed only once.
if (!mAlreadyStartedService && mLatlngTxtVu != null) {
mLatlngTxtVu.setText("Running ");
//Start location sharing service to app server.........
Intent intent = new Intent(this, LocationServicesForLocationUpdates.class);
startService(intent);
mAlreadyStartedService = true;
//Ends................................................
}
}
/**
* Show A Dialog with button to refresh the internet state.
*/
private void promptInternetConnect() {
AlertDialog.Builder builder = new AlertDialog.Builder(ParentHomeActivity.this);
builder.setTitle("No internet connection");
builder.setMessage("Please Check your internet connection");
String positiveText = "Refresh";
builder.setPositiveButton(positiveText,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
//Block the Application Execution until user grants the permissions
if (checkAndPromptForInternetConnection(dialog)) {
//Now make sure about location permission.
if (checkPermissions()) {
//Step 2: Start the Location Monitor Service
//Everything is there to start the service.
startedLocationServices();
} else if (!checkPermissions()) {
requestPermissions();
}
}
}
});
AlertDialog dialog = builder.create();
dialog.show();
}
/**
* Return the availability of GooglePlayServices
*/
public boolean isGooglePlayServicesAvailable() {
GoogleApiAvailability googleApiAvailability = GoogleApiAvailability.getInstance();
int status = googleApiAvailability.isGooglePlayServicesAvailable(this);
if (status != ConnectionResult.SUCCESS) {
if (googleApiAvailability.isUserResolvableError(status)) {
googleApiAvailability.getErrorDialog(this, status, 2404).show();
}
return false;
}
return true;
}
/**
* Return the current state of the permissions needed.
*/
private boolean checkPermissions() {
int permissionState1 = ActivityCompat.checkSelfPermission(this,
android.Manifest.permission.ACCESS_FINE_LOCATION);
int permissionState2 = ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_COARSE_LOCATION);
return permissionState1 == PackageManager.PERMISSION_GRANTED && permissionState2 == PackageManager.PERMISSION_GRANTED;
}
/**
* Start permissions requests.
*/
private void requestPermissions() {
boolean shouldProvideRationale =
ActivityCompat.shouldShowRequestPermissionRationale(this,
android.Manifest.permission.ACCESS_FINE_LOCATION);
boolean shouldProvideRationale2 =
ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.ACCESS_COARSE_LOCATION);
// Provide an additional rationale to the img_user. This would happen if the img_user denied the
// request previously, but didn't check the "Don't ask again" checkbox.
if (shouldProvideRationale || shouldProvideRationale2) {
Log.i(TAG, "Displaying permission rationale to provide additional context.");
showSnackbar(R.string.grantPermission,
android.R.string.ok, new View.OnClickListener() {
@Override
public void onClick(View view) {
// Request permission
ActivityCompat.requestPermissions(ParentHomeActivity.this,
new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION},
REQUEST_PERMISSIONS_REQUEST_CODE);
}
});
} else {
Log.i(TAG, "Requesting permission");
// Request permission. It's possible this can be auto answered if device policy
// sets the permission in a given state or the img_user denied the permission
// previously and checked "Never ask again".
ActivityCompat.requestPermissions(ParentHomeActivity.this,
new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION},
REQUEST_PERMISSIONS_REQUEST_CODE);
}
}
/**
* Shows a {@link Snackbar}.
*
* @param mainTextStringId The id for the string resource for the Snackbar text.
* @param actionStringId The text of the action item.
* @param listener The listener associated with the Snackbar action.
*/
private void showSnackbar(final int mainTextStringId, final int actionStringId,
View.OnClickListener listener) {
Snackbar.make(
findViewById(android.R.id.content),
getString(mainTextStringId),
Snackbar.LENGTH_INDEFINITE)
.setAction(getString(actionStringId), listener).show();
}
/**
* Callback received when a permissions request has been completed.
*/
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
@NonNull int[] grantResults) {
Log.i(TAG, "onRequestPermissionResult");
if (requestCode == REQUEST_PERMISSIONS_REQUEST_CODE) {
if (grantResults.length <= 0) {
// If img_user interaction was interrupted, the permission request is cancelled and you
// receive empty arrays.
Log.i(TAG, "User interaction was cancelled.");
} else if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
Log.i(TAG, "Permission granted, updates requested, starting location updates");
startedLocationServices();
} else {
// Permission denied.
// Notify the img_user via a SnackBar that they have rejected a core permission for the
// app, which makes the Activity useless. In a real app, core permissions would
// typically be best requested during a welcome-screen flow.
// Additionally, it is important to remember that a permission might have been
// rejected without asking the img_user for permission (device policy or "Never ask
// again" prompts). Therefore, a img_user interface affordance is typically implemented
// when permissions are denied. Otherwise, your app could appear unresponsive to
// touches or interactions which have required permissions.
showSnackbar(R.string.permissionDenied,
R.string.settings, new View.OnClickListener() {
@Override
public void onClick(View view) {
// Build intent that displays the App settings screen.
Intent intent = new Intent();
intent.setAction(
Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
Uri uri = Uri.fromParts("package",
BuildConfig.APPLICATION_ID, null);
intent.setData(uri);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
});
}
}
}
@Override
public void onDestroy() {
//Stop location sharing service to app server.........
stopService(new Intent(this, LocationServicesForLocationUpdates.class));
mAlreadyStartedService = false;
//Ends................................................
super.onDestroy();
}
}
如果你不理解我的问题，请随时询问，并告诉我解决问题的正确方法。我是android应用程序开发的新手。
共有2个答案
华英睿
你可以这样做：
public class MapsMarkerActivity extends AppCompatActivity
implements OnMapReadyCallback {
// Include the OnCreate() method here too, as described above.
@Override
public void onMapReady(GoogleMap googleMap) {
// Add a marker in Sydney, Australia,
// and move the map's camera to the same location.
LatLng sydney = new LatLng(-33.852, 151.211);
googleMap.addMarker(new MarkerOptions().position(sydney)
.title("Marker in Sydney"));
googleMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
}
代码来自Google文档页面
侯博裕
在OnMapReady()中，请创建一个新的LATLNG位置，并将其添加为MarkerOption
@Override
public void onMapReady(GoogleMap googleMap) {
.......
.......
// make sure you are getting your latitude and longitude string value
mlattitude = Double.parseDouble(intent.getStringExtra(LocationServicesForLocationUpdates.EXTRA_LATITUDE));
mlongitude = Double.parseDouble(intent.getStringExtra(LocationServicesForLocationUpdates.EXTRA_LONGITUDE));
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(new LatLng(mLattitude,mlongitude)) // My position
.zoom(14) // Zoom Level
.bearing(0) // camera position, (0 north , 180 south )
.tilt(90) // Inclinaison de la camera
.build();
googleMap.moveCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
LatLng position = new LatLng(mlattitude,mlongitude);
googleMap.addMarker(new MarkerOptions().position(position)
.title("my marker"));
}
编辑
不要忘记在onReceive()方法中调用GetMapAsync
LocalBroadcastManager.getInstance(this).registerReceiver(
new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
mlattitude = Double.parseDouble(intent.getStringExtra(LocationServicesForLocationUpdates.EXTRA_LATITUDE));
mlongitude = Double.parseDouble(intent.getStringExtra(LocationServicesForLocationUpdates.EXTRA_LONGITUDE));
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.main_map);
mapFragment.getMapAsync(MainActivity.this);
Log.d("latlng", "onReceive: " + mlongitude + mlattitude);
if (mlattitude != null && mlongitude != null) {
mLatlngTxtVu.setText("Latitude : " + mlattitude + "Longitude: " + mlongitude);
}
}
}, new IntentFilter(LocationServicesForLocationUpdates.ACTION_LOCATION_BROADCAST)
);
);
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