我正在开发一个应用程序，我想在地图中使用marker显示当前位置。我正在使用Google Map v2。在这里我可以在GPS关闭时显示地图和标记，但在GPS打开时在地图上看不到任何标记。我的要求是在地图上显示当前位置的标记
我试过这样，
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
//locationManger.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0,
this);
ArrayList<HashMap<String, String>> arl = (ArrayList<HashMap<String, String>>)
getIntent().getSerializableExtra("arrayList");
if(location!=null){
double latitude = location.getLatitude();
double langitude = location.getLongitude();
myPosition = new LatLng(latitude, langitude);
CameraPosition position= new CameraPosition.Builder().
target(myPosition).zoom(17).bearing(19).tilt(30).build();
//_googleMap.animateCamera(CameraUpdateFactory.newCameraPosition(position));
_googleMap.animateCamera(CameraUpdateFactory.newCameraPosition(position));
_googleMap.addMarker(new
MarkerOptions().position(myPosition).title("start"));
}
答案 0 :(得分：7)
使用下面对我有用的代码：
@Override
public void onLocationChanged(Location location) {
map.clear();
MarkerOptions mp = new MarkerOptions();
mp.position(new LatLng(location.getLatitude(), location.getLongitude()));
mp.title("my position");
map.addMarker(mp);
map.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location.getLongitude()), 16));
}
答案 1 :(得分：3)
使用它。它对我有用。
@Override
public void onLocationChanged(Location location) {
map.clear();
mp1 = new MarkerOptions();
mp1.position(new LatLng(location.getLatitude(),
location.getLongitude()));
mp1.draggable(true);
mp1.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_ROSE));
map.addMarker(mp1);
map.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location
.getLongitude()), 20));
}
答案 2 :(得分：2)
试试这个： -
private void initMap() {
if (googleMap != null) {
googleMap = ((MapFragment) getFragmentManager().findFragmentById(
R.id.map)).getMap();
// to set current location
googleMap.setMyLocationEnabled(true);
Marker pos_Marker = googleMap.addMarker(new MarkerOptions().position(starting).icon(BitmapDescriptorFactory.fromResource(R.drawable.ic_laumcher)).title("Starting Location").draggable(false));
pos_Marker.showInfoWindow();
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(START_locationpoint, 10));
googleMap.animateCamera(CameraUpdateFactory.zoomTo(15),2000, null);
// check if map is created successfully or not
if (googleMap == null) {
Toast.makeText(getApplicationContext(),
"Sorry! unable to create maps", Toast.LENGTH_SHORT)
.show();
}
}
答案 3 :(得分：2)
试试这个，它显示当前位置：
private void initilizeMap() {
if (googleMap == null) {
googleMap = ((MapFragment) getFragmentManager().findFragmentById(
R.id.map)).getMap();
// to set current location
googleMap.setMyLocationEnabled(true);
// check if map is created successfully or not
if (googleMap == null) {
Toast.makeText(getApplicationContext(),
"Sorry! unable to create maps", Toast.LENGTH_SHORT)
.show();
}
}
答案 4 :(得分：2)
你可以试试这个：
public class MapsActivity extends AppCompatActivity
implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
GoogleMap mGoogleMap;
SupportMapFragment mapFrag;
LocationRequest mLocationRequest;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
Marker mCurrLocationMarker;
private Circle mCircle;
double radiusInMeters = 100.0;
int strokeColor = 0xffff0000; //Color Code you want
int shadeColor = 0x44ff0000; //opaque red fill
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
getSupportActionBar().setTitle("Map Location Activity");
mapFrag = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFrag.getMapAsync(this);
}
@Override
public void onPause() {
super.onPause();
//stop location updates when Activity is no longer active
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
@Override
public void onMapReady(GoogleMap googleMap)
{
mGoogleMap=googleMap;
//mGoogleMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
//Initialize Google Play Services
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
//Location Permission already granted
buildGoogleApiClient();
mGoogleMap.setMyLocationEnabled(true);
} else {
//Request Location Permission
checkLocationPermission();
}
}
else {
buildGoogleApiClient();
mGoogleMap.setMyLocationEnabled(true);
}
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
@Override
public void onConnected(Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
}
@Override
public void onConnectionSuspended(int i) {}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {}
@Override
public void onLocationChanged(Location location)
{
mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
//Place current location marker
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
mCurrLocationMarker = mGoogleMap.addMarker(markerOptions);
CircleOptions addCircle = new CircleOptions().center(latLng).radius(radiusInMeters).fillColor(shadeColor).strokeColor(strokeColor).strokeWidth(8);
mCircle = mGoogleMap.addCircle(addCircle);
//move map camera
mGoogleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(11));
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
private void checkLocationPermission() {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
// Should we show an explanation?
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.ACCESS_FINE_LOCATION)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
new AlertDialog.Builder(this)
.setTitle("Location Permission Needed")
.setMessage("This app needs the Location permission, please accept to use location functionality")
.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
//Prompt the user once explanation has been shown
ActivityCompat.requestPermissions(MapsActivity.this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION );
}
})
.create()
.show();
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION );
}
}
}
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted, yay! Do the
// location-related task you need to do.
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
if (mGoogleApiClient == null) {
buildGoogleApiClient();
}
mGoogleMap.setMyLocationEnabled(true);
}
} else {
// permission denied, boo! Disable the
// functionality that depends on this permission.
Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
}
return;
}
// other 'case' lines to check for other
// permissions this app might request
}
}
答案 5 :(得分：0)
Out[x]答案 6 :(得分：0)
要获取当前位置，您可以在LocationManager上使用getLastKnownLocation（）方法：
locationManager = (LocationManager) getActivity().getSystemService(getActivity().LOCATION_SERVICE);
Location currentLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
LatLng current = new LatLng(currentLocation.getLatitude(), currentLocation.getLongitude());
googleMap.addMarker(new MarkerOptions().position(current).title("Marker Label").snippet("Marker Description"));
CameraPosition cameraPosition = new CameraPosition.Builder().target(current).zoom(14).build();
googleMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
答案 7 :(得分：-2)
#lang racket/base
(provide parse-bag)
(require
(for-syntax racket/base syntax/parse)
syntax/parse)
(struct bag (label objects) #:transparent)
(struct object (name) #:transparent)
(begin-for-syntax
(define-syntax-class obj-exp
#:datum-literals (object name)
(pattern (object (name <name>:str))
#:with result #'(object <name>))))
;; IMPLEMENTATION ONE
;; DESC: The naive but failing approach
;; UNCOMMENT TO TEST
#;(define-syntax (parse-bag stx)
(syntax-parse stx
#:datum-literals (label objects)
[(_ (label <label>:str)
(~optional (objects <object>:obj-exp ...)))
#'(bag <label>
(list <object>.result ...))]))
;; ?: attribute contains non-list value
;; value: #f
;; IMPLEMENTATION TWO
;; DESC: adding defaults will fail too
;; UNCOMMENT TO TEST
#;(define-syntax (parse-bag stx)
(syntax-parse stx
#:datum-literals (label objects)
[(_ (label <label>:str)
(~optional (objects <object>:obj-exp ...)
#:defaults ([(<object> 1) null]))) ; (HERE)
#'(bag <label>
(list <object>.result ...))]))
;; ?: attribute contains non-list value
;; value: #f
;; IMPLEMENTATION THREE
;; DESC: it won't fail when not using syntax-class attributes
;; UNCOMMENT TO TEST
#;(define-syntax (parse-bag stx)
(syntax-parse stx
#:datum-literals (label objects)
[(_ (label <label>:str)
(~optional (objects <object>:obj-exp ...)
#:defaults ([(<object> 1) null])))
#'(bag <label>
(list <object> ...))])) ; (HERE)
;; name: unbound identifier
;; IMPLEMENTATION FOUR
;; DESC: it works, but I find it ugly
;; UNCOMMENT TO TEST
#;(define-syntax (parse-bag stx)
(syntax-parse stx
#:datum-literals (label objects)
[(_ (label <label>:str)
(~optional (objects <object>:obj-exp ...)))
#`(bag <label>
(list #,@(if (attribute <object>)
#'(<object>.result ...)
#'())))]))
(module+ test (require rackunit)
(check-equal?
(parse-bag
(label "Biscuits")
(objects (object (name "Cookie"))
(object (name "Brownie"))))
(bag "Biscuits"
(list (object "Cookie")
(object "Brownie"))))
(check-equal?
(parse-bag (label "Sweets"))
(bag "Sweets" '()))
)