如何在google map android中获取当前位置

Question

    if (googleMap == null) {
        googleMap = ((MapFragment) getFragmentManager().findFragmentById(
                R.id.map)).getMap();

        // check if map is created successfully or not
        if (googleMap == null) {
            Toast.makeText(getApplicationContext(),
                    "Sorry! unable to create maps", Toast.LENGTH_SHORT)
                    .show();
        }
    }
    googleMap.setMyLocationEnabled(true);
    Location myLocation = googleMap.getMyLocation();  //Nullpointer exception.........
    LatLng myLatLng = new LatLng(myLocation.getLatitude(),
            myLocation.getLongitude());

    CameraPosition myPosition = new CameraPosition.Builder()
            .target(myLatLng).zoom(17).bearing(90).tilt(30).build();
    googleMap.animateCamera(
        CameraUpdateFactory.newCameraPosition(myPosition));

Answer 1

从Google Sample(CurrentPlaceDetailsOnMap)中为KotlinbyFusedLocationProviderClient，以便SetonMyLocationChangeListener不推荐使用

首先，将实现'com.google.android.libraries.places:places:2.4.0'添加到依赖项

接下来，在片段中添加以下变量

private lateinit var fusedLocationProviderClient: FusedLocationProviderClient
private var lastKnownLocation: Location? = null

接下来，在onviewcreated中添加

    fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(requireContext())

在onmapready中调用此方法

private fun 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 {
            val locationResult = fusedLocationProviderClient.lastLocation
            locationResult.addOnCompleteListener(context as Activity) { task ->
                if (task.isSuccessful) {
                    // Set the map's camera position to the current location of the device.
                    lastKnownLocation = task.result
                    if (lastKnownLocation != null) {
                        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(
                                LatLng(lastKnownLocation!!.latitude,
                                        lastKnownLocation!!.longitude), DEFAULT_ZOOM.toFloat()))
                    }
                } else {
                    logD("Current location is null. Using defaults.")
                    logD("Exception: ${task.exception}")
                    mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(LatLng(35.6892, 51.3890), 15.toFloat()))
                    mMap.uiSettings?.isMyLocationButtonEnabled = false
                }
            }
    } catch (e: SecurityException) {
        logD("Exception: ${e.message}")
    }
}

fun requestLocation(context: Context) {
        val mLocationRequest = LocationRequest.create()
        mLocationRequest.interval = 60000
        mLocationRequest.fastestInterval = 5000
        mLocationRequest.priority = LocationRequest.PRIORITY_HIGH_ACCURACY
        val mLocationCallback: LocationCallback = object : LocationCallback() {
            override fun onLocationResult(locationResult: LocationResult) {
                for (location in locationResult.locations) {
                    if (location != null && lastKnownLocation == null) {
                        lastKnownLocation = location
                    }
                }
            }
        }
        LocationServices.getFusedLocationProviderClient(context)
            .requestLocationUpdates(mLocationRequest, mLocationCallback, null)
    }

mMap.isMyLocationEnabled = true
mMap.uiSettings.isMyLocationButtonEnabled = false