未触发地图位置更改侦听器

Posted 2023-05-06

【中文标题】未触发地图位置更改侦听器

【英文标题】：Maps location change listener not triggered

【发布时间】：2020-08-27 22:45:19

【问题描述】：

我正在开发一个包含 Google 地图的应用程序。地图可以找到我的位置并在其上放置标记。但我写了 onLocationChangeListener 和。 Toast 显示我的坐标（经度高度）。但它不会在屏幕上呈现任何吐司，我不明白为什么。它应该渲染一个 toast 以显示我在更改和第一次找到时的坐标。

地图活动

class MapsActivity : AppCompatActivity(), OnMapReadyCallback, IOnLoadLocationListener,
     GoogleApiClient.ConnectionCallbacks,
    GoogleApiClient.OnConnectionFailedListener,
    com.google.android.gms.location.LocationListener

    private var mMap: GoogleMap? = null
    private lateinit var locationRequest: LocationRequest
    private lateinit var locationCallback: LocationCallback
    private lateinit var fusedLocationProviderClient: FusedLocationProviderClient
    private var currentMarker: Marker? = null
    private lateinit var myLocationRef: DatabaseReference
    private lateinit var dangerousArea: MutableList<LatLng>
    private lateinit var listener: IOnLoadLocationListener
    private var photoUrl: String? = null
    private lateinit var myCity: DatabaseReference
    private lateinit var lastLocation: Location
    private var geoQuery: GeoQuery? = null
    private lateinit var geoFire: GeoFire
    private lateinit var locationManager: LocationManager
    private lateinit var latLng: LatLng
    private lateinit var location: Location
    private lateinit var locationListener: LocationListener
    private lateinit var mLocation : Location
    private lateinit var mGoogleApiClient : GoogleApiClient
    private var UPDATE_INTERVAL: Long = 2000
    private var FASTEST_INTERVAL: Long = 5000


    override fun onCreate(savedInstanceState: Bundle?) 
        super.onCreate(savedInstanceState)
        setContentView(com.example.huaweichallange.R.layout.activity_maps)

        val personInfo = intent.extras!!.get("extra") as UserInfoModel
        photoUrl = personInfo.personPhoto


        Dexter.withActivity(this)
            .withPermission(android.Manifest.permission.ACCESS_FINE_LOCATION)
            .withListener(object : PermissionListener 
                override fun onPermissionGranted(response: PermissionGrantedResponse?) 
                    buildLocationRequest()
                    buildLocationCallBack()
                    fusedLocationProviderClient =
                        LocationServices.getFusedLocationProviderClient(this@MapsActivity)
                    initArea()
                    settingGeoFire()
                

                override fun onPermissionRationaleShouldBeShown(
                    permission: com.karumi.dexter.listener.PermissionRequest?,
                    token: PermissionToken?
                ) 

                

                override fun onPermissionDenied(response: PermissionDeniedResponse?) 
                    Toast.makeText(
                        this@MapsActivity,
                        "You must enable this permission",
                        Toast.LENGTH_SHORT
                    ).show()
                
            ).check()



    

    private fun settingGeoFire() 
        myLocationRef = FirebaseDatabase.getInstance().getReference("MyLocation")
        geoFire = GeoFire(myLocationRef)
    

    private fun initArea() 
        myCity = FirebaseDatabase.getInstance()
            .getReference("DangerousArea").child("MyCity")

        listener = this

        myCity.addValueEventListener(object : ValueEventListener 
            override fun onCancelled(p0: DatabaseError) 

            

            override fun onDataChange(dataSnapshot: DataSnapshot) 
                val latLngList = ArrayList<MyLatlng>()
                for (locationSnapShot in dataSnapshot.children) 
                    val latLng = locationSnapShot.getValue(MyLatlng::class.java)
                    latLngList.add(latLng!!)
                
                listener.onLocationLoadSuccess(latLngList)
            

        )
    

    private fun buildLocationCallBack() 
        locationCallback = object : LocationCallback() 
            override fun onLocationResult(locationResult: LocationResult?) 
                super.onLocationResult(locationResult)
                if (mMap != null) 
                    lastLocation = locationResult!!.lastLocation
                    addUserMarker()
                
            
        
    

    private fun addUserMarker() 

        geoFire.setLocation(
            "You",
            GeoLocation(lastLocation.latitude, lastLocation.longitude)
        )  _, _ ->
            if (currentMarker != null) currentMarker!!.remove()
            currentMarker = mMap!!.addMarker(
                MarkerOptions().position(
                    LatLng(
                        lastLocation.latitude,
                        lastLocation.longitude
                    )
                ).title("You").icon(BitmapDescriptorFactory.fromBitmap(getBitmap(photoUrl)))
            )
            mMap!!.animateCamera(CameraUpdateFactory.newLatLngZoom(currentMarker!!.position, 12.0f))

        
    
    fun getBitmap(url : String?) : Bitmap? 
        var bmp : Bitmap ? = null
        Picasso.get().load(url).into(object : com.squareup.picasso.Target 
            override fun onBitmapLoaded(bitmap: Bitmap?, from: Picasso.LoadedFrom?) 
                bmp =  bitmap
            

            override fun onPrepareLoad(placeHolderDrawable: Drawable?) 

            override fun onBitmapFailed(e: Exception?, errorDrawable: Drawable?) 
        )
        return bmp
    

    private fun buildLocationRequest() 
        locationRequest = LocationRequest()
        locationRequest.priority = LocationRequest.PRIORITY_HIGH_ACCURACY
        locationRequest.interval = 500
        locationRequest.fastestInterval = 300
        locationRequest.smallestDisplacement = 5f

    

    override fun onMapReady(googleMap: GoogleMap) 
        mMap = googleMap

        mMap!!.uiSettings.isZoomControlsEnabled = true


        if (fusedLocationProviderClient != null) 
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) 
                if (checkSelfPermission(android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED)
                    return
            
            fusedLocationProviderClient.requestLocationUpdates(
                locationRequest,
                locationCallback,
                Looper.myLooper()

            )
        
       val pref= [e-mail]("darkMode", Context.MODE_PRIVATE)
        val darkMode = pref.getString("darkMode","dark")
        if(darkMode!=null)
            useDarkMode(googleMap)
        


    

    private fun useDarkMode(googleMap: GoogleMap?) 
        try 
            val success : Boolean = googleMap!!.setMapStyle(
                MapStyleOptions.
            loadRawResourceStyle(this, com.example.huaweichallange.R.raw.map_style))
        
        catch (e: Resources.NotFoundException)
            Log.e("MapActivity","Map Style Cannot found")
        
    


    override fun onLocationLoadSuccess(latLng: List<MyLatlng>) 
        dangerousArea = ArrayList()
        for (myLatLng in latLng) 
            val convert = LatLng(myLatLng.latitude, myLatLng.longitude)

            dangerousArea.add(convert)
        
        val mapFragment = supportFragmentManager
            .findFragmentById(com.example.huaweichallange.R.id.map) as SupportMapFragment
        mapFragment.getMapAsync(this)
        if (mMap != null) 
            mMap!!.clear()

            addUserMarker()

        

    


    override fun onLocationLoadFailed(message: String) 
        Toast.makeText(this, "" + message, Toast.LENGTH_SHORT).show()
    

    override fun onStop() 
        fusedLocationProviderClient.removeLocationUpdates(locationCallback)
        super.onStop()
    


    override fun onConnected(p0: Bundle?) 

    

    override fun onConnectionSuspended(p0: Int) 

    

    override fun onConnectionFailed(p0: ConnectionResult) 

    

    override fun onLocationChanged(location: Location?) 


        val msg : String = "Updated Location: " + lastLocation!!.longitude+","+ lastLocation!!.latitude
        Toast.makeText(this@MapsActivity, msg.toDouble().toString(), Toast.LENGTH_SHORT).show()


        latLng = LatLng(location!!.latitude, location!!.longitude)

        val mapFragment : SupportMapFragment = supportFragmentManager.findFragmentById(com.example.huaweichallange.R.id.map) as SupportMapFragment
        mapFragment.getMapAsync(this)

    

【问题讨论】：

也许你可以通过移动你的设备来尝试一下，这可以触发onLocationChanged。地图可能已经获取了您设备的最后一个已知位置。

@DhavalShah 我连接了我的实际设备并走进屋内，但什么也没发生。

【参考方案1】：

您没有将您的活动设置为位置侦听器。您的活动实现了com.google.android.gms.location.LocationListener 接口，但是您将另一个回调（locationCallback）传递给您的fusedLocationProviderClient：

fusedLocationProviderClient.requestLocationUpdates(
    locationRequest,
    locationCallback, // you should replace this with your activity instance
    Looper.myLooper()
)

到：

fusedLocationProviderClient.requestLocationUpdates(
    locationRequest,
    this, // your activity instance - this
    Looper.myLooper()
)

那么你应该在你的onLocationChanged回调中拦截位置变化：

override fun onLocationChanged(location: Location?) 
   Log.v("your_tag", "Latitude:$location.latitude, Longitude:$location.longitude")

【讨论】：

但 fusedLocationProviderClient.requestLocationUpdates 需要 3 个参数“locationRequest、LocationCallback、Looper”。当我写“this”时，它会给出错误类型不匹配。

我也改为“this.locationCallback”，但也没有发生任何事情。

您尝试过 this@MapsActivity 吗？

是的，但是没有用。我只是将 toast 移到 buildLocationCallback 函数内部，它起作用了。

这不是你问的，onLocationResult 在设备位置信息可用时触发，而不是每次位置变化时触发