收集 GPS 坐标 [英] Collecting GPS co-Ordinates

问题描述

我正在使用 xamarin 构建本机 android 应用程序.问题是，该应用程序在模拟器上完美地收集和显示坐标，但是当我将它放在智能手机上(尝试了 2 部三星手机)时，它无法确定当前地址.额外的信息数据和位置已打开，所以我不确定问题出在哪里.谢谢你的帮助.这是帮助 https://developer.xamarin.com/的 xammarin 配方包装食谱/android/os_device_resources/gps/get_current_device_location/

I am building a native android app using xamarin. The issue is, that the application collects and displays the coordinates perfectly on the emulator but when I put it on a smartphone (tried 2 samsung phones) it comes up with can't determine the current address. Extra information data and locations are turned on so I am not sure where the issue is. Thanks for your help. here is the xammarin recipe encase that helps https://developer.xamarin.com/recipes/android/os_device_resources/gps/get_current_device_location/

    [Activity(Label = "NewRoute")]
    public class NewRouteActivity : Activity, ILocationListener
    {

        static readonly string TAG = "X:" + typeof(NewRouteActivity).Name;
        TextView _addressText;
        Location _currentLocation;
        LocationManager _locationManager;

        string _locationProvider;
        TextView _locationText;


        public async void OnLocationChanged(Location location) {
            _currentLocation = location;
            if (_currentLocation == null)
            {
                _locationText.Text = "Unable to determine your location. Try again in a short while.";
            }
            else
            {
                _locationText.Text = string.Format("{0:f6},{1:f6}", _currentLocation.Latitude, _currentLocation.Longitude);
                Address address = await ReverseGeocodeCurrentLocation();
                DisplayAddress(address);
            }
        }

        public void OnProviderDisabled(string provider) { }

        public void OnProviderEnabled(string provider) { }

        public void OnStatusChanged(string provider, Availability status, Bundle extras) { }

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            SetContentView(Resource.Layout.CreatetRoute);

            _addressText = FindViewById<TextView>(Resource.Id.address_text);
            _locationText = FindViewById<TextView>(Resource.Id.location_text);
            FindViewById<TextView>(Resource.Id.get_address_button).Click += AddressButton_OnClick;

            InitializeLocationManager();


            Button btnEndPoint = FindViewById<Button>(Resource.Id.btnEndPoint);
            btnEndPoint.Click += new EventHandler(AfterPointsCollected);
        }
        //Location Stuff
        void InitializeLocationManager()
        {
            _locationManager = (LocationManager)GetSystemService(LocationService);
            Criteria criteriaForLocationService = new Criteria
            {
                Accuracy = Accuracy.Fine
            };
            IList<string> acceptableLocationProviders = _locationManager.GetProviders(criteriaForLocationService, true);

            if (acceptableLocationProviders.Any())
            {
                _locationProvider = acceptableLocationProviders.First();
            }
            else
            {
                _locationProvider = string.Empty;
            }
            Log.Debug(TAG, "Using " + _locationProvider + ".");
        }
        //Override OnResume so that Activity1 will begin listening to the LocationManager when the activity comes into the foreground:
        protected override void OnResume()
        {
            base.OnResume();
            _locationManager.RequestLocationUpdates(_locationProvider, 0, 0, this);
        }
        async void AddressButton_OnClick(object sender, EventArgs eventArgs)
        {
            if (_currentLocation == null)
            {
                _addressText.Text = "Can't determine the current address. Try again in a few minutes.";
                return;
            }

            Address address = await ReverseGeocodeCurrentLocation();
            DisplayAddress(address);
        }

        async Task<Address> ReverseGeocodeCurrentLocation()
        {
            Geocoder geocoder = new Geocoder(this);
            IList<Address> addressList =
                await geocoder.GetFromLocationAsync(_currentLocation.Latitude, _currentLocation.Longitude, 10);

            Address address = addressList.FirstOrDefault();
            return address;
        }

        void DisplayAddress(Address address)
        {
            if (address != null)
            {
                StringBuilder deviceAddress = new StringBuilder();
                for (int i = 0; i < address.MaxAddressLineIndex; i++)
                {
                    deviceAddress.AppendLine(address.GetAddressLine(i));
                }
                // Remove the last comma from the end of the address.
                _addressText.Text = deviceAddress.ToString();
            }
            else
            {
                _addressText.Text = "Unable to determine the address. Try again in a few minutes.";
            }
        }

        //Override OnPause and unsubscribe Activity1 from the LocationManager when the activity goes into the background:
        protected override void OnPause()
        {
            base.OnPause();
            _locationManager.RemoveUpdates(this);
        }
        //Changing Activity
        void AfterPointsCollected(object sender, EventArgs e)
        {
            //context   //activity
            Intent intent = new Intent(this, typeof(AfterPointsCollectedActivity));
            //starts the activity with the intent above
            this.StartActivity(intent);

        }

推荐答案

您的手机可能正在运行 MarshMallow，现在需要您请求位置服务权限.

Your phones are probably running MarshMallow which now require that you request permission for location services.

您可以在此处阅读有关它的更多信息 https://blog.xamarin.com/requesting-runtime-permissions-in-android-marshmallow/.您可能想要使用这个 Nuget 包来为您处理所有这些.https://github.com/jamesmontemagno/Xamarin.Plugins/tree/master/Geolocator

You can read more about it here https://blog.xamarin.com/requesting-runtime-permissions-in-android-marshmallow/. You might want to use this Nuget package that handles all that for you. https://github.com/jamesmontemagno/Xamarin.Plugins/tree/master/Geolocator

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