使用搜索栏在地图上过滤图钉及其值

Question

我正在尝试根据您在搜索栏中所写的内容来过滤地图上的图钉。因此，例如，如果您这样写："Unit"，那么只会显示地址为 "Unit....(ed states)" 的引脚。我从一些代码开始，但我不确定我应该如何继续。现在，当我输入内容时，每个图钉都会加载，而不是与搜索栏上输入的文本匹配的图钉。我想我必须在添加引脚之前使用过滤器功能。

这是我的起始页：

public StartPage ()
{
    searchBar.TextChanged += (sender2, e2) => FilterContacts(searchBar.Text);

    searchBar.SearchButtonPressed += (sender2, e2) => FilterContacts(searchBar.Text);
}

这就是过滤发生的地方。我从我的数据库中获取数据。

private  async void FilterContacts (string filter)
    {
        map.Pins.Clear ();
        if (string.IsNullOrWhiteSpace (filter)) {

        } else {

            var getItems = await phpApi.getInfo ();

            foreach (var currentItem in getItems["results"]) {

                theName = currentItem ["Name"].ToString (); //theName = string
                theAdress = currentItem ["Adress"].ToString (); //theAdress = String

                var theUserPosition = theAdress;
                Geocoder gc = new Geocoder ();
                Task<IEnumerable<Position>> result =
                    gc.GetPositionsForAddressAsync (theUserPosition);

                if (theAdress != null) {

                    IEnumerable<Position> data = await result;

                    foreach (Position p in data) {

                        var pin = new Pin ();
                        pin.Position = new Position (p.Latitude, p.Longitude);
                        pin.Label = theName;
                        pin.Address = theAdress;                    
                        map.Pins.Add (pin);

                        theAdress.ToLower ().Contains (filter.ToLower ());


                    }
                }
            }
        }

    }

Answer 1

加载数据并对其进行一次地理编码并存储；然后只调用过滤逻辑

public StartPage ()
{
    searchBar.TextChanged += (sender2, e2) => FilterPins(searchBar.Text);

    searchBar.SearchButtonPressed += (sender2, e2) => FilterPins(searchBar.Text);
}

// create a list to store our Pins 
List<Pin> myPins = new List<Pin>();

private async override void OnAppearing() {

  if (myPins.Count == 0) {
    myPins = await LoadData();

    filterPins(string.Empty);
  }
}

// load the data, geocode, store results
private async List<Pin> LoadData() {

  var pins = new List<Pin>();

  var getItems = await phpApi.getInfo ();

  foreach (var currentItem in getItems["results"]) {

    Geocoder gc = new Geocoder ();
    var pos = await gc.GetPositionsForAddressAsync (theUserPosition);

    foreach (Position p in pos) {

      var pin = new Pin ();
      pin.Position = new Position (p.Latitude, p.Longitude);
      pin.Label = theName;
      pin.Address = theAdress;                    

      pins.Add(pin);
    }     
  }

  return pins;
}

private  async void FilterPins (string filter)
{
  map.Pins.Clear ();

  foreach(Pin p in myPins) {
    if (string.IsNullOrWhiteSpace(filter) || (p.Address.Contains(filter)) {
      map.Pins.Add(p);
    }
  }
}

使用搜索栏在地图上过滤图钉及其值

Filter pins and its value on a map with a searchbar

c#

xamarin

xamarin.forms