Completamento automatico di Google Place in Xamarin.Forms

Question

Qualcuno ha integrato il completamento automatico di Google Place utilizzando Xamarin.Forms? Devo usarlo su una mappa per suggerimenti sulla posizione. Ho visto solo risorse per Xamarin.Android e Xamarin.iOS ma da parte dell'implementazione di AutoCompleteView, che anch'io non conosco. Sarei molto grato se qualcuno potesse guidarmi con questo. Grazie!

Answer 1

Il completamento automatico del luogo può essere implementato utilizzando l'API di Google Place, ogni volta che l'utente immette un carattere, la posizione corrispondente con il carattere immesso verrà recuperata dal server di Google e rilegata in Interfaccia utente.

Ecco il link come utilizzare Google Map Luogo API in forma Xamarin: http://www.appliedcodelog.com/2015/05/google-place-api-with-autocomplete-in.html

Inoltre, si prega di leggere sulla Gazzetta Google Places Web Service API: https://developers.google.com/places/web-service/autocomplete

Answer 2

Per iOS

[assembly: ExportRenderer(typeof(CustomAutoCompleteLocation), typeof(CustomAutoCompleteRenderer))] 
namespace Aesthetic.iOS.Renderer 
{ 
    public class CustomAutoCompleteProfileRenderer : EntryRenderer 
    { 
     IntPtr inptr; 
     string tx = "1"; 
     CustomAutoCompleteLocation _view; 
     Place place; 
     UITextField textView; 

     public UIWindow Window 
     { 
      get; 
      set; 
     } 
     protected override void OnElementChanged(ElementChangedEventArgs<Entry> e) 
     { 
      base.OnElementChanged(e); 

      _view = (CustomAutoCompleteLocation)Element; 
      if (Control != null) 
      { 
       textView = (UITextField)Control; 
       textView.Font = UIFont.FromName("Lato-Light", textView.Font.PointSize); 
       textView.BorderStyle = UITextBorderStyle.Line; 
       textView.Layer.BorderWidth = 1f; 
       textView.Layer.CornerRadius = 0f; 
       // do whatever you want to the textField here! 

       UIView paddingView = new UIView(new RectangleF(10, 16, 10, 16)); 
       textView.LeftView = paddingView; 
       textView.LeftViewMode = UITextFieldViewMode.Always; 
      } 
     } 
     protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e) 
     { 
      var x = sender as CustomAutoComplete; 

      if (e.PropertyName == "IsFocused") 
      { 
       if (tx == "1") 
       { 
        Device.BeginInvokeOnMainThread(() => 
        { 

         Window = new UIWindow(UIScreen.MainScreen.Bounds); 


         var controller = new LocationViewController(); 

         Window.RootViewController = controller; 
         // make the window visible 
         Window.MakeKeyAndVisible(); 
         controller.PlaceSelected1 += HandlePlaceSelection; 
        }); 
        tx = "2"; 
       } 
       else if (tx == "2") tx = "3"; 
       else if (tx == "3") tx = "4"; 
       else if (tx == "4") tx = "1"; 
      } 
     } 

     private void HandlePlaceSelection(object sender, string locationData) 
     { 

      textView.Text = locationData; 
      Window.Hidden = true; 
     } 
    } 
} 

E questo è il controller di visualizzazione di posizione

public partial class LocationViewController : UIViewController 
    { 
     public delegate void PlaceSelected(object sender, string locationData); 
     UITextField txtLocation; 
     public UIView backgroundView; 
     // UITextView txtLocation; 
     UIImageView googleAttribution; 
     UITableView tableViewLocationAutoComplete; 

     public event PlaceSelected PlaceSelected1; 
     public string strSampleString { get; set; } 
     LocationPredictionClass objAutoCompleteLocationClass; 
     string strAutoCompleteQuery; 
     LocationAutoCompleteTableSource objLocationAutoCompleteTableSource; 

     public LocationViewController() : base() 
     { 

     } 

     public override void ViewDidLoad() 
     { 
      base.ViewDidLoad(); 
      FnInitializeView(); 
      FnClickEventInit(); 
     } 

     void FnInitializeView() 
     { 


      backgroundView = new UIView(View.Frame); 
      backgroundView.BackgroundColor = UIColor.White; 
      View.AddSubview(backgroundView); 

      txtLocation = new UITextField(); 
      txtLocation.Frame = new CoreGraphics.CGRect(20, 20, View.Frame.Width-20, 45.0f); 
      txtLocation.TranslatesAutoresizingMaskIntoConstraints = false; 
      txtLocation.ReturnKeyType = UIReturnKeyType.Done; 
      txtLocation.BackgroundColor = UIColor.FromRGB(221,221,221); 
      txtLocation.TextColor = UIColor.Black; 

      View.AddSubview(txtLocation); 

      txtLocation.BecomeFirstResponder(); 

      tableViewLocationAutoComplete = new UITableView(); 
      tableViewLocationAutoComplete.Frame = new CoreGraphics.CGRect(txtLocation.Frame.X, txtLocation.Frame.Height+ txtLocation.Frame.Y, View.Frame.Width, View.Frame.Height - txtLocation.Frame.Height - txtLocation.Frame.Y); 
      tableViewLocationAutoComplete.BackgroundColor = UIColor.White; 
      tableViewLocationAutoComplete.Source = objLocationAutoCompleteTableSource; 
      View.AddSubview(tableViewLocationAutoComplete); 

      tableViewLocationAutoComplete.Hidden = false; 
      txtLocation.ShouldReturn += (textField) => textField.ResignFirstResponder(); 

      StringBuilder builderLocationAutoComplete = new StringBuilder(Constants.strPlacesAutofillUrl); 
      builderLocationAutoComplete.Append("?input={0}").Append("&key=").Append(Constants.strGooglePlaceAPILey); 
      strAutoCompleteQuery = builderLocationAutoComplete.ToString(); 
      builderLocationAutoComplete.Clear(); 
      builderLocationAutoComplete = null; 
     } 

     void FnClickEventInit() 
     { 
      txtLocation.EditingChanged += async delegate (object sender, EventArgs e) 
      { 
       if (string.IsNullOrWhiteSpace(txtLocation.Text)) 
       { 
        tableViewLocationAutoComplete.Hidden = true; 
       } 
       else 
       { 
        if (txtLocation.Text.Length > 2) 
        { 

         //Autofill 
         string strFullURL = string.Format(strAutoCompleteQuery, txtLocation.Text); 
         objAutoCompleteLocationClass = await RestRequestClass.LocationAutoComplete(strFullURL); 


         if (objAutoCompleteLocationClass != null && objAutoCompleteLocationClass.status == "OK") 
         { 
          if (objAutoCompleteLocationClass.predictions.Count > 0) 
          { 
           if (objLocationAutoCompleteTableSource != null) 
           { 
            objLocationAutoCompleteTableSource.LocationRowSelectedEventAction -= LocationSelectedFromAutoFill; 
            objLocationAutoCompleteTableSource = null; 
           } 

           tableViewLocationAutoComplete.Hidden = false; 
           objLocationAutoCompleteTableSource = new LocationAutoCompleteTableSource(objAutoCompleteLocationClass.predictions); 
           objLocationAutoCompleteTableSource.LocationRowSelectedEventAction += LocationSelectedFromAutoFill; 
           tableViewLocationAutoComplete.Source = objLocationAutoCompleteTableSource; 
           tableViewLocationAutoComplete.ReloadData(); 
          } 
          else 
           tableViewLocationAutoComplete.Hidden = true; 
         } 
         else 
         { 
          tableViewLocationAutoComplete.Hidden = true; 
         } 
        } 
       } 
      }; 

     } 

     void LocationSelectedFromAutoFill(Prediction objPrediction) 
     { 
      DismissViewController(true, null); 
      Console.WriteLine(objPrediction.description); 
      PlaceSelected1(this, objPrediction.description); 
      txtLocation.ResignFirstResponder(); 
     } 
    } 

    public class RestRequestClass 
    { 
     static async Task<string> CallService(string strURL) 
     { 
      WebClient client = new WebClient(); 
      string strResult; 
      try 
      { 
       strResult = await client.DownloadStringTaskAsync(new Uri(strURL)); 
      } 
      catch 
      { 
       strResult = "Exception"; 
      } 
      finally 
      { 
       client.Dispose(); 
       client = null; 
      } 
      return strResult; 
     } 

     internal static async Task<LocationPredictionClass> LocationAutoComplete(string strFullURL) 
     { 
      LocationPredictionClass objLocationPredictClass = null; 
      LocationPredictionClass objLocationPredictClass12 = new LocationPredictionClass(); 
      objLocationPredictClass12.predictions = new List<Prediction>(); 
      string strResult = await CallService(strFullURL); 
      if (strResult != "Exception") 
      { 
       objLocationPredictClass = JsonConvert.DeserializeObject<LocationPredictionClass>(strResult); 
      } 

      foreach (Prediction objPred in objLocationPredictClass.predictions) 
      { 
       if (objPred.types[0] == "country") 
       { 
        objLocationPredictClass12.predictions.Add(objPred); 
        objLocationPredictClass12.status = "OK"; 
       } 
      } 


      // string[] strPredictiveText = new string[data.Count]; 
      //int index = 0; 
      // foreach (Prediction objPred in data) 
      // { 
      //  strPredictiveText[index] = objPred.description; 
      //  index++; 
      // } 

      return objLocationPredictClass12; 
     } 

    } 


    public class MatchedSubstring 
    { 
     public int length { get; set; } 
     public int offset { get; set; } 
    } 

    public class Term 
    { 
     public int offset { get; set; } 
     public string value { get; set; } 
    } 

    public class Prediction 
    { 
     public string description { get; set; } 
     public string id { get; set; } 
     public List<MatchedSubstring> matched_substrings { get; set; } 
     public string place_id { get; set; } 
     public string reference { get; set; } 
     public List<Term> terms { get; set; } 
     public List<string> types { get; set; } 
    } 

    public class LocationPredictionClass 
    { 
     public List<Prediction> predictions { get; set; } 
     public string status { get; set; } 
    } 

    public class Constants 
    { 
     public static string strGooglePlaceAPILey = "AIzaSyBXJntNIs2aAvKIRwrgCEwOGwnigbSWep8"; 
     public static string strPlacesAutofillUrl = "https://maps.googleapis.com/maps/api/place/autocomplete/json"; 
    } 

    public class LocationAutoCompleteTableSource : UITableViewSource 
    { 
     const string strCellIdentifier = "Cell"; 
     readonly List<Prediction> lstLocations; 
     internal event Action<Prediction> LocationRowSelectedEventAction; 

     public LocationAutoCompleteTableSource(List<Prediction> arrItems) 
     { 
      lstLocations = arrItems; 
     } 

     public override nint RowsInSection(UITableView tableview, nint section) 
     { 
      return lstLocations.Count; 

     } 

     public override UIView GetViewForFooter(UITableView tableView, nint section) 
     { 
      return new UIView(); 
     } 

     public override UITableViewCell GetCell(UITableView tableView, Foundation.NSIndexPath indexPath) 
     { 
      UITableViewCell cell = tableView.DequeueReusableCell(strCellIdentifier) ?? new UITableViewCell(UITableViewCellStyle.Default, strCellIdentifier); 
      cell.TextLabel.Text = lstLocations[indexPath.Row].description; 
      cell.TextLabel.Font = UIFont.SystemFontOfSize(12); 
      return cell; 
     } 
     public override void RowSelected(UITableView tableView, Foundation.NSIndexPath indexPath) 
     { 
      if (LocationRowSelectedEventAction != null) 
      { 
       LocationRowSelectedEventAction(lstLocations[indexPath.Row]); 
      } 
      tableView.DeselectRow(indexPath, true); 
     } 
    } 
}