// Handle selection events in the spatial operations picker.
private void OperationModel_ValueChanged(object sender, EventArgs e)
{
// Get the data model that contains the spatial operation choices.
PickerDataModel operationsModel = (PickerDataModel)_operationPicker.Model;
// If an operation hasn't been selected, return.
if (operationsModel.SelectedItem == "")
{
return;
}
// Remove any currently displayed result.
_polygonsOverlay.Graphics.Remove(_resultGraphic);
// Polygon geometry from the input graphics.
Geometry polygonOne = _graphicOne.Geometry;
Geometry polygonTwo = _graphicTwo.Geometry;
// Result polygon for spatial operations.
Geometry resultPolygon = null;
// Run the selected spatial operation on the polygon graphics and get the result geometry.
switch (operationsModel.SelectedItem)
{
case "Union":
resultPolygon = GeometryEngine.Union(polygonOne, polygonTwo);
break;
case "Difference":
resultPolygon = GeometryEngine.Difference(polygonOne, polygonTwo);
break;
case "Symmetric difference":
resultPolygon = GeometryEngine.SymmetricDifference(polygonOne, polygonTwo);
break;
case "Intersection":
resultPolygon = GeometryEngine.Intersection(polygonOne, polygonTwo);
break;
}
// Create a black outline symbol to use for the result polygon.
SimpleLineSymbol outlineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, Color.Black, 1);
// Create a solid red fill symbol for the result polygon graphic.
SimpleFillSymbol resultSymbol = new SimpleFillSymbol(SimpleFillSymbolStyle.Solid, Color.Red, outlineSymbol);
// Create the result polygon graphic and add it to the graphics overlay.
_resultGraphic = new Graphic(resultPolygon, resultSymbol);
_polygonsOverlay.Graphics.Add(_resultGraphic);
}
private void CreateLayout()
{
// Lay out the spatial operations UI vertically.
_operationToolsView.Axis = UILayoutConstraintAxis.Vertical;
// Create a label to prompt for a spatial operation.
UILabel operationLabel = new UILabel(new CGRect(5, 0, View.Bounds.Width, 30))
{
Text = "Choose a spatial operation:",
TextAlignment = UITextAlignment.Left,
TextColor = UIColor.Blue
};
// Create a picker model with spatial operation choices.
List <string> operationsList = new List <string> {
"", "Difference", "Intersection", "Symmetric difference", "Union"
};
PickerDataModel operationModel = new PickerDataModel(operationsList);
// Handle the selection change for spatial operations.
operationModel.ValueChanged += OperationModel_ValueChanged;
// Create a picker to show the spatial operations.
_operationPicker = new UIPickerView(new CGRect(20, 25, View.Bounds.Width - 20, 100))
{
Model = operationModel
};
// Create a button to reset the operation result.
UIButton resetButton = new UIButton(UIButtonType.Plain);
resetButton.Frame = new CGRect(20, 110, View.Bounds.Width - 20, 30);
resetButton.SetTitle("Reset operation", UIControlState.Normal);
resetButton.SetTitleColor(UIColor.Blue, UIControlState.Normal);
resetButton.TouchUpInside += ResetButton_TouchUpInside;
// Add the controls to the tools UI (stack view).
_operationToolsView.AddSubviews(operationLabel, _operationPicker, resetButton);
// Add the map view and tools sub-views to the view.
View.AddSubviews(_myMapView, _operationToolsView);
// Set the view background color.
View.BackgroundColor = UIColor.White;
}