SketchOnMap.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"             
             xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Xamarin.Forms;assembly=Esri.ArcGISRuntime.Xamarin.Forms"
             x:Class="ArcGISRuntimeXamarin.Samples.SketchOnMap.SketchOnMap">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition Height="70"/>
        </Grid.RowDefinitions>
        <esriUI:MapView x:Name="MyMapView"
                    Grid.Row="0"/>
        <Grid x:Name="DrawToolsGrid"
              BackgroundColor="White"
              Grid.Row="0"
              WidthRequest="260"
              HorizontalOptions="Center" VerticalOptions="Start"
              Margin="0,10"
              IsVisible="False">
            <Grid.RowDefinitions>
                <RowDefinition Height="5"/>
                <RowDefinition Height="50"/>
                <RowDefinition Height="40"/>
                <RowDefinition/>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Label Grid.Row="1" Grid.Column="0"
                    HorizontalOptions="End" VerticalOptions="Center"
                    Text="Sketch shape:"/>
            <Picker x:Name="SketchModePicker"
                    Grid.Row="1" Grid.Column="1"
                    Margin="0,0,5,0"
                    HorizontalOptions="Fill" VerticalOptions="Center"/>
            <Button Grid.Row="2" Grid.Column="1" 
                    BorderColor="Gray"
                    Text="Draw" 
                    WidthRequest="100" HeightRequest="35"
                    HorizontalOptions="Center" VerticalOptions="Start"
                    Clicked="DrawButtonClick"/>
            <Button x:Name="EditButton"
                    BorderColor="Gray"
                    Grid.Row="2" Grid.Column="0"
                    Text="Edit"
                    WidthRequest="100" HeightRequest="35"
                    HorizontalOptions="Center" VerticalOptions="Start"
                    IsEnabled="False"
                    Clicked="EditButtonClick"/>
        </Grid>
        <Grid Grid.Row="1">
            <Grid.ColumnDefinitions>
                <ColumnDefinition/>
                <ColumnDefinition/>
                <ColumnDefinition/>
                <ColumnDefinition/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Button x:Name="DrawEditButton"
                Grid.Column="0"
                Text="Sketch"
                Clicked="ShowDrawTools"/>
            <Button Grid.Column="1"
                Text="Undo"
                Command="{Binding UndoCommand}"/>
            <Button Grid.Column="2"
                Text="Redo"
                Command="{Binding RedoCommand}"/>
            <Button Grid.Column="3"
                Text="Done"
                Command="{Binding CompleteCommand}"/>
            <Button x:Name="ClearButton" 
                Grid.Column="4"
                Text="Clear"
                IsEnabled="False"
                Clicked="ClearButtonClick"/>
        </Grid>
    </Grid>
</ContentPage>