Xamarin September – Stacked Control

Step 1

If not already, follow Setup and Start on how to Install and get Started with Visual Studio 2017 or in Windows 10 choose Start, and then from the Start Menu locate and select Visual Studio 2017.

Step 2

Once Visual Studio Community 2017 has started, from the Menu choose File, then New then Project…

Step 3

From New Project choose Visual C# from Installed, Templates then choose Cross Platform App (Xamarin) and then type in a Name and select a Location and then select Ok to create the Project

Step 4

Then in New Cross Platform App you need to select the Blank App Template then from UI Technology select Xamarin.Forms and in Code Sharing Strategy select Shared Project and then select Ok to continue

Step 5

The Xamarin Mac Agent will be displayed allowing connection to an Apple Mac but this can be dismissed with Close if running solely on Windows 10

Step 6

Then in New Universal Windows Project you need to select the Target Version to be Windows 10 Creators Update (10.0; Build 15063) and the Minimum Version to Windows 10 Creators Update (10.0; Build 15063) and then select Ok

Step 7

From the Menu choose Project, then Add New Item…

From the Add New Item choose Visual C# from Installed then choose Code then select Code File and then in the Name as Stacked.cs and then select Add to add the file to the Project

Step 9

Then in the Code View for Stacked.cs the following should be entered:

using System;
using System.Collections.Generic;
using System.Linq;
using Xamarin.Forms;

namespace StackedControl
{
    public class Stacked : Grid
    {
        private List<Color> _palette = new List<Color>();
        private List<double> _items = new List<double>();

        private List<double> Percentages()
        {
            List<double> results = new List<double>();
            double total = _items.Sum();
            foreach (double item in _items)
            {
                results.Add((item / total) * 100);
            }
            return results.OrderBy(o => o).ToList();
        }

        private BoxView GetBox(Color colour, int column)
        {
            BoxView box = new BoxView()
            {
                InputTransparent = true,
                VerticalOptions = LayoutOptions.FillAndExpand,
                HorizontalOptions = LayoutOptions.FillAndExpand,
                BackgroundColor = colour
            };
            box.SetValue(Grid.ColumnProperty, column);
            return box;
        }

        private void Layout()
        {
            this.RowSpacing = 0;
            this.ColumnSpacing = 0;
            List<double> percentages = Percentages();
            this.ColumnDefinitions.Clear();
            for (int index = 0; index < percentages.Count(); index++)
            {
                double percentage = percentages[index];
                ColumnDefinition column = new ColumnDefinition()
                {
                    Width = new GridLength(percentage, GridUnitType.Star)
                };
                this.ColumnDefinitions.Add(column);
                Color colour = (index < _palette.Count()) ? _palette[index] : Color.Black;
                Children.Add(GetBox(colour, index));
            }
        }

        public List<Color> Palette
        {
            get { return _palette; }
            set { _palette = value; }
        }

        public List<double> Items
        {
            get { return _items; }
            set { _items = value; Layout(); }
        }

        public void Fibonacci(params Color[] colours)
        {
            Palette = colours.ToList();
            Func<int, int> fibonacci = null;
            fibonacci = value => value > 1 ?
            fibonacci(value - 1) + fibonacci(value - 2) : value;
            Items = Enumerable.Range(0, Palette.Count())
            .Select(fibonacci).Select(s => (double)s).ToList();
        }
    }
}

Step 10

In the Solution Explorer select MainPage.xaml from the Shared Project

Step 11

From the Menu choose View and then Open

Step 12

The XAML View will be displayed, and in this remove the Label then between the ContentPage and /ContentPage elements, enter the following XAML:

<Grid>
	<Grid.RowDefinitions>
		<RowDefinition Height="*" />
		<RowDefinition Height="Auto" />
	</Grid.RowDefinitions>
	<local:Stacked Grid.Row="0" x:Name="Display" Margin="50"/>
	<Grid Grid.Row="1" Margin="10">
		<Button Text="Show" HorizontalOptions="Center" WidthRequest="100" Clicked="Show_Clicked"/>
	</Grid>
</Grid>

It should appear as such:

Step 13

In the Solution Explorer select the Expand arrow next to MainPage.xaml to open MainPage.cs, then select this from the Shared Project

Step 14

From the Menu choose View and then Open

Step 15

Once in the Code View, below the public MainPage() { … } the following Code should be entered:

private void Show_Clicked(object sender, EventArgs e)
{
	Display.Fibonacci(
		Color.Black,
		Color.Gray,
		Color.Red,
		Color.Orange,
		Color.Yellow,
		Color.Green,
		Color.Cyan,
		Color.Blue,
		Color.Magenta,
		Color.Purple);
}

It should then appear as such:

Step 16

That completes the application, so from the Menu choose Build and then Build Solution

Step 17

Then from the Menu choose Debug then Start Debugging to run the Application in the Android Emulator

Step 18

Once started the Application should then appear in the Android Emulator

Step 19

After the Application has started running you can then select Show which should display a Stacked Chart based on the Palette in a Fibonacci sequence

Step 20

To Exit the Application select Stop in Visual Studio

Step 21

Another option is to run as a Universal Windows Application. From Solution Explorer select the Project ending with .UWP (Universal Windows), then from the Menu choose Project then Set as StartUp Project

Step 22

Then again from the Menu choose Build and then select the Deploy option ending with .UWP

Step 23

Then once again from the Menu choose Debug then Start Debugging to run the Application in Windows 10

Step 24

Once started the Application should then appear

Step 25

After the Application has started running you can then select Show which should display a Stacked Chart based on the Palette in a Fibonacci sequence

Step 26

To Exit the Application select Stop in Visual Studio

Step 27

Also if you have Mac with the Xamarin tools installed and have enabled and connected to the Xamarin Mac Agent. From Solution Explorer select the Project ending with .iOS, then from the Menu choose Project then Set as StartUp Project

Step 28

Then once again from the Menu choose Debug then Start Debugging to run the Application for iOS

Step 29

Once started the Application should then appear

Step 30

After the Application has started running you can then select Show which should display a Stacked Chart based on the Palette in a Fibonacci sequence

Step 31

To Exit the Application select Stop in Visual Studio

Thanks for Julia Boichentsova for helping with iOS screenshots

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