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dinhbathi2702/HorizontalList.cs

Last active July 3, 2018 15:33
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  1. dinhbathi2702 renamed this gist Jul 3, 2018. 1 changed file with 0 additions and 0 deletions.
    0 HorizontalListXamarinForms.txt → HorizontalList.cs
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  2. dinhbathi2702 renamed this gist Jul 3, 2018. 1 changed file with 0 additions and 0 deletions.
    0 gistfile1.txt → HorizontalListXamarinForms.txt
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  3. dinhbathi2702 created this gist Jul 3, 2018.
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    using System;
    using System.Collections;
    using System.Collections.Generic;
    using System.Windows.Input;
    using Xamarin.Forms;

    namespace Core.Controls
    {
    public class HorizontalList : Grid
    {
    private ICommand _innerSelectedCommand;
    private readonly ScrollView _scrollView;
    private readonly StackLayout _itemsStackLayout;

    public event EventHandler SelectedItemChanged;

    public StackOrientation ListOrientation { get; set; }

    public double Spacing { get; set; }

    public static readonly BindableProperty SelectedCommandProperty =
    BindableProperty.Create("SelectedCommand", typeof(ICommand), typeof(HorizontalList), null);

    public static readonly BindableProperty ItemsSourceProperty =
    BindableProperty.Create("ItemsSource", typeof(IEnumerable), typeof(HorizontalList), default(IEnumerable<object>), BindingMode.TwoWay, propertyChanged: ItemsSourceChanged);

    public static readonly BindableProperty SelectedItemProperty =
    BindableProperty.Create("SelectedItem", typeof(object), typeof(HorizontalList), null, BindingMode.TwoWay, propertyChanged: OnSelectedItemChanged);

    public static readonly BindableProperty ItemTemplateProperty =
    BindableProperty.Create("ItemTemplate", typeof(DataTemplate), typeof(HorizontalList), default(DataTemplate));

    public ICommand SelectedCommand
    {
    get { return (ICommand)GetValue(SelectedCommandProperty); }
    set { SetValue(SelectedCommandProperty, value); }
    }

    public IEnumerable ItemsSource
    {
    get { return (IEnumerable)GetValue(ItemsSourceProperty); }
    set { SetValue(ItemsSourceProperty, value); }
    }

    public object SelectedItem
    {
    get { return (object)GetValue(SelectedItemProperty); }
    set { SetValue(SelectedItemProperty, value); }
    }

    public DataTemplate ItemTemplate
    {
    get { return (DataTemplate)GetValue(ItemTemplateProperty); }
    set { SetValue(ItemTemplateProperty, value); }
    }

    private static void ItemsSourceChanged(BindableObject bindable, object oldValue, object newValue)
    {
    var itemsLayout = (HorizontalList)bindable;
    itemsLayout.SetItems();
    }

    public HorizontalList()
    {
    _scrollView = new ScrollView();

    _itemsStackLayout = new StackLayout
    {
    BackgroundColor = BackgroundColor,
    Padding = Padding,
    Spacing = Spacing,
    HorizontalOptions = LayoutOptions.FillAndExpand
    };

    _scrollView.BackgroundColor = BackgroundColor;
    _scrollView.Content = _itemsStackLayout;
    Children.Add(_scrollView);
    }

    protected virtual void SetItems()
    {
    _itemsStackLayout.Children.Clear();
    _itemsStackLayout.Spacing = Spacing;

    _innerSelectedCommand = new Command<View>(view =>
    {
    SelectedItem = view.BindingContext;
    SelectedItem = null; // Allowing item second time selection
    });

    _itemsStackLayout.Orientation = ListOrientation;
    _scrollView.Orientation = ListOrientation == StackOrientation.Horizontal
    ? ScrollOrientation.Horizontal
    : ScrollOrientation.Vertical;

    if (ItemsSource == null)
    {
    return;
    }

    foreach (var item in ItemsSource)
    {
    _itemsStackLayout.Children.Add(GetItemView(item));
    }

    _itemsStackLayout.BackgroundColor = BackgroundColor;
    SelectedItem = null;
    }

    protected virtual View GetItemView(object item)
    {
    var content = ItemTemplate.CreateContent();
    var view = content as View;

    if (view == null)
    {
    return null;
    }

    view.BindingContext = item;

    var gesture = new TapGestureRecognizer
    {
    Command = _innerSelectedCommand,
    CommandParameter = view
    };

    AddGesture(view, gesture);

    return view;
    }

    private void AddGesture(View view, TapGestureRecognizer gesture)
    {
    view.GestureRecognizers.Add(gesture);

    var layout = view as Layout<View>;

    if (layout == null)
    {
    return;
    }

    foreach (var child in layout.Children)
    {
    AddGesture(child, gesture);
    }
    }

    private static void OnSelectedItemChanged(BindableObject bindable, object oldValue, object newValue)
    {
    var itemsView = (HorizontalList)bindable;
    if (newValue == oldValue && newValue != null)
    {
    return;
    }

    itemsView.SelectedItemChanged?.Invoke(itemsView, EventArgs.Empty);

    if (itemsView.SelectedCommand?.CanExecute(newValue) ?? false)
    {
    itemsView.SelectedCommand?.Execute(newValue);
    }
    }
    }
    }