/wp-toolkit/Microsoft.Phone.Controls.Toolkit.WP7/ListPicker/ListPickerPage.xaml.cs

// (c) Copyright Microsoft Corporation.

// This source is subject to the Microsoft Public License (Ms-PL).

// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.

// All other rights reserved.



using System;

using System.Collections;

using System.Collections.Generic;

using System.ComponentModel;

using System.Globalization;

using System.Linq;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Media;

using System.Windows.Media.Animation;

using System.Windows.Navigation;

using Microsoft.Phone.Shell;



namespace Microsoft.Phone.Controls

{

    /// <summary>

    /// Displays the list of items and allows single or multiple selection.

    /// </summary>

    public partial class ListPickerPage : PhoneApplicationPage

    {

        private const string StateKey_Value = "ListPickerPage_State_Value";



        private PageOrientation _lastOrientation;



        private IList<WeakReference> _itemsToAnimate;



        /// <summary>

        /// Gets or sets the string of text to display as the header of the page.

        /// </summary>

        public string HeaderText { get; set; }



        /// <summary>

        /// Gets or sets the list of items to display.

        /// </summary>

        public IList Items { get; private set; }



        /// <summary>

        /// Gets or sets the selection mode.

        /// </summary>

        public SelectionMode SelectionMode { get; set; }



        /// <summary>

        /// Gets or sets the selected item.

        /// </summary>

        public object SelectedItem { get; set; }



        /// <summary>

        /// Gets or sets the list of items to select.

        /// </summary>

        public IList SelectedItems { get; private set; }



        /// <summary>

        /// Gets or sets the item template

        /// </summary>

        public DataTemplate FullModeItemTemplate { get; set; }



        /// <summary>

        /// Whether the picker page is open or not.

        /// </summary>

        private bool IsOpen

        {

            get { return (bool)GetValue(IsOpenProperty); }

            set { SetValue(IsOpenProperty, value); }

        }



        private static readonly DependencyProperty IsOpenProperty =

            DependencyProperty.Register("IsOpen",

                                        typeof(bool),

                                        typeof(ListPickerPage),

                                        new PropertyMetadata(false, new PropertyChangedCallback(OnIsOpenChanged)));



        private static void OnIsOpenChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)

        {

            (o as ListPickerPage).OnIsOpenChanged();

        }



        private void OnIsOpenChanged()

        {

            UpdateVisualState(true);

        }



        /// <summary>

        /// Creates a list picker page.

        /// </summary>

        public ListPickerPage()

        {

            InitializeComponent();



            Items = new List<object>();

            SelectedItems = new List<object>();



            Loaded += OnLoaded;

            Unloaded += OnUnloaded;

        }



        private void OnLoaded(object sender, RoutedEventArgs e)

        {

            OrientationChanged += OnOrientationChanged;

            _lastOrientation = Orientation;



            // Customize the ApplicationBar Buttons by providing the right text

            if (null != ApplicationBar)

            {

                foreach (object obj in ApplicationBar.Buttons)

                {

                    IApplicationBarIconButton button = obj as IApplicationBarIconButton;

                    if (null != button)

                    {

                        if ("DONE" == button.Text)

                        {

                            button.Text = LocalizedResources.ControlResources.DateTimePickerDoneText;

                            button.Click += OnDoneButtonClick;

                        }

                        else if ("CANCEL" == button.Text)

                        {

                            button.Text = LocalizedResources.ControlResources.DateTimePickerCancelText;

                            button.Click += OnCancelButtonClick;

                        }

                    }

                }

            }



            // Add a projection for each list item and turn it to -90

            // (rotationX) so it is hidden.

            SetupListItems(-90);



            PlaneProjection headerProjection = (PlaneProjection)HeaderTitle.Projection;

            if (null == headerProjection)

            {

                headerProjection = new PlaneProjection();

                HeaderTitle.Projection = headerProjection;

            }

            headerProjection.RotationX = -90;



            Picker.Opacity = 1;



            Dispatcher.BeginInvoke(() =>

                {

                    IsOpen = true;

                });

        }



        private void OnUnloaded(object sender, RoutedEventArgs e)

        {

            OrientationChanged -= OnOrientationChanged;

        }



        private void SetupListItems(double degree)

        {

            _itemsToAnimate = ItemsControlExtensions.GetItemsInViewPort(Picker);



            for (int i = 0; i < _itemsToAnimate.Count; i++)

            {

                FrameworkElement item = (FrameworkElement)_itemsToAnimate[i].Target;

                if (null != item)

                {

                    PlaneProjection p = (PlaneProjection)item.Projection;

                    if (null == p)

                    {

                        p = new PlaneProjection();

                        item.Projection = p;

                    }

                    p.RotationX = degree;

                }

            }

        }



        /// <summary>

        /// Called when a page becomes the active page in a frame.

        /// </summary>

        /// <param name="e">An object that contains the event data.</param>

        protected override void OnNavigatedTo(NavigationEventArgs e)

        {

            if (null == e)

            {

                throw new ArgumentNullException("e");

            }



            base.OnNavigatedTo(e);



            // Restore Value if returning to application (to avoid inconsistent state)

            if (State.ContainsKey(StateKey_Value))

            {

                State.Remove(StateKey_Value);



                // Back out from picker page for consistency with behavior of core pickers in this scenario

                if (NavigationService.CanGoBack)

                {

                    NavigationService.GoBack();

                    return;

                }

            }



            // Automatically uppercase the text for the header.

            if (null != HeaderText)

            {

                HeaderTitle.Text = HeaderText.ToUpper(CultureInfo.CurrentCulture);

            }



            Picker.DataContext = Items;



            Picker.SelectionMode = SelectionMode;



            if (null != FullModeItemTemplate)

            {

                Picker.ItemTemplate = FullModeItemTemplate;

            }



            if (SelectionMode == SelectionMode.Single)

            {

                ApplicationBar.IsVisible = false;



                Picker.SelectedItem = SelectedItem;

            }

            else

            {

                ApplicationBar.IsVisible = true;

                Picker.ItemContainerStyle = (Style)Resources["ListBoxItemCheckedStyle"];



                foreach (object item in Items)

                {

                    if (null != SelectedItems && SelectedItems.Contains(item))

                    {

                        Picker.SelectedItems.Add(item);

                    }

                }

            }

        }



        private void OnDoneButtonClick(object sender, EventArgs e)

        {

            // Commit the value and close

            SelectedItem = Picker.SelectedItem;

            SelectedItems = Picker.SelectedItems;

            ClosePickerPage();

        }



        private void OnCancelButtonClick(object sender, EventArgs e)

        {

            // Close without committing a value

            SelectedItem = null;

            SelectedItems = null;

            ClosePickerPage();

        }



        /// <summary>

        /// Called when the Back key is pressed.

        /// </summary>

        /// <param name="e">Event arguments.</param>

        protected override void OnBackKeyPress(CancelEventArgs e)

        {

            if (null == e)

            {

                throw new ArgumentNullException("e");

            }



            // Cancel back action so we can play the Close state animation (then go back)

            e.Cancel = true;

            SelectedItem = null;

            SelectedItems = null;

            ClosePickerPage();

        }



        private void ClosePickerPage()

        {

            // Prevent user from selecting an item as the picker is closing,

            // disabling the control would cause the UI to change so instead

            // it's hidden from hittesting.

            Picker.IsHitTestVisible = false;



            IsOpen = false;

        }



        private void OnClosedStoryboardCompleted(object sender, EventArgs e)

        {

            // Close the picker page

            if (NavigationService.CanGoBack)

            {

                NavigationService.GoBack();

            }

        }



        /// <summary>

        /// Called when a page is no longer the active page in a frame.

        /// </summary>

        /// <param name="e">An object that contains the event data.</param>

        protected override void OnNavigatedFrom(NavigationEventArgs e)

        {

            if (null == e)

            {

                throw new ArgumentNullException("e");

            }



            base.OnNavigatedFrom(e);



            // Save Value if navigating away from application

            if (e.Uri.IsExternalNavigation())

            {

                State[StateKey_Value] = StateKey_Value;

            }

        }



        private void OnOrientationChanged(object sender, OrientationChangedEventArgs e)

        {

            PageOrientation newOrientation = e.Orientation;



            RotateTransition transitionElement = new RotateTransition();



            // Adjust padding if possible



            if (null != MainGrid)

            {

                switch (newOrientation)

                {

                    case PageOrientation.Portrait:

                    case PageOrientation.PortraitUp:

                        HeaderTitle.Margin = new Thickness(24, 12, 12, 12);

                        Picker.Margin = new Thickness(24, 12, 0, 0);



                        transitionElement.Mode = (_lastOrientation == PageOrientation.LandscapeLeft) ?

                        RotateTransitionMode.In90Counterclockwise : RotateTransitionMode.In90Clockwise;



                        break;

                    case PageOrientation.Landscape:

                    case PageOrientation.LandscapeLeft:

                        HeaderTitle.Margin = new Thickness(24, 24, 0, 0);

                        Picker.Margin = new Thickness(24, 24, 0, 0);



                        transitionElement.Mode = (_lastOrientation == PageOrientation.LandscapeRight) ?

                        RotateTransitionMode.In180Counterclockwise : RotateTransitionMode.In90Clockwise;

                        break;

                    case PageOrientation.LandscapeRight:

                        HeaderTitle.Margin = new Thickness(24, 24, 0, 0);

                        Picker.Margin = new Thickness(24, 24, 0, 0);



                        transitionElement.Mode = (_lastOrientation == PageOrientation.PortraitUp) ?

                        RotateTransitionMode.In90Counterclockwise : RotateTransitionMode.In180Clockwise;

                        break;

                }

            }



            PhoneApplicationPage phoneApplicationPage = (PhoneApplicationPage)(((PhoneApplicationFrame)Application.Current.RootVisual)).Content;

            ITransition transition = transitionElement.GetTransition(phoneApplicationPage);

            transition.Completed += delegate

            {

                transition.Stop();

            };

            transition.Begin();



            _lastOrientation = newOrientation;

        }



        private void UpdateVisualState(bool useTransitions)

        {

            if (useTransitions)

            {

                // If the Picker is scrolling stop it from moving, this is both

                // consistant with Metro and allows for attaching the animations

                // to the correct, in view items.

                ScrollViewer scrollViewer = Picker.GetVisualChildren().OfType<ScrollViewer>().FirstOrDefault();

                if (scrollViewer != null)

                {

                    scrollViewer.ScrollToVerticalOffset(scrollViewer.VerticalOffset);

                }



                if (!IsOpen)

                {

                    SetupListItems(0);

                }



                Storyboard mainBoard = new Storyboard();



                Storyboard headerBoard = AnimationForElement(HeaderTitle, 0);

                mainBoard.Children.Add(headerBoard);



                for (int i = 0; i < _itemsToAnimate.Count; i++)

                {

                    FrameworkElement element = (FrameworkElement)_itemsToAnimate[i].Target;

                    Storyboard board = AnimationForElement(element, i + 1);

                    mainBoard.Children.Add(board);

                }



                if (!IsOpen)

                {

                    mainBoard.Completed += OnClosedStoryboardCompleted;

                }



                mainBoard.Begin();

            }

            else if (!IsOpen)

            {

                OnClosedStoryboardCompleted(null, null);

            }

        }



        private Storyboard AnimationForElement(FrameworkElement element, int index)

        {

            double delay = 30;

            double duration = (IsOpen) ? 350 : 250;

            double from = (IsOpen) ? -45 : 0;

            double to = (IsOpen) ? 0 : 90;

            ExponentialEase ee = new ExponentialEase()

            {

                EasingMode = (IsOpen) ? EasingMode.EaseOut : EasingMode.EaseIn,

                Exponent = 5,

            };



            DoubleAnimation anim = new DoubleAnimation()

            {

                Duration = new Duration(TimeSpan.FromMilliseconds(duration)),

                From = from,

                To = to,

                EasingFunction = ee,

            };



            Storyboard.SetTarget(anim, element);

            Storyboard.SetTargetProperty(anim, new PropertyPath("(UIElement.Projection).(PlaneProjection.RotationX)"));



            Storyboard board = new Storyboard();

            board.BeginTime = TimeSpan.FromMilliseconds(delay * index);

            board.Children.Add(anim);



            return board;

        }



        private void OnPickerTapped(object sender, System.Windows.Input.GestureEventArgs e)

        {

            // We listen to the tap event because SelectionChanged does not fire if the user picks the already selected item.



            // Only close the page in Single Selection mode.

            if (SelectionMode == SelectionMode.Single)

            {

                // Commit the value and close

                SelectedItem = Picker.SelectedItem;

                ClosePickerPage();

            }

        }

    }

}