public ListViewDemoPage(ListViewCachingStrategy cachingStrategy)
{
Title = "ListView demos";
Content = new StackLayout {
Children =
{
CreateSubpageButton(new DemoListViewWithTextCell(cachingStrategy)
{
Header = "plain header", Footer = "plain footer"
}),
CreateSubpageButton(new DemoListViewWithStringViewCell(cachingStrategy)
{
Header = new DemoLabel("header label"), Footer = new DemoLabel("footer label")
}),
CreateSubpageButton(new DemoListViewWithItemViewCell(cachingStrategy)),
CreateSubpageButton(new DemoListViewWithGroups(cachingStrategy)),
CreateSubpageButton(new DemoListViewWithGroupsAndHeaderTemplate(cachingStrategy)),
CreateSubpageButton(new DemoListViewWithGestureRecognizers(cachingStrategy)),
CreateSubpageButton(new DemoListViewForRecycling(cachingStrategy)),
CreateSubpageButton(new DemoListViewForRecyclingWithTemplateSelector(cachingStrategy)),
CreateSubpageButton(new DemoListViewForRecyclingWithGroups(cachingStrategy)),
},
};
}
public DemoListViewForRecyclingWithGroups(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
ItemsSource = new List <StringGroup> {
new StringGroup(new [] { "A4", "B4" }, "Group 4"),
new StringGroup(new [] { "A5", "B5" }, "Group 5"),
};
ItemTemplate = new DataTemplate(typeof(GroupRecycleCell));
IsGroupingEnabled = true;
GroupDisplayBinding = new Binding(nameof(StringGroup.Title));
BackgroundColor = Color.GhostWhite;
Label header;
Header = header = new Label()
{
Text = "Reverse"
};
header.GestureRecognizers.Add(new TapGestureRecognizer {
Command = new Command(o => {
ItemsSource = (ItemsSource as IEnumerable <StringGroup>)
.Reverse()
.Select(sg => new StringGroup((sg as IEnumerable <string>).Reverse(), sg.Title))
.ToList();
})
});
// Reset instance count for each test
GroupRecycleCell.InstanceCount = 0;
}
public ListView([Parameter("CachingStrategy")] ListViewCachingStrategy cachingStrategy) : this()
{
if (Device.OS == TargetPlatform.Android || Device.OS == TargetPlatform.iOS)
{
CachingStrategy = cachingStrategy;
}
}
public ListView([Parameter("CachingStrategy")] ListViewCachingStrategy cachingStrategy) : this()
{
if (Device.RuntimePlatform == Device.Android || Device.RuntimePlatform == Device.iOS || Device.RuntimePlatform == Device.macOS)
{
CachingStrategy = cachingStrategy;
}
}
public ModListView(ListViewCachingStrategy strategy) : base(strategy)
{
InitializeComponent();
ItemSelected += (sender, e) => SelectedItem = null;
}
public override AView GetView(int position, AView convertView, ViewGroup parent)
{
Cell cell = null;
Performance.Start(out string reference);
ListViewCachingStrategy cachingStrategy = Controller.CachingStrategy;
var nextCellIsHeader = false;
if (cachingStrategy == ListViewCachingStrategy.RetainElement || convertView == null)
{
if (_listView.IsGroupingEnabled)
{
List <Cell> cells = GetCellsFromPosition(position, 2);
if (cells.Count > 0)
{
cell = cells[0];
}
if (cells.Count == 2)
{
nextCellIsHeader = cells[1].GetIsGroupHeader <ItemsView <Cell>, Cell>();
}
}
if (cell == null)
{
cell = GetCellForPosition(position);
if (cell == null)
{
return(new AView(_context));
}
}
}
var cellIsBeingReused = false;
var layout = convertView as ConditionalFocusLayout;
if (layout != null)
{
cellIsBeingReused = true;
convertView = layout.GetChildAt(0);
}
else
{
layout = new ConditionalFocusLayout(_context)
{
Orientation = Orientation.Vertical
};
_layoutsCreated.Add(layout);
}
if (((cachingStrategy & ListViewCachingStrategy.RecycleElement) != 0) && convertView != null)
{
var boxedCell = convertView as INativeElementView;
if (boxedCell == null)
{
throw new InvalidOperationException($"View for cell must implement {nameof(INativeElementView)} to enable recycling.");
}
cell = (Cell)boxedCell.Element;
public ExtendedListView(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
this.ItemSelected += OnItemSelected;
this.ItemTapped += OnItemTapped;
this.ItemAppearing += OnItemAppearing;
this.ItemDisappearing += OnItemDisappering;
}
public DataGrid(ListViewCachingStrategy cachingStrategy)
{
InitializeComponent();
_sortingOrders = new Dictionary <int, SortingOrder>();
_listView = new ListView(cachingStrategy)
{
BackgroundColor = Color.Transparent,
ItemTemplate = new DataGridRowTemplateSelector(),
SeparatorVisibility = SeparatorVisibility.None,
};
_listView.ItemSelected += (s, e) => {
if (SelectionEnabled)
{
SelectedItem = _listView.SelectedItem;
}
else
{
_listView.SelectedItem = null;
}
ItemSelected?.Invoke(this, e);
};
_listView.Refreshing += (s, e) => {
Refreshing?.Invoke(this, e);
};
_listView.SetBinding(ListView.RowHeightProperty, new Binding("RowHeight", source: this));
Grid.SetRow(_listView, 1);
Children.Add(_listView);
}
public DeselectListView(ListViewCachingStrategy strategy) : base(strategy)
{
ItemTapped += (args, sender) =>
{
SelectedItem = null;
};
}
public ItemsView(ListViewCachingStrategy cachingStrategy) : this()
{
if ((Device.OS == TargetPlatform.Android) || (Device.OS == TargetPlatform.iOS))
{
this.CachingStrategy = cachingStrategy;
}
}
public override AView GetView(int position, AView convertView, ViewGroup parent)
{
Cell cell = null;
Performance.Start(out string reference);
ListViewCachingStrategy cachingStrategy = Controller.CachingStrategy;
var nextCellIsHeader = false;
if (cachingStrategy == ListViewCachingStrategy.RetainElement || convertView == null)
{
if (_listView.IsGroupingEnabled)
{
List <Cell> cells = GetCellsFromPosition(position, 2);
if (cells.Count > 0)
{
cell = cells[0];
}
if (cells.Count == 2)
{
nextCellIsHeader = cells[1].GetIsGroupHeader <ItemsView <Cell>, Cell>();
}
}
if (cell == null)
{
cell = GetCellForPosition(position);
if (cell == null)
{
Performance.Stop(reference);
return(new AView(_context));
}
}
}
var cellIsBeingReused = false;
var layout = convertView as ConditionalFocusLayout;
if (layout != null)
{
cellIsBeingReused = true;
convertView = layout.GetChildAt(0);
_layoutsCreated[position] = layout;
}
else
{
// This means the cell was already created during the measuring phase
// so we just reuse the layout already created for the cell
// This only ever happens if the ListView is forced to measure itself because
// it has infinite height
if (convertView == null && cell.Handler?.PlatformView is AView aView &&
aView.Parent is ConditionalFocusLayout cfl)
{
layout = cfl;
}
void InitTest(ListViewCachingStrategy cachingStrategy, bool useTemplate)
{
List <GroupedData> groups = GetGroups();
var listView = new ListView(cachingStrategy)
{
ItemsSource = groups,
ItemTemplate = new DataTemplate(typeof(MyCell)),
HasUnevenRows = true,
// Must be grouped to repro
IsGroupingEnabled = true
};
if (useTemplate)
{
listView.GroupHeaderTemplate = new DataTemplate(typeof(HeaderCell));
}
else
{
listView.GroupDisplayBinding = new Binding(nameof(GroupedData.GroupName));
}
// Must attach to the ListView's events to repro
listView.ItemAppearing += ListView_ItemAppearing;
listView.ItemDisappearing += ListView_ItemDisappearing;
var horStack = new StackLayout
{
Orientation = StackOrientation.Horizontal,
Children = { _scroll, listView },
HeightRequest = 300
};
Button nextButton = new Button {
Text = "Next", AutomationId = TestButtonId
};
nextButton.Clicked += NextButton_Clicked;
StackLayout stack = new StackLayout
{
Children = { new Label {
Text = Instructions
}, _groupsAppearing, _groupsDisappearing, horStack, nextButton }
};
Content = stack;
var lastGroup = groups.Last();
var lastItem = lastGroup.First();
var firstGroup = groups.First();
var firstItem = firstGroup.First();
Device.StartTimer(TimeSpan.FromSeconds(1), () => { listView.ScrollTo(lastItem, lastGroup, ScrollToPosition.End, true); return(false); });
Device.StartTimer(TimeSpan.FromSeconds(2), () => { listView.ScrollTo(firstItem, firstItem, ScrollToPosition.MakeVisible, true); return(false); });
_TestNumber++;
}
/// <summary>
/// Initializes a new instance of the <see cref="T:AiForms.Renderers.CollectionView"/> class.
/// </summary>
/// <param name="cachingStrategy">Caching strategy.</param>
public CollectionView(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
ScrollController = new ScrollController(this);
SetLoadMoreCompletion = (isEnd) =>
{
SetLoadMoreCompletionAction?.Invoke(isEnd);
};
}
Button GetButton <T>(ListViewCachingStrategy strategy) where T : Cell
{
return(new Button
{
Text = $"{typeof(T).Name} {strategy}",
Command = new Command(async() => await Navigation.PushAsync(new MyPage <T>(strategy)))
});
}
public ListView([Parameter("CachingStrategy")] ListViewCachingStrategy cachingStrategy) : this()
{
// null => UnitTest "platform"
if (Device.RuntimePlatform == null ||
Device.RuntimePlatform == Device.Android ||
Device.RuntimePlatform == Device.iOS ||
Device.RuntimePlatform == Device.macOS)
CachingStrategy = cachingStrategy;
}
public InfiniteListView(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
_keyboardHelper = FreshIOC.Container.Resolve <IKeyboardHelper>();
_gestureDismiss = new TapGestureRecognizer
{
Command = new Command(() => _keyboardHelper.HideKeyboard())
};
}
public DemoListView(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
// ListView ignores caching stragey on platforms where recycling is not supported.
// ListView will use caching strategy when runtimePlatform is null ("unit test mode"),
// which can be set when initialising Xamarin.Forms.Mocks.
if (CachingStrategy != cachingStrategy)
{
throw new ArgumentException("Caching strategy must not be ignored.");
}
}
/// <include file="../../docs/Microsoft.Maui.Controls/ListView.xml" path="//Member[@MemberName='.ctor']/Docs" />
public ListView([Parameter("CachingStrategy")] ListViewCachingStrategy cachingStrategy) : this()
{
// Unknown => UnitTest "platform"
if (DeviceInfo.Platform == DevicePlatform.Unknown ||
DeviceInfo.Platform == DevicePlatform.Android ||
DeviceInfo.Platform == DevicePlatform.iOS ||
DeviceInfo.Platform == DevicePlatform.macOS)
{
CachingStrategy = cachingStrategy;
}
}
static CrawlingStrategy GetCrawlingStrategy(ListViewCachingStrategy cachingStrategy)
{
if ((cachingStrategy & ListViewCachingStrategy.RecycleElement) != 0)
{
return(recycleStrategy);
}
else
{
return(retainStrategy);
}
}
public MyPage(ListViewCachingStrategy strategy)
{
_DataSource = Enumerable.Range(0, 10).Select(n => new VariableHeightItem()).ToList();
var listView = new ListView(strategy)
{
HasUnevenRows = true, ItemsSource = _DataSource, ItemTemplate = new DataTemplate(typeof(T))
};
var button = new Button {
Text = "Click me"
};
button.Clicked += async(sender, e) =>
{
for (int i = 0; i < _DataSource.Count; i++)
{
var target = _DataSource[i];
if (DeviceInfo.Platform == DevicePlatform.iOS)
{
if (typeof(T) == typeof(MyViewCell))
{
target.Text = "I am an exceptionally long string that should cause the label to wrap, thus increasing the size of the cell such that the entirety of the string is readable by human eyes. Hurrah.";
}
else if (strategy == ListViewCachingStrategy.RetainElement)
{
target.Text = "Look, I'm taller!";
}
else
{
target.Text = $"I'm only taller in {ListViewCachingStrategy.RetainElement} mode. :(";
}
}
else
{
if (typeof(T) == typeof(MyViewCell))
{
target.Text = "I am an exceptionally long string that should cause the label to wrap, thus increasing the size of the cell such that the entirety of the string is readable by human eyes. Hurrah.";
}
else
{
target.Text = "Look, I'm taller!";
}
}
await Task.Delay(1000);
}
};
Content = new StackLayout {
Children = { button, listView }
};
Title = $"{typeof(T).Name} {strategy}";
}
public DemoListViewWithStringViewCell(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
ItemsSource = new List <string> {
"Item A2", "Item B2", "Item C2"
};
ItemTemplate = new DataTemplate(typeof(StringDemoCell));
BackgroundColor = Color.GhostWhite;
HeightRequest = 200;
ItemTapped += (sender, e) => App.ShowMessage("Success", e.Item + " tapped");
}
public DemoListViewWithTextCell(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
ItemsSource = new List <string> {
"Item A1", "Item B1", "Item C1"
};
ItemTemplate = new DataTemplate(typeof(TextCell));
BackgroundColor = Color.GhostWhite;
ItemTemplate.SetBinding(TextCell.TextProperty, ".");
ItemTapped += (sender, e) => App.ShowMessage("Success", e.Item + " tapped");
}
public InfiniteListView(ListViewCachingStrategy strategy) : base(strategy)
{
try
{
ItemAppearing += InfiniteListView_ItemAppearing;
ItemTapped += InfiniteListView_OnItemTapped;
}
catch (System.Exception ex)
{
}
}
public DemoListViewWithGestureRecognizers(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
ItemsSource = new List <Item> {
new Item {
Name = "Item"
}
};
ItemTemplate = new DataTemplate(typeof(ItemGestureCell));
BackgroundColor = Color.GhostWhite;
ItemTapped += (sender, e) => App.ShowMessage("ListView Cell", (e.Item as Item).Name + " tapped");
}
public DemoListViewWithGroupsAndHeaderTemplate(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
ItemsSource = new List <List <string> > {
new StringGroup(new [] { "A6", "B6", "C6" }, "Group 6"),
new StringGroup(new [] { "A7", "B7", "C7" }, "Group 7"),
};
ItemTemplate = new DataTemplate(typeof(StringDemoCell));
IsGroupingEnabled = true;
GroupHeaderTemplate = new DataTemplate(typeof(GroupHeaderCell));
BackgroundColor = Color.GhostWhite;
ItemTapped += (sender, e) => App.ShowMessage("Success", (e.Item as string) + " tapped");
}
public DemoListViewWithGroups(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
ItemsSource = new List <List <string> > {
new StringGroup(new [] { "A4", "B4", "C4" }, "Group 4"),
new StringGroup(new [] { "A5", "B5", "C5" }, "Group 5"),
};
ItemTemplate = new DataTemplate(typeof(StringDemoCell));
IsGroupingEnabled = true;
GroupDisplayBinding = new Binding(nameof(StringGroup.Title));
BackgroundColor = Color.GhostWhite;
ItemTapped += (sender, e) => App.ShowMessage("Success", (e.Item as string) + " tapped");
}
public ListViewCustomCellPage(ListViewCachingStrategy strategy)
{
DataTemplate it = new DataTemplate(typeof(CustomCell));
it.SetBinding(CustomCell.TextProperty, "Title");
it.SetBinding(CustomCell.DetailProperty, "SubTitle");
ListView listV = new ListView(strategy)
{
HasUnevenRows = true,
ItemTemplate = it,
ItemsSource = GetData()
};
Content = listV;
}
public DemoListViewWithItemViewCell(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
ItemsSource = new List <Item> {
new Item {
Name = "Item A3"
}, new Item {
Name = "Item B3"
}, new Item {
Name = "Item C3"
}
};
ItemTemplate = new DataTemplate(typeof(ItemDemoCell));
BackgroundColor = Color.GhostWhite;
ItemTapped += (sender, e) => App.ShowMessage("Success", (e.Item as Item).Name + " tapped");
}
public BsdListView(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
this.ItemAppearing += OnItemAppearing;
this.ItemTapped += OnItemTapped;
this.IsPullToRefreshEnabled = true;
this.HasUnevenRows = true;
this.SelectionMode = ListViewSelectionMode.None;
this.SeparatorVisibility = SeparatorVisibility.None;
this.BackgroundColor = Color.FromHex("#eeeeee");
this.SetBinding(RefreshCommandProperty, new Binding("RefreshCommand"));
this.SetBinding(IsRefreshingProperty, new Binding("IsRefreshing"));
this.SetBinding(ItemsSourceProperty, new Binding("Data"));
InfiniteScrollBehavior behavior = new InfiniteScrollBehavior();
behavior.SetBinding(InfiniteScrollBehavior.IsLoadingMoreProperty, new Binding("IsBusy"));
this.Behaviors.Add(behavior);
}
public PageableListView(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
_loadingActivityIndicator = new ActivityIndicator
{
HorizontalOptions = LayoutOptions.Center,
VerticalOptions = LayoutOptions.Center,
Color = Color.Gray,
IsRunning = true,
IsVisible = false
};
var busyIndicatorContainer = new Grid();
busyIndicatorContainer.Children.Add(_loadingActivityIndicator, 0, 0);
Footer = busyIndicatorContainer;
ItemAppearing += OnItemAppearing;
ItemSelected += OnItemSelected;
}
public ExtendedListView(ListViewCachingStrategy strategy) : base(strategy)
{
}
public ListViewCustomCellPage(ListViewCachingStrategy strategy)
{
DataTemplate it = new DataTemplate(typeof(CustomCell));
it.SetBinding(CustomCell.TextProperty, "Title");
it.SetBinding(CustomCell.DetailProperty, "SubTitle");
ListView listV = new ListView(strategy)
{
HasUnevenRows = true,
ItemTemplate = it,
ItemsSource = GetData()
};
Content = listV;
}
/// <summary>
/// Initializes a new instance of the <see cref="T:DLToolkit.Forms.Controls.FlowListView"/> class.
/// </summary>
/// <param name="cachingStrategy">Caching strategy.</param>
public FlowListView(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
InitialSetup();
}
public AlternatingListView(ListViewCachingStrategy cachingStrategy) : base(cachingStrategy)
{
}
