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[英]Xamarin.Forms MVVM TapGestureRecognizer to a Label in a ViewCell of ListView (in partial files)
[英]Apply TapGestureRecognizer to a Label in Horizontal list - Xamarin Forms
我正在嘗試將一些數字的水平列表作為ListView的一個項,並且看起來很不錯。
我接下來想要的是,當我滾動任何項目的水平列表時,我希望水平列表中的中間一個項目被自動選擇,並且希望所選值顯示在該項目的標簽中,因此我希望另一個水平項目列表也將自動滾動並執行相同操作(各個標簽的所有值應分別保持其偏移值的差異)。
這有些棘手,我知道GestureRecognizer將在這里提供幫助,但是由於我是xamarin的新手,所以我在這里在哪里以及如何實現它感到困惑。我將在此處編寫所有提供上述屏幕截圖的代碼。
namespace ViewsAndComponents
{
class LVItem : INotifyPropertyChanged
{
private double _offset;
private string _num;
public string Num
{
get { return _num; }
internal set
{
_num = value;
OnPropertyChanged("Num");
}
}
public double Offset
{
get { return _offset; }
internal set
{
_offset = value;
OnPropertyChanged("Offset");
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
public partial class SVInsideLVItem : ContentPage
{
ObservableCollection<LVItem> Items = new ObservableCollection<LVItem>();
ListView timePlannerLV;
Label tL;
public SVInsideLVItem()
{
InitializeComponent();
Items.Add(new LVItem() { Num = "label-1", Offset = 5 });
Items.Add(new LVItem() { Num = "label-2", Offset = 1 });
Items.Add(new LVItem() { Num = "label-3", Offset = 3 });
Items.Add(new LVItem() { Num = "label-4", Offset = 2 });
Items.Add(new LVItem() { Num = "label-5", Offset = 4 });
timePlannerLV = new ListView
{
// Source of data items.
ItemsSource = Items,
HasUnevenRows = true,
RowHeight = -1,
//each item; it must return a Cell derivative.)
ItemTemplate = new DataTemplate(() =>
{
Label numL = new Label()
{
TextColor = Color.Black,
HorizontalTextAlignment = TextAlignment.Start,
FontSize = Device.GetNamedSize(NamedSize.Small, new Label())
};
numL.SetBinding<LVItems>(Label.TextProperty, indexer => indexer.Num);
List<int> items = new List<int>();
items.Add(1);
items.Add(2);
items.Add(3);
items.Add(4);
items.Add(5);
items.Add(6);
items.Add(7);
items.Add(8);
items.Add(9);
items.Add(10);
items.Add(11);
items.Add(12);
items.Add(13);
items.Add(14);
items.Add(15);
items.Add(16);
items.Add(17);
items.Add(18);
items.Add(19);
items.Add(20);
StackLayout sLayout = new StackLayout()
{
Orientation = StackOrientation.Horizontal,
};
for (int i = 0; i < items.Count; i++)
{
Label label = new Label()
{
HorizontalTextAlignment = TextAlignment.Center,
TextColor = Color.Black,
FontSize = Device.GetNamedSize(NamedSize.Small, new Label())
};
label.Text = items[i].ToString();
sLayout.Children.Add(label);
}
ScrollView scroll = new ScrollView
{
Orientation = ScrollOrientation.Horizontal,
Content = new StackLayout
{
Children =
{
sLayout
}
}
};
AbsoluteLayout layout = new AbsoluteLayout();
AbsoluteLayout.SetLayoutFlags(numL, AbsoluteLayoutFlags.All);
AbsoluteLayout.SetLayoutBounds(numL, new Rectangle(0.2, 0.2, 0.8, 0.25));
AbsoluteLayout.SetLayoutFlags(scroll, AbsoluteLayoutFlags.All);
AbsoluteLayout.SetLayoutBounds(scroll, new Rectangle(0.3, 0.6, 0.8, 0.2));
layout.Children.Add(numL);
layout.Children.Add(scroll);
return new ViewCell
{
View = new StackLayout
{
Children =
{
layout,
new BoxView{HeightRequest=1,BackgroundColor=Color.Gray}
}
}
};
})
};
this.Content = new StackLayout
{
Children =
{
timePlannerLV
}
};
}
}
}
任何幫助將不勝感激..在此先感謝..
我不確定您要在這里做什么。但是您需要在創建的標簽中添加手勢識別器。 所以,像這樣添加它:
Label label = new Label()
{
HorizontalTextAlignment = TextAlignment.Center,
TextColor = Color.Black,
FontSize = Device.GetNamedSize(NamedSize.Small, new Label())
};
label.Text = items[i].ToString();
var gestureRecognizer = new TapGestureRecognizer {
TappedCallback = o => selectedLabel.Text = o,
NumberOfTapsRequired = 1
};
label.GestureRecognizers.Add (gestureRecognizer);
sLayout.Children.Add(label);
希望這可以幫助您相處。
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