क्या आप कृपया मुझे बता सकते हैं कि मैं Xamarin फॉर्म्स एप्लिकेशन में लॉन्ग प्रेस जेस्चर को कैसे पहचान सकता हूं?

यह मेरा xaml पेज है जिसे मैंने इस थ्रेड के संदर्भ में बनाया है: Xamarin.forms.DataGrid

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:DataGridSample_01"
xmlns:dg="clr-namespace:Xamarin.Forms.DataGrid;assembly=Xamarin.Forms.DataGrid"
x:Class="DataGridSample_01.MainPage">

 <ContentView BackgroundColor="White" Padding="20" >
  <dg:DataGrid ItemsSource="{Binding Data}" SelectionEnabled="True" RowHeight="70" HeaderHeight="50" BorderColor="#CCCCCC" HeaderBackground="#E0E6F8" ActiveRowColor="#8899AA">
     <dg:DataGrid.Columns>
     <dg:DataGridColumn Title="Logo" PropertyName="Logo" Width="50" SortingEnabled="False">
        <dg:DataGridColumn.CellTemplate>
           <DataTemplate>
              <Image Source="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" Aspect="AspectFit" HeightRequest="60" />
           </DataTemplate>
        </dg:DataGridColumn.CellTemplate>
     </dg:DataGridColumn>
     <dg:DataGridColumn Title="Team" PropertyName="Name" Width="2*" >
     </dg:DataGridColumn>
     <dg:DataGridColumn Title="Win" PropertyName="Win" Width="2*">
        <dg:DataGridColumn.CellTemplate>
           <DataTemplate>
              <Picker x:Name="Fruits" Title="Fruits" HorizontalOptions="FillAndExpand">
                 <Picker.Items>
                    <x:String>Apple</x:String>
                    <x:String>Mango</x:String>
                    <x:String>PineApple</x:String>
                    <x:String>Orange</x:String>
                 </Picker.Items>
              </Picker>
           </DataTemplate>
        </dg:DataGridColumn.CellTemplate>
     </dg:DataGridColumn>
     <dg:DataGridColumn Title="Loose" PropertyName="Loose"  Width="1*">                    
     </dg:DataGridColumn>
     <dg:DataGridColumn PropertyName="Home">
        <dg:DataGridColumn.FormattedTitle>
           <FormattedString>
              <Span Text="Home" ForegroundColor="Black" FontSize="13" FontAttributes="Bold"/>
              <Span Text=" (win-loose)" ForegroundColor="#333333" FontSize="11" />
           </FormattedString>
        </dg:DataGridColumn.FormattedTitle>
     </dg:DataGridColumn>
     <dg:DataGrid.RowsBackgroundColorPalette>
        <dg:PaletteCollection>
           <Color>#FFFFFF</Color>
        </dg:PaletteCollection>
     </dg:DataGrid.RowsBackgroundColorPalette>
  </dg:DataGrid>
 </ContentView>
</ContentPage>

मैं इमेज कंट्रोल पर लॉन्ग प्रेस जेस्चर पहचानकर्ता जोड़ना चाहता हूं। मैंने इसे StackOverflow Thread। लेकिन यह काम नहीं कर रहा है।

मैं इसके लिए बहुत नया हूं। किसी भी प्रकार के मदद की बहुत सराहना की जाएगी।

5
Mars 12 पद 2018, 10:55

1 उत्तर

सबसे बढ़िया उत्तर

आप किसी भी नियंत्रण में LongPressGestureRecognizer जोड़ने के लिए Effect का उपयोग कर सकते हैं।

प्रपत्रों में, एक नया साझा प्रभाव बनाएँ।

using System;
using System.Windows.Input;
using Xamarin.Forms;

namespace App15
{
  public class LongPressedEffect : RoutingEffect
  {
    public LongPressedEffect() : base("MyApp.LongPressedEffect")
    {

    }

    public static readonly BindableProperty CommandProperty = BindableProperty.CreateAttached("Command", typeof(ICommand), typeof(LongPressedEffect), (object)null);
    public static ICommand GetCommand(BindableObject view)
    {

        //do something you want 
        Console.WriteLine("long press Gesture recognizer has been striked");


        return (ICommand)view.GetValue(CommandProperty);
    }

    public static void SetCommand(BindableObject view, ICommand value)
    {
        view.SetValue(CommandProperty, value);

    }


    public static readonly BindableProperty CommandParameterProperty = BindableProperty.CreateAttached("CommandParameter", typeof(object), typeof(LongPressedEffect), (object)null);
    public static object GetCommandParameter(BindableObject view)
    {

        return view.GetValue(CommandParameterProperty);
    }

    public static void SetCommandParameter(BindableObject view, object value)
    {
        view.SetValue(CommandParameterProperty, value);
    }
  }
}

एंड्रॉइड प्रोजेक्ट में

using System;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;

using App15;
using App15.Droid;    

[assembly: ResolutionGroupName("MyApp")]
[assembly: ExportEffect(typeof(AndroidLongPressedEffect), "LongPressedEffect")]
namespace AndroidAppNamespace.Effects
{

  public class AndroidLongPressedEffect : PlatformEffect
  {
    private bool _attached;

    public static void Initialize() { }

    public AndroidLongPressedEffect()
    {
    }

    protected override void OnAttached()
    {
        //because an effect can be detached immediately after attached (happens in listview), only attach the handler one time.
        if (!_attached)
        {
            if (Control != null)
            {
                Control.LongClickable = true;
                Control.LongClick += Control_LongClick;
            }
            else
            {
                Container.LongClickable = true;
                Container.LongClick += Control_LongClick;
            }
            _attached = true;
        }
    }


    // Invoke the command if there is one
    private void Control_LongClick(object sender, Android.Views.View.LongClickEventArgs e)
    {
        Console.WriteLine("Invoking long click command");
        var command = LongPressedEffect.GetCommand(Element);
        command?.Execute(LongPressedEffect.GetCommandParameter(Element));
    }


    protected override void OnDetached()
    {
        if (_attached)
        {
            if (Control != null)
            {
                Control.LongClickable = true;
                Control.LongClick -= Control_LongClick;
            }
            else
            {
                Container.LongClickable = true;
                Container.LongClick -= Control_LongClick;
            }
            _attached = false;
        }
    }
}

आईओएस परियोजना में

using Foundation;
using UIKit;
using App15;
using App15.iOS;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

[assembly: ResolutionGroupName("MyApp")]
[assembly: ExportEffect(typeof(iOSLongPressedEffect), "LongPressedEffect")]
namespace App15.iOS
{
  public class iOSLongPressedEffect : PlatformEffect
  {
    private bool _attached;
    private readonly UILongPressGestureRecognizer _longPressRecognizer;

    public iOSLongPressedEffect()
    {
        _longPressRecognizer = new UILongPressGestureRecognizer(HandleLongClick);
    }


    protected override void OnAttached()
    {
        //because an effect can be detached immediately after attached (happens in listview), only attach the handler one time
        if (!_attached)
        {
            Container.AddGestureRecognizer(_longPressRecognizer);
            _attached = true;
        }
    }


    // Invoke the command if there is one       
    private void HandleLongClick(UILongPressGestureRecognizer sender)
    {
        if(sender.State==UIGestureRecognizerState.Began)
        {
            var command = LongPressedEffect.GetCommand(Element);
            command?.Execute(LongPressedEffect.GetCommandParameter(Element));
        }


    }

    protected override void OnDetached()
    {
        if (_attached)
        {
            Container.RemoveGestureRecognizer(_longPressRecognizer);
            _attached = false;
        }
    }

  }
}

अब, आप नियंत्रणों में LongPressGestureRecognizer जोड़ सकते हैं। जैसे लेबल या छवि।

<Label Text="Long Press Me!" local:LongPressedEffect.Command="{Binding ShowAlertCommand}" local:LongPressedEffect.CommandParameter="{Binding .}">
  <Label.Effects>
      <local:LongPressedEffect />
  </Label.Effects>
</Label>

<Image Source="{Binding}" local:LongPressedEffect.Command="{Binding ShowAlertCommand}" local:LongPressedEffect.CommandParameter="{Binding .}">
   <Image.Effects>
        <local:LongPressedEffect />
   </Image.Effects>
</Image>

प्रभाव के बारे में अधिक विवरण के लिए आप यहां

3
Lucas Zhang - MSFT 13 पद 2018, 08:57