xamarin - NumberOfTapsRequired 不适用于 > 2

Question

我有 Xamarin Forms 项目，在我的页面上有以下代码:

<Image Source="genea_login_logo.png">
    <Image.GestureRecognizers>
        <TapGestureRecognizer Command="{Binding LogoCommand}" NumberOfTapsRequired="2" />
    </Image.GestureRecognizers>
</Image>

它按预期工作。但是，当我将 NumberOfTapsRequired 从 2 更改为 5 时，它不再起作用。这种行为是预期的吗？是否可以实现5键命令？

编辑:这仅适用于 Android。

Answer 1

实际上，具有超过 2 个 NumberOfTapsRequired 的 TapGestureRecognizer 在 Android 中不起作用。您可以实现某种逻辑来实现这种效果。

在 XAML 中

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="Demo.Views.MainPage"             
             Title="MainPage">
    <Grid HorizontalOptions="Center" VerticalOptions="Center">       

        <Image Source="icon.png">
            <Image.GestureRecognizers>
                <TapGestureRecognizer Tapped="TapGestureRecognizer_OnTapped"/>
            </Image.GestureRecognizers>
        </Image>

    </Grid>
</ContentPage>

代码隐藏...

    private DateTime? LastTap = null;
    private byte NumberOfTaps = 0;

    private const int NumberOfTapsRequired = 3;
    private const int ToleranceInMs = 1000;

    private async void TapGestureRecognizer_OnTapped(object sender, EventArgs e)
    {
        if (LastTap ==  null || (DateTime.Now - LastTap.Value).TotalMilliseconds < ToleranceInMs)
        {
            if (NumberOfTaps == (NumberOfTapsRequired - 1))
            {

                await App.Current.MainPage.DisplayAlert("Hi", "Hi from Gesture", "Ok");

                NumberOfTaps = 0;
                LastTap = null;
                return;
            }
            else
            {
                NumberOfTaps++;
                LastTap = DateTime.Now;
            }
        }
        else
        {
            NumberOfTaps=1;
            LastTap = DateTime.Now;
        }
    }