Xamarin.Forms TapGestureRecognizer 在 IOS 中不起作用

Question

我使用 TapGestureRecognizer 已经有一段时间了，我从一开始就遇到了这个问题（我第一次在 IOS 设备上测试应用程序时，由于某种原因我在运行模拟器时遇到了问题，所以我一直在使用一个物理 IOS 设备（iPhone 12 Pro Max）），似乎我的 TapGestureRecognizer 没有在 IOS 设备上被触发。在 UWP 上（我主要测试它是最快的）我可以在我的应用程序上的选项卡等之间切换（我对所有按钮都使用 TapGestureRecognizer）。

这是我能够在 UWP 中使用按钮但不能在 IOS 上使用按钮的更简单示例之一。

XAML：

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="fotbal.Oblibene" xmlns:viewModel="clr-namespace:fotbal;assembly=fotbal" xmlns:fotbal="clr-namespace:fotbal">
    <Grid x:Name="Menu_Grid" />
</ContentPage>

CS：

Menu_Grid.ColumnSpacing = 30;

Menu_Grid.Margin = new Thickness(15, 0, 0, 0);

for (int i = 0; i < 5; i++) Menu_Grid.ColumnDefinitions.Add(new ColumnDefinition { Width = GridLength.Auto });
Menu_Grid.RowDefinitions.Add(new RowDefinition());

var page_switcher_tap_recognizer = new TapGestureRecognizer();
page_switcher_tap_recognizer.Tapped += (sender, e) =>
{
    tab_switcher(sender, Menu_Grid, Oblibene_ScrollView);
};

int j = 0;
            foreach (KeyValuePair<string, string> kvp in oblibene_categories)
            {
                Grid grid = new Grid
                {
                    RowDefinitions = { new RowDefinition { Height = new GridLength(1, GridUnitType.Star) }, new RowDefinition { Height = new GridLength(3) } },
                    ColumnDefinitions = { new ColumnDefinition() }
                };

                Label label = new Label { TextColor = Color.FromHex("#888888"), Text = kvp.Key, FontAttributes = FontAttributes.Bold, FontSize = 15, HorizontalOptions = LayoutOptions.Center, VerticalOptions = LayoutOptions.Center };

                BoxView boxView = new BoxView { Color = Color.White };
                if (kvp.Value == selected_category)
                {
                    label.TextColor = Color.FromHex("#439564");
                    boxView.Color = Color.FromHex("#439564");
                }

                var label_page_switcher_tap_recognizer = new TapGestureRecognizer();
                label_page_switcher_tap_recognizer.Tapped += (sender, e) =>
                {
                    tab_switcher(sender, Menu_Grid, Oblibene_ScrollView);
                };

                label.GestureRecognizers.Add(label_page_switcher_tap_recognizer);

                var boxview_page_switcher_tap_recognizer = new TapGestureRecognizer();
                boxview_page_switcher_tap_recognizer.Tapped += (sender, e) =>
                {
                    tab_switcher(sender, Menu_Grid, Oblibene_ScrollView);
                };
                boxView.GestureRecognizers.Add(boxview_page_switcher_tap_recognizer);

                grid.Children.Add(label);

                grid.Children.Add(new NeatFrame { Content = boxView, CornerRadius = 2 }, 0, 1);

                var grid_page_switcher_tap_recognizer = new TapGestureRecognizer();
                grid_page_switcher_tap_recognizer.Tapped += (sender, e) =>
                {
                    tab_switcher(sender, Menu_Grid, Oblibene_ScrollView);
                };
                grid.GestureRecognizers.Add(grid_page_switcher_tap_recognizer);

                Menu_Grid.Children.Add(grid, j, 0);
                j++;
            }

Answer 1

正如ToolmakerSteve 提到的那样，一个手势只适用于单个视图，您不能为多个视图设置相同的手势。

因此，创建不同的手势并执行相同的操作，然后逐个添加视图。

var page_switcher_tap_recognizer = new TapGestureRecognizer();
page_switcher_tap_recognizer.Tapped += (sender, e) =>
{
    tab_switcher(sender, Menu_Grid, Oblibene_ScrollView);
};

var page_switcher_tap_recognizer2 = new TapGestureRecognizer();
page_switcher_tap_recognizer2.Tapped += (sender, e) =>
{
    tab_switcher(sender, Menu_Grid, Oblibene_ScrollView);
};


label.GestureRecognizers.Add(page_switcher_tap_recognizer);
boxView.GestureRecognizers.Add(page_switcher_tap_recognizer2);