Question

我有一个带有ListView的页面，其中显示了一些带有音频数据的单元格。

视图：

<?xml version="1.0" encoding="UTF-8"?>
<ViewCell xmlns="http://xamarin.com/schemas/2014/forms"
   xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
   xmlns:audioViews="clr-namespace:Lama.Forms.Source.UI.CustomControls.AudioViews;assembly=Lama.Forms"
   x:Class="Lama.Forms.Source.UI.Pages.MainPages.MacOSAudiofileCellView"
   Padding="0" HasShadow="False" >

<StackLayout BackgroundColor="{Binding BackgroundColor}" Orientation="Vertical" Margin="0,2,0,2" Spacing="0">
    <StackLayout.GestureRecognizers>
        <TapGestureRecognizer Command="{Binding SelectCellCommand}" />
    </StackLayout.GestureRecognizers>

    <Grid RowSpacing="0" ColumnSpacing="0" VerticalOptions="FillAndExpand" Margin="0,0,0,5">
        <Grid.RowDefinitions>
            <RowDefinition Height="75" />
            <RowDefinition Height="75" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="10" />
            <ColumnDefinition Width="75" />
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>

...

        <!-- The Playback Buttons -->
        <Grid Grid.Row="1" Grid.Column="1">

            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*" />
                <ColumnDefinition Width="*" />
            </Grid.ColumnDefinitions>

            <!-- Play Button -->
            <Image Source="{Binding PlayButtonIcon}">
                <Image.GestureRecognizers>
                    <TapGestureRecognizer Command="{Binding PlayCommand}" />
                </Image.GestureRecognizers>
            </Image>

            <!-- Stop Button -->
            <Image Source="{Binding StopButtonIcon}" Grid.Column="1">
                <Image.GestureRecognizers>
                    <TapGestureRecognizer Command="{Binding StopCommand}" />
                </Image.GestureRecognizers>
            </Image>
        </Grid>

        <!-- The Grid for Filename, Artist and Title -->
        <Grid Grid.Row="0" Grid.Column="2" Grid.ColumnSpan="2" RowSpacing="0" ColumnSpacing="0">
            <Grid.RowDefinitions>
                <RowDefinition Height="*" />
                <RowDefinition Height="*" />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*" />
                <ColumnDefinition Width="*" />
            </Grid.ColumnDefinitions>

            <!-- The Filename -->
            <StackLayout Grid.ColumnSpan="2" Margin="10,0,0,0"
                         Orientation="Horizontal" VerticalOptions="Fill">

                <Label Text="Filename:"
                       VerticalTextAlignment="Center"
                       WidthRequest="100"
                       VerticalOptions="Fill"
                       Style="{StaticResource CellLabel}" />

                <Label x:Name="LblFilename" Text="{Binding Filename}"
                       VerticalTextAlignment="Center"
                       VerticalOptions="Fill"
                       Style="{StaticResource CellLabel}"/>

                <StackLayout.GestureRecognizers>
                    <TapGestureRecognizer Command="{Binding ChooseNewFilenameCommand}"/>
                </StackLayout.GestureRecognizers>

            </StackLayout>

            <!-- The Artist -->
            <StackLayout Grid.Row="1" Grid.Column="0" Margin="10,0,0,0" Orientation="Horizontal">
                <StackLayout.GestureRecognizers>
                    <TapGestureRecognizer Command="{Binding ChooseNewArtistCommand}"/>
                </StackLayout.GestureRecognizers>
                <Label Text="Artist:"
                               WidthRequest="100"
                               VerticalTextAlignment="Center" 
                               Style="{StaticResource CellLabel}"/>

                <Label Text="{Binding Artist}"
                           VerticalTextAlignment="Center"
                           Style="{StaticResource CellLabel}"/>
            </StackLayout>

            ...
</ViewCell>

ViewModel：

public class AudiofileCellViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged = delegate { };

    #region Commands
    public Command SelectCellCommand { get; }
    public Command ChooseNewFilenameCommand { get; }
    public Command ChooseNewArtistCommand { get; }

    public Command PlayCommand { get; }
    public Command StopCommand { get; }
    #endregion

    #region CTOr
    protected BaseAudiofileCellViewModel()
    {
        SelectCellCommand = new Command(SelectCell);
        ChooseNewFilenameCommand = new Command(async () => await ChooseNewFilename());
        ChooseNewArtistCommand = new Command(ChooseNewArtist);
        ChooseNewTitleCommand = new Command(ChooseNewTitle);
        ChooseNewAlbumCommand = new Command(ChooseNewAlbum);
        ChooseNewCommentCommand = new Command(ChooseNewComment);
        ChooseNewKeyCommand = new Command(ChooseNewKey);
        ChooseNewBpmCommand = new Command(ChooseNewBpm);

        PlayCommand = new Command(async () => await PlayAudiofile());
        StopCommand = new Command(StopAllAudiofiles);
    }
    #endregion

为标签定义了一些命令，这些命令将在Tap上调用。这适用于Xamarin.Forms.UWP，但是如果我切换到Xamarin.Forms.Mac，它们不会启动。我可以看到，通过主页上的动画视图发生了某些事情，该事件在单击时出现断断续续的情况，但从未遇到断点。我正在运行最新的稳定器：Xamarin.Forms 3.1.0.697729

Answer 1

macOS当前没有TapGestureHandler实现，实际上根本没有Gesture处理程序，因为当前的macOS平台不支持它们。有一个写为NSClickGestureRecognizer的Xamarin，但是在不同的Forms控件上以及在macOS上如何实现它们上存在问题。

在UWP上这很有意义，因为Microsoft不仅在UWP中具有触摸界面实现，而且在操作系统本身也具有触摸界面实现；如果您没有触摸界面，则操作系统会将鼠标/触控板的点击转换为“基于触摸的点击”，并且UWP touch API“正好”工作。

现在，将来macOS Mojave将通过苹果将基于iOS的仅框架移植到macOS来支持iOS应用，因此 UIKit框架已移植，您将能够使用UIKit而不是仅仅AppKit。因此，这将支持将鼠标/触控板的点击转换为本地UITapGestureRecognizer事件。我还没有深入研究Mojave，以了解实际效果如何以及AppKit小部件是否会继承UIKit功能，但是由于您使用的是Xamarin.Forms，因此您只需要等到Xamarin支持新的OS功能（当然至少在触摸支持方面，您的应用只能是Mojave。

Xamarin.Forms.Mac命令未调用

1 个答案: