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手势先生-自定义视图

gesture-recognition xamarin.forms xamarin c#

DirtyNative · 技术社区 · 8 年前

我有一个SKCanvasView绘制一些图形,现在有一个需要得到水龙头的位置。在阅读了几篇文章之后,我决定通过手势先生. 因为包中没有SKCanvasView的标准实现,所以我需要自己实现它。

我的猜测是 IGestureAwareControl公司

public class AudioWaveView : SKCanvasView, IGestureAwareControl

这个需要实现一系列事件和命令:

    public GestureHandler GestureHandler { get; }
    public ICommand DownCommand { get; set; }
    public object DownCommandParameter { get; set; }
    public ICommand UpCommand { get; set; }
    public object UpCommandParameter { get; set; }
    public ICommand TappingCommand { get; set; }
    public object TappingCommandParameter { get; set; }
    public ICommand TappedCommand { get; set; }
    public object TappedCommandParameter { get; set; }
    public ICommand DoubleTappedCommand { get; set; }
    public object DoubleTappedCommandParameter { get; set; }
    public ICommand LongPressingCommand { get; set; }
    public object LongPressingCommandParameter { get; set; }
    public ICommand LongPressedCommand { get; set; }
    public object LongPressedCommandParameter { get; set; }
    public ICommand PinchingCommand { get; set; }
    public object PinchingCommandParameter { get; set; }
    public ICommand PinchedCommand { get; set; }
    public object PinchedCommandParameter { get; set; }
    public ICommand PanningCommand { get; set; }
    public object PanningCommandParameter { get; set; }
    public ICommand PannedCommand { get; set; }
    public object PannedCommandParameter { get; set; }
    public ICommand SwipedCommand { get; set; }
    public object SwipedCommandParameter { get; set; }
    public ICommand RotatingCommand { get; set; }
    public object RotatingCommandParameter { get; set; }
    public ICommand RotatedCommand { get; set; }
    public object RotatedCommandParameter { get; set; }
    public event EventHandler<DownUpEventArgs> Down;
    public event EventHandler<DownUpEventArgs> Up;
    public event EventHandler<TapEventArgs> Tapping;
    public event EventHandler<TapEventArgs> Tapped;
    public event EventHandler<TapEventArgs> DoubleTapped;
    public event EventHandler<LongPressEventArgs> LongPressing;
    public event EventHandler<LongPressEventArgs> LongPressed;
    public event EventHandler<PinchEventArgs> Pinching;
    public event EventHandler<PinchEventArgs> Pinched;
    public event EventHandler<PanEventArgs> Panning;
    public event EventHandler<PanEventArgs> Panned;
    public event EventHandler<SwipeEventArgs> Swiped;
    public event EventHandler<RotateEventArgs> Rotating;
    public event EventHandler<RotateEventArgs> Rotated;

谢谢

1 回复 | 直到 8 年前

MichaÅ Å»oÅnieruk 8 年前

Microsoft's Touch Manipulations article regarding SkiaSharp . 它使用效果来支持触摸操作,有关效果的更多详细信息,请参见: Invoking Events from Effects

基本上,您需要将TouchEffect添加到添加了CanvasView的容器中(甚至可以将该效果添加到CanvasView中,上面链接的文章中有这样一个示例):

<Grid BackgroundColor="White" Grid.Row="1">
    <skia:SKCanvasView x:Name="canvasView" PaintSurface="OnCanvasViewPaintSurface" />
    <Grid.Effects>
        <tt:TouchEffect Capture="True" TouchAction="OnTouchEffectAction" />
    </Grid.Effects>
</Grid>

然后为TouchAction事件添加一个处理程序,如下所示。您需要首先将触摸点转换为像素,然后检查

void OnTouchEffectAction(object sender, TouchActionEventArgs args)
{
        if (args.Type != TouchActionType.Pressed)
        {
            return;
        }

        var pointLocation = args.Location;
        var point =
            new SKPoint((float)(canvasView.CanvasSize.Width * pointLocation.X / canvasView.Width),
                        (float)(canvasView.CanvasSize.Height * pointLocation.Y / canvasView.Height));

        // TODO: Handle your touch here
}