ios - Xamarin 跨平台双滑块

Question

有人听说过 Xamarin Forms 的双面滑块吗？我正在寻找，但似乎找不到。原生 Xamarin Forms Slider 非常漂亮，但它只支持 1 个标记。我正在寻找一个每侧有两个标记的滑块。

有没有人听说过或知道如何扩展 Xamarin 控件以添加类似的功能。

在这件事上，任何帮助都将不胜感激。

我在这里找到了范围滑块

https://components.xamarin.com/view/rangeslider

不幸的是，该控件具有 iOS 4 的外观，并且无法从我读过的内容中进行风格化或视觉更新。

Answer 1

答案是真的没有任何原生的，您可以尝试扩展原生滑块或将两个滑块堆叠在一起以获得所需的效果。

你也可以签出

https://components.xamarin.com/view/rangeslider

但它看起来很旧并且不容易扩展。

让我们去 Xamarin 给我们一个双滑块！！！还是elseee？？！

Answer 2

这是iOS的实现。希望能帮助到你！

public class UIRangeSlider : UIControl
{
    public nfloat MinValue;
    public nfloat MaxValue;
    public nfloat MinRange;
    public nfloat SelectedMinValue;
    public nfloat SelectedMaxValue;
    public Action<UIRangeSlider> ThumbChanged;

    private UIImageView minThumb, maxThumb, track, trackBackground;
    nfloat padding = 15.0f;
    bool maxThumbOn = false;
    bool minThumbOn = false;
    nfloat distanceFromCenter;

    public UIRangeSlider(CGRect frame)
        : base(frame)
    {
        trackBackground = new UIImageView(Resources.SliderTrackBackground.StretchableImage(1, 1));
        trackBackground.Center = Center;
        AddSubview(trackBackground);

        track = new UIImageView(Resources.SliderTrackGreen);
        track.Center = Center;
        AddSubview(track);

        minThumb = new UIImageView(Resources.SliderHandle, Resources.SliderHandle);
        minThumb.Frame = new CGRect(0, 0, Frame.Size.Height, Frame.Size.Height);
        minThumb.ContentMode = UIViewContentMode.Center;
        AddSubview(minThumb);

        maxThumb = new UIImageView(Resources.SliderHandle, Resources.SliderHandle);
        maxThumb.Frame = new CGRect(0, 0, Frame.Size.Height, Frame.Size.Height);
        maxThumb.ContentMode = UIViewContentMode.Center;
        AddSubview(maxThumb);
    }

    public override void LayoutSubviews()
    {
        base.LayoutSubviews();
        minThumb.Center = new CGPoint(XForValue(SelectedMinValue), Center.Y - Frame.Top);
        maxThumb.Center = new CGPoint(XForValue(SelectedMaxValue), Center.Y - Frame.Top);

        // minThumb.Layer.BorderColor = UIColor.Red.CGColor;
        // minThumb.Layer.BorderWidth = 1.0f;

        // maxThumb.Layer.BorderColor = UIColor.Red.CGColor;
        // maxThumb.Layer.BorderWidth = 1.0f;

        UpdateTrackHighlight();
    }

    private nfloat XForValue(nfloat val)
    {
        return (Frame.Size.Width - (padding * 2)) * ((val - MinValue) / (MaxValue - MinValue)) + padding;
    }

    private nfloat ValueForX(nfloat x)
    {
        return MinValue + (x - padding) / (Frame.Size.Width - (padding * 2)) * (MaxValue - MinValue);
    }

    public override bool ContinueTracking(UITouch uitouch, UIEvent uievent)
    {
        if (!minThumbOn && !maxThumbOn)
            return true;

        var touchPoint = uitouch.LocationInView(this);
        if (minThumbOn)
        {
            var xValue = (nfloat)Math.Max(XForValue(MinValue), Math.Min(touchPoint.X - distanceFromCenter, XForValue(SelectedMaxValue - MinRange)));
            var yValue = minThumb.Center.Y - Frame.Top;
            minThumb.Center = new CGPoint(xValue, yValue);
            SelectedMinValue = ValueForX(minThumb.Center.X);
        }

        if (maxThumbOn)
        {
            var xValue = (nfloat) Math.Min(XForValue(MaxValue), Math.Max(touchPoint.X - distanceFromCenter, XForValue(SelectedMinValue + MinRange)));
            var yValue = maxThumb.Center.Y - Frame.Top;
            maxThumb.Center = new CGPoint(xValue, yValue);
            SelectedMaxValue = ValueForX(maxThumb.Center.X);
        }

        UpdateTrackHighlight();
        this.SetNeedsLayout();

        if (ThumbChanged != null)
            ThumbChanged(this);

        return true;
    }

    public override bool BeginTracking(UITouch uitouch, UIEvent uievent)
    {
        var touchPoint = uitouch.LocationInView(this);

        if (minThumb.Frame.Contains(touchPoint))
        {
            minThumbOn = true;
            distanceFromCenter = touchPoint.X - minThumb.Center.X;
        }
        else if (maxThumb.Frame.Contains(touchPoint))
        {
            maxThumbOn = true;
            distanceFromCenter = touchPoint.X - maxThumb.Center.X;
        }

        return true;
    }

    public override void EndTracking(UITouch uitouch, UIEvent uievent)
    {
        minThumbOn = false;
        maxThumbOn = false;
    }

    private void UpdateTrackHighlight()
    {
        track.Frame = new CGRect(minThumb.Center.X, 
            maxThumb.Center.Y - (track.Frame.Height / 2),
            maxThumb.Center.X - minThumb.Center.X,
            track.Frame.Size.Height);

        // track.Layer.BorderColor = UIColor.Black.CGColor;
        // track.Layer.BorderWidth = 1.0f;

        trackBackground.Frame = new CGRect(1, 
            maxThumb.Center.Y - (trackBackground.Frame.Height / 2),
            Frame.Width-2, trackBackground.Frame.Size.Height);

        // trackBackground.Layer.BorderColor = UIColor.Red.CGColor;
        // trackBackground.Layer.BorderWidth = 1.0f;
    }
}