protected override void OnAttached()
{
UISlider nativeSlider = Control as UISlider;
Slider formsSlider = Element as Slider;
// make the thumb image invisible if the user hasn't previously changed the slider's value
if (!_userHasChangedSliderValue)
{
_visibleThumbImage = nativeSlider.ThumbImage(UIControlState.Normal);
nativeSlider.SetThumbImage(new UIImage(), UIControlState.Normal);
}
// listen for the user pressing on the slider. this also reports slides.
nativeSlider.AddGestureRecognizer(new UILongPressGestureRecognizer(pressRecognizer =>
{
// make the thumb image visible
if (!_userHasChangedSliderValue)
{
nativeSlider.SetThumbImage(_visibleThumbImage, UIControlState.Normal);
_userHasChangedSliderValue = true;
}
// update the slider value - we subtract 25 from the width of the frame to get the right offset (fudgey)
CGPoint pointTapped = pressRecognizer.LocationInView(pressRecognizer.View);
float percent = (float)((pointTapped.X - nativeSlider.Frame.Location.X) / (nativeSlider.Frame.Size.Width - 25));
float newNativeValue = nativeSlider.MinValue + (percent * (nativeSlider.MaxValue - nativeSlider.MinValue));
nativeSlider.SetValue(newNativeValue, false);
formsSlider.Value = formsSlider.Minimum + (percent * (formsSlider.Maximum - formsSlider.Minimum));
})
{
MinimumPressDuration = 0
});
}
