void Panned(NSObject r)
{
var recognizer = r as UIPanGestureRecognizer;
var touchPoint = recognizer.LocationInView(View);
switch (recognizer.State)
{
case UIGestureRecognizerState.Began:
originalTouchPoint = touchPoint;
break;
case UIGestureRecognizerState.Changed:
var offset = touchPoint.Y - originalTouchPoint.Y;
offset = offset > 0 ? NMath.Pow(offset, 0.7f) : -NMath.Pow(-offset, 0.7f);
rubberView.Transform = CGAffineTransform.MakeTranslation(0, offset);
break;
case UIGestureRecognizerState.Ended:
case UIGestureRecognizerState.Cancelled:
var timingParameters = UISpringTiming.MakeTimingParameters(damping: 0.6f, response: .3f);
var animator = new UIViewPropertyAnimator(duration: 0, parameters: timingParameters);
animator.AddAnimations(() => rubberView.Transform = CGAffineTransform.MakeIdentity());
animator.Interruptible = true;
animator.StartAnimation();
break;
default:
break;
}
}
void AnimateToRest()
{
var timingParameters = UISpringTiming.MakeTimingParameters(damping: 0.4f, response: 0.2f);
var animator = new UIViewPropertyAnimator(duration: 0, parameters: timingParameters);
animator.AddAnimations(() => {
Transform = CGAffineTransform.MakeScale(1, 1);
BackgroundColor = isOn ? onColor : offColor;
});
animator.Interruptible = true;
animator.StartAnimation();
}
void AnimateView()
{
var timingParameters = UISpringTiming.MakeTimingParameters(damping: dampingRatio, response: frequencyResponse);
animator = new UIViewPropertyAnimator(duration: 0, parameters: timingParameters);
animator.AddAnimations(() => {
var translation = View.Bounds.Width - 2 * margin - 80;
springView.Transform = CGAffineTransform.MakeTranslation(translation, 0);
});
animator.AddCompletion((x) => {
springView.Transform = CGAffineTransform.MakeIdentity();
AnimateView();
});
animator.StartAnimation();
}
void Panned(NSObject r)
{
var recognizer = r as UIPanGestureRecognizer;
var touchPoint = recognizer.LocationInView(View);
var velocity = recognizer.VelocityInView(View);
switch (recognizer.State)
{
case UIGestureRecognizerState.Began:
originalTouchPoint = touchPoint;
break;
case UIGestureRecognizerState.Changed:
var offset = touchPoint.Y - originalTouchPoint.Y;
if (offset > 0)
{
offset = NMath.Pow(offset, 0.7f);
}
else if (offset < -verticalOffset * 2)
{
offset = -verticalOffset * 2 - NMath.Pow(-(offset + verticalOffset * 2f), 0.7f);
}
accelerationView.Transform = CGAffineTransform.MakeTranslation(0, offset);
TrackPause(velocity.Y, offset);
break;
case UIGestureRecognizerState.Ended:
case UIGestureRecognizerState.Cancelled:
var timingParameters = UISpringTiming.MakeTimingParameters(damping: 0.8f, response: 0.3f);
var animator = new UIViewPropertyAnimator(0, timingParameters);
animator.AddAnimations(() => {
accelerationView.Transform = CGAffineTransform.MakeIdentity();
pauseLabel.Alpha = 0;
});
animator.Interruptible = true;
animator.StartAnimation();
hasPaused = false;
break;
default:
break;
}
}
private void StartAnimationIfNeeded()
{
if (animator.Running)
{
return;
}
var timingParameters = UISpringTiming.MakeTimingParameters(damping: 1, response: 0.4f);
animator = new UIViewPropertyAnimator(0, timingParameters);
animator.AddAnimations(() => {
momentumView.Transform = isOpen ? closedTransform : CGAffineTransform.MakeIdentity();
});
animator.AddCompletion((position) => {
if (position == UIViewAnimatingPosition.End)
{
isOpen = !isOpen;
}
});
animator.StartAnimation();
}
void Panned(object r)
{
var recognizer = r as UIPanGestureRecognizer;
switch (recognizer.State)
{
case UIGestureRecognizerState.Began:
StartAnimationIfNeeded();
animator.PauseAnimation();
animationProgress = animator.FractionComplete;
break;
case UIGestureRecognizerState.Changed:
var fraction = -recognizer.TranslationInView(momentumView).Y / closedTransform.y0;
if (isOpen)
{
fraction *= -1;
}
if (animator.Reversed)
{
fraction *= -1;
}
animator.FractionComplete = fraction + animationProgress;
break;
case UIGestureRecognizerState.Ended:
case UIGestureRecognizerState.Cancelled:
var yVelocity = recognizer.VelocityInView(momentumView).Y;
var shouldClose = yVelocity > 0; // todo: should use projection instead
if (yVelocity == 0)
{
animator.ContinueAnimation(parameters: null, durationFactor: 0);
break;
}
if (isOpen)
{
if (!shouldClose && !animator.Reversed)
{
animator.Reversed = !animator.Reversed;
}
if (shouldClose && animator.Reversed)
{
animator.Reversed = !animator.Reversed;
}
}
else
{
if (shouldClose && !animator.Reversed)
{
animator.Reversed = !animator.Reversed;
}
if (!shouldClose && animator.Reversed)
{
animator.Reversed = !animator.Reversed;
}
}
var fractionRemaining = 1 - animator.FractionComplete;
var distanceRemaining = fractionRemaining * closedTransform.y0;
if (distanceRemaining == 0)
{
animator.ContinueAnimation(null, 0);
break;
}
var relativeVelocity = NMath.Min(NMath.Abs(yVelocity) / distanceRemaining, 30);
var timingParameters = UISpringTiming.MakeTimingParameters(damping: 0.8f, response: 0.3f, initialVelocity: new CGVector(dx: relativeVelocity, dy: relativeVelocity));
var preferredDuration = new UIViewPropertyAnimator(duration: 0, parameters: timingParameters).Duration;
var durationFactor = preferredDuration / animator.Duration;
animator.ContinueAnimation(parameters: timingParameters, durationFactor: (nfloat)durationFactor);
break;
default:
break;
}
}
