void Select(RingView view)
{
foreach (var v in RingViews)
{
if (v.Selected)
{
v.Selected = false;
v.SelectionState?.Invoke();
}
v.FannedOut = false;
}
view.Selected = true;
selectedView = view;
view.ActionClosure?.Invoke();
}
void SetupRings(int itemCount)
{
// Define some nice colors.
var borderColorSelected = UIColor.FromHSBA(0.07f, 0.81f, 0.98f, 1).CGColor;
var borderColorNormal = UIColor.DarkGray.CGColor;
var fillColorSelected = UIColor.FromHSBA(0.07f, 0.21f, 0.98f, 1);
var fillColorNormal = UIColor.White;
// We define generators to return closures which we use to define
// the different states of our item ring views.
Func <RingView, Action> selectedGenerator = (view) => () => {
view.Layer.BorderColor = borderColorSelected;
view.BackgroundColor = fillColorSelected;
};
Func <RingView, Action> normalGenerator = (view) => () => {
view.Layer.BorderColor = borderColorNormal;
view.BackgroundColor = fillColorNormal;
};
CGPoint startPosition = Bounds.GetCenter();
Func <RingView, Action> locationNormalGenerator = (view) => () => {
view.Center = startPosition;
if (!view.Selected)
{
view.Alpha = 0;
}
};
Func <RingView, CGVector, Action> locationFanGenerator = (view, offset) => () => {
view.Center = startPosition.Add(offset);
view.Alpha = 1;
};
// tau is a full circle in radians
var tau = NMath.PI * 2;
var absoluteRingSegment = tau / 4;
var requiredLengthPerRing = RingRadius * 2 + 5;
var totalRequiredCirlceSegment = requiredLengthPerRing * (itemCount - 1);
var fannedControlRadius = NMath.Max(requiredLengthPerRing, totalRequiredCirlceSegment / absoluteRingSegment);
var normalDistance = new CGVector(0, -fannedControlRadius);
var scale = UIScreen.MainScreen.Scale;
// Setup our item views.
for (int index = 0; index < itemCount; index++)
{
var view = new RingView(Bounds);
view.StateClosures [Selected] = selectedGenerator(view);
view.StateClosures [Normal] = normalGenerator(view);
nfloat angle = index / (nfloat)(itemCount - 1) * absoluteRingSegment;
var fan = normalDistance.Apply(MakeRotation(angle)).RoundTo(scale);
view.StateClosures [LocationFan] = locationFanGenerator(view, fan);
view.StateClosures [LocationOrigin] = locationNormalGenerator(view);
AddSubview(view);
RingViews.Add(view);
var gr = new UITapGestureRecognizer(Tap);
view.AddGestureRecognizer(gr);
}
// Setup the initial selection state.
var rv = RingViews [0];
AddSubview(rv);
rv.Selected = true;
selectedView = rv;
UpdateViews(animated: false);
}