/// <summary>
/// Hides a modal frame.
/// </summary>
/// <param name="previousFrameName">The name of the modal frame to close.</param>
/// <param name="nextFrameName">The name of the frame that will be revealed as a result of closing the modal.</param>
/// <param name="transitionInfo">The transition info describing the animation.</param>
public async Task CloseModal(string previousFrameName, string nextFrameName, FrameSectionsTransitionInfo transitionInfo) // Runs on background thread.
{
await HidePreviousFrameAndShowNextFrame(previousFrameName, nextFrameName, UpdateView);
async Task UpdateView(FrameInfo previousFrame, FrameInfo nextFrame) // Runs on the UI thread
{
switch (transitionInfo)
{
case DelegatingFrameSectionsTransitionInfo frameTransition:
await frameTransition.Run(frameToHide : previousFrame.Frame, frameToShow : nextFrame.Frame, frameToShowIsAboveFrameToHide : false);
break;
case UIViewControllerSectionsTransitionInfo viewControllerTransitionInfo:
await previousFrame.ModalViewController.Close(viewControllerTransitionInfo);
break;
default:
throw new InvalidOperationException($"Unsupported transition info type '{transitionInfo.GetType()}'.");
}
}
}
/// <summary>
/// Changes the active section.
/// </summary>
/// <param name="previousFrameName">The name of the frame that will no longer be active.</param>
/// <param name="nextFrameName">The name of the frame that will be active.</param>
/// <param name="transitionInfo">The transition info describing the animation.</param>
public async Task ChangeActiveSection(string previousFrameName, string nextFrameName, FrameSectionsTransitionInfo transitionInfo) // Runs on background thread.
{
await HidePreviousFrameAndShowNextFrame(previousFrameName, nextFrameName, UpdateView);
async Task UpdateView(FrameInfo previousFrame, FrameInfo nextFrame) // Runs on the UI thread
{
switch (transitionInfo)
{
case DelegatingFrameSectionsTransitionInfo frameTransition:
if (previousFrame.Index > nextFrame.Index)
{
// If the previous frame is on top of the next one, we hide the previous frame to reveal the next one underneath.
// 1. We must first hide all frames that would be visible between our two target frames.
var framesToHideInstantly = _frames.Values
.Where(f => f.State == FrameState.Shown && f.Index > nextFrame.Index && f.Index < previousFrame.Index);
foreach (var f in framesToHideInstantly)
{
f.Frame.Visibility = Visibility.Collapsed;
f.State = FrameState.Hidden;
}
// 2. Animate the previous frame
await frameTransition.Run(frameToHide : previousFrame.Frame, frameToShow : nextFrame.Frame, frameToShowIsAboveFrameToHide : false);
// 3. Once faded out, collapse the previous frame.
previousFrame.Frame.Visibility = Visibility.Collapsed;
}
else
{
// Otherwise, the next frame is displayed on top of the previous one.
await frameTransition.Run(frameToHide : previousFrame.Frame, frameToShow : nextFrame.Frame, frameToShowIsAboveFrameToHide : true);
// 5. Collapse the previous frame that is no longer visible.
previousFrame.Frame.Visibility = Visibility.Collapsed;
}
break;
case UIViewControllerSectionsTransitionInfo viewControllerTransitionInfo:
throw new InvalidOperationException($"UIViewControllerTransitionInfo is only supported for modal operations.");
default:
throw new InvalidOperationException($"Unsupported transition info type '{transitionInfo.GetType()}'.");
}
}
}