/// <summary>
/// Invoked when a touch gesture begins.
/// </summary>
/// <param name="touches">To be added.</param>
/// <param name="evt">To be added.</param>
/// <remarks>To be added.</remarks>
public override void TouchesBegan(NSSet touches, UIEvent evt)
{
base.TouchesBegan(touches, evt);
if (NumberOfTouches > 1)
{
State = UIGestureRecognizerState.Failed;
return;
}
// A new touch cancels any outstanding Touches.
if (_timer != null)
{
_timer.Dispose();
}
_timer = new Timer
{
AutoReset = false,
Enabled = true,
Interval = HoldToBeginThresholdMilliseconds
};
_timer.Elapsed += TimerOnElapsed;
DownAt = GetTouchPoint();
ViewWasAt = View.Center;
State = UIGestureRecognizerState.Possible;
#if DRAGDROP_VERBOSE_DEBUGGING
Debug.WriteLine("DragDropGesture #{0}: Begin at {1},{2}", ++_serial, DownAt.X, DownAt.Y);
#endif
}
GestureRecognizerState GetGestureRecognizerStateFromUIState(UIGestureRecognizerState state)
{
switch (state)
{
case UIGestureRecognizerState.Possible:
return(GestureRecognizerState.Possible);
case UIGestureRecognizerState.Began:
return(GestureRecognizerState.Began);
case UIGestureRecognizerState.Changed:
return(GestureRecognizerState.Changed);
case UIGestureRecognizerState.Ended:
return(GestureRecognizerState.Ended);
case UIGestureRecognizerState.Cancelled:
return(GestureRecognizerState.Cancelled);
case UIGestureRecognizerState.Failed:
return(GestureRecognizerState.Failed);
default:
throw new ArgumentOutOfRangeException();
}
}
void LongTapAction(UIGestureRecognizerState state, bool inside)
{
switch (state)
{
case UIGestureRecognizerState.Began:
break;
case UIGestureRecognizerState.Ended:
if (!inside)
{
return;
}
if (_longCommand == null)
{
TapAction();
}
else if (_longCommand?.CanExecute(_longParameter) ?? false)
{
_longCommand.Execute(_longParameter);
}
break;
case UIGestureRecognizerState.Cancelled:
case UIGestureRecognizerState.Failed:
break;
}
}
public DragDropEventArgs(UIGestureRecognizerState state, CGPoint point, CGPoint delta, CGPoint viewWasAt)
{
State = state;
Point = point;
Delta = delta;
ViewWasAt = viewWasAt;
}
private void LongTapAction(UIGestureRecognizerState state)
{
switch (state)
{
case UIGestureRecognizerState.Began:
break;
case UIGestureRecognizerState.Ended:
if (_longCommand == null)
{
TapAction();
}
else
{
TaskMonitor.Create(
async() =>
{
await Task.Delay(50);
_longCommand.Execute(_longParameter);
});
}
break;
case UIGestureRecognizerState.Cancelled:
case UIGestureRecognizerState.Failed:
break;
}
}
public static GestureState ToGestureState(this UIGestureRecognizerState state)
{
var name = Enum.GetName(typeof(UIGestureRecognizerState), state);
GestureState result;
if (Enum.TryParse <GestureState>(name, out result))
{
return(result);
}
return(GestureState.Possible);
}
private void LongTapAction(UIGestureRecognizerState state)
{
switch (state)
{
case UIGestureRecognizerState.Began:
TaskMonitor.Create(TapAnimationAsync(0.5, 0, _alpha, false));
break;
case UIGestureRecognizerState.Ended:
case UIGestureRecognizerState.Cancelled:
case UIGestureRecognizerState.Failed:
TaskMonitor.Create(TapAnimationAsync(0.5, _alpha));
break;
}
}
/// <summary>
/// Invoked when a touch gesture is cancelled.
/// </summary>
/// <param name="touches">To be added.</param>
/// <param name="evt">To be added.</param>
/// <remarks>To be added.</remarks>
public override void TouchesCancelled(NSSet touches, UIEvent evt)
{
base.TouchesCancelled(touches, evt);
if (_timer != null)
{
_timer.Dispose();
}
_timer = null;
State = UIGestureRecognizerState.Failed;
#if DRAGDROP_VERBOSE_DEBUGGING
Debug.WriteLine("DragDropGesture #{0}: Cancelled", _serial);
#endif
}
private void TrackGestureEnded(UIGestureRecognizerState state)
{
if (InteractionInProgress)
{
InteractionInProgress = false;
if (!shouldCompleteTransition || state == UIGestureRecognizerState.Cancelled)
{
CancelInteractiveTransition();
}
else
{
FinishInteractiveTransition();
}
}
}
/// <summary>
/// Inboked when a touch gesture moves.
/// </summary>
/// <param name="touches">To be added.</param>
/// <param name="evt">To be added.</param>
/// <remarks>To be added.</remarks>
public override void TouchesMoved(NSSet touches, UIEvent evt)
{
base.TouchesMoved(touches, evt);
if (State == UIGestureRecognizerState.Failed)
{
return;
}
// After long press:
if (DidLongPress)
{
var dragat = GetTouchPoint();
if (dragat == DragAt)
{
return; // Not noteworthy.
}
DragAt = dragat;
if (!StayedPut(DownAt, DragAt))
{
DidDrag = true;
OnDragging(this, new DragDropEventArgs(State, DragAt, Delta, ViewWasAt, DownAt));
State = UIGestureRecognizerState.Changed;
}
}
// Before long press:
else
{
if (StayedPut(GetTouchPoint(), DownAt))
{
return;
}
if (_timer != null)
{
_timer.Dispose();
}
_timer = null;
State = UIGestureRecognizerState.Failed;
#if DRAGDROP_VERBOSE_DEBUGGING
Debug.WriteLine("DragDropGesture #{0}: Moved prematurely", _serial);
#endif
}
}
private async void LongTapAction(UIGestureRecognizerState state)
{
switch (state)
{
case UIGestureRecognizerState.Began:
await TapAnimation(0.5, 0, _alpha, false);
break;
case UIGestureRecognizerState.Ended:
case UIGestureRecognizerState.Cancelled:
case UIGestureRecognizerState.Failed:
await TapAnimation(0.5, _alpha);
break;
}
}
/// <summary>
/// Invoked when the timer elapsed.
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="elapsedEventArgs">The <see cref="ElapsedEventArgs"/> instance containing the event data.</param>
private void TimerOnElapsed(object sender, ElapsedEventArgs elapsedEventArgs)
{
var timer = sender as Timer;
// Could be from an previous timer that wasn't stopped in time.
if (timer == _timer)
{
DidLongPress = true;
_timer.Stop();
_timer.Dispose();
_timer = null;
#if DRAGDROP_VERBOSE_DEBUGGING
Debug.WriteLine("DragDropGesture #{0}: Held", _serial);
#endif
OnHeld(this, new DragDropEventArgs(default(UIGestureRecognizerState), DragAt, Delta, ViewWasAt, DownAt));
State = UIGestureRecognizerState.Changed;
}
}
/// <summary>
/// Inboked when a touch gesture moves.
/// </summary>
/// <param name="touches">To be added.</param>
/// <param name="evt">To be added.</param>
/// <remarks>To be added.</remarks>
public override void TouchesMoved(NSSet touches, UIEvent evt)
{
base.TouchesMoved(touches, evt);
if (State == UIGestureRecognizerState.Failed)
{
return;
}
// After long press:
if (DidLongPress)
{
var dragat = GetTouchPoint();
if (dragat == DragAt)
{
return; // Not noteworthy.
}
DragAt = dragat;
if (!StayedPut(DownAt, DragAt))
{
DidDrag = true;
//OnDragging(this, new DragDropEventArgs(State, DragAt, Delta, ViewWasAt));
State = UIGestureRecognizerState.Changed;
}
}
// Before long press:
else
{
if (StayedPut(GetTouchPoint(), DownAt))
{
return;
}
if (_timer != null)
{
_timer.Dispose();
}
_timer = null;
State = UIGestureRecognizerState.Failed;
}
}
/// <summary>
/// Resets the state of the gesture recognizer.
/// </summary>
/// <remarks>To be added.</remarks>
public override void Reset()
{
base.Reset();
if (_timer != null)
{
_timer.Stop();
_timer.Dispose();
}
_timer = null;
State = UIGestureRecognizerState.Possible;
DownAt = CGPoint.Empty;
DragAt = CGPoint.Empty;
DidLongPress = false;
DidDrag = false;
#if DRAGDROP_VERBOSE_DEBUGGING
Debug.WriteLine("DragDropGesture #{0}: Reset", _serial);
#endif
}
/// <summary>
/// Invoked when a touch gesture ends.
/// </summary>
/// <param name="touches">To be added.</param>
/// <param name="evt">To be added.</param>
/// <remarks>To be added.</remarks>
public override void TouchesEnded(NSSet touches, UIEvent evt)
{
base.TouchesEnded(touches, evt);
if (_timer != null)
{
_timer.Dispose();
}
_timer = null;
if (DidDrag)
{
State = UIGestureRecognizerState.Recognized;
OnDropped(this, new DragDropEventArgs(State, DragAt, Delta, ViewWasAt, DownAt));
}
else
{
State = UIGestureRecognizerState.Failed;
}
}
public static void MapGestureStateToInteractor(UIGestureRecognizerState state, float progress, Interactor interactor, Action triggerSegue)
{
if (interactor == null)
{
return;
}
switch (state)
{
case UIGestureRecognizerState.Began:
interactor.HasStarted = true;
triggerSegue?.Invoke();
break;
case UIGestureRecognizerState.Changed:
interactor.ShouldFinish = progress > PercentTreshold;
interactor.UpdateInteractiveTransition(progress);
break;
case UIGestureRecognizerState.Cancelled:
interactor.HasStarted = false;
interactor.CancelInteractiveTransition();
break;
case UIGestureRecognizerState.Ended:
interactor.HasStarted = false;
if (interactor.ShouldFinish)
{
interactor.FinishInteractiveTransition();
}
else
{
interactor.CancelInteractiveTransition();
}
break;
default:
break;
}
}
private async void LongTapAction(UIGestureRecognizerState state)
{
switch (state)
{
case UIGestureRecognizerState.Began:
await Task.Delay(500);
_longCommand?.Execute(_longParameter);
break;
case UIGestureRecognizerState.Ended:
if (_longCommand == null)
{
TapAction();
}
break;
case UIGestureRecognizerState.Cancelled:
case UIGestureRecognizerState.Failed:
break;
}
}
GestureState UIStateToNodeState(UIGestureRecognizerState state)
{
switch (state)
{
case UIGestureRecognizerState.Began:
return(GestureState.Began);
case UIGestureRecognizerState.Cancelled:
return(GestureState.Cancelled);
case UIGestureRecognizerState.Changed:
return(GestureState.Update);
case UIGestureRecognizerState.Ended:
return(GestureState.Ended);
case UIGestureRecognizerState.Failed:
return(GestureState.Failed);
case UIGestureRecognizerState.Possible:
return(GestureState.Possible);
}
return(GestureState.Failed);
}
private void HandleDragByGestureState(
UIGestureRecognizerState state,
UIGestureRecognizer gesture,
ref int from,
ref NSIndexPath pathTo,
ref iOSViewCell draggedViewCell)
{
switch (state)
{
case UIGestureRecognizerState.Began:
var selectedIndexPath = Control.IndexPathForItemAtPoint(gesture.LocationInView(Control));
if (selectedIndexPath != null)
{
draggedViewCell = (iOSViewCell)Control.CellForItem(selectedIndexPath);
if (draggedViewCell.FormsCell is DraggableViewCell draggableViewCell)
{
if (!draggableViewCell.IsDraggable)
{
Control.CancelInteractiveMovement();
return;
}
draggableViewCell.IsDragAndDropping = true;
}
from = (int)selectedIndexPath.Item;
Control.BeginInteractiveMovementForItem(selectedIndexPath);
Element.IsDragAndDropping = true;
Element.DragAndDropStartedCommand?.Execute(
new DragAndDropInfo(from, -1, Element.BindingContext));
}
break;
case UIGestureRecognizerState.Changed:
if (draggedViewCell == null)
{
return;
}
var gestureLocation = gesture.LocationInView(gesture.View);
var changedPath = Control.IndexPathForItemAtPoint(gestureLocation);
if (changedPath != null)
{
draggedViewCell = (iOSViewCell)Control.CellForItem(changedPath);
if (draggedViewCell == null ||
(draggedViewCell.FormsCell is DraggableViewCell draggableViewCell &&
!draggableViewCell.IsDraggable))
{
pathTo = null;
// System.Diagnostics.Debug.WriteLine("Cancel change state");
return;
}
pathTo = changedPath;
// System.Diagnostics.Debug.WriteLine($"State changed to {pathTo.Item}");
}
switch (Element.DragAndDropDirection)
{
case DragAndDropDirection.HorizontalOnly:
Control.UpdateInteractiveMovement(new CGPoint(gestureLocation.X, draggedViewCell.Center.Y));
break;
case DragAndDropDirection.VerticalOnly:
Control.UpdateInteractiveMovement(new CGPoint(draggedViewCell.Center.X, gestureLocation.Y));
break;
default:
Control.UpdateInteractiveMovement(gestureLocation);
break;
}
break;
case UIGestureRecognizerState.Ended:
if (from < 0 || pathTo == null)
{
// System.Diagnostics.Debug.WriteLine($"Ended but cancelled cause incorrect parameters");
Control.CancelInteractiveMovement();
return;
}
var targetViewCell = (iOSViewCell)Control.CellForItem(pathTo);
if (targetViewCell?.FormsCell is DraggableViewCell targetDraggableViewCell &&
!targetDraggableViewCell.IsDraggable)
{
// System.Diagnostics.Debug.WriteLine($"Ended but cancelled cause target is not draggable");
Control.CancelInteractiveMovement();
return;
}
// System.Diagnostics.Debug.WriteLine($"Ended from: {from} to: {pathTo.Item}");
Control.EndInteractiveMovement();
if (_itemsSource is IList itemsSourceList)
{
try
{
_isMovedBackfire = true;
var item = itemsSourceList[from];
itemsSourceList.RemoveAt(from);
itemsSourceList.Insert((int)pathTo.Item, item);
var to = itemsSourceList.IndexOf(item);
Element.IsDragAndDropping = false;
if (draggedViewCell?.FormsCell is DraggableViewCell draggableViewCell)
{
draggableViewCell.IsDragAndDropping = false;
Element.DragAndDropEndedCommand?.Execute(
new DragAndDropInfo(from, to, draggableViewCell.BindingContext));
}
draggedViewCell = null;
}
finally
{
_isMovedBackfire = false;
}
}
break;
default:
Control.CancelInteractiveMovement();
break;
}
}
private void TrackGestureEnded(UIGestureRecognizerState state)
{
if (InteractionInProgress) {
InteractionInProgress = false;
if (!shouldCompleteTransition || state == UIGestureRecognizerState.Cancelled) {
CancelInteractiveTransition ();
} else {
FinishInteractiveTransition ();
}
}
}
GestureState UIStateToNodeState(UIGestureRecognizerState state)
{
switch (state) {
case UIGestureRecognizerState.Began:
return GestureState.Began;
case UIGestureRecognizerState.Cancelled:
return GestureState.Cancelled;
case UIGestureRecognizerState.Changed:
return GestureState.Update;
case UIGestureRecognizerState.Ended:
return GestureState.Ended;
case UIGestureRecognizerState.Failed:
return GestureState.Failed;
case UIGestureRecognizerState.Possible:
return GestureState.Possible;
}
return GestureState.Failed;
}
