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@@ -5,8 +5,313 @@ namespace Terminal.Gui;
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public partial class View // Focus and cross-view navigation management (TabStop, TabIndex, etc...)
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{
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+ #region HasFocus
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- private NavigationDirection _focusDirection;
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+ // Backs `HasFocus` and is the ultimate source of truth whether a View has focus or not.
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+ private bool _hasFocus;
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+
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+ /// <summary>
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+ /// Gets or sets whether this view has focus.
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+ /// </summary>
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+ /// <remarks>
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+ /// <para>
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+ /// Only Views that are visible, enabled, and have <see cref="CanFocus"/> set to <see langword="true"/> are focusable. If
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+ /// these conditions are not met when this property is set to <see langword="true"/> <see cref="HasFocus"/> will not change.
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+ /// </para>
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+ /// <para>
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+ /// Setting this property causes the <see cref="OnEnter"/> and <see cref="OnLeave"/> virtual methods (and <see cref="Enter"/> and
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+ /// <see cref="Leave"/> events to be raised). If the event is cancelled, <see cref="HasFocus"/> will not be changed.
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+ /// </para>
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+ /// <para>
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+ /// Setting this property to <see langword="true"/> will recursively set <see cref="HasFocus"/> to
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+ /// <see langword="true"/> for all SuperViews up the hierarchy.
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+ /// </para>
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+ /// <para>
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+ /// Setting this property to <see langword="true"/> will cause the subview furthest down the hierarchy that is
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+ /// focusable to also gain focus (as long as <see cref="TabStop"/>
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+ /// </para>
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+ /// <para>
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+ /// Setting this property to <see langword="false"/> will recursively set <see cref="HasFocus"/> to
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+ /// <see langword="false"/> for any focused subviews.
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+ /// </para>
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+ /// </remarks>
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+ public bool HasFocus
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+ {
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+ set => SetHasFocus (value, this);
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+ get => _hasFocus;
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+ }
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+
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+ /// <summary>
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+ /// Causes this view to be focused. Calling this method has the same effect as setting <see cref="HasFocus"/> to
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+ /// <see langword="true"/>.
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+ /// </summary>
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+ public void SetFocus ()
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+ {
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+ HasFocus = true;
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+ }
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+
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+ /// <summary>
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+ /// Internal API that sets <see cref="HasFocus"/>. This method is called by `HasFocus_set` and other methods that
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+ /// need to set or remove focus from a view.
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+ /// </summary>
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+ /// <param name="newHasFocus">The new setting for <see cref="HasFocus"/>.</param>
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+ /// <param name="view">The view that will be gaining or losing focus.</param>
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+ /// <remarks>
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+ /// If <paramref name="newHasFocus"/> is <see langword="false"/> and there is a focused subview (<see cref="Focused"/>
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+ /// is not <see langword="null"/>),
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+ /// this method will recursively remove focus from any focused subviews of <see cref="Focused"/>.
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+ /// </remarks>
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+ private bool SetHasFocus (bool newHasFocus, View view)
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+ {
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+ if (HasFocus != newHasFocus)
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+ {
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+ if (newHasFocus)
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+ {
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+ Debug.Assert (view is null || SuperView is null || ApplicationNavigation.IsInHierarchy (SuperView, view));
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+
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+ if (OnEnter (view))
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+ {
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+ // The change happened
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+ // HasFocus is now true
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+ }
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+ else
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+ {
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+ // The event was cancelled or view is not focusable
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+ return false;
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+ }
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+ }
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+ else
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+ {
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+ if (OnLeave (view))
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+ {
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+ // The change happened
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+ // HasFocus is now false
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+ }
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+ else
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+ {
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+ // The event was cancelled or view was not focused
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+ return false;
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+ }
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+ }
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+
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+ SetNeedsDisplay ();
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+ }
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+
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+ return true;
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+ }
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+
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+ /// <summary>
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+ /// Called when view is entering focus. This method is called by <see cref="SetHasFocus"/> and other methods that
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+ /// set or remove focus from a view.
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+ /// </summary>
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+ /// <param name="leavingView">The previously focused view. If <see langword="null"/> there is no previously focused view.</param>
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+ /// <returns><see langword="true"/> if <see cref="HasFocus"/> was changed to <see langword="true"/>.</returns>
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+ /// <exception cref="InvalidOperationException"></exception>
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+ private bool EnterFocus ([CanBeNull] View leavingView)
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+ {
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+ // Pre-conditions
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+ if (_hasFocus)
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+ {
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+ throw new InvalidOperationException ($"EnterFocus should not be called if the view already has focus.");
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+ }
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+
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+ if (CanFocus && SuperView?.CanFocus == false)
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+ {
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+ throw new InvalidOperationException ($"It is not possible to EnterFocus if the View's SuperView has CanFocus = false.");
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+ }
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+
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+ if (!CanBeVisible (this) || !Enabled)
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+ {
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+ return false;
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+ }
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+
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+ if (!CanFocus)
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+ {
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+ return false;
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+ }
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+
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+ // Verify all views up the superview-hierarchy are focusable.
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+ if (SuperView is { })
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+ {
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+ View super = SuperView;
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+
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+ while (super is { })
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+ {
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+ // TODO: Check Visible & Enabled too!
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+ if (!super.CanFocus)
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+ {
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+ return false;
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+ }
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+ super = super.SuperView;
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+ }
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+ }
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+
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+ bool previousValue = HasFocus;
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+
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+ // Call the virtual method
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+ if (OnEnter (leavingView))
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+ {
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+ // The event was cancelled
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+ return false;
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+ }
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+
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+ var args = new FocusEventArgs (leavingView, this);
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+ Enter?.Invoke (this, args);
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+ if (args.Cancel)
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+ {
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+ // The event was cancelled
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+ return false;
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+ }
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+
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+ // Now, these things need to be true for us to set _hasFocus to true:
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+ // All views down v's view-hierarchy need to gain focus, if they don't already have it.
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+ // Any of them may cancel gaining focus, so we need to do that first.
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+
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+ _hasFocus = true;
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+
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+ // By setting _hasFocus to true we've definitively changed HasFocus for this view
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+
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+ if (SuperView is { })
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+ {
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+ SuperView.Focused = this;
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+ }
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+
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+ if (!RestoreFocus (TabStop))
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+ {
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+ // Couldn't restore focus, so use Advance to navigate
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+ if (!AdvanceFocus (NavigationDirection.Forward, TabStop))
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+ {
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+ // Couldn't advance, so we're the most-focusable view in the application
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+ ApplicationNavigation.SetFocused (this);
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+ }
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+ }
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+
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+ // All views down the superview-hierarchy need to have HasFocus == true
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+
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+ // Post-conditions - prove correctness
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+ if (HasFocus == previousValue)
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+ {
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+ throw new InvalidOperationException ($"EnterFocus was not cancelled and the HasFocus value did not change.");
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+ }
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+ return true;
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+ }
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+
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+ /// <summary>Virtual method invoked when this view is gaining focus (entering).</summary>
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+ /// <param name="leavingView">The view that is leaving focus.</param>
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+ /// <returns> <see langword="true"/>, if the event is to be cancelled, <see langword="false"/> otherwise.</returns>
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+ protected virtual bool OnEnter ([CanBeNull] View leavingView)
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+ {
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+ return false;
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+ }
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+
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+ /// <summary>Raised when the view is gaining (entering) focus. Can be cancelled.</summary>
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+ /// <remarks>
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+ /// Raised by <see cref="EnterFocus"/>.
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+ /// </remarks>
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+ public event EventHandler<FocusEventArgs> Enter;
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+
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+ /// <summary>
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+ /// Called when view is entering focus. This method is called by <see cref="SetHasFocus"/> and other methods that
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+ /// set or remove focus from a view.
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+ /// </summary>
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+ /// <param name="enteringView">The previously focused view. If <see langword="null"/> there is no previously focused view.</param>
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+ /// <returns><see langword="true"/> if <see cref="HasFocus"/> was changed.</returns>
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+ /// <exception cref="InvalidOperationException"></exception>
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+ private bool LeaveFocus ([CanBeNull] View enteringView)
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+ {
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+ // Pre-conditions
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+ if (_hasFocus)
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+ {
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+ throw new InvalidOperationException ($"LeaveFocus should not be called if the view does not have focus.");
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+ }
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+
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+ // Before we can leave focus, we need to make sure that all views down the subview-hierarchy have left focus.
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+ // Any of them may cancel losing focus, so we need to do that first.
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+ if (ApplicationNavigation.GetFocused () != this)
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+ {
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+ // Save the most focused view in the subview-hierarchy
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+ View originalBottom = ApplicationNavigation.GetFocused ();
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+ // Start at the bottom and work our way up to us
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+ View bottom = originalBottom;
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+
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+ while (bottom is { } && bottom != this)
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+ {
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+ if (bottom.HasFocus && !bottom.SetHasFocus (false, enteringView))
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+ {
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+ // The change was cancelled
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+ return false;
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+ }
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+ bottom = bottom.SuperView;
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+ }
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+
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+ PreviouslyMostFocused = originalBottom;
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+ }
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+
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+ bool previousValue = HasFocus;
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+
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+ // Call the virtual method
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+ if (OnLeave (enteringView))
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+ {
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+ // The event was cancelled
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+ return false;
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+ }
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+
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+ var args = new FocusEventArgs (enteringView, this);
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+ Leave?.Invoke (this, args);
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+ if (args.Cancel)
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+ {
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+ // The event was cancelled
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+ return false;
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+ }
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+
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+ Focused = null;
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+
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+ if (SuperView is { })
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+ {
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+ SuperView.Focused = null;
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+ }
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+
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+ _hasFocus = false;
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+
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+ if (ApplicationNavigation.GetFocused () != this)
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+ {
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+ PreviouslyMostFocused = null;
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+
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+ if (SuperView is { })
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+ {
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+ SuperView.PreviouslyMostFocused = this;
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+ }
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+ }
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+
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+ // Post-conditions - prove correctness
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+ if (HasFocus == previousValue)
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+ {
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+ throw new InvalidOperationException ($"LeaveFocus was not cancelled and the HasFocus value did not change.");
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+ }
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+ return true;
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+ }
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+
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+ /// <summary>
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+ /// Caches the most focused subview when this view is losing focus. This is used by <see cref="RestoreFocus"/>.
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+ /// </summary>
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+ [CanBeNull]
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+ internal View PreviouslyMostFocused { get; set; }
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+
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+ /// <summary>Virtual method invoked when this view is losing focus (leaving).</summary>
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+ /// <param name="enteringView">The view that is gaining focus.</param>
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+ /// <returns> <see langword="true"/>, if the event is to be cancelled, <see langword="false"/> otherwise.</returns>
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+ protected virtual bool OnLeave ([CanBeNull] View enteringView)
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+ {
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+ return false;
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+ }
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+
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+ /// <summary>Raised when the view is gaining (entering) focus. Can be cancelled.</summary>
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+ /// <remarks>
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+ /// Raised by <see cref="LeaveFocus"/>.
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+ /// </remarks>
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+ public event EventHandler<FocusEventArgs> Leave;
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+
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+ #endregion HasFocus
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/// <summary>
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/// Advances the focus to the next or previous view in <see cref="View.TabIndexes"/>, based on
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@@ -19,20 +324,18 @@ public partial class View // Focus and cross-view navigation management (TabStop
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/// </para>
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/// </remarks>
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/// <param name="direction"></param>
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- /// <param name="groupOnly">If <see langword="true"/> will advance into ...</param>
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+ /// <param name="behavior"></param>
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/// <returns>
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/// <see langword="true"/> if focus was changed to another subview (or stayed on this one), <see langword="false"/>
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/// otherwise.
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/// </returns>
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public bool AdvanceFocus (NavigationDirection direction, TabBehavior? behavior)
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{
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- if (!CanBeVisible (this))
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+ if (!CanBeVisible (this)) // TODO: is this check needed?
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{
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return false;
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}
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- FocusDirection = direction;
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-
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if (TabIndexes is null || TabIndexes.Count == 0)
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{
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return false;
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@@ -71,40 +374,13 @@ public partial class View // Focus and cross-view navigation management (TabStop
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{
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if (behavior == TabBehavior.TabGroup && behavior == TabStop && SuperView?.TabStop == TabBehavior.TabGroup)
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{
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- // Go up the hierarchy
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- // Leave
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+ // Go up the hierarchy and leave
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Focused.SetHasFocus (false, this);
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- // Signal that nothing is focused, and callers should try a peer-subview
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- Focused = null;
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+ // TODO: Should we check the return value of SetHasFocus?
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return false;
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}
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-
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- //Focused.RestoreFocus (TabBehavior.TabStop);
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-
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- //if (Focused is { })
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- //{
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- // return true;
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- //}
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-
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- // Wrap around
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- //if (SuperView is {})
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- //{
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- // if (direction == NavigationDirection.Forward)
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- // {
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- // return false;
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- // }
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- // else
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- // {
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- // return false;
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-
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- // //SuperView.FocusFirst (groupOnly);
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- // }
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- // return true;
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- //}
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- //next = index.Length - 1;
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-
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}
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View view = index [next];
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@@ -137,6 +413,104 @@ public partial class View // Focus and cross-view navigation management (TabStop
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return false;
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}
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+
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+ /// <summary>
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+ /// INTERNAL API to restore focus to the subview that had focus before this view lost focused.
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+ /// </summary>
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+ /// <returns>
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+ /// Returns true if focus was restored to a subview, false otherwise.
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+ /// </returns>
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+ internal bool RestoreFocus (TabBehavior? behavior)
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+ {
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+ if (Focused is null && _subviews?.Count > 0)
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+ {
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+ // TODO: Find the previous focused view and set focus to it
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+ if (PreviouslyMostFocused is { } && PreviouslyMostFocused.TabStop == behavior)
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+ {
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+ SetFocus (PreviouslyMostFocused);
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+
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+ return true;
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+ }
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+ return true;
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+ }
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+
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+ return false;
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+ }
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+
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+ /// <summary>
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+ /// Internal API that causes <paramref name="viewToEnterFocus"/> to enter focus.
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+ /// <paramref name="viewToEnterFocus"/> does not need to be a subview.
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+ /// Recursively sets focus DOWN in the view hierarchy.
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+ /// </summary>
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+ /// <param name="viewToEnterFocus"></param>
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+ private void SetFocus (View viewToEnterFocus)
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+ {
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+ if (viewToEnterFocus is null)
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+ {
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+ return;
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+ }
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+
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+ if (!viewToEnterFocus.CanFocus || !viewToEnterFocus.Visible || !viewToEnterFocus.Enabled)
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+ {
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+ return;
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+ }
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+
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+ // If viewToEnterFocus is already the focused view, don't do anything
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+ if (Focused?._hasFocus == true && Focused == viewToEnterFocus)
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+ {
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+ return;
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+ }
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+
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+ // If a subview has focus and viewToEnterFocus is the focused view's superview OR viewToEnterFocus is this view,
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+ // then make viewToEnterFocus.HasFocus = true and return
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|
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+ if ((Focused?._hasFocus == true && Focused?.SuperView == viewToEnterFocus) || viewToEnterFocus == this)
|
|
|
+ {
|
|
|
+ if (!viewToEnterFocus._hasFocus)
|
|
|
+ {
|
|
|
+ viewToEnterFocus._hasFocus = true;
|
|
|
+ }
|
|
|
+
|
|
|
+ return;
|
|
|
+ }
|
|
|
+
|
|
|
+ // Make sure that viewToEnterFocus is a subview of this view
|
|
|
+ View c;
|
|
|
+
|
|
|
+ for (c = viewToEnterFocus._superView; c != null; c = c._superView)
|
|
|
+ {
|
|
|
+ if (c == this)
|
|
|
+ {
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ if (c is null)
|
|
|
+ {
|
|
|
+ throw new ArgumentException (@$"The specified view {viewToEnterFocus} is not part of the hierarchy of {this}.");
|
|
|
+ }
|
|
|
+
|
|
|
+ // If a subview has focus, make it leave focus. This will leave focus up the hierarchy.
|
|
|
+ Focused?.SetHasFocus (false, viewToEnterFocus);
|
|
|
+
|
|
|
+ // make viewToEnterFocus Focused and enter focus
|
|
|
+ View f = Focused;
|
|
|
+ Focused = viewToEnterFocus;
|
|
|
+ Focused?.SetHasFocus (true, f, true);
|
|
|
+ Focused?.FocusDeepest (null, NavigationDirection.Forward);
|
|
|
+
|
|
|
+ // Recursively set focus down the view hierarchy
|
|
|
+ if (SuperView is { })
|
|
|
+ {
|
|
|
+ SuperView.SetFocus (this);
|
|
|
+ }
|
|
|
+ else
|
|
|
+ {
|
|
|
+ // If there is no SuperView, then this is a top-level view
|
|
|
+ SetFocus (this);
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+
|
|
|
#if AUTO_CANFOCUS
|
|
|
// BUGBUG: This is a poor API design. Automatic behavior like this is non-obvious and should be avoided. Instead, callers to Add should be explicit about what they want.
|
|
|
// Set to true in Add() to indicate that the view being added to a SuperView has CanFocus=true.
|
|
|
@@ -286,14 +660,9 @@ public partial class View // Focus and cross-view navigation management (TabStop
|
|
|
/// </remarks>
|
|
|
public event EventHandler CanFocusChanged;
|
|
|
|
|
|
- /// <summary>Raised when the view is gaining (entering) focus. Can be cancelled.</summary>
|
|
|
- /// <remarks>
|
|
|
- /// Raised by the <see cref="OnEnter"/> virtual method.
|
|
|
- /// </remarks>
|
|
|
- public event EventHandler<FocusEventArgs> Enter;
|
|
|
-
|
|
|
/// <summary>Returns the currently focused Subview inside this view, or <see langword="null"/> if nothing is focused.</summary>
|
|
|
/// <value>The currently focused Subview.</value>
|
|
|
+ [CanBeNull]
|
|
|
public View Focused { get; private set; }
|
|
|
|
|
|
/// <summary>
|
|
|
@@ -354,38 +723,9 @@ public partial class View // Focus and cross-view navigation management (TabStop
|
|
|
return null;
|
|
|
}
|
|
|
|
|
|
- private bool _hasFocus;
|
|
|
-
|
|
|
- /// <summary>
|
|
|
- /// Gets or sets whether this view has focus.
|
|
|
- /// </summary>
|
|
|
- /// <remarks>
|
|
|
- /// <para>
|
|
|
- /// Causes the <see cref="OnEnter"/> and <see cref="OnLeave"/> virtual methods (and <see cref="Enter"/> and
|
|
|
- /// <see cref="Leave"/> events to be raised) when the value changes.
|
|
|
- /// </para>
|
|
|
- /// <para>
|
|
|
- /// Setting this property to <see langword="false"/> will recursively set <see cref="HasFocus"/> to
|
|
|
- /// <see langword="false"/>
|
|
|
- /// for any focused subviews.
|
|
|
- /// </para>
|
|
|
- /// </remarks>
|
|
|
- public bool HasFocus
|
|
|
- {
|
|
|
- // Force the specified view to have focus
|
|
|
- set => SetHasFocus (value, this, true);
|
|
|
- get => _hasFocus;
|
|
|
- }
|
|
|
-
|
|
|
/// <summary>Returns a value indicating if this View is currently on Top (Active)</summary>
|
|
|
public bool IsCurrentTop => Application.Current == this;
|
|
|
|
|
|
- /// <summary>Raised when the view is losing (leaving) focus. Can be cancelled.</summary>
|
|
|
- /// <remarks>
|
|
|
- /// Raised by the <see cref="OnLeave"/> virtual method.
|
|
|
- /// </remarks>
|
|
|
- public event EventHandler<FocusEventArgs> Leave;
|
|
|
-
|
|
|
/// <summary>
|
|
|
/// Returns the most focused Subview in the chain of subviews (the leaf view that has the focus), or
|
|
|
/// <see langword="null"/> if nothing is focused.
|
|
|
@@ -416,251 +756,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
|
|
|
/// Raises the <see cref="CanFocusChanged"/> event.
|
|
|
/// </remarks>
|
|
|
public virtual void OnCanFocusChanged () { CanFocusChanged?.Invoke (this, EventArgs.Empty); }
|
|
|
-
|
|
|
- // BUGBUG: The focus API is poorly defined and implemented. It deeply intertwines the view hierarchy with the tab order.
|
|
|
-
|
|
|
- /// <summary>Invoked when this view is gaining focus (entering).</summary>
|
|
|
- /// <param name="leavingView">The view that is leaving focus.</param>
|
|
|
- /// <returns> <see langword="true"/>, if the event was handled, <see langword="false"/> otherwise.</returns>
|
|
|
- /// <remarks>
|
|
|
- /// <para>
|
|
|
- /// Overrides must call the base class method to ensure that the <see cref="Enter"/> event is raised. If the event
|
|
|
- /// is handled, the method should return <see langword="true"/>.
|
|
|
- /// </para>
|
|
|
- /// </remarks>
|
|
|
- public virtual bool OnEnter (View leavingView)
|
|
|
- {
|
|
|
- // BUGBUG: _hasFocus should ALWAYS be false when this method is called.
|
|
|
- if (_hasFocus)
|
|
|
- {
|
|
|
- Debug.WriteLine ($"BUGBUG: HasFocus should be false when OnEnter is called - Leaving: {leavingView} Entering: {this}");
|
|
|
-
|
|
|
- // return true;
|
|
|
- }
|
|
|
-
|
|
|
- var args = new FocusEventArgs (leavingView, this);
|
|
|
- Enter?.Invoke (this, args);
|
|
|
-
|
|
|
- if (args.Handled)
|
|
|
- {
|
|
|
- return true;
|
|
|
- }
|
|
|
-
|
|
|
- return false;
|
|
|
- }
|
|
|
-
|
|
|
- /// <summary>Invoked when this view is losing focus (leaving).</summary>
|
|
|
- /// <param name="enteringView">The view that is entering focus.</param>
|
|
|
- /// <returns> <see langword="true"/>, if the event was handled, <see langword="false"/> otherwise.</returns>
|
|
|
- /// <remarks>
|
|
|
- /// <para>
|
|
|
- /// Overrides must call the base class method to ensure that the <see cref="Leave"/> event is raised. If the event
|
|
|
- /// is handled, the method should return <see langword="true"/>.
|
|
|
- /// </para>
|
|
|
- /// </remarks>
|
|
|
- public virtual bool OnLeave (View enteringView)
|
|
|
- {
|
|
|
- // BUGBUG: _hasFocus should ALWAYS be true when this method is called.
|
|
|
- if (!_hasFocus)
|
|
|
- {
|
|
|
- Debug.WriteLine ($"BUGBUG: HasFocus should be true when OnLeave is called - Leaving: {this} Entering: {enteringView}");
|
|
|
-
|
|
|
- //return true;
|
|
|
- }
|
|
|
-
|
|
|
- var args = new FocusEventArgs (this, enteringView);
|
|
|
- Leave?.Invoke (this, args);
|
|
|
-
|
|
|
- if (args.Handled)
|
|
|
- {
|
|
|
- return true;
|
|
|
- }
|
|
|
-
|
|
|
- return false;
|
|
|
- }
|
|
|
-
|
|
|
- /// <summary>
|
|
|
- /// Causes this view to be focused. All focusable views up the Superview hierarchy will also be focused.
|
|
|
- /// </summary>
|
|
|
- public void SetFocus ()
|
|
|
- {
|
|
|
- if (!CanBeVisible (this) || !Enabled)
|
|
|
- {
|
|
|
- if (HasFocus)
|
|
|
- {
|
|
|
- // If this view is focused, make it leave focus
|
|
|
- SetHasFocus (false, this);
|
|
|
- }
|
|
|
-
|
|
|
- return;
|
|
|
- }
|
|
|
-
|
|
|
- // Recursively set focus upwards in the view hierarchy
|
|
|
- if (SuperView is { })
|
|
|
- {
|
|
|
- SuperView.SetFocus (this);
|
|
|
- }
|
|
|
- else
|
|
|
- {
|
|
|
- SetFocus (this);
|
|
|
- }
|
|
|
- }
|
|
|
-
|
|
|
- /// <summary>
|
|
|
- /// INTERNAL API that gets or sets the focus direction for this view and all subviews.
|
|
|
- /// Setting this property will set the focus direction for all views up the SuperView hierarchy.
|
|
|
- /// </summary>
|
|
|
- internal NavigationDirection FocusDirection
|
|
|
- {
|
|
|
- get => SuperView?.FocusDirection ?? _focusDirection;
|
|
|
- set
|
|
|
- {
|
|
|
- if (SuperView is { })
|
|
|
- {
|
|
|
- SuperView.FocusDirection = value;
|
|
|
- }
|
|
|
- else
|
|
|
- {
|
|
|
- _focusDirection = value;
|
|
|
- }
|
|
|
- }
|
|
|
- }
|
|
|
-
|
|
|
- /// <summary>
|
|
|
- /// INTERNAL helper for calling <see cref="FocusDeepest"/> or <see cref="FocusLast"/> based on
|
|
|
- /// <see cref="FocusDirection"/>.
|
|
|
- /// FocusDirection is not public. This API is thus non-deterministic from a public API perspective.
|
|
|
- /// </summary>
|
|
|
- internal void RestoreFocus (TabBehavior? behavior)
|
|
|
- {
|
|
|
- if (Focused is null && _subviews?.Count > 0)
|
|
|
- {
|
|
|
- FocusDeepest (behavior, FocusDirection);
|
|
|
- }
|
|
|
- }
|
|
|
-
|
|
|
- /// <summary>
|
|
|
- /// Internal API that causes <paramref name="viewToEnterFocus"/> to enter focus.
|
|
|
- /// <paramref name="viewToEnterFocus"/> does not need to be a subview.
|
|
|
- /// Recursively sets focus DOWN in the view hierarchy.
|
|
|
- /// </summary>
|
|
|
- /// <param name="viewToEnterFocus"></param>
|
|
|
- private void SetFocus (View viewToEnterFocus)
|
|
|
- {
|
|
|
- if (viewToEnterFocus is null)
|
|
|
- {
|
|
|
- return;
|
|
|
- }
|
|
|
-
|
|
|
- if (!viewToEnterFocus.CanFocus || !viewToEnterFocus.Visible || !viewToEnterFocus.Enabled)
|
|
|
- {
|
|
|
- return;
|
|
|
- }
|
|
|
-
|
|
|
- // If viewToEnterFocus is already the focused view, don't do anything
|
|
|
- if (Focused?._hasFocus == true && Focused == viewToEnterFocus)
|
|
|
- {
|
|
|
- return;
|
|
|
- }
|
|
|
-
|
|
|
- // If a subview has focus and viewToEnterFocus is the focused view's superview OR viewToEnterFocus is this view,
|
|
|
- // then make viewToEnterFocus.HasFocus = true and return
|
|
|
- if ((Focused?._hasFocus == true && Focused?.SuperView == viewToEnterFocus) || viewToEnterFocus == this)
|
|
|
- {
|
|
|
- if (!viewToEnterFocus._hasFocus)
|
|
|
- {
|
|
|
- viewToEnterFocus._hasFocus = true;
|
|
|
- }
|
|
|
-
|
|
|
- return;
|
|
|
- }
|
|
|
-
|
|
|
- // Make sure that viewToEnterFocus is a subview of this view
|
|
|
- View c;
|
|
|
-
|
|
|
- for (c = viewToEnterFocus._superView; c != null; c = c._superView)
|
|
|
- {
|
|
|
- if (c == this)
|
|
|
- {
|
|
|
- break;
|
|
|
- }
|
|
|
- }
|
|
|
-
|
|
|
- if (c is null)
|
|
|
- {
|
|
|
- throw new ArgumentException (@$"The specified view {viewToEnterFocus} is not part of the hierarchy of {this}.");
|
|
|
- }
|
|
|
-
|
|
|
- // If a subview has focus, make it leave focus. This will leave focus up the hierarchy.
|
|
|
- Focused?.SetHasFocus (false, viewToEnterFocus);
|
|
|
-
|
|
|
- // make viewToEnterFocus Focused and enter focus
|
|
|
- View f = Focused;
|
|
|
- Focused = viewToEnterFocus;
|
|
|
- Focused?.SetHasFocus (true, f, true);
|
|
|
- Focused?.FocusDeepest (null, NavigationDirection.Forward);
|
|
|
-
|
|
|
- // Recursively set focus down the view hierarchy
|
|
|
- if (SuperView is { })
|
|
|
- {
|
|
|
- SuperView.SetFocus (this);
|
|
|
- }
|
|
|
- else
|
|
|
- {
|
|
|
- // If there is no SuperView, then this is a top-level view
|
|
|
- SetFocus (this);
|
|
|
- }
|
|
|
- }
|
|
|
-
|
|
|
- /// <summary>
|
|
|
- /// Internal API that sets <see cref="HasFocus"/>. This method is called by <c>HasFocus_set</c> and other methods that
|
|
|
- /// need to set or remove focus from a view.
|
|
|
- /// </summary>
|
|
|
- /// <param name="newHasFocus">The new setting for <see cref="HasFocus"/>.</param>
|
|
|
- /// <param name="view">The view that will be gaining or losing focus.</param>
|
|
|
- /// <param name="force">
|
|
|
- /// <see langword="true"/> to force Enter/Leave on <paramref name="view"/> regardless of whether it
|
|
|
- /// already HasFocus or not.
|
|
|
- /// </param>
|
|
|
- /// <remarks>
|
|
|
- /// If <paramref name="newHasFocus"/> is <see langword="false"/> and there is a focused subview (<see cref="Focused"/>
|
|
|
- /// is not <see langword="null"/>),
|
|
|
- /// this method will recursively remove focus from any focused subviews of <see cref="Focused"/>.
|
|
|
- /// </remarks>
|
|
|
- private void SetHasFocus (bool newHasFocus, View view, bool force = false)
|
|
|
- {
|
|
|
- if (HasFocus != newHasFocus || force)
|
|
|
- {
|
|
|
- _hasFocus = newHasFocus;
|
|
|
-
|
|
|
- if (newHasFocus)
|
|
|
- {
|
|
|
- Debug.Assert (view is null || SuperView is null || ApplicationNavigation.IsInHierarchy (SuperView, view));
|
|
|
- OnEnter (view);
|
|
|
- ApplicationNavigation.Focused = this;
|
|
|
-
|
|
|
- //_hasFocus = true;
|
|
|
- }
|
|
|
- else
|
|
|
- {
|
|
|
- OnLeave (view);
|
|
|
-
|
|
|
- //_hasFocus = false;
|
|
|
- }
|
|
|
-
|
|
|
- SetNeedsDisplay ();
|
|
|
- }
|
|
|
-
|
|
|
- // Remove focus down the chain of subviews if focus is removed
|
|
|
- if (!newHasFocus && Focused is { })
|
|
|
- {
|
|
|
- View f = Focused;
|
|
|
- f.OnLeave (view);
|
|
|
- f.SetHasFocus (false, view, true);
|
|
|
- Focused = null;
|
|
|
- }
|
|
|
- }
|
|
|
-
|
|
|
+
|
|
|
#region Tab/Focus Handling
|
|
|
|
|
|
#nullable enable
|
Tig