@ -18,13 +18,17 @@ namespace Avalonia.Input.Navigation
/// </summary>
/// <param name="element">The element.</param>
/// <param name="direction">The tab direction. Must be Next or Previous.</param>
/// <param name="outsideElement">
/// If true will not descend into <paramref name="element"/> to find next control.
/// </param>
/// <returns>
/// The next element in the specified direction, or null if <paramref name="element"/>
/// was the last in the requested direction.
/// </returns>
public static IInputElement GetNextInTabOrder (
IInputElement element ,
NavigationDirection direction )
NavigationDirection direction ,
bool outsideElement = false )
{
Contract . Requires < ArgumentNullException > ( element ! = null ) ;
Contract . Requires < ArgumentException > (
@ -40,42 +44,43 @@ namespace Avalonia.Input.Navigation
switch ( mode )
{
case KeyboardNavigationMode . Continue :
return GetNextInContainer ( element , container , direction ) ? ?
GetFirstInNextContainer ( element , direction ) ;
return GetNextInContainer ( element , container , direction , outsideElement ) ? ?
GetFirstInNextContainer ( element , element , direction ) ;
case KeyboardNavigationMode . Cycle :
return GetNextInContainer ( element , container , direction ) ? ?
GetFocusableDescende nt ( container , direction ) ;
return GetNextInContainer ( element , container , direction , outsideElement ) ? ?
GetFocusableDescenda nt ( container , direction ) ;
case KeyboardNavigationMode . Contained :
return GetNextInContainer ( element , container , direction ) ;
return GetNextInContainer ( element , container , direction , outsideElement ) ;
default :
return GetFirstInNextContainer ( container , direction ) ;
return GetFirstInNextContainer ( element , container , direction ) ;
}
}
else
{
return GetFocusableDescende nts ( element ) . FirstOrDefault ( ) ;
return GetFocusableDescenda nts ( element , direction ) . FirstOrDefault ( ) ;
}
}
/// <summary>
/// Gets the first or last focusable descende nt of the specified element.
/// Gets the first or last focusable descenda nt of the specified element.
/// </summary>
/// <param name="container">The element.</param>
/// <param name="direction">The direction to search.</param>
/// <returns>The element or null if not found.##</returns>
private static IInputElement GetFocusableDescende nt ( IInputElement container , NavigationDirection direction )
private static IInputElement GetFocusableDescenda nt ( IInputElement container , NavigationDirection direction )
{
return direction = = NavigationDirection . Next ?
GetFocusableDescende nts ( container ) . FirstOrDefault ( ) :
GetFocusableDescende nts ( container ) . LastOrDefault ( ) ;
GetFocusableDescenda nts ( container , direction ) . FirstOrDefault ( ) :
GetFocusableDescenda nts ( container , direction ) . LastOrDefault ( ) ;
}
/// <summary>
/// Gets the focusable descende nts of the specified element.
/// Gets the focusable descenda nts of the specified element.
/// </summary>
/// <param name="element">The element.</param>
/// <returns>The element's focusable descendents.</returns>
private static IEnumerable < IInputElement > GetFocusableDescendents ( IInputElement element )
/// <param name="direction">The tab direction. Must be Next or Previous.</param>
/// <returns>The element's focusable descendants.</returns>
private static IEnumerable < IInputElement > GetFocusableDescendants ( IInputElement element , NavigationDirection direction )
{
var mode = KeyboardNavigation . GetTabNavigation ( ( InputElement ) element ) ;
@ -103,16 +108,25 @@ namespace Avalonia.Input.Navigation
foreach ( var child in children )
{
if ( child . CanFocus ( ) )
var customNext = GetCustomNext ( child , direction ) ;
if ( customNext . handled )
{
yield return child ;
yield return customNext . next ;
}
if ( child . CanFocusDescendents ( ) )
else
{
foreach ( var descendent in GetFocusableDescendents ( child ) )
if ( child . CanFocus ( ) )
{
yield return descendent ;
yield return child ;
}
if ( child . CanFocusDescendants ( ) )
{
foreach ( var descendant in GetFocusableDescendants ( child , direction ) )
{
yield return descendant ;
}
}
}
}
@ -124,19 +138,23 @@ namespace Avalonia.Input.Navigation
/// <param name="element">The starting element/</param>
/// <param name="container">The container.</param>
/// <param name="direction">The direction.</param>
/// <param name="outsideElement">
/// If true will not descend into <paramref name="element"/> to find next control.
/// </param>
/// <returns>The next element, or null if the element is the last.</returns>
private static IInputElement GetNextInContainer (
IInputElement element ,
IInputElement container ,
NavigationDirection direction )
NavigationDirection direction ,
bool outsideElement )
{
if ( direction = = NavigationDirection . Next )
if ( direction = = NavigationDirection . Next & & ! outsideElement )
{
var descendent = GetFocusableDescende nts ( element ) . FirstOrDefault ( ) ;
var descendant = GetFocusableDescenda nts ( element , direction ) . FirstOrDefault ( ) ;
if ( descende nt ! = null )
if ( descenda nt ! = null )
{
return descende nt ;
return descenda nt ;
}
}
@ -167,11 +185,11 @@ namespace Avalonia.Input.Navigation
if ( element ! = null & & direction = = NavigationDirection . Previous )
{
var descendent = GetFocusableDescende nts ( element ) . LastOrDefault ( ) ;
var descendant = GetFocusableDescenda nts ( element , direction ) . LastOrDefault ( ) ;
if ( descende nt ! = null )
if ( descenda nt ! = null )
{
return descende nt ;
return descenda nt ;
}
}
@ -184,10 +202,12 @@ namespace Avalonia.Input.Navigation
/// <summary>
/// Gets the first item that should be focused in the next container.
/// </summary>
/// <param name="element">The element being navigated away from.</param>
/// <param name="container">The container.</param>
/// <param name="direction">The direction of the search.</param>
/// <returns>The first element, or null if there are no more elements.</returns>
private static IInputElement GetFirstInNextContainer (
IInputElement element ,
IInputElement container ,
NavigationDirection direction )
{
@ -203,13 +223,20 @@ namespace Avalonia.Input.Navigation
var siblings = parent . GetVisualChildren ( )
. OfType < IInputElement > ( )
. Where ( FocusExtensions . CanFocusDescende nts ) ;
. Where ( FocusExtensions . CanFocusDescenda nts ) ;
var sibling = direction = = NavigationDirection . Next ?
siblings . SkipWhile ( x = > x ! = container ) . Skip ( 1 ) . FirstOrDefault ( ) :
siblings . TakeWhile ( x = > x ! = container ) . LastOrDefault ( ) ;
if ( sibling ! = null )
{
var customNext = GetCustomNext ( sibling , direction ) ;
if ( customNext . handled )
{
return customNext . next ;
}
if ( sibling . CanFocus ( ) )
{
next = sibling ;
@ -217,24 +244,34 @@ namespace Avalonia.Input.Navigation
else
{
next = direction = = NavigationDirection . Next ?
GetFocusableDescende nts ( sibling ) . FirstOrDefault ( ) :
GetFocusableDescende nts ( sibling ) . LastOrDefault ( ) ;
GetFocusableDescenda nts ( sibling , direction ) . FirstOrDefault ( ) :
GetFocusableDescenda nts ( sibling , direction ) . LastOrDefault ( ) ;
}
}
if ( next = = null )
{
next = GetFirstInNextContainer ( parent , direction ) ;
next = GetFirstInNextContainer ( element , parent , direction ) ;
}
}
else
{
next = direction = = NavigationDirection . Next ?
GetFocusableDescende nts ( container ) . FirstOrDefault ( ) :
GetFocusableDescende nts ( container ) . LastOrDefault ( ) ;
GetFocusableDescenda nts ( container , direction ) . FirstOrDefault ( ) :
GetFocusableDescenda nts ( container , direction ) . LastOrDefault ( ) ;
}
return next ;
}
private static ( bool handled , IInputElement next ) GetCustomNext ( IInputElement element , NavigationDirection direction )
{
if ( element is ICustomKeyboardNavigation custom )
{
return custom . GetNext ( element , direction ) ;
}
return ( false , null ) ;
}
}
}
danwalmsley
9 years ago
GitHub