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Java javax.swing Class LayoutFocusTraversalPolicy（JDK8）

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Java™ Platform
Standard Ed. 8
javax.swing

Class LayoutFocusTraversalPolicy

  • All Implemented Interfaces:
    Serializable 

    public class LayoutFocusTraversalPolicy
extends SortingFocusTraversalPolicy
implements Serializable
    A SortingFocusTraversalPolicy which sorts Components based on their size, position, and orientation. Based on their size and position, Components are roughly categorized into rows and columns. For a Container with horizontal orientation, columns run left-to-right or right-to-left, and rows run top- to-bottom. For a Container with vertical orientation, columns run top-to- bottom and rows run left-to-right or right-to-left. See ComponentOrientation for more information. All columns in a row are fully traversed before proceeding to the next row.
    Since:
    1.4
    See Also:
    ComponentOrientation

    • Constructor Detail

      • LayoutFocusTraversalPolicy

        public LayoutFocusTraversalPolicy()
        Constructs a LayoutFocusTraversalPolicy.

    • Method Detail

      • getComponentAfter

        public Component getComponentAfter(Container aContainer,
                                   Component aComponent)
        Returns the Component that should receive the focus after aComponent. aContainer must be a focus cycle root of aComponent.

        By default, LayoutFocusTraversalPolicy implicitly transfers focus down- cycle. That is, during normal focus traversal, the Component traversed after a focus cycle root will be the focus-cycle-root's default Component to focus. This behavior can be disabled using the setImplicitDownCycleTraversal method.

        If aContainer is focus traversal policy provider, the focus is always transferred down-cycle.

        Overrides:
        getComponentAfter in class SortingFocusTraversalPolicy
        Parameters:
        aContainer - a focus cycle root of aComponent or a focus traversal policy provider
        aComponent - a (possibly indirect) child of aContainer, or aContainer itself
        Returns:
        the Component that should receive the focus after aComponent, or null if no suitable Component can be found
        Throws:
        IllegalArgumentException - if aContainer is not a focus cycle root of aComponent or a focus traversal policy provider, or if either aContainer or aComponent is null

      • getComponentBefore

        public Component getComponentBefore(Container aContainer,
                                    Component aComponent)
        Returns the Component that should receive the focus before aComponent. aContainer must be a focus cycle root of aComponent.

        By default, LayoutFocusTraversalPolicy implicitly transfers focus down- cycle. That is, during normal focus traversal, the Component traversed after a focus cycle root will be the focus-cycle-root's default Component to focus. This behavior can be disabled using the setImplicitDownCycleTraversal method.

        If aContainer is focus traversal policy provider, the focus is always transferred down-cycle.

        Overrides:
        getComponentBefore in class SortingFocusTraversalPolicy
        Parameters:
        aContainer - a focus cycle root of aComponent or a focus traversal policy provider
        aComponent - a (possibly indirect) child of aContainer, or aContainer itself
        Returns:
        the Component that should receive the focus before aComponent, or null if no suitable Component can be found
        Throws:
        IllegalArgumentException - if aContainer is not a focus cycle root of aComponent or a focus traversal policy provider, or if either aContainer or aComponent is null

      • getFirstComponent

        public Component getFirstComponent(Container aContainer)
        Returns the first Component in the traversal cycle. This method is used to determine the next Component to focus when traversal wraps in the forward direction.
        Overrides:
        getFirstComponent in class SortingFocusTraversalPolicy
        Parameters:
        aContainer - a focus cycle root of aComponent or a focus traversal policy provider whose first Component is to be returned
        Returns:
        the first Component in the traversal cycle of aContainer, or null if no suitable Component can be found
        Throws:
        IllegalArgumentException - if aContainer is null

      • getLastComponent

        public Component getLastComponent(Container aContainer)
        Returns the last Component in the traversal cycle. This method is used to determine the next Component to focus when traversal wraps in the reverse direction.
        Overrides:
        getLastComponent in class SortingFocusTraversalPolicy
        Parameters:
        aContainer - a focus cycle root of aComponent or a focus traversal policy provider whose last Component is to be returned
        Returns:
        the last Component in the traversal cycle of aContainer, or null if no suitable Component can be found
        Throws:
        IllegalArgumentException - if aContainer is null
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Java™ Platform
Standard Ed. 8

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