- java.lang.Object
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- java.awt.FocusTraversalPolicy
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- javax.swing.InternalFrameFocusTraversalPolicy
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- javax.swing.SortingFocusTraversalPolicy
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- javax.swing.LayoutFocusTraversalPolicy
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- 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. SeeComponentOrientation
for more information. All columns in a row are fully traversed before proceeding to the next row.- Since:
- 1.4
- See Also:
ComponentOrientation
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Constructor Summary
Constructors Constructor and Description LayoutFocusTraversalPolicy()
Constructs a LayoutFocusTraversalPolicy.
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Method Summary
Methods Modifier and Type Method and Description protected boolean
accept(Component aComponent)
Determines whether the specifiedComponent
is an acceptable choice as the new focus owner.Component
getComponentAfter(Container aContainer, Component aComponent)
Returns the Component that should receive the focus after aComponent.Component
getComponentBefore(Container aContainer, Component aComponent)
Returns the Component that should receive the focus before aComponent.Component
getFirstComponent(Container aContainer)
Returns the first Component in the traversal cycle.Component
getLastComponent(Container aContainer)
Returns the last Component in the traversal cycle.-
Methods inherited from class javax.swing.SortingFocusTraversalPolicy
getComparator, getDefaultComponent, getImplicitDownCycleTraversal, setComparator, setImplicitDownCycleTraversal
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Methods inherited from class javax.swing.InternalFrameFocusTraversalPolicy
getInitialComponent
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Methods inherited from class java.awt.FocusTraversalPolicy
getInitialComponent
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-
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Constructor Detail
-
LayoutFocusTraversalPolicy
public LayoutFocusTraversalPolicy()
Constructs a LayoutFocusTraversalPolicy.
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Method Detail
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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 classSortingFocusTraversalPolicy
- Parameters:
aContainer
- a focus cycle root of aComponent or a focus traversal policy provideraComponent
- 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
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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 classSortingFocusTraversalPolicy
- Parameters:
aContainer
- a focus cycle root of aComponent or a focus traversal policy provideraComponent
- 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
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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 classSortingFocusTraversalPolicy
- 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
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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 classSortingFocusTraversalPolicy
- 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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accept
protected boolean accept(Component aComponent)
Determines whether the specifiedComponent
is an acceptable choice as the new focus owner. This method performs the following sequence of operations:- Checks whether
aComponent
is visible, displayable, enabled, and focusable. If any of these properties isfalse
, this method returnsfalse
. - If
aComponent
is an instance ofJTable
, returnstrue
. - If
aComponent
is an instance ofJComboBox
, then returns the value ofaComponent.getUI().isFocusTraversable(aComponent)
. - If
aComponent
is aJComponent
with aJComponent.WHEN_FOCUSED
InputMap
that is neithernull
nor empty, returnstrue
. - Returns the value of
DefaultFocusTraversalPolicy.accept(aComponent)
.
- Overrides:
accept
in classSortingFocusTraversalPolicy
- Parameters:
aComponent
- theComponent
whose fitness as a focus owner is to be tested- Returns:
true
ifaComponent
is a valid choice for a focus owner; otherwisefalse
- See Also:
Component.isVisible()
,Component.isDisplayable()
,Component.isEnabled()
,Component.isFocusable()
,ComboBoxUI.isFocusTraversable(javax.swing.JComboBox)
,JComponent.getInputMap(int)
,DefaultFocusTraversalPolicy.accept(java.awt.Component)
- Checks whether
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Document created the 11/06/2005, last modified the 04/03/2020
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