- 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. SeeComponentOrientationfor more information. All columns in a row are fully traversed before proceeding to the next row.- Since:
- 1.4
- See Also:
ComponentOrientation, Serialized Form
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Constructor Summary
Constructors Constructor Description LayoutFocusTraversalPolicy()Constructs a LayoutFocusTraversalPolicy.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected booleanaccept(Component aComponent)Determines whether the specifiedComponentis an acceptable choice as the new focus owner.ComponentgetComponentAfter(Container aContainer, Component aComponent)Returns the Component that should receive the focus after aComponent.ComponentgetComponentBefore(Container aContainer, Component aComponent)Returns the Component that should receive the focus before aComponent.ComponentgetFirstComponent(Container aContainer)Returns the first Component in the traversal cycle.ComponentgetLastComponent(Container aContainer)Returns the last Component in the traversal cycle.-
Methods declared in class javax.swing.SortingFocusTraversalPolicy
getComparator, getDefaultComponent, getImplicitDownCycleTraversal, setComparator, setImplicitDownCycleTraversal
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Methods declared in class javax.swing.InternalFrameFocusTraversalPolicy
getInitialComponent
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Methods declared in class java.awt.FocusTraversalPolicy
getInitialComponent
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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
setImplicitDownCycleTraversalmethod.If aContainer is focus traversal policy provider, the focus is always transferred down-cycle.
- Overrides:
getComponentAfterin 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
setImplicitDownCycleTraversalmethod.If aContainer is focus traversal policy provider, the focus is always transferred down-cycle.
- Overrides:
getComponentBeforein 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:
getFirstComponentin 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:
getLastComponentin 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 specifiedComponentis an acceptable choice as the new focus owner. This method performs the following sequence of operations:- Checks whether
aComponentis visible, displayable, enabled, and focusable. If any of these properties isfalse, this method returnsfalse. - If
aComponentis an instance ofJTable, returnstrue. - If
aComponentis an instance ofJComboBox, then returns the value ofaComponent.getUI().isFocusTraversable(aComponent). - If
aComponentis aJComponentwith aJComponent.WHEN_FOCUSEDInputMapthat is neithernullnor empty, returnstrue. - Returns the value of
DefaultFocusTraversalPolicy.accept(aComponent).
- Overrides:
acceptin classSortingFocusTraversalPolicy- Parameters:
aComponent- theComponentwhose fitness as a focus owner is to be tested- Returns:
trueifaComponentis 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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