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org.eclipse.swt.widgets
Class Layout
java.lang.Object
org.eclipse.swt.widgets.Layout
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Direct Known Subclasses:
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AbstractColumnLayout,
ColumnLayout,
FillLayout,
FormLayout,
GridLayout,
PageBook.PageBookLayout,
RowLayout,
SourceViewer.RulerLayout,
StackLayout,
TableLayout,
TableWrapLayout,
WizardDialog.PageContainerFillLayout
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public abstract class Layout
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Object
A layout controls the position and size
of the children of a composite widget.
This class is the abstract base class for
layouts.
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See Also:
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Composite.setLayout(Layout),
Sample code and further information
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Method Summary
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protected abstract
Point
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computeSize
(
Composite composite,
int wHint,
int hHint,
boolean flushCache)
Computes and returns the size of the specified
composite's client area according to this layout. |
protected boolean
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flushCache
(
Control control)
Instruct the layout to flush any cached values
associated with the control specified in the argument
control. |
protected abstract void
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layout
(
Composite composite,
boolean flushCache)
Lays out the children of the specified composite
according to this layout. |
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Methods inherited from class java.lang.
Object
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clone,
equals,
finalize,
getClass,
hashCode,
notify,
notifyAll,
toString,
wait,
wait,
wait
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Layout
public Layout()
computeSize
protected abstract
Point computeSize(
Composite composite,
int wHint,
int hHint,
boolean flushCache)
- Computes and returns the size of the specified
composite's client area according to this layout.
This method computes the size that the client area
of the composite must be in order to position all
children at their preferred size inside the
composite according to the layout algorithm
encoded by this layout.
When a width or height hint is supplied, it is
used to constrain the result. For example, if a
width hint is provided that is less than the
width of the client area, the layout may choose
to wrap and increase height, clip, overlap, or
otherwise constrain the children.
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Parameters:
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composite - a composite widget using this layout -
wHint - width (SWT.DEFAULT for preferred size) -
hHint - height (SWT.DEFAULT for preferred size) -
flushCache - true means flush cached layout values
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Returns:
- a point containing the computed size (width, height)
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See Also:
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layout(org.eclipse.swt.widgets.Composite, boolean),
Control.getBorderWidth(),
Control.getBounds(),
Control.getSize(),
Control.pack(boolean),
"computeTrim, getClientArea for controls that implement them"
flushCache
protected boolean flushCache(
Control control)
- Instruct the layout to flush any cached values
associated with the control specified in the argument
control.
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Parameters:
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control - a control managed by this layout
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Returns:
- true if the Layout has flushed all cached information associated with control
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Since:
- 3.1
layout
protected abstract void layout(
Composite composite,
boolean flushCache)
- Lays out the children of the specified composite
according to this layout.
This method positions and sizes the children of a
composite using the layout algorithm encoded by this
layout. Children of the composite are positioned in
the client area of the composite. The position of
the composite is not altered by this method.
When the flush cache hint is true, the layout is
instructed to flush any cached values associated
with the children. Typically, a layout will cache
the preferred sizes of the children to avoid the
expense of computing these values each time the
widget is laid out.
When layout is triggered explicitly by the programmer
the flush cache hint is true. When layout is triggered
by a resize, either caused by the programmer or by the
user, the hint is false.
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Parameters:
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composite - a composite widget using this layout -
flushCache - true means flush cached layout values
Guidelines for using Eclipse APIs.
Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.
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