Class ColumnLayout
- java.lang.Object
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- org.eclipse.swt.widgets.Layout
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- org.eclipse.ui.forms.widgets.ColumnLayout
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- All Implemented Interfaces:
ILayoutExtension
public final class ColumnLayout extends Layout implements ILayoutExtension
This layout manager arranges children of the composite parent in vertical columns. All the columns are identical size and children are stretched horizontally to fill the column width. The goal is to give layout some reasonable range of column numbers to allow it to handle various parent widths. That way, column number will drop to the lowest number in the range when width decreases, and grow up to the highest number in the range when allowed by the parent width.In addition, the layout attempts to 'fill the space' equally i.e. to avoid large gaps at the and of the last column.
Child controls are layed out according to their 'natural' (preferred) size. For 'stretchy' controls that do not have natural preferred size, it is possible to set width and/or height hints using ColumnLayoutData objects.
- Since:
- 3.0
- See Also:
ColumnLayoutData
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Field Summary
Fields Modifier and Type Field Description int
bottomMargin
Bottom margin (default is 5).int
horizontalSpacing
Horizontal spacing between columns (default is 5).int
leftMargin
Left margin (default is 5).int
maxNumColumns
Maximum number of columns (default is 3).int
minNumColumns
Minimum number of columns (default is 1).int
rightMargin
Right margin (default is 5).int
topMargin
Top margin (default is 5).int
verticalSpacing
Vertical spacing between controls (default is 5).
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Constructor Summary
Constructors Constructor Description ColumnLayout()
Creates a new instance of the column layout.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
computeMaximumWidth(Composite parent, boolean changed)
Computes the maximum width of the parent.int
computeMinimumWidth(Composite parent, boolean changed)
Computes the minimum width of the parent.protected 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.protected void
layout(Composite parent, boolean flushCache)
Lays out the children of the specified composite according to this layout.-
Methods inherited from class org.eclipse.swt.widgets.Layout
flushCache
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Field Detail
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minNumColumns
public int minNumColumns
Minimum number of columns (default is 1).
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maxNumColumns
public int maxNumColumns
Maximum number of columns (default is 3).
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horizontalSpacing
public int horizontalSpacing
Horizontal spacing between columns (default is 5).
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verticalSpacing
public int verticalSpacing
Vertical spacing between controls (default is 5).
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topMargin
public int topMargin
Top margin (default is 5).
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leftMargin
public int leftMargin
Left margin (default is 5).
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bottomMargin
public int bottomMargin
Bottom margin (default is 5).
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rightMargin
public int rightMargin
Right margin (default is 5).
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Method Detail
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computeSize
protected Point computeSize(Composite composite, int wHint, int hHint, boolean flushCache)
Description copied from class:Layout
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.
- Specified by:
computeSize
in classLayout
- Parameters:
composite
- a composite widget using this layoutwHint
- width (SWT.DEFAULT
for preferred size)hHint
- height (SWT.DEFAULT
for preferred size)flushCache
-true
means flush cached layout values- Returns:
- a point containing the computed size (width, height)
- See Also:
Layout.layout(org.eclipse.swt.widgets.Composite, boolean)
,Control.getBorderWidth()
,Control.getBounds()
,Control.getSize()
,Control.pack(boolean)
, "computeTrim, getClientArea for controls that implement them"
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layout
protected void layout(Composite parent, boolean flushCache)
Description copied from class:Layout
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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computeMaximumWidth
public int computeMaximumWidth(Composite parent, boolean changed)
Description copied from interface:ILayoutExtension
Computes the maximum width of the parent. All widgets capable of word wrapping should return the length of the entire text with wrapping turned off.- Specified by:
computeMaximumWidth
in interfaceILayoutExtension
- Parameters:
parent
- the parent compositechanged
-true
if the cached information should be flushed,false
otherwise.- Returns:
- the maximum width of the parent composite
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computeMinimumWidth
public int computeMinimumWidth(Composite parent, boolean changed)
Description copied from interface:ILayoutExtension
Computes the minimum width of the parent. All widgets capable of word wrapping should return the width of the longest word that cannot be broken any further.- Specified by:
computeMinimumWidth
in interfaceILayoutExtension
- Parameters:
parent
- the parent compositechanged
-true
if the cached information should be flushed,false
otherwise.- Returns:
- the minimum width of the parent composite
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