Class GridLayout
Composite
in a grid.
GridLayout
has a number of configuration fields, and the
controls it lays out can have an associated layout data object, called
GridData
. The power of GridLayout
lies in the
ability to configure GridData
for each control in the layout.
The following code creates a shell managed by a GridLayout
with 3 columns:
Display display = new Display(); Shell shell = new Shell(display); GridLayout gridLayout = new GridLayout(); gridLayout.numColumns = 3; shell.setLayout(gridLayout);
The numColumns
field is the most important field in a
GridLayout
. Widgets are laid out in columns from left
to right, and a new row is created when numColumns
+ 1
controls are added to the Composite
.
-
Field Summary
Modifier and TypeFieldDescriptionint
horizontalSpacing specifies the number of points between the right edge of one cell and the left edge of its neighbouring cell to the right.boolean
makeColumnsEqualWidth specifies whether all columns in the layout will be forced to have the same width.int
marginBottom specifies the number of points of vertical margin that will be placed along the bottom edge of the layout.int
marginHeight specifies the number of points of vertical margin that will be placed along the top and bottom edges of the layout.int
marginLeft specifies the number of points of horizontal margin that will be placed along the left edge of the layout.int
marginRight specifies the number of points of horizontal margin that will be placed along the right edge of the layout.int
marginTop specifies the number of points of vertical margin that will be placed along the top edge of the layout.int
marginWidth specifies the number of points of horizontal margin that will be placed along the left and right edges of the layout.int
numColumns specifies the number of cell columns in the layout.int
verticalSpacing specifies the number of points between the bottom edge of one cell and the top edge of its neighbouring cell underneath. -
Constructor Summary
ConstructorDescriptionConstructs a new instance of this class with a single column.GridLayout
(int numColumns, boolean makeColumnsEqualWidth) Constructs a new instance of this class given the number of columns, and whether or not the columns should be forced to have the same width. -
Method Summary
Modifier and TypeMethodDescriptionprotected 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 boolean
flushCache
(Control control) Instruct the layout to flush any cached values associated with the control specified in the argumentcontrol
.protected void
Lays out the children of the specified composite according to this layout.toString()
Returns a string containing a concise, human-readable description of the receiver.
-
Field Details
-
numColumns
public int numColumnsnumColumns specifies the number of cell columns in the layout. If numColumns has a value less than 1, the layout will not set the size and position of any controls. The default value is 1. -
makeColumnsEqualWidth
public boolean makeColumnsEqualWidthmakeColumnsEqualWidth specifies whether all columns in the layout will be forced to have the same width. The default value is false. -
marginWidth
public int marginWidthmarginWidth specifies the number of points of horizontal margin that will be placed along the left and right edges of the layout. The default value is 5. -
marginHeight
public int marginHeightmarginHeight specifies the number of points of vertical margin that will be placed along the top and bottom edges of the layout. The default value is 5. -
marginLeft
public int marginLeftmarginLeft specifies the number of points of horizontal margin that will be placed along the left edge of the layout. The default value is 0.- Since:
- 3.1
-
marginTop
public int marginTopmarginTop specifies the number of points of vertical margin that will be placed along the top edge of the layout. The default value is 0.- Since:
- 3.1
-
marginRight
public int marginRightmarginRight specifies the number of points of horizontal margin that will be placed along the right edge of the layout. The default value is 0.- Since:
- 3.1
-
marginBottom
public int marginBottommarginBottom specifies the number of points of vertical margin that will be placed along the bottom edge of the layout. The default value is 0.- Since:
- 3.1
-
horizontalSpacing
public int horizontalSpacinghorizontalSpacing specifies the number of points between the right edge of one cell and the left edge of its neighbouring cell to the right. The default value is 5. -
verticalSpacing
public int verticalSpacingverticalSpacing specifies the number of points between the bottom edge of one cell and the top edge of its neighbouring cell underneath. The default value is 5.
-
-
Constructor Details
-
GridLayout
public GridLayout()Constructs a new instance of this class with a single column. -
GridLayout
public GridLayout(int numColumns, boolean makeColumnsEqualWidth) Constructs a new instance of this class given the number of columns, and whether or not the columns should be forced to have the same width. If numColumns has a value less than 1, the layout will not set the size and position of any controls.- Parameters:
numColumns
- the number of columns in the gridmakeColumnsEqualWidth
- whether or not the columns will have equal width- Since:
- 2.0
-
-
Method Details
-
computeSize
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"
-
flushCache
Description copied from class:Layout
Instruct the layout to flush any cached values associated with the control specified in the argumentcontrol
.- Overrides:
flushCache
in classLayout
- Parameters:
control
- a control managed by this layout- Returns:
- true if the Layout has flushed all cached information associated with control
-
layout
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.
-
toString
Returns a string containing a concise, human-readable description of the receiver.
-