Class FormLayout
- All Implemented Interfaces:
LayoutManager
,LayoutManager2
,Serializable
To use FormLayout you first define the grid by specifying the
columns and rows. In a second step you add components to the grid. You can
specify columns and rows via human-readable String descriptions or via
arrays of ColumnSpec
and RowSpec
instances.
Each component managed by a FormLayout is associated with an instance of
CellConstraints
. The constraints object specifies where a component
should be located on the form's grid and how the component should be
positioned. In addition to its constraints object the
FormLayout
also considers each component's minimum and
preferred sizes in order to determine a component's size.
FormLayout has been designed to work with non-visual builders that help you
specify the layout and fill the grid. For example, the
ButtonBarBuilder2
assists you in building button
bars; it creates a standardized FormLayout and provides a minimal API that
specializes in adding buttons and Actions. Other builders can create
frequently used panel design, for example a form that consists of rows of
label-component pairs.
FormLayout has been prepared to work with different types of sizes as
defined by the Size
interface.
Example 1 (Plain FormLayout):
The following example creates a panel with 3 data columns and 3 data rows;
the columns and rows are specified before components are added
to the form.
FormLayout layout = new FormLayout( "right:pref, 6dlu, 50dlu, 4dlu, default", // columns "pref, 3dlu, pref, 3dlu, pref"); // rows CellConstraints cc = new CellConstraints(); JPanel panel = new JPanel(layout); panel.add(new JLabel("Label1"), cc.xy (1, 1)); panel.add(new JTextField(), cc.xywh(3, 1, 3, 1)); panel.add(new JLabel("Label2"), cc.xy (1, 3)); panel.add(new JTextField(), cc.xy (3, 3)); panel.add(new JLabel("Label3"), cc.xy (1, 5)); panel.add(new JTextField(), cc.xy (3, 5)); panel.add(new JButton("/u2026"), cc.xy (5, 5)); return panel;
Example 2 (Using PanelBuilder):
This example creates the same panel as above using the
PanelBuilder
to add components to the form.
FormLayout layout = new FormLayout( "right:pref, 6dlu, 50dlu, 4dlu, default", // columns "pref, 3dlu, pref, 3dlu, pref"); // rows PanelBuilder builder = new PanelBuilder(layout); CellConstraints cc = new CellConstraints(); builder.addLabel("Label1", cc.xy (1, 1)); builder.add(new JTextField(), cc.xywh(3, 1, 3, 1)); builder.addLabel("Label2", cc.xy (1, 3)); builder.add(new JTextField(), cc.xy (3, 3)); builder.addLabel("Label3", cc.xy (1, 5)); builder.add(new JTextField(), cc.xy (3, 5)); builder.add(new JButton("/u2026"), cc.xy (5, 5)); return builder.getPanel();
Example 3 (Using DefaultFormBuilder):
This example utilizes the
DefaultFormBuilder
that
ships with the source distribution.
FormLayout layout = new FormLayout( "right:pref, 6dlu, 50dlu, 4dlu, default"); // 5 columns; add rows later DefaultFormBuilder builder = new DefaultFormBuilder(layout); builder.append("Label1", new JTextField(), 3); builder.append("Label2", new JTextField()); builder.append("Label3", new JTextField()); builder.append(new JButton("/u2026")); return builder.getPanel();
- Version:
- $Revision: 1.24 $
- Author:
- Karsten Lentzsch
- See Also:
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic final class
Stores column and row origins.static interface
An interface that describes how to measure aComponent
. -
Constructor Summary
ConstructorsConstructorDescriptionConstructs an empty FormLayout.FormLayout
(ColumnSpec[] colSpecs) Constructs a FormLayout using the given column specifications.FormLayout
(ColumnSpec[] colSpecs, RowSpec[] rowSpecs) Constructs a FormLayout using the given column and row specifications.FormLayout
(String encodedColumnSpecs) Constructs a FormLayout using the given encoded column specifications.FormLayout
(String encodedColumnSpecs, LayoutMap layoutMap) Constructs a FormLayout using the given encoded column specifications and LayoutMap.FormLayout
(String encodedColumnSpecs, String encodedRowSpecs) Constructs a FormLayout using the given encoded column and row specifications and the default LayoutMap.FormLayout
(String encodedColumnSpecs, String encodedRowSpecs, LayoutMap layoutMap) Constructs a FormLayout using the given encoded column and row specifications and the given LayoutMap. -
Method Summary
Modifier and TypeMethodDescriptionvoid
addGroupedColumn
(int columnIndex) Adds the specified column index to the last column group.void
addGroupedRow
(int rowIndex) Adds the specified row index to the last row group.void
addLayoutComponent
(Component comp, Object constraints) Adds the specified component to the layout, using the specifiedconstraints
object.void
addLayoutComponent
(String name, Component component) Throws anUnsupportedOperationException
.void
appendColumn
(ColumnSpec columnSpec) Appends the given column specification to the right hand side of all columns.void
Appends the given row specification to the bottom of all rows.int
Returns the number of columns in this layout.int[][]
Returns a deep copy of the column groups.getColumnSpec
(int columnIndex) Returns theColumnSpec
at the specified column index.getConstraints
(Component component) Looks up and returns the constraints for the specified component.boolean
Returns whether invisible components shall be taken into account by this layout.float
getLayoutAlignmentX
(Container parent) Returns the alignment along the x axis.float
getLayoutAlignmentY
(Container parent) Returns the alignment along the y axis.getLayoutInfo
(Container parent) Computes and returns the horizontal and vertical grid origins.int
Returns the number of rows in this layout.int[][]
Returns a deep copy of the row groups.getRowSpec
(int rowIndex) Returns theRowSpec
at the specified row index.void
insertColumn
(int columnIndex, ColumnSpec columnSpec) Inserts the specified column at the specified position.void
Inserts the specified column at the specified position.void
invalidateLayout
(Container target) Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.void
layoutContainer
(Container parent) Lays out the specified container using this form layout.maximumLayoutSize
(Container target) Returns the maximum dimensions for this layout given the components in the specified target container.minimumLayoutSize
(Container parent) Determines the minimum size of theparent
container using this form layout.preferredLayoutSize
(Container parent) Determines the preferred size of theparent
container using this form layout.void
removeColumn
(int columnIndex) Removes the column with the given column index from the layout.void
Removes the specified component from this layout.void
removeRow
(int rowIndex) Removes the row with the given row index from the layout.void
setColumnGroups
(int[][] colGroupIndices) Sets the column groups, where each column in a group gets the same group wide width.void
setColumnSpec
(int columnIndex, ColumnSpec columnSpec) Sets theColumnSpec
at the specified column index.void
setConstraints
(Component component, CellConstraints constraints) Sets the constraints for the specified component in this layout.void
setHonorsVisibility
(boolean b) Specifies whether invisible components shall be taken into account by this layout for computing the layout size and setting component bounds.void
setHonorsVisibility
(Component component, Boolean b) Specifies whether the given component shall be taken into account for sizing and positioning.void
setRowGroups
(int[][] rowGroupIndices) Sets the row groups, where each row in such a group gets the same group wide height.void
setRowSpec
(int rowIndex, RowSpec rowSpec) Sets theRowSpec
at the specified row index.
-
Constructor Details
-
FormLayout
public FormLayout()Constructs an empty FormLayout. Columns and rows must be added before components can be added to the layout container.This constructor is intended to be used in environments that add columns and rows dynamically.
-
FormLayout
Constructs a FormLayout using the given encoded column specifications. The constructed layout has no rows; these must be added before components can be added to the layout container. The string decoding uses the default LayoutMap.This constructor is intended to be used with builder classes that add rows dynamically, such as the
DefaultFormBuilder
.Examples:
// Label, gap, component FormLayout layout = new FormLayout( "pref, 4dlu, pref"); // Right-aligned label, gap, component, gap, component FormLayout layout = new FormLayout( "right:pref, 4dlu, 50dlu, 4dlu, 50dlu"); // Left-aligned labels, gap, components, gap, components FormLayout layout = new FormLayout( "left:pref, 4dlu, pref, 4dlu, pref");
See the class comment for more examples.- Parameters:
encodedColumnSpecs
- comma separated encoded column specifications- Throws:
NullPointerException
- if encodedColumnSpecs isnull
- See Also:
-
FormLayout
Constructs a FormLayout using the given encoded column specifications and LayoutMap. The constructed layout has no rows; these must be added before components can be added to the layout container.This constructor is intended to be used with builder classes that add rows dynamically, such as the
DefaultFormBuilder
.Examples:
// Label, gap, component FormLayout layout = new FormLayout( "pref, 4dlu, pref", myLayoutMap); // Right-aligned label, gap, component, gap, component FormLayout layout = new FormLayout( "right:pref, @lcgap, 50dlu, 4dlu, 50dlu", myLayoutMap); // Left-aligned labels, gap, components, gap, components FormLayout layout = new FormLayout( "left:pref, @lcgap, pref, @myGap, pref", myLayoutMap);
See the class comment for more examples.- Parameters:
encodedColumnSpecs
- comma separated encoded column specificationslayoutMap
- expands layout column and row variables- Throws:
NullPointerException
- ifencodedColumnSpecs
orlayoutMap
isnull
- Since:
- 1.2
- See Also:
-
FormLayout
Constructs a FormLayout using the given encoded column and row specifications and the default LayoutMap.This constructor is recommended for most hand-coded layouts.
Examples:
FormLayout layout = new FormLayout( "pref, 4dlu, pref", // columns "p, 3dlu, p"); // rows FormLayout layout = new FormLayout( "right:pref, 4dlu, pref", // columns "p, 3dlu, p, 3dlu, fill:p:grow"); // rows FormLayout layout = new FormLayout( "left:pref, 4dlu, 50dlu", // columns "p, 2px, p, 3dlu, p, 9dlu, p"); // rows FormLayout layout = new FormLayout( "max(75dlu;pref), 4dlu, default", // columns "p, 3dlu, p, 3dlu, p, 3dlu, p"); // rows
See the class comment for more examples.- Parameters:
encodedColumnSpecs
- comma separated encoded column specificationsencodedRowSpecs
- comma separated encoded row specifications- Throws:
NullPointerException
- if encodedColumnSpecs or encodedRowSpecs isnull
- See Also:
-
FormLayout
Constructs a FormLayout using the given encoded column and row specifications and the given LayoutMap.Examples:
FormLayout layout = new FormLayout( "pref, 4dlu, pref", // columns "p, 3dlu, p", // rows myLayoutMap); // custom LayoutMap FormLayout layout = new FormLayout( "right:pref, 4dlu, pref", // columns "p, @lgap, p, @lgap, fill:p:grow",// rows myLayoutMap); // custom LayoutMap FormLayout layout = new FormLayout( "left:pref, 4dlu, 50dlu", // columns "p, 2px, p, 3dlu, p, 9dlu, p", // rows myLayoutMap); // custom LayoutMap FormLayout layout = new FormLayout( "max(75dlu;pref), 4dlu, default", // columns "p, 3dlu, p, 3dlu, p, 3dlu, p", // rows myLayoutMap); // custom LayoutMap
See the class comment for more examples.- Parameters:
encodedColumnSpecs
- comma separated encoded column specificationsencodedRowSpecs
- comma separated encoded row specificationslayoutMap
- expands layout column and row variables- Throws:
NullPointerException
- ifencodedColumnSpecs
,encodedRowSpecs
, orlayoutMap
isnull
- Since:
- 1.2
-
FormLayout
Constructs a FormLayout using the given column specifications. The constructed layout has no rows; these must be added before components can be added to the layout container.- Parameters:
colSpecs
- an array of column specifications.- Throws:
NullPointerException
- ifcolSpecs
isnull
- Since:
- 1.1
-
FormLayout
Constructs a FormLayout using the given column and row specifications.- Parameters:
colSpecs
- an array of column specifications.rowSpecs
- an array of row specifications.- Throws:
NullPointerException
- if colSpecs or rowSpecs isnull
-
-
Method Details
-
getColumnCount
public int getColumnCount()Returns the number of columns in this layout.- Returns:
- the number of columns
-
getColumnSpec
Returns theColumnSpec
at the specified column index.- Parameters:
columnIndex
- the column index of the requestedColumnSpec
- Returns:
- the
ColumnSpec
at the specified column - Throws:
IndexOutOfBoundsException
- if the column index is out of range
-
setColumnSpec
Sets theColumnSpec
at the specified column index.- Parameters:
columnIndex
- the index of the column to be changedcolumnSpec
- theColumnSpec
to be set- Throws:
NullPointerException
- if the column specification is nullIndexOutOfBoundsException
- if the column index is out of range
-
appendColumn
Appends the given column specification to the right hand side of all columns.- Parameters:
columnSpec
- the column specification to be added- Throws:
NullPointerException
- if the column specification is null
-
insertColumn
Inserts the specified column at the specified position. Shifts components that intersect the new column to the right hand side and readjusts column groups.The component shift works as follows: components that were located on the right hand side of the inserted column are shifted one column to the right; component column span is increased by one if it intersects the new column.
Column group indices that are greater or equal than the given column index will be increased by one.
- Parameters:
columnIndex
- index of the column to be insertedcolumnSpec
- specification of the column to be inserted- Throws:
IndexOutOfBoundsException
- if the column index is out of range
-
removeColumn
public void removeColumn(int columnIndex) Removes the column with the given column index from the layout. Components will be rearranged and column groups will be readjusted. Therefore, the column must not contain components and must not be part of a column group.The component shift works as follows: components that were located on the right hand side of the removed column are moved one column to the left; component column span is decreased by one if it intersects the removed column.
Column group indices that are greater than the column index will be decreased by one.
Note: If one of the constraints mentioned above is violated, this layout's state becomes illegal and it is unsafe to work with this layout. A typical layout implementation can ensure that these constraints are not violated. However, in some cases you may need to check these conditions before you invoke this method. The Forms extras contain source code for class
FormLayoutUtils
that provides the required test methods:
#columnContainsComponents(Container, int)
and
#isGroupedColumn(FormLayout, int)
.- Parameters:
columnIndex
- index of the column to remove- Throws:
IndexOutOfBoundsException
- if the column index is out of rangeIllegalStateException
- if the column contains components or if the column is already grouped- See Also:
-
getRowCount
public int getRowCount()Returns the number of rows in this layout.- Returns:
- the number of rows
-
getRowSpec
Returns theRowSpec
at the specified row index.- Parameters:
rowIndex
- the row index of the requestedRowSpec
- Returns:
- the
RowSpec
at the specified row - Throws:
IndexOutOfBoundsException
- if the row index is out of range
-
setRowSpec
Sets theRowSpec
at the specified row index.- Parameters:
rowIndex
- the index of the row to be changedrowSpec
- theRowSpec
to be set- Throws:
NullPointerException
- if the row specification is nullIndexOutOfBoundsException
- if the row index is out of range
-
appendRow
Appends the given row specification to the bottom of all rows.- Parameters:
rowSpec
- the row specification to be added to the form layout- Throws:
NullPointerException
- if the rowSpec is null
-
insertRow
Inserts the specified column at the specified position. Shifts components that intersect the new column to the right and readjusts column groups.The component shift works as follows: components that were located on the right hand side of the inserted column are shifted one column to the right; component column span is increased by one if it intersects the new column.
Column group indices that are greater or equal than the given column index will be increased by one.
- Parameters:
rowIndex
- index of the row to be insertedrowSpec
- specification of the row to be inserted- Throws:
IndexOutOfBoundsException
- if the row index is out of range
-
removeRow
public void removeRow(int rowIndex) Removes the row with the given row index from the layout. Components will be rearranged and row groups will be readjusted. Therefore, the row must not contain components and must not be part of a row group.The component shift works as follows: components that were located below the removed row are moved up one row; component row span is decreased by one if it intersects the removed row.
Row group indices that are greater than the row index will be decreased by one.
Note: If one of the constraints mentioned above is violated, this layout's state becomes illegal and it is unsafe to work with this layout. A typical layout implementation can ensure that these constraints are not violated. However, in some cases you may need to check these conditions before you invoke this method. The Forms extras contain source code for class
FormLayoutUtils
that provides the required test methods:
#rowContainsComponents(Container, int)
and
#isGroupedRow(FormLayout, int)
.- Parameters:
rowIndex
- index of the row to remove- Throws:
IndexOutOfBoundsException
- if the row index is out of rangeIllegalStateException
- if the row contains components or if the row is already grouped- See Also:
-
getConstraints
Looks up and returns the constraints for the specified component. A copy of the actualCellConstraints
object is returned.- Parameters:
component
- the component to be queried- Returns:
- the
CellConstraints
for the specified component - Throws:
NullPointerException
- if component isnull
or has not been added to the container
-
setConstraints
Sets the constraints for the specified component in this layout.- Parameters:
component
- the component to be modifiedconstraints
- the constraints to be applied- Throws:
NullPointerException
- if the component or constraints object isnull
-
getColumnGroups
public int[][] getColumnGroups()Returns a deep copy of the column groups.- Returns:
- the column groups as two-dimensional int array
-
setColumnGroups
public void setColumnGroups(int[][] colGroupIndices) Sets the column groups, where each column in a group gets the same group wide width. Each group is described by an array of integers that are interpreted as column indices. The parameter is an array of such group descriptions.Examples:
// Group columns 1, 3 and 4. setColumnGroups(new int[][]{ {1, 3, 4}}); // Group columns 1, 3, 4, and group columns 7 and 9 setColumnGroups(new int[][]{ {1, 3, 4}, {7, 9}});
- Parameters:
colGroupIndices
- a two-dimensional array of column groups indices- Throws:
IndexOutOfBoundsException
- if an index is outside the gridIllegalArgumentException
- if a column index is used twice
-
addGroupedColumn
public void addGroupedColumn(int columnIndex) Adds the specified column index to the last column group. In case there are no groups, a new group will be created.- Parameters:
columnIndex
- the column index to be set grouped
-
getRowGroups
public int[][] getRowGroups()Returns a deep copy of the row groups.- Returns:
- the row groups as two-dimensional int array
-
setRowGroups
public void setRowGroups(int[][] rowGroupIndices) Sets the row groups, where each row in such a group gets the same group wide height. Each group is described by an array of integers that are interpreted as row indices. The parameter is an array of such group descriptions.Examples:
// Group rows 1 and 2. setRowGroups(new int[][]{ {1, 2}}); // Group rows 1 and 2, and group rows 5, 7, and 9. setRowGroups(new int[][]{ {1, 2}, {5, 7, 9}});
- Parameters:
rowGroupIndices
- a two-dimensional array of row group indices.- Throws:
IndexOutOfBoundsException
- if an index is outside the grid
-
addGroupedRow
public void addGroupedRow(int rowIndex) Adds the specified row index to the last row group. In case there are no groups, a new group will be created.- Parameters:
rowIndex
- the index of the row that should be grouped
-
getHonorsVisibility
public boolean getHonorsVisibility()Returns whether invisible components shall be taken into account by this layout. This container-wide setting can be overridden per component. SeesetHonorsVisibility(boolean)
for details.- Returns:
true
if the component visibility is honored by this FormLayout,false
if it is ignored. This setting can be overridden for individual CellConstraints usingsetHonorsVisibility(Component, Boolean)
.- Since:
- 1.2
-
setHonorsVisibility
public void setHonorsVisibility(boolean b) Specifies whether invisible components shall be taken into account by this layout for computing the layout size and setting component bounds. If set totrue
invisible components will be ignored by the layout. If set tofalse
components will be taken into account regardless of their visibility. Visible components are always used for sizing and positioning.The default value for this setting is
true
. It is useful to set the value tofalse
(in other words to ignore the visibility) if you switch the component visibility dynamically and want the container to retain the size and component positions.This container-wide default setting can be overridden per component using
setHonorsVisibility(Component, Boolean)
.Components are taken into account, if
- they are visible, or
- they have no individual setting and the container-wide settings
ignores the visibility (honorsVisibility set to
false
), or - the individual component ignores the visibility.
- Parameters:
b
-true
to honor the visibility, i.e. to exclude invisible components from the sizing and positioning,false
to ignore the visibility, in other words to layout visible and invisible components- Since:
- 1.2
-
setHonorsVisibility
Specifies whether the given component shall be taken into account for sizing and positioning. This setting overrides the container-wide default. SeesetHonorsVisibility(boolean)
for details.- Parameters:
component
- the component that shall get an individual settingb
-Boolean.TRUE
to override the container default and honor the visibility for the given component,Boolean.FALSE
to override the container default and ignore the visibility for the given component,null
to use the container default value as specified bygetHonorsVisibility()
.- Since:
- 1.2
-
addLayoutComponent
Throws anUnsupportedOperationException
. Does not add the specified component with the specified name to the layout.- Specified by:
addLayoutComponent
in interfaceLayoutManager
- Parameters:
name
- indicates entry's position and anchorcomponent
- component to add- Throws:
UnsupportedOperationException
- always
-
addLayoutComponent
Adds the specified component to the layout, using the specifiedconstraints
object. Note that constraints are mutable and are, therefore, cloned when cached.- Specified by:
addLayoutComponent
in interfaceLayoutManager2
- Parameters:
comp
- the component to be addedconstraints
- the component's cell constraints- Throws:
NullPointerException
- ifconstraints
isnull
IllegalArgumentException
- ifconstraints
is not aCellConstraints
or a String that cannot be used to construct aCellConstraints
-
removeLayoutComponent
Removes the specified component from this layout.Most applications do not call this method directly.
- Specified by:
removeLayoutComponent
in interfaceLayoutManager
- Parameters:
comp
- the component to be removed.- See Also:
-
minimumLayoutSize
Determines the minimum size of theparent
container using this form layout.Most applications do not call this method directly.
- Specified by:
minimumLayoutSize
in interfaceLayoutManager
- Parameters:
parent
- the container in which to do the layout- Returns:
- the minimum size of the
parent
container - See Also:
-
preferredLayoutSize
Determines the preferred size of theparent
container using this form layout.Most applications do not call this method directly.
- Specified by:
preferredLayoutSize
in interfaceLayoutManager
- Parameters:
parent
- the container in which to do the layout- Returns:
- the preferred size of the
parent
container - See Also:
-
maximumLayoutSize
Returns the maximum dimensions for this layout given the components in the specified target container.- Specified by:
maximumLayoutSize
in interfaceLayoutManager2
- Parameters:
target
- the container which needs to be laid out- Returns:
- the maximum dimensions for this layout
- See Also:
-
getLayoutAlignmentX
Returns the alignment along the x axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the farthest away from the origin, 0.5 is centered, etc.- Specified by:
getLayoutAlignmentX
in interfaceLayoutManager2
- Parameters:
parent
- the parent container- Returns:
- the value
0.5f
to indicate center alignment
-
getLayoutAlignmentY
Returns the alignment along the y axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the farthest away from the origin, 0.5 is centered, etc.- Specified by:
getLayoutAlignmentY
in interfaceLayoutManager2
- Parameters:
parent
- the parent container- Returns:
- the value
0.5f
to indicate center alignment
-
invalidateLayout
Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.- Specified by:
invalidateLayout
in interfaceLayoutManager2
- Parameters:
target
- the container that holds the layout to be invalidated
-
layoutContainer
Lays out the specified container using this form layout. This method reshapes components in the specified container in order to satisfy the constraints of thisFormLayout
object.Most applications do not call this method directly.
The form layout performs the following steps:
- find components that occupy exactly one column or row
- compute minimum widths and heights
- compute preferred widths and heights
- give cols and row equal size if they share a group
- compress default columns and rows if total is less than pref size
- give cols and row equal size if they share a group
- distribute free space
- set components bounds
- Specified by:
layoutContainer
in interfaceLayoutManager
- Parameters:
parent
- the container in which to do the layout- See Also:
-
getLayoutInfo
Computes and returns the horizontal and vertical grid origins. Performs the same layout process as#layoutContainer
but does not layout the components.This method has been added only to make it easier to debug the form layout. You must not call this method directly; It may be removed in a future release or the visibility may be reduced.
- Parameters:
parent
- theContainer
to inspect- Returns:
- an object that comprises the grid x and y origins
-