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FormLayout (JGoodies)

FormLayout is a powerful, flexible and precise general purpose layout manager. It places components in a grid of columns and rows, allowing specified components to span multiple columns or rows. Not all columns/rows necessarily have the same width/height.

FormLayout

Unlike other grid-based layout managers, FormLayout uses 1-based column/row indices. And it uses "real" columns/rows as gaps. Therefore the unusual column/row numbers in the above screenshot. Using gap columns/rows has the advantage that you can give gaps different sizes.

Use the column and row headers to insert or delete columns/rows and change column/row properties. JFormDesigner automatically adds/removes gap columns if you add/remove a column/row.

Compared to other layout managers, FormLayout provides following outstanding features:

  • Default alignment of components in a column/row.
  • Specification of minimum and maximum column width or row height.
  • Supports different units: Dialog units, Pixel, Point, Millimeter, Centimeter and Inch. Especially Dialog units are very useful to create layouts that scale with the screen resolution.
  • Column/row templates.
  • Column/row grouping.

FormLayout is open source and not part of the standard Java distribution. You must ship an additional library with your application. JFormDesigner includes forms.jar, forms-javadoc.zip and forms-src.zip in its redist folder. For more documentation and tutorials, visit forms.dev.java.net.

IDE plug-ins: If you use FormLayout the first time, the JFormDesigner IDE plug-in ask you whether it should copy the required library (and its source code and documentation) to the IDE project and add it to the classpath of the IDE project.

Layout properties

A container with this layout manager has following layout properties:

Property Name Description
columnSpecs Comma separated encoded column specifications. This property is for experts only. Use the column header instead of editing this property.
rowSpecs Comma separated encoded row specifications. This property is for experts only. Use the row headers instead of editing this property.

Column/row properties

Each column and row has its own properties. Use the column and row headers to change column/row properties.

FormLayout column properties

Property Name Description
Column/Row The index of the column/row. Use the arrow buttons (or Alt+Left, Alt+Right, Alt+Up, Alt+Down keys) to edit the properties of the previous or next column/row.
Template FormLayout provides several predefined templates for columns and rows. Here you can choose one.
Specification The column/row specification. This is a string representation of the options below.
Default alignment The default alignment of the components within a column/row. Used if the value of the component constraint properties "h align" or "v align" are set to DEFAULT.
Size The width of a column or height of a row. You can use default, preferred or minimum component size. Or a constant size. It is also possible to specify a minimum and a maximum size. Note that the maximum size does not limit the column/row size if the column/row can grow (see resize behavior).
Resize behavior The resize weight of the column/row.
Grouping See column/row grouping for details.

Tip: The column/row context menu allows you to alter many of these options for multi-selections.

Constraints properties

A component contained in a container with this layout manager has following constraints properties:

Property Name Description
grid x Specifies the component's horizontal grid origin (column index).
grid y Specifies the component's vertical grid origin (row index).
grid width Specifies the component's horizontal grid extend (number of columns). Default is 1.
grid height Specifies the component's vertical grid extend (number of rows). Default is 1.
h align The horizontal alignment of the component within its cell. Possible values: DEFAULT, LEFT, CENTER, RIGHT and FILL. Default is DEFAULT.
v align The vertical alignment of the component within its cell. Possible values: DEFAULT, TOP, CENTER, BOTTOM and FILL. Default is DEFAULT.
insets Specifies the external padding of the component, the minimum amount of space between the component and the edges of its display area. Default is [0,0,0,0].
Note that the insets do not increase the column width or row height (in contrast to the GridBagConstraints.insets).

Tip: The component context menu allows you to alter the alignment for multi-selections.

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