Tutorial Example
tutorial_formbuilder.xml in the
CookFormLayout Java Web Start demo.
Introduction
In previous two tutorials, one problem was persistent. One always had to specify
the CellConstraints even when we were adding components in order. JGoodies
DefaultFormBuilder (supported via <formbuilder>)
solves the problem by using an internal cursor that keeps track of the
current location to add the new component.
In this tutorial, you will see that all CellConstraints specifications are avoided.
Instead, we use tags
<form-nextline> and
<form-nextcolumn>
to move the cursor location. Also, columnspan and nextline
attributes of <form-label>
can be used to advance the cursor and adjust the new component size.
In most cases, we can also simply add a single cell component directly to
the <formbuilder>.
1. Specify DefaultFormBuilder
To use the PanelBuilder, first place
<formbuilder> inside a
<panel> tag, and then place a
<formlayout> tag inside
the <formbuilder>.
<panel> <formbuilder> <formlayout columnspec="pref, 4dlu, 50dlu, 4dlu, min" rowspec="pref, 2dlu, pref, 2dlu, pref, 2dlu, pref" > <form-rowgroup rows="3, 5, 7"/> </formlayout> </formbuilder> </panel>
It is very important to have the <formlayout specified or
errors would occur.
2. Add Swing Components
With <formbuilder, it is straightfoward to add Swing components
that only takes a single cell.
<label text="Label 3"/> <textfield/> <button text="..."/>
For associated label and components using
<form-label>
<form-label text="Label 1" columnspan="3" nextline="true"> <textfield/> </form-label>
Note that, to add a Swing component (w/o label) that spans several columns,
one still uses <form-label> to do the job, just without the
text attribute specified.
3. Control Internal Layout Cursor Location
Use <form-nextline> and
<form-nextcolumn> to
advance the internal cursor location. <form-label> also
has the ability to end the current row with nextline="true" attribute
setting.
