Tutorials : Building Easy Java GUIs with Thinlet, Part 2 :

Building Easy Java GUIs with Thinlet, Part 2

by Keld H. Hansen

Part 1 of this series presented the architecture of a Thinlet application: a Java program and an XML configuration file defining the GUI—that's how simple it is. Part 2 explores some of Thinlet's more advanced features—like menus, dialogs, tabbed panes, and trees.

Using Menus

To create this menu, you need a configuration file:

<panel columns="1" gap="4" top="4" left="4" bottom="4" right="4">
  <menubar colspan="3" weightx="1">
    <menu text="File">
      <menuitem text="Open..." action="open()" />
      <menuitem text="Save As..." action="save()" />
      <separator/>
      <menuitem text="Clear" action="clear(area)" />
    </menu>
  </menubar>
  <textarea name="area" columns="25" rows="8"/>
</panel>

Alt+F displays the File menu choices; Ctrl+C will clear the text area. The config file has this format:

<menu text="File" mnemonic="0">
  <menuitem text="Open..." action="open()" />
  <menuitem text="Save As..." action="save()" />
  <separator/>
  <menuitem text="Clear" action="clear(area)" accelerator="Ctrl C"/>
</menu>

Menus can be very complex. Figure 3 is an example, taken from Thinlet's Showcase (select the "Widgets" item).

If the body of the GUI will scroll, then you might not want the menu bar to take part in the scrolling. To avoid this, set the scrollable property on a panel inside the main panel. Here's the config file:

<panel columns="1" gap="4" top="4" left="4" bottom="4" right="4">
  <menubar colspan="3" weightx="1">
   . . .
  </menubar>
  <panel scrollable="true" weightx="1" weighty="1">
    <textarea name="area" columns="70" rows="20"/>
  </panel> 
</panel>

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