Java Reference
In-Depth Information
fixGUI(Frame) isinvokedwithareferencetothe TempVerter framewindow
( TempVerter.this provides that reference). It first invokes
f.getComponents()[0] toobtainthepanelthatwasaddedtotheframewindow.
( Listing 7-2 identifies this panel as pnlLayout .)
pnl / pnlLayout contains three Panel instances (recall pnlTemp ). The second
line fetches the first of these instances and assigns its reference to pnlRow . The third
within this panel.
Thefourthlinefetchesthesecond Panel instancethatcontainstheResultlabeland
its associated textfield. The fifth line extracts this label.
The sixth line invokes getPreferredSize() on the Result label, and then in-
vokes Component 's void setPreferredSize(Dimension preferredS-
ize) method with this preferred size to shrink the width of the Degrees label so that
both textfields are left-aligned.
The seventh line fetches the third Panel instance, which contains the two buttons,
of the Convert to Celsius button to that of the wider Convert to Fahrenheit button.
Introducing fixGUI(Frame) into TempVerter is only part of the solution. We
dow's pack() and setVisible() method calls.
fixGUI() mustbecalledafter pack() becausethepreferredsizesarenotknown
until after pack() has been called. This method must be called before setVis-
ible() becauseitchangespreferredsizes. setVisible() canaccommodatethese
after calling setVisible() , pack() will have to be called a second time.
Note Although fixGUI() isconvenientfortrivialapplications,youwon'tneedto
scope of this chapter). fixGUI() can be tedious to code, and you need to revise it
whenever you change the GUI.Graphics, Colors, and Fonts
The Component class declares a void paint(Graphics g) method to paint
a component. Painting occurs when a component is first shown or when it has been
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