Java Reference
In-Depth Information
77
78
private static final int
FRAME_WIDTH =
400
;
79
private static final int
FRAME_HEIGHT =
250
;
80
81
private static final int
AREA_ROWS =
10
;
82
private static final int
AREA_COLUMNS =
30
;
83
84
private static final double
DEFAULT_RATE =
5
;
85
private static final double
INITIAL_BALANCE
=
1000
;
86 }
485
486
S
ELF
C
HECK
22.
What is the difference between a text field and a text area?
23.
Why did the
InvestmentFrame
program call
resultArea.setEditable(false)
?
24.
How would you modify the
InvestmentFrame
program if you didn't
want to use scroll bars?
H
OW
T
O
10.1: Implementing a Graphical User
Interface (GUI)
A GUI program allows users to supply inputs and specify actions. The
InvestmentViewer3
program has only one input and one action. More
sophisticated programs have more interesting user interactions, but the basic
principles are the same.
Step 1 Enumerate the actions that your program needs to carry out.
For example, the investment viewer has a single action, to add interest. Other
programs may have different actions, perhaps for making deposits, inserting coins,
and so on.
Step 2 For each action, enumerate the inputs that you need.
