Sams Teach Yourself Java™ in 24 Hours (Covering Java 7 and Android)

ptg7068951

Creating Your Own Component 181

The first step in creating your own user interface component is to decide
the existing component from which to inherit. The ClockPanelcomponent
is a subclass of JPanel.

The ClockPanelclass is defined in Listing 13.3. This class represents panel
components that include a label displaying the current date and time.
Enter the text from Listing 13.3 into a new empty Java file and save the file.

LISTING 13.3 The Full Text of ClockPanel.java
1: importjavax.swing.;
2: importjava.awt.;
3: importjava.util.*;
4:
5: public classClockPanel extendsJPanel {
6: publicClockPanel() {
7: super();
8: String currentTime = getTime();
9: JLabel time = new JLabel(“Time:“);
10: JLabel current = newJLabel(currentTime);
11: add(time);
12: add(current);
13: }
14:
15: finalString getTime() {
16: String time;
17: // get current time and date
18: Calendar now = Calendar.getInstance();
19: int hour = now.get(Calendar.HOUR_OF_DAY);
20: intminute = now.get(Calendar.MINUTE);
21: intmonth = now.get(Calendar.MONTH) + 1;
22: intday = now.get(Calendar.DAY_OF_MONTH);
23: int year = now.get(Calendar.YEAR);
24:
25: String monthName = “”;
26: switch(month) {
27: case(1):
28: monthName = “January”;
29: break;
30: case(2):
31: monthName = “February”;
32: break;
33: case(3):
34: monthName = “March”;
35: break;
36: case(4):
37: monthName = “April”;
38: break;
39: case(5):
40: monthName = “May”;
41: break;
42: case(6):