ActionListener with array
I'm pretty new to Java and don't have much experience in it. I've created a Calendar GUI that put the days of the month in a JButton, and the JButtons into a JButton array. What I'd like to do is when a day is clicked, it will open a Schedule of Appointments.
When creating the JButton array, I add an ActionListener to each JButton created. However, the ActionListener is throwing a NullPointerException indicating that there's no longer a reference to the object. I'm not sure where I lost it. Below is the code although not all of it to actually run. It's rather long and windy, but hopefully someone can help. Perhaps there's a simpler way to handle this.
Any help would be appreciated!
protectedclass CalendarGridextends JPanel
{
private String[] daysOfWeek ={"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
JButton button =null;
JButton[] buttonsArray =null;
public CalendarGrid(GregorianCalendar d)
{
setLayout(new BorderLayout());
//create the days of week labels and add to panel's NORTH border
JPanel dowPanel = getDaysOfWeek();
add(dowPanel, BorderLayout.NORTH);
//create the days for the month and add to panel's CENTER
JPanel cdPanel = getCalendarDays(d);
add(cdPanel, BorderLayout.CENTER);
}
private JPanel getDaysOfWeek()
{
JPanel dowContent =new JPanel();
dowContent.setLayout(new GridLayout(1,GRIDCOLS));
for (int i = 0; i < daysOfWeek.length; i++)
{
JLabel l =new JLabel(daysOfWeek[i], JLabel.CENTER);
l.setForeground(Color.red);
dowContent.add(l);
}
dowContent.setBackground(Color.cyan);
add(dowContent);
return dowContent;
}
private JPanel getCalendarDays(GregorianCalendar d)
{
boolean bCurrentDay =false;
String dayString;
JPanel cdContent =new JPanel();
cdContent.setLayout(new GridLayout(6, GRIDCOLS));
//GregorianCalendar d = new GregorianCalendar();
int currentDay = d.get(Calendar.DAY_OF_MONTH);
d.set(Calendar.DAY_OF_MONTH, 1);
int day = d.get(Calendar.DAY_OF_MONTH);
int maxDays = d.getMaximum(Calendar.DAY_OF_MONTH);
int month = d.get(Calendar.MONTH);
int weekday = d.get(Calendar.DAY_OF_WEEK);
int numDays = 0;
JButton[] buttonsArray =new JButton[maxDays + 1];
//JButton button = null;
// blank out button labels until first day of month
setBlanks(cdContent, button, weekday, bCurrentDay);
//create button and add to buttonsArray
do
{
if (day == currentDay)
bCurrentDay =true;
else
bCurrentDay =false;
dayString = String.valueOf(day);
button = addButton(dayString, cdContent, d, bCurrentDay);
buttonsArray[numDays] = button;
buttonsArray[numDays].addActionListener (new daySelected());
cdContent.add(button);
//System.out.println("button in array occurance: " + numDays +buttonsArray[numDays]);
d.add(Calendar.DAY_OF_MONTH, 1);
day = d.get(Calendar.DAY_OF_MONTH);
numDays++;
}while (d.get(Calendar.MONTH) == month);
// blank out button labels until first day of month
setBlanks(cdContent, button, weekday, bCurrentDay);
add(cdContent, BorderLayout.CENTER);
return cdContent;
}
privatevoid setBlanks(JPanel cdContent, JButton button,int weekday,boolean bCurrentDay)
{
for (int i = Calendar.SUNDAY; i < weekday; i++)
{
button = addButton(" ", cdContent, d, bCurrentDay);
cdContent.add(button);
}
}
private JButton addButton(String label, JPanel cdContent, GregorianCalendar d,boolean bCurrentDay)
{
JButton button =new JButton(label);
button.setFocusPainted(true);
if (label ==" " || bCurrentDay)
button.setBorderPainted(false);
else
button.setBorderPainted(true);
return button;
}
privateclass daySelectedimplements ActionListener
{
publicvoid actionPerformed(ActionEvent evt)
{
int idx = 0;
int buttonNbr = 0;
System.out.println("button in array occurance: 20 " + buttonsArray[20]);
//String buttonText = buttonsArray[idx].getText();
//if (evt.equals(buttonsArray[idx]))
//{
//System.out.println(buttonsArray);
//String buttonText = buttonsArray[idx].getText();
//buttonNbr = Integer.parseInt(buttonText);
//System.out.println("buttonNbr: "+ buttonNbr);
//}
//} while (idx < buttonsArray.length);
//d.set(Calendar.DAY_OF_MONTH, buttonNbr);
//ScheduleFrame frame = new ScheduleFrame(d);
//frame.show();
}
}
}
}
