CODEWITHSUNDEEP
javaswingjcomponentjcalendar
Fabio Poloni
Fabio Poloni

Reputation: 8371

JComponent painting issue

I'm trying to create a custom Calendar in Java. For this I extend javax.swing.JComponent.

public class GMCalendar extends JComponent { ... }

In my constructor I do some basic setup and load my image:

calendarDay = Toolkit.getDefaultToolkit().createImage(getClass().getResource("/resources/images/calendar_day.png"));

And in paintComponent it should draw my calendar, but it won't draw all, which looks very weird.

public void paintComponent(Graphics g) {
    super.paintComponent(g);

    Calendar calendar = Calendar.getInstance();
    calendar.add(Calendar.MONTH, currentMonth);
    int numberOfWeeks = calendar.getActualMaximum(Calendar.WEEK_OF_MONTH);

    for (int i = 0; i < 7; i++) {
        for (int j = 0; j < numberOfWeeks; j++) {
            int x = i * (DAY_SIZE + DAY_SPACE);
            int y = j * (DAY_SIZE + DAY_SPACE);
            g.drawImage(calendarDay, x, y, null);
        }
    }
}

The result is either nothing or something like this:

Weird calendar

It seems like paintComponent gets called before the component has a size bigger than 1x1.

This is in my main():

GMContainerFrame cf = new GMContainerFrame();
cf.setMinimumSize(new Dimension(800,600));
cf.setVisible(true);

This is from the constructor of GMContainerFrame (which doesn't use a LayoutManager!):

calendarFrame = new GMMiniFrame("Kalender", new GMCalendar(), 230);

GMMiniFrame extends JSplitPane.

Upvotes: 3

Views: 161

Answers (1)

mKorbel
mKorbel

Reputation: 109823

  • don't to reinvent the wheel, use JPanels, better with JLabels layed by GridLayout

  • by using JLabels (JPanel nesting multiple JComponents) there no reason for paintComponents

  • notice JLabel is transparent, non_opaque,

  • use JCalendar/JDatePicker from SwingX, my favorite is JCalendar by Kai Toedter, (no issue with renderer, editor, special days, min and max Date)

Upvotes: 4

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