Java Reference
In-Depth Information
Let's now implement the
Pageable
interface in the
SketchView
class. We must add three methods to the
class
getNumberOfPages()
that returns the number of pages to be printed,
getPrintable()
that
returns a reference to the
Printable
object that will print a page with a given index, and
getPageFormat()
that returns a reference to a
PageFormat
object corresponding to a particular page.
import javax.swing.*;
import java.awt.*;
import java.util.*; // For Observer
import java.awt.event.*; // For events
import javax.swing.event.*; // For mouse input adapter
import java.awt.geom.*;
import java.awt.print.*;
class SketchView extends JComponent
implements Observer,
Constants,
ActionListener,
Printable,
Pageable {
// Always two pages
public int getNumberOfPages() {
return 2;
}
// Return the Printable object that will render the page
public Printable getPrintable(int pageIndex) {
if(pageIndex == 0) // For the first page
return new SketchCoverPage(theApp); // return the cover page
else
return this;
}
public PageFormat getPageFormat(int pageIndex) {
// Code to define the PageFormat object for the page...
}
public int print(Graphics g,
PageFormat pageFormat,
int pageIndex)
throws PrinterException {
// Revised printing code...
}
// Plus the rest of the class as before...
}
The first two methods are already implemented here. We will always print two pages, the first page
being printed by a
SketchCoverPage
object and the second page by the view object. Since we are
providing custom
PageFormat
objects for each page, we will need to amend the
print()
method in
SketchView
to just use the
PageFormat
object it gets. First, let's see how we can produce the
PageFormat
object for a page. To make use of some of the methods we have discussed, we will double
the size of the margins for the cover page but leave the margins for the other page at their default sizes.
We will also sort out whether the second page should be printed in portrait or landscape orientation.
Here's the code to do that:
