Wednesday, 3 October 2012

Java Swing PDF Viewer

I'll use pdf-renderer to create an pdf viewer in java swing application.
  • Dependencies
  • 
        org.swinglabs
        pdf-renderer
        1.0.5
    
    
        com.google.guava
        guava
        13.0.1
    
    
  • PDF Viewer
  • import com.google.common.base.CharMatcher;
    import com.sun.pdfview.PDFFile;
    import com.sun.pdfview.PDFPage;
    import com.sun.pdfview.PagePanel;
    
    import javax.swing.*;
    import java.awt.*;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import java.io.File;
    import java.io.IOException;
    import java.io.RandomAccessFile;
    import java.nio.ByteBuffer;
    import java.nio.channels.FileChannel;
    
    import static com.google.common.base.Strings.isNullOrEmpty;
    
    public class PdfViewer extends JPanel {
        private static enum Navigation {GO_FIRST_PAGE, FORWARD, BACKWARD, GO_LAST_PAGE, GO_N_PAGE}
    
        private static final CharMatcher POSITIVE_DIGITAL = CharMatcher.anyOf("0123456789");
        private static final String GO_PAGE_TEMPLATE = "%s of %s";
        private static final int FIRST_PAGE = 1;
        private int currentPage = FIRST_PAGE;
        private JButton btnFirstPage;
        private JButton btnPreviousPage;
        private JTextField txtGoPage;
        private JButton btnNextPage;
        private JButton btnLastPage;
        private PagePanel pagePanel;
        private PDFFile pdfFile;
    
        public PdfViewer() {
            initial();
        }
    
        private void initial() {
            setLayout(new BorderLayout(0, 0));
            JPanel topPanel = new JPanel(new FlowLayout(FlowLayout.CENTER));
            add(topPanel, BorderLayout.NORTH);
            btnFirstPage = createButton("|<<");
            topPanel.add(btnFirstPage);
            btnPreviousPage = createButton("<<");
            topPanel.add(btnPreviousPage);
            txtGoPage = new JTextField(10);
            txtGoPage.setHorizontalAlignment(JTextField.CENTER);
            topPanel.add(txtGoPage);
            btnNextPage = createButton(">>");
            topPanel.add(btnNextPage);
            btnLastPage = createButton(">>|");
            topPanel.add(btnLastPage);
            JScrollPane scrollPane = new JScrollPane();
            add(scrollPane, BorderLayout.CENTER);
            JPanel viewPanel = new JPanel(new BorderLayout(0, 0));
            scrollPane.setViewportView(viewPanel);
    
            pagePanel = new PagePanel();
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            pagePanel.setPreferredSize(screenSize);
            viewPanel.add(pagePanel, BorderLayout.CENTER);
    
            disableAllNavigationButton();
    
            btnFirstPage.addActionListener(new PageNavigationListener(Navigation.GO_FIRST_PAGE));
            btnPreviousPage.addActionListener(new PageNavigationListener(Navigation.BACKWARD));
            btnNextPage.addActionListener(new PageNavigationListener(Navigation.FORWARD));
            btnLastPage.addActionListener(new PageNavigationListener(Navigation.GO_LAST_PAGE));
            txtGoPage.addActionListener(new PageNavigationListener(Navigation.GO_N_PAGE));
        }
    
        private JButton createButton(String text) {
            JButton button = new JButton(text);
            button.setPreferredSize(new Dimension(55, 20));
    
            return button;
        }
    
        private void disableAllNavigationButton() {
            btnFirstPage.setEnabled(false);
            btnPreviousPage.setEnabled(false);
            btnNextPage.setEnabled(false);
            btnLastPage.setEnabled(false);
        }
    
        private boolean isMoreThanOnePage(PDFFile pdfFile) {
            return pdfFile.getNumPages() > 1;
        }
    
        private class PageNavigationListener implements ActionListener {
            private final Navigation navigation;
    
            private PageNavigationListener(Navigation navigation) {
                this.navigation = navigation;
            }
    
            public void actionPerformed(ActionEvent e) {
                if (pdfFile == null) {
                    return;
                }
    
                int numPages = pdfFile.getNumPages();
                if (numPages <= 1) {
                    disableAllNavigationButton();
                } else {
                    if (navigation == Navigation.FORWARD && hasNextPage(numPages)) {
                        goPage(currentPage, numPages);
                    }
    
                    if (navigation == Navigation.GO_LAST_PAGE) {
                        goPage(numPages, numPages);
                    }
    
                    if (navigation == Navigation.BACKWARD && hasPreviousPage()) {
                        goPage(currentPage, numPages);
                    }
    
                    if (navigation == Navigation.GO_FIRST_PAGE) {
                        goPage(FIRST_PAGE, numPages);
                    }
    
                    if (navigation == Navigation.GO_N_PAGE) {
                        String text = txtGoPage.getText();
                        boolean isValid = false;
                        if (!isNullOrEmpty(text)) {
                            boolean isNumber = POSITIVE_DIGITAL.matchesAllOf(text);
                            if (isNumber) {
                                int pageNumber = Integer.valueOf(text);
                                if (pageNumber >= 1 && pageNumber <= numPages) {
                                    goPage(Integer.valueOf(text), numPages);
                                    isValid = true;
                                }
                            }
                        }
    
                        if (!isValid) {
                            JOptionPane.showMessageDialog(PdfViewer.this, format("Invalid page number '%s' in this document", text));
                            txtGoPage.setText(format(GO_PAGE_TEMPLATE, currentPage, numPages));
                        }
                    }
                }
            }
    
            private void goPage(int pageNumber, int numPages) {
                currentPage = pageNumber;
                PDFPage page = pdfFile.getPage(currentPage);
                pagePanel.showPage(page);
                boolean notFirstPage = isNotFirstPage();
                btnFirstPage.setEnabled(notFirstPage);
                btnPreviousPage.setEnabled(notFirstPage);
                txtGoPage.setText(format(GO_PAGE_TEMPLATE, currentPage, numPages));
                boolean notLastPage = isNotLastPage(numPages);
                btnNextPage.setEnabled(notLastPage);
                btnLastPage.setEnabled(notLastPage);
            }
    
            private boolean hasNextPage(int numPages) {
                return (++currentPage) <= numPages;
            }
    
            private boolean hasPreviousPage() {
                return (--currentPage) >= FIRST_PAGE;
            }
    
            private boolean isNotLastPage(int numPages) {
                return currentPage != numPages;
            }
    
            private boolean isNotFirstPage() {
                return currentPage != FIRST_PAGE;
            }
        }
    
        public PagePanel getPagePanel() {
            return pagePanel;
        }
    
        public void setPDFFile(PDFFile pdfFile) {
            this.pdfFile = pdfFile;
            currentPage = FIRST_PAGE;
            disableAllNavigationButton();
            txtGoPage.setText(format(GO_PAGE_TEMPLATE, FIRST_PAGE, pdfFile.getNumPages()));
            boolean moreThanOnePage = isMoreThanOnePage(pdfFile);
            btnNextPage.setEnabled(moreThanOnePage);
            btnLastPage.setEnabled(moreThanOnePage);
        }
    }
    
    Line:58-59 automatically match the current screen resolution. The default is 800*600.

    The utility method "format" is here: format

  • Tester
  • public static void main(String[] args) {
            try {
                long heapSize = Runtime.getRuntime().totalMemory();
                System.out.println("Heap Size = " + heapSize);
    
                JFrame frame = new JFrame("PDF Test");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
                //load a pdf from a byte buffer
                File file = new File("/Users/Sean/Documents/test-pdf.pdf");
                RandomAccessFile raf = new RandomAccessFile(file, "r");
                FileChannel channel = raf.getChannel();
                ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());
                final PDFFile pdffile = new PDFFile(buf);
                PdfViewer pdfViewer = new PdfViewer();
                pdfViewer.setPDFFile(pdffile);
                frame.add(pdfViewer);
                frame.pack();
                frame.setVisible(true);
    
                PDFPage page = pdffile.getPage(0);
                pdfViewer.getPagePanel().showPage(page);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
  • screen shots


3 comments:

  1. Hi,
    This is a very good tutorial to view the pdf.It is working perfectly.Thank You very much for giving this valuable information.I need one more functionality in this.Besides the pagination i need to add print button and when i click on the print button that page should get printed.How to add this functionality.Once again thanks for sharing the information.

    ReplyDelete
  2. Hey excellent tutorial, but I have an error with the format function/method. Where can I find it? thnx

    ReplyDelete