可打印无法正常工作 [英] Printable not working properly

问题描述

我有一个系统，用户可以在该系统中注册学生，科目和每个科目的学生成绩，以及主题和日期.您可以通过输入学生的代码，然后从组合框中选择主题来搜索特定主题中的特定学生成绩.如果您进行搜索，这些内容将显示在jTable1中.

I have a system where the user can register students, subjects, and the student grade in each subject, together with the topic and the date. You can search a particular student grades in a particular subject by entering the code of the student, and by selecting the subject from a combobox. If you search it, those things are displayed in the jTable1.

然后，我有一个PRINT按钮.当用户单击打印"按钮时，jTable1中显示的内容将转到jTable2，这两个表之间的区别在于jTable1显示学生的姓名和主题名称，但是jTable2没有.为了更好的理解，这是一张照片:

Then, I have a PRINT button. When the user clicks the Print button, the content that is being displayed in the jTable1, goes to a jTable2, the difference between those 2 tables is that the jTable1 displays the name of the student, and the name of the subject, but the jTable2 doesn't. Here is a pic for better understanding:

因此，当用户单击按钮以打印jTable2时，我在此处使用此代码:

So, when the user clicked the button to Print the jTable2, I was using this code right here:

        MessageFormat header = new MessageFormat("Ficha Pedagógica - "+jComboBox1.getSelectedItem());

    MessageFormat footer = new MessageFormat("Página {0,number,integer}");

    try{
        jTable2.print(JTable.PrintMode.NORMAL, header, null);
    }
    catch(java.awt.print.PrinterException e){
        System.out.println("error");
    }

事实是，我希望打印两个标题，但是使用内置打印功能无法实现.因此，在堆栈溢出"中，我找到了这个主题:

The fact is, that I wanted 2 headlines to be printed, but such thing couldn't be achieved using the built-in print function. So, here in Stack Overflow, I found this topic:

如何使用使用JTable的MessageFormat

找到这个之后，我尝试使用那里给出的代码.因为我是一个初学者，所以即使代码中包含了所有注释，我也无法完全理解它.因此，我尝试实现它，但是现在，当我单击打印"按钮时，什么也没有发生.这是我的打印"按钮的代码:

After I found this, I tried using the code given there. Since I'm a beginner, even with all the comments in the code, I couldn't fully understand it. So, I tried to implement it, but now, when I click the "Print" button, nothing happens. This is my code of the Print button:

private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:
        try{
        Class.forName(driver);
        con = DriverManager.getConnection(str_conn,usuario,senha);
        stmt = con.createStatement();
        sql = "select topico, nota, datanota from notas where notas.cod_aluno ="+jTextField1.getText()+" and notas.cod_curso ="+jTextField2.getText()+" order by notas.datanota";
        rs = stmt.executeQuery(sql);
        if(rs == null){
            return;
        }
        ResultSetMetaData rsmd;
        rsmd = rs.getMetaData();
        Vector vetColuna = new Vector();
        for(int i = 0;i<rsmd.getColumnCount();i++){
            vetColuna.add(rsmd.getColumnLabel(i+1));
        }
        Vector vetLinhas = new Vector();

        while(rs.next()){
            Vector vetLinha = new Vector();
            for(int i = 0;i<rsmd.getColumnCount();i++){
                vetLinha.add(rs.getObject(i+1));
            }
            vetLinhas.add(vetLinha);
            jTable2.setModel(new DefaultTableModel(vetLinhas,vetColuna));
        }
    }catch(ClassNotFoundException ex){
        JOptionPane.showMessageDialog(null,"Erro\nNão foi possível carregar o driver.");
        System.out.println("Nao foi possivel carregar o driver");
        ex.printStackTrace();
    }catch(SQLException ex){
        JOptionPane.showMessageDialog(null,"Erro\nCertifique-se de que todos os\ncampos estejam preenchidos corretamente.");
        System.out.println("Problema com o SQL");
        ex.printStackTrace();
    }

    /*MessageFormat header = new MessageFormat("Ficha Pedagógica - "+jComboBox1.getSelectedItem());

    MessageFormat footer = new MessageFormat("Página {0,number,integer}");

    try{
        jTable2.print(JTable.PrintMode.NORMAL, header, null);
    }
    catch(java.awt.print.PrinterException e){
        System.out.println("gsgd");
    }*/    
DefaultTableModel dtm = new DefaultTableModel(new String[] { "Column 1" }, 1);
JTable jTable2 = new JTable(dtm) {
@Override
public Printable getPrintable(PrintMode printMode, MessageFormat headerFormat, MessageFormat footerFormat) {
   return new TablePrintable(this, printMode, headerFormat, footerFormat);
        }
    };
}         

"TablePrintable"类的代码如下:

The code for the "TablePrintable" class is the following:

static class TablePrintable implements Printable {

    private final JTable table;
    private final JTableHeader header;
    private final TableColumnModel colModel;
    private final int totalColWidth;
    private final JTable.PrintMode printMode;
    private final MessageFormat headerFormat;
    private final MessageFormat footerFormat;
    private int last = -1;
    private int row = 0;
    private int col = 0;
    private final Rectangle clip = new Rectangle(0, 0, 0, 0);
    private final Rectangle hclip = new Rectangle(0, 0, 0, 0);
    private final Rectangle tempRect = new Rectangle(0, 0, 0, 0);
    private static final int H_F_SPACE = 8;
    private static final float HEADER_FONT_SIZE = 18.0f;
    private static final float FOOTER_FONT_SIZE = 12.0f;
    private final Font headerFont;
    private final Font footerFont;

    public TablePrintable(JTable table, JTable.PrintMode printMode, MessageFormat headerFormat,
            MessageFormat footerFormat) {

        this.table = table;

        header = table.getTableHeader();
        colModel = table.getColumnModel();
        totalColWidth = colModel.getTotalColumnWidth();

        if (header != null) {
            // the header clip height can be set once since it's unchanging
            hclip.height = header.getHeight();
        }

        this.printMode = printMode;

        this.headerFormat = headerFormat;
        this.footerFormat = footerFormat;

        // derive the header and footer font from the table's font
        headerFont = table.getFont().deriveFont(Font.BOLD, HEADER_FONT_SIZE);
        footerFont = table.getFont().deriveFont(Font.PLAIN, FOOTER_FONT_SIZE);
    }

    @Override
    public int print(Graphics graphics, PageFormat pageFormat, int pageIndex) throws PrinterException {

        // for easy access to these values
        final int imgWidth = (int) pageFormat.getImageableWidth();
        final int imgHeight = (int) pageFormat.getImageableHeight();

        if (imgWidth <= 0) {
            throw new PrinterException("Width of printable area is too small.");
        }

        // to pass the page number when formatting the header and footer
        // text
        Object[] pageNumber = new Object[] { Integer.valueOf(pageIndex + 1) };

        // fetch the formatted header text, if any
        String headerText = null;
        if (headerFormat != null) {
            headerText = headerFormat.format(pageNumber);
        }

        // fetch the formatted footer text, if any
        String footerText = null;
        if (footerFormat != null) {
            footerText = footerFormat.format(pageNumber);
        }

        // to store the bounds of the header and footer text
        Rectangle2D hRect = null;
        Rectangle2D fRect = null;

        // the amount of vertical space needed for the header and footer
        // text
        int headerTextSpace = 0;
        int footerTextSpace = 0;

        // the amount of vertical space available for printing the table
        int availableSpace = imgHeight;

        // if there's header text, find out how much space is needed for it
        // and subtract that from the available space
        if (headerText != null) {
            graphics.setFont(headerFont);
            int nbLines = headerText.split("\n").length;
            hRect = graphics.getFontMetrics().getStringBounds(headerText, graphics);

            hRect = new Rectangle2D.Double(hRect.getX(), Math.abs(hRect.getY()), hRect.getWidth(),
                    hRect.getHeight() * nbLines);

            headerTextSpace = (int) Math.ceil(hRect.getHeight() * nbLines);
            availableSpace -= headerTextSpace + H_F_SPACE;
        }

        // if there's footer text, find out how much space is needed for it
        // and subtract that from the available space
        if (footerText != null) {
            graphics.setFont(footerFont);
            fRect = graphics.getFontMetrics().getStringBounds(footerText, graphics);

            footerTextSpace = (int) Math.ceil(fRect.getHeight());
            availableSpace -= footerTextSpace + H_F_SPACE;
        }

        if (availableSpace <= 0) {
            throw new PrinterException("Height of printable area is too small.");
        }

        // depending on the print mode, we may need a scale factor to
        // fit the table's entire width on the page
        double sf = 1.0D;
        if (printMode == JTable.PrintMode.FIT_WIDTH && totalColWidth > imgWidth) {

            // if not, we would have thrown an acception previously
            assert imgWidth > 0;

            // it must be, according to the if-condition, since imgWidth > 0
            assert totalColWidth > 1;

            sf = (double) imgWidth / (double) totalColWidth;
        }

        // dictated by the previous two assertions
        assert sf > 0;

        // This is in a loop for two reasons:
        // First, it allows us to catch up in case we're called starting
        // with a non-zero pageIndex. Second, we know that we can be called
        // for the same page multiple times. The condition of this while
        // loop acts as a check, ensuring that we don't attempt to do the
        // calculations again when we are called subsequent times for the
        // same page.
        while (last < pageIndex) {
            // if we are finished all columns in all rows
            if (row >= table.getRowCount() && col == 0) {
                return NO_SUCH_PAGE;
            }

            // rather than multiplying every row and column by the scale
            // factor
            // in findNextClip, just pass a width and height that have
            // already
            // been divided by it
            int scaledWidth = (int) (imgWidth / sf);
            int scaledHeight = (int) ((availableSpace - hclip.height) / sf);

            // calculate the area of the table to be printed for this page
            findNextClip(scaledWidth, scaledHeight);

            last++;
        }

        // create a copy of the graphics so we don't affect the one given to
        // us
        Graphics2D g2d = (Graphics2D) graphics.create();

        // translate into the co-ordinate system of the pageFormat
        g2d.translate(pageFormat.getImageableX(), pageFormat.getImageableY());

        // to save and store the transform
        AffineTransform oldTrans;

        // if there's footer text, print it at the bottom of the imageable
        // area
        if (footerText != null) {
            oldTrans = g2d.getTransform();

            g2d.translate(0, imgHeight - footerTextSpace);

            String[] lines = footerText.split("\n");
            printText(g2d, lines, fRect, footerFont, imgWidth);

            g2d.setTransform(oldTrans);
        }

        // if there's header text, print it at the top of the imageable area
        // and then translate downwards
        if (headerText != null) {
            String[] lines = headerText.split("\n");
            printText(g2d, lines, hRect, headerFont, imgWidth);

            g2d.translate(0, headerTextSpace + H_F_SPACE);
        }

        // constrain the table output to the available space
        tempRect.x = 0;
        tempRect.y = 0;
        tempRect.width = imgWidth;
        tempRect.height = availableSpace;
        g2d.clip(tempRect);

        // if we have a scale factor, scale the graphics object to fit
        // the entire width
        if (sf != 1.0D) {
            g2d.scale(sf, sf);

            // otherwise, ensure that the current portion of the table is
            // centered horizontally
        } else {
            int diff = (imgWidth - clip.width) / 2;
            g2d.translate(diff, 0);
        }

        // store the old transform and clip for later restoration
        oldTrans = g2d.getTransform();
        Shape oldClip = g2d.getClip();

        // if there's a table header, print the current section and
        // then translate downwards
        if (header != null) {
            hclip.x = clip.x;
            hclip.width = clip.width;

            g2d.translate(-hclip.x, 0);
            g2d.clip(hclip);
            header.print(g2d);

            // restore the original transform and clip
            g2d.setTransform(oldTrans);
            g2d.setClip(oldClip);

            // translate downwards
            g2d.translate(0, hclip.height);
        }

        // print the current section of the table
        g2d.translate(-clip.x, -clip.y);
        g2d.clip(clip);
        table.print(g2d);

        // restore the original transform and clip
        g2d.setTransform(oldTrans);
        g2d.setClip(oldClip);

        // draw a box around the table
        g2d.setColor(Color.BLACK);
        g2d.drawRect(0, 0, clip.width, hclip.height + clip.height);

        // dispose the graphics copy
        g2d.dispose();

        return PAGE_EXISTS;
    }

    private void printText(Graphics2D g2d, String[] lines, Rectangle2D rect, Font font, int imgWidth) {

        g2d.setColor(Color.BLACK);
        g2d.setFont(font);

        for (int i = 0; i < lines.length; i++) {
            int tx;

            // if the text is small enough to fit, center it
            if (rect.getWidth() < imgWidth) {
                tx = (int) (imgWidth / 2 - g2d.getFontMetrics().getStringBounds(lines[i], g2d).getWidth() / 2);

                // otherwise, if the table is LTR, ensure the left side of
                // the text shows; the right can be clipped
            } else if (table.getComponentOrientation().isLeftToRight()) {
                tx = 0;

                // otherwise, ensure the right side of the text shows
            } else {
                tx = -(int) (Math.ceil(rect.getWidth()) - imgWidth);
            }

            int ty = (int) Math.ceil(Math.abs(rect.getY() + i * rect.getHeight() / lines.length));
            g2d.drawString(lines[i], tx, ty);
        }
    }

    private void findNextClip(int pw, int ph) {
        final boolean ltr = table.getComponentOrientation().isLeftToRight();

        // if we're ready to start a new set of rows
        if (col == 0) {
            if (ltr) {
                // adjust clip to the left of the first column
                clip.x = 0;
            } else {
                // adjust clip to the right of the first column
                clip.x = totalColWidth;
            }

            // adjust clip to the top of the next set of rows
            clip.y += clip.height;

            // adjust clip width and height to be zero
            clip.width = 0;
            clip.height = 0;

            // fit as many rows as possible, and at least one
            int rowCount = table.getRowCount();
            int rowHeight = table.getRowHeight(row);
            do {
                clip.height += rowHeight;

                if (++row >= rowCount) {
                    break;
                }

                rowHeight = table.getRowHeight(row);
            } while (clip.height + rowHeight <= ph);
        }

        // we can short-circuit for JTable.PrintMode.FIT_WIDTH since
        // we'll always fit all columns on the page
        if (printMode == JTable.PrintMode.FIT_WIDTH) {
            clip.x = 0;
            clip.width = totalColWidth;
            return;
        }

        if (ltr) {
            // adjust clip to the left of the next set of columns
            clip.x += clip.width;
        }

        // adjust clip width to be zero
        clip.width = 0;

        // fit as many columns as possible, and at least one
        int colCount = table.getColumnCount();
        int colWidth = colModel.getColumn(col).getWidth();
        do {
            clip.width += colWidth;
            if (!ltr) {
                clip.x -= colWidth;
            }

            if (++col >= colCount) {
                // reset col to 0 to indicate we're finished all columns
                col = 0;

                break;
            }

            colWidth = colModel.getColumn(col).getWidth();
        } while (clip.width + colWidth <= pw);

    }
}

但是，就像我说的那样，当我单击打印"按钮时，什么也没有发生.可能出什么问题了?

But, like I said, when I click the "print" button, nothing happens. What could be going wrong?

推荐答案

使用新修改的JTable，只需调用它的print方法即可.

With your newly modify JTable, you should only need to call it's print method.

DefaultTableModel dtm = new DefaultTableModel(new String[] { "Column 1" }, 1);
JTable jTable2 = new JTable(dtm) {
    @Override
    public Printable getPrintable(PrintMode printMode, MessageFormat headerFormat, MessageFormat footerFormat) {
        return new TablePrintable(this, printMode, headerFormat, footerFormat);
    }
};

try{
    jTable2.print(JTable.PrintMode.NORMAL, header, null);
}
catch(java.awt.print.PrinterException e){
    System.out.println("error");
}

由于您已经覆盖了getPrintable方法以返回自己的实现，因此这将用于物理打印表格...

Because you've overridden the getPrintable method to return your own implementation, this is what will be used to physically print the table...

已更新

标题文本需要用\n分隔，例如...

The header text needs to be separated by a \n, for example...

MessageFormat header = new MessageFormat("Testing, 01\n02\n03");

可以生产...

已更新

据我所知，在无法完全运行代码的情况下，您的打印代码应类似于...

As near as I can tell, without been able to fully run the code, your print code should look something like...

private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {

    Vector vetColuna = new Vector();
    Vector vetLinhas = new Vector();
    try {
        Class.forName(driver);
        con = DriverManager.getConnection(str_conn, usuario, senha);
        stmt = con.createStatement();
        sql = "select topico, nota, datanota from notas where notas.cod_aluno =" + jTextField1.getText() + " and notas.cod_curso =" + jTextField2.getText() + " order by notas.datanota";
        rs = stmt.executeQuery(sql);
        if (rs == null) {
            return;
        }
        ResultSetMetaData rsmd;
        rsmd = rs.getMetaData();
        for (int i = 0; i < rsmd.getColumnCount(); i++) {
            vetColuna.add(rsmd.getColumnLabel(i + 1));
        }

        while (rs.next()) {
            Vector vetLinha = new Vector();
            for (int i = 0; i < rsmd.getColumnCount(); i++) {
                vetLinha.add(rs.getObject(i + 1));
            }
            vetLinhas.add(vetLinha);
        }
    } catch (ClassNotFoundException ex) {
        JOptionPane.showMessageDialog(null, "Erro\nNão foi possível carregar o driver.");
        System.out.println("Nao foi possivel carregar o driver");
        ex.printStackTrace();
    } catch (SQLException ex) {
        JOptionPane.showMessageDialog(null, "Erro\nCertifique-se de que todos os\ncampos estejam preenchidos corretamente.");
        System.out.println("Problema com o SQL");
        ex.printStackTrace();
    }

    MessageFormat header = new MessageFormat("Ficha Pedagógica - " + jComboBox1.getSelectedItem() + "\nNome do Aluno - " + jTextField1.getText());

    DefaultTableModel dtm = new DefaultTableModel(vetLinhas, vetColuna);
    JTable jTable2 = new JTable(dtm) {
        @Override
        public Printable getPrintable(PrintMode printMode, MessageFormat headerFormat, MessageFormat footerFormat) {
            return new TablePrintable(this, printMode, headerFormat, footerFormat);
        }
    };
    try {
        jTable2.setSize(jTable2.getPreferredSize());
        JTableHeader tableHeader = jTable2.getTableHeader();
        tableHeader.setSize(tableHeader.getPreferredSize());
        jTable2.print(JTable.PrintMode.FIT_WIDTH);
    } catch (PrinterException ex) {
        ex.printStackTrace();
    }

}

这篇关于可打印无法正常工作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！