Question

与此thread相关我有一个问题，是否有人知道是否有可能覆盖/更改MessageFormat headerFormat JTable.PrintMode的更大字体（字体类型，大小，颜色）或者我必须绘制g2.drawString（“我的页眉/页脚”）和JTable #print（）separatelly

Answer 1

正如大家已经提到的那样（当我在度假时放松:-) - TablePrintable紧密编织以保密，无法创建子类，无法配置页眉/页脚打印。钩子的唯一选择是包装表的默认可打印，让它在没有页眉/页脚的情况下完成它的工作并接管页眉/页脚打印。

到目前为止所显示的片段的问题在于它们不能很好地与多页面一起使用 - 当然，所有作者都知道并提及 - 因为默认的可打印认为没有页眉/页脚并且可以自由使用所需的空间被他们。毫不奇怪： - ）

所以问题是：有没有办法让默认不打印到页眉/页脚的区域？是的，它是：双wopper（ehh ..包装器）就是答案 - 通过将给定的pageFormat包装成一个返回调整后的getImageableHeight / Y的页面，使默认打印相信它具有更少的可打印空间。类似的东西：

public class CustomPageFormat extends PageFormat {

    private PageFormat delegate;
    private double headerHeight;
    private double footerHeight;

    public CustomPageFormat(PageFormat format, double headerHeight, double footerHeight) {
        this.delegate = format;
        this.headerHeight = headerHeight;
        this.footerHeight = footerHeight;
    }
    /** 
     * @inherited <p>
     */
    @Override
    public double getImageableY() {
        return delegate.getImageableY() + headerHeight;
    }

    /** 
     * @inherited <p>
     */
    @Override
    public double getImageableHeight() {
        return delegate.getImageableHeight() - headerHeight - footerHeight;
    }

    // all other methods simply delegate

然后在可打印的包装中使用（页脚必须以类似的方式完成）：

public class CustomTablePrintable implements Printable {

    Printable tablePrintable;
    JTable table;
    MessageFormat header; 
    MessageFormat footer;

    public CustomTablePrintable(MessageFormat header, MessageFormat footer) {
        this.header = header;
        this.footer = footer;
    }

    public void setTablePrintable(JTable table, Printable printable) {
        tablePrintable = printable;        
        this.table = table;
    }

    @Override
    public int print(Graphics graphics, PageFormat pageFormat, 
            int pageIndex) throws PrinterException {
        // grab an untainted graphics
        Graphics2D g2d = (Graphics2D)graphics.create();
        // calculate the offsets and wrap the pageFormat
        double headerOffset = calculateHeaderHeight(g2d, pageIndex);
        CustomPageFormat wrappingPageFormat = new CustomPageFormat(pageFormat, headerOffset, 0);
        // feed the wrapped pageFormat into the default printable
        int exists = tablePrintable.print(graphics, wrappingPageFormat, pageIndex);
        if (exists != PAGE_EXISTS) {
            g2d.dispose();
            return exists;
        }
        // translate the graphics to the start of the original pageFormat and draw header
        g2d.translate(pageFormat.getImageableX(), pageFormat.getImageableY());
        printHeader(g2d, pageIndex, (int) pageFormat.getImageableWidth());
        g2d.dispose();

        return PAGE_EXISTS;        
    }


    protected double calculateHeaderHeight(Graphics2D g, int pageIndex) {
        if (header == null) return 0;
        Object[] pageNumber = new Object[]{new Integer(pageIndex + 1)};
        String text = header.format(pageNumber);
        Font headerFont = table.getFont().deriveFont(Font.BOLD, 18f);
        g.setFont(headerFont);
        Rectangle2D rect = g.getFontMetrics().getStringBounds(text, g);
        return rect.getHeight();
    }

    protected void printHeader(Graphics2D g, int pageIndex, int imgWidth) {
        Object[] pageNumber = new Object[]{new Integer(pageIndex + 1)};
        String text = header.format(pageNumber);
        Font headerFont = table.getFont().deriveFont(Font.BOLD, 18f);
        g.setFont(headerFont);
        Rectangle2D rect = g.getFontMetrics().getStringBounds(text, g);
        // following is c&p from TablePrintable printText
        int tx;

        // if the text is small enough to fit, center it
        if (rect.getWidth() < imgWidth) {
            tx = (int) ((imgWidth - rect.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()));
        g.setColor(Color.BLACK);
        g.drawString(text, tx, ty);

    }
}

最后从表的getPrintable返回，如：

    final JTable table = new JTable(myModel){

        /** 
         * @inherited <p>
         */
        @Override
        public Printable getPrintable(PrintMode printMode,
                MessageFormat headerFormat, MessageFormat footerFormat) {
            Printable printable = super.getPrintable(printMode, null, null);
            CustomTablePrintable custom = new CustomTablePrintable(headerFormat, footerFormat);
            custom.setTablePrintable(this, printable);
            return custom;
        }

    };

可以实现printHeader / Footer来执行任何操作。

在一天结束时：“我是否需要调用g.drawString（...）”这一问题的答案仍为“是”。但至少它安全地在桌子之外： - ）

MessageFormat header / footerFormat如何更改JTable打印的Font

1 个答案: