| 标题 | java打印和打印预览机制实例代码 |
| 内容 | 代码如下: import java.awt.basicstroke; import java.awt.borderlayout; import java.awt.color; import java.awt.component; import java.awt.dimension; import java.awt.font; import java.awt.fontmetrics; import java.awt.graphics; import java.awt.graphics2d; import java.awt.gridlayout; import java.awt.event.actionevent; import java.awt.event.actionlistener; import java.awt.event.mouseadapter; import java.awt.event.mouseevent; import java.awt.print.pageformat; import java.awt.print.printable; import java.awt.print.printerexception; import java.awt.print.printerjob; import javax.swing.jbutton; import javax.swing.jdialog; import javax.swing.jframe; import javax.swing.jpanel; import javax.swing.jscrollpane; import javax.swing.jtextarea; import javax.swing.swingutilities; import javax.swing.windowconstants; import javax.swing.text.badlocationexception; import javax.swing.text.document; /** * 使用了原始的分页方式去渲染jtextarea，提供了打印预览机制。 * <p> * 事实上，我们还可以通过其他方式打印jtextarea： * <ol> * <li>{@code component.print(graphics g);} or * {@code component.printall(graphics g);}</li> * <li>{@code component.paint(graphics g);} or * {@code component.paintall(graphics g);} whose rending may be slightly * different to the previous method (for example, <code>jframe</code>)</li> * <li>{@code jtable.print();} or {@code jtextcomponent.print();} provide * especially powerful and convenient printing mechanism</li> * </ol> * * @author gaowen */ public class printuicomponent extends jpanel implements actionlistener, printable { private static final long serialversionuid = 4797002827940419724l; private static jframe frame; private jtextarea textareatoprint; private printerjob job; private int[] pagebreaks;// array of page break line positions private string[] textlines; private header header; public printuicomponent() { super(new borderlayout()); textareatoprint = new jtextarea(50, 20); for (int i = 1; i <= 50; i++) { textareatoprint.append(line + i + \n); } jscrollpane scrollpane = new jscrollpane(textareatoprint); scrollpane.setpreferredsize(new dimension(250, 200)); add(scrollpane, borderlayout.center); jbutton printbutton = new jbutton(print this textarea); printbutton.setname(printbutton); printbutton.addactionlistener(this); jbutton printpreviewbutton = new jbutton(print preview); printpreviewbutton.setname(printpreviewbutton); printpreviewbutton.addactionlistener(this); jpanel buttongroup = new jpanel(new gridlayout(2, 1)); buttongroup.add(printbutton); buttongroup.add(printpreviewbutton); add(buttongroup, borderlayout.south); /* initialize printerjob */ initprinterjob(); } public static void main(string[] args) { swingutilities.invokelater(new runnable() { @override public void run() { createandshowgui(); } }); } private static void createandshowgui() { frame = new jframe(print ui example); frame.setcontentpane(new printuicomponent()); frame.pack(); frame.setlocationrelativeto(null); frame.setdefaultcloseoperation(windowconstants.exit_on_close); frame.setvisible(true); } private void inittextlines() { document doc = textareatoprint.getdocument(); try { string text = doc.gettext(0, doc.getlength()); textlines = text.split(\n); } catch (badlocationexception e) { e.printstacktrace(); } } private void initprinterjob() { job = printerjob.getprinterjob(); job.setjobname(print textarea);// 出现在系统打印任务列表 job.setprintable(this); } @override public int print(graphics graphics, pageformat pageformat, int pageindex) throws printerexception { /* * it is safe to use a copy of this graphics as this will not involve * changes to it. */ graphics2d g2 = (graphics2d) graphics.create(); /* calculate pagebreaks */ font font = new font(serif, font.plain, 12); fontmetrics metrics = g2.getfontmetrics(font); int lineheight = metrics.getheight(); if (pagebreaks == null) { inittextlines(); int linesperpage = (int) (pageformat.getimageableheight() / lineheight); int numbreaks = (textlines.length - 1) / linesperpage; pagebreaks = new int[numbreaks]; for (int b = 0; b < numbreaks; b++) { pagebreaks[b] = (b + 1) * linesperpage; } } /* condition to exit printing */ if (pageindex > pagebreaks.length) { return no_such_page; } /* (0,0) is outside the imageable area, translate to avoid clipping */ g2.translate(pageformat.getimageablex(), pageformat.getimageabley()); /* draw each line that is on this page */ int y = 0; int start = (pageindex == 0) ? 0 : pagebreaks[pageindex - 1]; int end = (pageindex == pagebreaks.length) ? textlines.length : pagebreaks[pageindex]; for (int line = start; line < end; line++) { y += lineheight; g2.drawstring(textlines[line], 0, y); } /* dispose of the graphics copy */ g2.dispose(); /* tell the caller that this page is part of the printed document */ return page_exists; } @override public void actionperformed(actionevent e) { object actioneventsource = e.getsource(); if (actioneventsource instanceof jbutton) { jbutton button = (jbutton) actioneventsource; if (button.getname().equals(printbutton)) { pagebreaks = null;// reset pagination boolean ok = job.printdialog(); if (ok) { try { job.print(); } catch (printerexception ex) { /* the job did not successfully complete */ ex.printstacktrace(); } } } else if (button.getname().equals(printpreviewbutton)) { pagebreaks = null;// reset pagination createandshowpreviewdialog(); } } } private void createandshowpreviewdialog() { jdialog previewdialog = new jdialog(frame, print preview dialog, true); jpanel contentpane = new jpanel(new borderlayout()); previewarea previewarea = new previewarea(); previewarea.addmouselistener(new previewareamouseadapter(previewarea)); jscrollpane scrollpane = new jscrollpane(previewarea); contentpane.add(scrollpane, borderlayout.center); header = new header(previewarea); contentpane.add(header, borderlayout.north); previewdialog.setcontentpane(contentpane); previewdialog.setsize(600, 600); previewdialog .setdefaultcloseoperation(windowconstants.dispose_on_close); previewdialog.setvisible(true); } private class header extends component { private static final long serialversionuid = -1741188309769027249l; private previewarea previewarea; private boolean paintable; private header(previewarea previewarea) { this.previewarea = previewarea; } private void setpaintable(boolean paintable) { this.paintable = paintable; } @override public void paint(graphics g) { if (paintable) { g.setcolor(color.gray); g.drawstring( string.valueof(previewarea.getpageindex() + 1) + / + string.valueof(pagebreaks.length + 1) + pages (click left mouse button to preview next page; right to previous), 10, 15); } } @override public dimension getpreferredsize() { return new dimension(super.getpreferredsize().width, 20); } } private class previewarea extends component { private static final long serialversionuid = -6384174997251439843l; private pageformat pageformat; private int pageindex; private int w; private int h; private final int marginx = 10; private final int marginy = 20; private previewarea() { pageformat = job.pagedialog(job.defaultpage()); pageindex = 0; w = (int) pageformat.getwidth(); h = (int) pageformat.getheight(); } private int getpageindex() { return pageindex; } private void setpageindex(int pageindex) { this.pageindex = pageindex; } @override public dimension getpreferredsize() { return new dimension(w + 2 * marginx, h + 2 * marginy); } @override public void paint(graphics g) { graphics2d g2 = (graphics2d) g.create(); g2.translate(marginx, marginy); g2.drawrect(0, 0, w, h); int ix = (int) (pageformat.getimageablex() - 1); int iy = (int) (pageformat.getimageabley() - 1); int iw = (int) (pageformat.getimageablewidth() + 1); int ih = (int) (pageformat.getimageableheight() + 1); g2.setstroke(new basicstroke(1f, basicstroke.cap_round, basicstroke.join_round, 10f, new float[] { 5, 5 }, 0f)); g2.drawrect(ix, iy, iw, ih); try { printuicomponent.this.print(g2, pageformat, pageindex); } catch (printerexception e) { e.printstacktrace(); } g2.dispose(); header.setpaintable(true); header.repaint(); } } private class previewareamouseadapter extends mouseadapter { private previewarea previewarea; private previewareamouseadapter(previewarea previewarea) { this.previewarea = previewarea; } @override public void mouseclicked(mouseevent e) { int currentindex = previewarea.getpageindex(); if (e.getbutton() == mouseevent.button1) { /* next page */ if (currentindex < pagebreaks.length) { previewarea.setpageindex(currentindex + 1); previewarea.repaint(); } } else if (e.getbutton() == mouseevent.button3) { /* previous page */ if (currentindex > 0) { previewarea.setpageindex(currentindex - 1); previewarea.repaint(); } } } } } |
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