同时使用 QPrinter、QPainter 和 QTextDocument 时获取错误消息

在我的Qt应用程序中，我想创建一个预览页面，其中包含包含页眉，页脚标题和表格视图的内容。

这是我使用的代码：

void MainWindow::print(QPrinter *printer)
{
    int xscale = 50;
    int yscale = 30;
    QPoint top_left = QPoint(xscale, yscale);
    QPoint top_right = QPoint(xscale + 552, yscale + 20);
    QPoint bottom_left = QPoint(xscale, yscale + 1020);
    QPoint bottom_right = QPoint(xscale + 492, yscale + 1020);
    QPainter painter(printer);
    painter.setRenderHints(QPainter::Antialiasing |
                       QPainter::TextAntialiasing |
                       QPainter::SmoothPixmapTransform, true);
    // Header
    painter.setFont(QFont("Arial", 10));
    painter.drawImage(top_left, QImage(":/images/images/logo.png"));
    painter.drawText(top_right, "Header");
    // Print the Table
    QString strStream;
    QTextStream out(&strStream);
    out << "<html>n"
            "<head>n"
                 "<meta content="text/html; charset=utf-8">n"
                 "<title>Demo MyTableView</title>n"
                 "<style tyle="text/css">th{font-size: 14pt}n td{font-size: 12pt}n table td + td + td + td{font-weight:bold}</style>"
             "</head>n"
             "<body bgcolor=#ffffff link=#5000A0>n"
                 "<table cellspacing="0" cellpadding="2" border="1" width="100%">n";
    // Print the headers
    out << "<thead><tr bgcolor="#ffffff">";
    for (int column = 0; column < columnCount; column++)
        if (!myTableView->isColumnHidden(column))
            out << QString("<th>%1</th>").arg(myTableView->model()->headerData(column, Qt::Horizontal).toString());
    out << "</tr></thead>n";
    // Print the data
    for (int row = 0; row < rowCount; row++) {
        out << "<tr>";
        for (int column = 0; column < columnCount; column++) {
            if (!myTableView->isColumnHidden(column)) {
                QString data = myTableView->model()->data(myTableView->model()->index(row, column)).toString().simplified();
                out << QString("<td bkcolor=0 align=center>%1</td>").arg((!data.isEmpty()) ? data : QString("&nbsp;"));
            }
        }
        out << "</tr>n";
    }
    out <<  "</table>n"
        "</body>n"
        "</html>n";
    QTextDocument *document = new QTextDocument();
    document->setHtml(strStream);
    document->print(printer);  // I got the error messages at here
    delete document;
    // Footer
    painter.setFont(QFont("Arial", 10));
    painter.drawText(bottom_left, "Copyright 2013");
    // Get current date and time
    QDateTime dateTime = QDateTime::currentDateTime();
    QString dateTimeString = dateTime.toString();
    painter.drawText(bottom_right, dateTimeString);
}

当我运行应用程序时，我只在预览页面中看到页眉和页脚标题，没有显示表格视图。然后我使用 qDebug（）进行检查，并收到错误消息

QPrinter::setDocName: Cannot be changed while printer is active
QPainter::begin: A paint device can only be painted by one painter at a time.

在生产线上

document->print(printer);

如何解决此问题以使用页眉，页脚标题和表格视图正常打印数据？

感谢您的帮助！

好吧，如果Qt抱怨一次使用多个画家，请使其仅使用一个：）换句话说，只需将MainWindow::print()函数中的代码拆分为文档每个部分的较小例程：

void MainWindow::drawHeader(QPrinter *printer)
{
    QPainter painter(printer);
    // .. Draw the header
    [..]
}
void MainWindow::drawFooter(QPrinter *printer)
{
    QPainter painter(printer);
    painter.setFont(QFont("Arial", 10));
    painter.drawText(bottom_left, "Copyright 2013");
    [..]
}
void MainWindow::drawTable(QPrinter *printer)
{
    QTextDocument document;
    document.print(printer);
    [..]
}

最后：

void MainWindow::print(QPrinter *printer)
{
    // Init something.
    drawHeader(printer);
    drawTable(printer);
    drawFooter(printer);
    [..]
}

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