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我正在使用 QTextEdit 小部件向用户显示格式良好的聊天窗口。为了保持基本的测试，我对我的 html 使用以下格式：

    QString style = is_message_sent_by_myself ?
        "background-color:rgb(255,255,255);font-size:14px;color:rgb(10,10,10);" :
        "background-color:rgb(249,86,79);font-size:14px;color:rgb(255,255,255);";

    QString format("<div style='%1'> %2 </div> <div style='font-size:3px;'> &zwnj; </div>");
    QString text_to_append = format.arg(style).arg(message.toHtmlEscaped());

    QTextEdit->append(text_to_append)

这在我自己创建 html 时效果很好，但是在使用 QT 5.6 生成它时，QTextEdit->append(text_to_be_append)我得到了不同（甚至不一致）的结果。

首先，当运行上述代码段一次时，会生成以下 html（通过 获取QTextEdit->toHtml()）：

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
<html>
    <head>
        <meta name="qrichtext" content="1" />
        <style type="text/css">
            p, li { white-space: pre-wrap; }
        </style>
    </head>
    <body style=" font-family:'MS Shell Dlg 2'; font-size:8.25pt; font-weight:400; font-style:normal;">
        <p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; background-color:#ffffff;"><span style=" font-size:14px; color:#0a0a0a; background-color:#ffffff;">Some message </span></p>
        <p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-size:3px;">&zwnj; </span></p>
    </body>
</html>

（这看起来很适合第一条消息）

但是再次执行代码后，出现了不一致：

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
<html>
    <head>
        <meta name="qrichtext" content="1" />
        <style type="text/css">
            p, li { white-space: pre-wrap; }
        </style>
    </head>
    <body style=" font-family:'MS Shell Dlg 2'; font-size:8.25pt; font-weight:400; font-style:normal;">
        <p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; background-color:#ffffff;"><span style=" font-size:14px; color:#0a0a0a; background-color:#ffffff;">Some message </span></p>
        <p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-size:3px;">&zwnj; </span></p>
        <p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-size:14px; color:#ffffff; background-color:#f9564f;">Some message </span></p>
        <p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-size:3px;">&zwnj; </span></p>
    </body>
</html>

（看起来像这样，但应该像这样）

如您所见，第三个<p>标签中缺少背景颜色属性。其中背景颜色属性存在于第一个<p>标签中。相同的代码一遍又一遍地重复，随后的调用不断生成<p>没有背景颜色属性的标签。

为什么会发生这种情况，我该如何解决这个问题？

我在 Windows 10 x64 上使用 QT 5.6 和 Visual Studio 2015 插件（非官方插件）。

这就是我创建 QTextEdit 框的方式（包括 a 的所有其他组件tabPage）：

PAChatClientUI::PAChatClientUI(QTabWidget* tabs_container, QObject *parent)
    : QObject(parent), tabs_container_(tabs_container)
{
    QString suffix = QString::number((size_t)this, 16);

    tab_ = new QWidget();
    tab_->setObjectName("tab_" + suffix);

    tab_grid_layout_ = new QGridLayout(tab_);
    tab_grid_layout_->setSpacing(6);
    tab_grid_layout_->setContentsMargins(11, 11, 11, 11);
    tab_grid_layout_->setObjectName("tab_grid_layout_" + suffix);

    chat_container_grid_ = new QGridLayout();
    chat_container_grid_->setSpacing(6);
    chat_container_grid_->setObjectName("chat_container_grid_" + suffix);

    chat_container_button_grid_ = new QHBoxLayout();
    chat_container_button_grid_->setSpacing(6);
    chat_container_button_grid_->setObjectName("chat_container_button_grid_" + suffix);

    chat_manager_bot_remove_ = new QPushButton(tab_);
    chat_manager_bot_remove_->setObjectName("chat_manager_bot_remove_" + suffix);
    chat_manager_bot_remove_->setMinimumSize(QSize(119, 23));

    chat_container_button_grid_->addWidget(chat_manager_bot_remove_);

    chat_manager_keep_chat_ = new QPushButton(tab_);
    chat_manager_keep_chat_->setObjectName("chat_manager_keep_chat_" + suffix);
    chat_manager_keep_chat_->setMinimumSize(QSize(119, 23));

    chat_container_button_grid_->addWidget(chat_manager_keep_chat_);

    chat_manager_end_chat_ = new QPushButton(tab_);
    chat_manager_end_chat_->setObjectName("chat_manager_end_chat_" + suffix);
    chat_manager_end_chat_->setMinimumSize(QSize(118, 23));

    chat_container_button_grid_->addWidget(chat_manager_end_chat_);

    chat_manager_send_ = new QPushButton(tab_);
    chat_manager_send_->setObjectName("chat_manager_send_" + suffix);
    chat_manager_send_->setMinimumSize(QSize(119, 23));

    chat_container_button_grid_->addWidget(chat_manager_send_);

    chat_container_grid_->addLayout(chat_container_button_grid_, 3, 0, 1, 1);

    chat_box_text_messages_ =
        //new QPlainTextEdit(tab_);
        new QTextEdit(tab_);
    chat_box_text_messages_->setObjectName("chat_box_text_messages_" + suffix);
    chat_box_text_messages_->setMinimumSize(QSize(495, 178));

    chat_container_grid_->addWidget(chat_box_text_messages_, 1, 0, 1, 1);

    chat_box_text_input_message_ = new QLineEdit(tab_);
    chat_box_text_input_message_->setObjectName("chat_box_text_input_message_" + suffix);
    chat_box_text_input_message_->setMinimumSize(QSize(495, 20));
    chat_box_text_input_message_->setMaximumSize(QSize(16777215, 16777215));

    chat_container_grid_->addWidget(chat_box_text_input_message_, 2, 0, 1, 1);

    tab_grid_layout_->addLayout(chat_container_grid_, 0, 0, 1, 1);

    chat_manager_bot_remove_->setText("Remove Bot");
    chat_manager_keep_chat_->setText("Keep Chat");
    chat_manager_end_chat_->setText("End Chat");
    chat_manager_send_->setText("Send");

    QPalette p = chat_box_text_messages_->palette();

    p.setColor(QPalette::Active, QPalette::Base, Qt::black);
    p.setColor(QPalette::Inactive, QPalette::Base, Qt::black);
    chat_box_text_messages_->setPalette(p);

    chat_box_text_messages_->setWordWrapMode(QTextOption::WordWrap);
    chat_box_text_messages_->setReadOnly(true);

    //Add nice html messages:
    AddMessage(true, "Some message");

    AddMessage(false, "Some message");

    AddMessage(true, "Some message");

    AddMessage(false, "Some message");

    tabs_container_->addTab(tab_, " 6");
}

void PAChatClientUI::AddMessage(bool me, const QString& message)
{
    QString style = me ?
        "background-color:rgb(255,255,255);font-size:14px;color:rgb(10,10,10);" :
        "background-color:rgb(249,86,79);font-size:14px;color:rgb(255,255,255);";

    QString format("<div style='%1'> %2 </div> <div style='font-size:3px;'> &zwnj; </div>");
    QString safe_msg = format.arg(style).arg(message.toHtmlEscaped());
    qDebug() << "Writing: " << safe_msg;
    chat_box_text_messages_->append(safe_msg);
    qDebug() << "HTML: " << chat_box_text_messages_->toHtml();
}

编辑：

我试图根据答案和我的想法编辑代码，产生以下两个代码结果：

void PAChatClientUI::AddMessage(bool me, const QString& message)
{
    QString style = me ?
        "background-color:rgb(255,255,255);font-size:14px;color:rgb(10,10,10);" :
        "background-color:rgb(249,86,79);font-size:14px;color:rgb(255,255,255);";

    QString format("<div style='%1'> %2 </div> <div style='font-size:3px;'> &zwnj; </div>");
    QString safe_msg = format.arg(style).arg(message.toHtmlEscaped());
    qDebug() << "Writing: " << safe_msg;
    QTextCursor cursor = chat_box_text_messages_->textCursor();

    if (!cursor.atStart())
        cursor.insertBlock();
    cursor.insertHtml(safe_msg);
    qDebug() << "HTML: " << chat_box_text_messages_->toHtml();
}

这产生了完全相同的效果，因此为了避免 QT “转换” HTML，我认为我可以只写 QT 所写的内容，但会发生完全相同的问题：

void PAChatClientUI::AddMessage(bool me, const QString& message)
{
    QString bgColor  = me ? "ffffff" : "f9564f";
    QString txtColor = me ? "0a0a0a" : "ffffff";

    QString to_append("\
        <p style=\" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; background-color:#" + bgColor + ";\"><span style=\" font-size:14px; color:#" + txtColor + "; background-color:#" + bgColor + ";\">" + message.toHtmlEscaped() + " </span></p>\
        <p style=\" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;\"><span style=\" font-size:3px;\">&zwnj; </span></p>\
    ");

    chat_box_text_messages_->append(to_append);
}
4

2 回答 2

1

编辑：这个建议不能解决问题；为了完整起见，它留在这里。

QTextEditQTextDocument在附加文本块时对底层做一些 RichText 魔术。尝试明确地创建一个块并使用QTextCursor::insertHtml()而不是QTextEdit::append()：

QTextCursor cursor = m_ui.entryText->textCursor();

if(!cursor.atStart())
    cursor.insertBlock();
cursor.insertHtml(htmlText);

这也应该提高大量文本的性能。

于 2016-04-26T08:37:29.350 回答
0

<div>将两个打包到一个常见的调用中时，我能够重现这种行为append()；将它们分成两个调用会产生预期的外观（此处使用 Qt 4.7）。

于 2016-04-28T12:05:15.973 回答