qplaintextedit 更改消息颜色

Question

我正在尝试根据消息为文本着色，我尝试了很多东西，但它们改变了所有文本颜色，而不仅仅是我需要的消息，正是那个错误。

if(Something)
    text = tr("");
if(SomethingElse)
    text = tr("");

ui->plainText->appendPlainText(text);

Answer 1

来自 Qt。医生。关于 QPlainTextEdit:

Text can be formatted in a limited way, either using a syntax highlighter (see below), or by appending html-formatted text with appendHtml().

如果是OP，我会推荐后者。

这是通过用最少的 HTML-markup:

包围纯文本来完成的

<p style='color: #ff0000'> ... </p>

另一个问题是纯文本可能包含 HTML 中具有 meta-meaning 的字符，字面意思是：< > & " '。考虑到这些，我添加了一个简单的格式化程序，将它们转换为 resp。 HTML 个实体。

顺便说一句。它将 "\n" 转换为 "<br/>"，这可能有用也可能没用。

我的样本testQPlainTextEdit-Colored.cc:

#include <QtWidgets>

const QString& makeText()
{
  static const QString texts[] = {
    QString::fromLatin1("Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua."),
    QString::fromLatin1("Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat."),
    QString::fromLatin1("Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur."),
    QString::fromLatin1("Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."),
    QString::fromLatin1("Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi."),
    QString::fromLatin1("Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat."),
    QString::fromLatin1("Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat."),
    QString::fromLatin1("Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum."),
    QString::fromUtf8("HTML Meta-Characters: < > & \" ' and\nnon-ASCII characters: \xc3\xa4 \xc3\xb6 \xc3\xbc \xc3\x9f \xc3\x84 \xc3\x96 \xc3\x9c")
  };
  enum { NTexts = sizeof texts / sizeof *texts };
  return texts[qrand() % NTexts];
}

const QString formatHtml(const QString &qText, const QColor &qColor)
{
  QString qHtmlText
    = QString::fromLatin1("<p style='color: ")
    + qColor.name(QColor::HexRgb)
    + QString::fromLatin1("'>");
  for (const QChar qChar : qText) {
    switch (qChar.unicode()) {
      case '<': qHtmlText += QString::fromLatin1("&lt;"); break;
      case '>': qHtmlText += QString::fromLatin1("&gt;"); break;
      case '&': qHtmlText += QString::fromLatin1("&amp;"); break;
      case '"': qHtmlText += QString::fromLatin1("&quot;"); break;
      case '\'': qHtmlText += QString::fromLatin1("&apos;"); break;
      case '\n': qHtmlText += QString::fromLatin1("<br/>"); break;
      default: qHtmlText += qChar; // everything else unchanged
    }
  }
  qHtmlText += QString::fromLatin1("</p>");
  return qHtmlText;
}

int main(int argc, char **argv)
{
  qDebug() << "Qt Version:" << QT_VERSION_STR;
  QApplication app(argc, argv);
  // setup GUI
  QPlainTextEdit qTxtEdit;
  qTxtEdit.show();
  // install signal handlers
  QTimer qTimer;
  qTimer.setInterval(1000); // 1000 ms = 1 s
  QObject::connect(&qTimer, &QTimer::timeout,
    [&]() {
      const QColor qColor(qrand() % 4 == 1 ? 0xFF0000 : 0x000000);
      qTxtEdit.appendHtml(formatHtml(makeText(), qColor));
    });
  qTimer.start();
  // runtime loop
  return app.exec();
}

它在 Windows 10 中的样子：

Answer 2

试试这个

if(youNeedRed)
    ui->plainTextEdit->appendHtml("<div style='color: red;'> RedText </div>");
else 
    ui->plainTextEdit->appendHtml("<div style='color: blue;'> BlueText </div>");

请参考Qt Rich Text HTML subset

qplaintextedit 更改消息颜色

qt plaintextedit change message color

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