文本颜色 QPlainTextEdit QT

Question

I have class

class plainTextEditor: public QPlainTextEdit
{
    Q_OBJECT
public:
   void setTextColor(const QColor &c); // default function setTextColor(const QColor &c) from QTextEdit
   {
      QTextCharFormat fmt;
      fmt.setForeground(QBrush(c));
      this->mergeCurrentCharFormat(fmt);
   }
};

和：

plainTextEditor *mainText = new plainTextEditor(centralWidget);

我在启动窗口构造函数中使用此代码：

ui->mainText->setTextColor(Qt::red);

但是如果我删除所有文本并再次写入，文本颜色将恢复为黑色。我尝试修复：

connect(ui->mainText, &QPlainTextEdit::textChanged, [this](){
   ui->mainText->setTextColor(Qt::red);
};

但是如果我选择所有文本并粘贴，文本部分颜色为黑色

Answer 1

如果您的目标是简单地设置所有文本的颜色，则可以使用Qt样式表！

下面的示例将背景色更改为黑色，将文本颜色更改为红色：

QPlainTextEdit *edit = new QPlainTextEdit(this);
//StyleSheet here
edit->setStyleSheet("QPlainTextEdit {background-color: black; color: red;}");
edit->appendPlainText("HELLO!");

编辑：不使用样式表：

QPlainTextEdit *edit = new QPlainTextEdit(this);
//Here we are using the HTML capabilities of Qt
//Converting the string using toHtmlEscaped to allow html special characters to be displayed
//Using blockSignals to not generate loop on text manipulation
//Using <pre> tag to allow multiple spaces
connect(edit, &QPlainTextEdit::textChanged, this, [=]{
    const QString plainText = edit->toPlainText().toHtmlEscaped();
    edit->blockSignals(true);
    edit->clear();
    edit->appendHtml("<p style="color:red;white-space:pre">" + plainText + "</p>"
    edit->blockSignals(false);
});
edit->appendPlainText("HELLO!");