可编辑的多色QLineEdit

1 回答

• 4

  我最后通过跟踪光标位置，最后一个选择开始和长度以及最后一个文本大小来实现它 . 当发出 textEdited() 信号时，我使用它们来确定插入和/或删除的文本，然后重放颜色数组中的插入和/或删除，以便将其同步到文本 .

  您可以指定用于用户插入的文本的颜色 . 如果未指定，将使用系统默认值，具体取决于系统主题 .

  唯一的问题是 it doesn't support Undo ，因为我不知道如何区分 textEdited() 信号是否是由撤销操作引起的 .

  ---

  ColorLineEdit.h

  #ifndef COLORLINEEDIT_H
  #define COLORLINEEDIT_H
  
  #include <QLineEdit>
  
  class ColorLineEdit : public QLineEdit
  {
      Q_OBJECT
  public:
      explicit ColorLineEdit(QWidget *parent = 0);
      void setCharColors(const QList<QColor> &colors = QList<QColor>());
      void setColorForInsertedText(const QColor &colorForInsertedText) { this->colorForInsertedText = colorForInsertedText; }
  
  signals:
  
  private slots:
      void onSelectionChanged();
      void onTextEdited(const QString &text);
  
  private:
      int lastTextSize;
      QList<QColor> colors;
      QColor colorForInsertedText;
      int lastSelectedTextSize;
      int lastSelectionStart;
  };
  
  #endif // COLORLINEEDIT_H
  

  ColorLineEdit.cpp

  #include "colorlineedit.h"
  #include <QTextLayout>
  
  ColorLineEdit::ColorLineEdit(QWidget *parent) :
      QLineEdit(parent)
  {
      connect(this, SIGNAL(selectionChanged()), SLOT(onSelectionChanged()));
      connect(this, SIGNAL(textEdited(QString)), SLOT(onTextEdited(QString)));
      lastSelectedTextSize = 0;
      lastSelectionStart = -1;
      lastTextSize = 0;
  }
  
  void ColorLineEdit::setCharColors(const QList<QColor> &colors)
  {
      // See http://stackoverflow.com/questions/14417333/how-can-i-change-color-of-part-of-the-text-in-qlineedit.
      QList<QInputMethodEvent::Attribute> attributes;
      int size = colors.size();
      attributes.reserve(size);
      for (int ii = 0; ii < size ; ii++) {
          if (colors[ii].isValid()) {
              QTextCharFormat charFormat;
              charFormat.setForeground(QBrush(colors[ii]));
              const int start = ii - cursorPosition();
              const int length = 1;
              attributes.append(QInputMethodEvent::Attribute(QInputMethodEvent::TextFormat, start, length, charFormat));
          }
      }
  
      QLineEdit::inputMethodEvent(&QInputMethodEvent(QString(), attributes));
  
      lastTextSize = text().size();
      this->colors = colors;
  }
  
  void ColorLineEdit::onSelectionChanged()
  {
      lastSelectionStart = selectionStart();
      lastSelectedTextSize = selectedText().size();
  }
  
  void ColorLineEdit::onTextEdited(const QString &text)
  {
      if (!lastSelectedTextSize) {
          // We don't have a selection, so it's either
          // an insertion or deletion, but not both.
          int delta = text.size() - lastTextSize;
          if (delta > 0) {
              // User has inserted text.
              int pos = cursorPosition() - delta;
              for (int ii = 0; ii < delta; ii++) {
                  colors.insert(pos, colorForInsertedText);
              }
          } else {
              // User has erased text.
              int pos = cursorPosition();
              colors.erase(colors.begin() + pos, colors.begin() + pos - delta);
          }
      } else {
          // There was a selection, so we have both removed
          // and inserted text.
          int pos = lastSelectionStart;
          int removedCount = lastSelectedTextSize;
          int insertedCount = cursorPosition() - pos;
          colors.erase(colors.begin() + pos, colors.begin() + pos + removedCount);
          for (int ii = 0; ii < insertedCount; ii++) {
              colors.insert(pos, colorForInsertedText);
          }
      }
  
      setCharColors(colors);
  }
  

  Sample usage

  #include "colorlineedit.h"
  #include <QApplication>
  
  int main(int argc, char *argv[])
  {
      QApplication a(argc, argv);
  
      ColorLineEdit lineEdit;
      QList<QColor> colors;
      colors.append(Qt::red);
      colors.append(Qt::red);
      colors.append(Qt::red);
      colors.append(Qt::red);
      lineEdit.setText("abcd");
      lineEdit.setColorForInsertedText(Qt::blue);
      lineEdit.setCharColors(colors);
      lineEdit.show();
  
      return a.exec();
  }
  

  

  

  :)

  回复于 2024-04-28T05:17:35+08:00