在 PyQt5 的 QTreeWidget 中使用 QTextCursor

Question

I would like to underline something in a QTreeWidget with a red wave like this:

I tried to pull this off with a QTextCursor but apparently it's not possible. Anyone knows another way?

As an exemple, here is a way to underline a word with QTextCursor:

import sys
from PyQt5.QtCore import *
from PyQt5 import QtWidgets, QtGui, uic

def drawGUI():
    app = QtWidgets.QApplication(sys.argv)
    w = QtWidgets.QWidget()
    editBox = QtWidgets.QTextEdit(w)
    text = 'THE_WORD'
    editBox.setText(text)

    cursor = editBox.textCursor()
    format_ = QtGui.QTextCharFormat()
    format_.setUnderlineStyle(QtGui.QTextCharFormat.WaveUnderline)
    regex = QRegExp('\\bTHE_WORD\\b')
    index = regex.indexIn(editBox.toPlainText(), 0)
    cursor.setPosition(index)
    cursor.movePosition(QtGui.QTextCursor.EndOfWord, 1)
    cursor.mergeCharFormat(format_)

    w.show()
    sys.exit(app.exec_())

if __name__ == '__main__':
    drawGUI()

Answer 1

There are probably several ways to accomplish this. One way is with a custom delegate.

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QTreeWidget, QTreeWidgetItem, QApplication, QStyledItemDelegate


class CustomDelegate(QStyledItemDelegate):
    def paint(self, painter: QtGui.QPainter, option: QtWidgets.QStyleOptionViewItem, index: QtCore.QModelIndex):
        options = QtWidgets.QStyleOptionViewItem(option)
        self.initStyleOption(options, index)
        if options.text != 'THE_WORD':
            return super().paint(painter, option, index)
        doc = QtGui.QTextDocument(options.text)
        format_ = QtGui.QTextCharFormat()
        format_.setUnderlineStyle(QtGui.QTextCharFormat.WaveUnderline)
        format_.setUnderlineColor(QtCore.Qt.red)
        cursor = doc.find(options.text)
        cursor.movePosition(QtGui.QTextCursor.Start, QtGui.QTextCursor.MoveAnchor)
        cursor.selectionStart()
        cursor.movePosition(QtGui.QTextCursor.End, QtGui.QTextCursor.KeepAnchor)
        cursor.selectionEnd()
        cursor.setCharFormat(format_)
        painter.save()
        painter.translate(option.rect.x(), option.rect.y())
        doc.setDocumentMargin(0)  # The text will be misaligned without this.
        doc.drawContents(painter)
        painter.restore()


app = QApplication(sys.argv)
w = QTreeWidget()
delegate = CustomDelegate(w)
w.setItemDelegate(delegate)
w.resize(300, 100)
w.setColumnCount(3)
w.addTopLevelItem(QTreeWidgetItem(['Foo', 'THE_WORD', 'Bar']))

w.show()
sys.exit(app.exec_())