How to select a QTextEdit paragraph?

Question

Hello everyone and thanks for your time, I need to select a entire and correct paragraph (from dot to dot) on cursorPositionChanged() or selectionChanged() but I can't do it so far using Python + Qt4, I've tried using cursor.position() and cursor.BlockUnderCursor, QString's functions indexOf() and lastIndexOf() to locate the next and previous "dot" to calculate the paragraph section but always fail. Hope you can help me. Regards. LordFord.

Answer 1

Fragment of text from dot to dot is called sentence, not paragraph. Here's a working example (see the comments):

import sys
from PyQt4 import QtCore, QtGui


class Example(QtGui.QTextEdit):

    def __init__(self):
        super(Example, self).__init__()
        self.cursorPositionChanged.connect(self.updateSelection)
        self.selectionChanged.connect(self.updateSelection)
        self.setPlainText("Lorem ipsum ...")
        self.show()

    def updateSelection(self):
        cursor = self.textCursor() # current position
        cursor.setPosition(cursor.anchor()) # ignore existing selection
        # find a dot before current position
        start_dot = self.document().find(".", cursor, QtGui.QTextDocument.FindBackward)
        if start_dot.isNull(): # if first sentence
            # generate a cursor pointing at document start
            start_dot = QtGui.QTextCursor(self.document())
            start_dot.movePosition(QtGui.QTextCursor.Start)
        # find beginning of the sentence (skip dots and spaces)
        start = self.document().find(QtCore.QRegExp("[^.\\s]"), start_dot)
        if start.isNull(): # just in case
            start = start_dot
        # -1 because the first (found) letter should also be selected
        start_pos = start.position() - 1
        if start_pos < 0: # if first sentence
            start_pos = 0
        #find a dot after current position
        end = self.document().find(".", cursor)
        if end.isNull(): # if last sentence
            # generate a cursor pointing at document end
            end = QtGui.QTextCursor(self.document())
            end.movePosition(QtGui.QTextCursor.End)
        cursor.setPosition(start_pos) #set selection start
        #set selection end
        cursor.setPosition(end.position(), QtGui.QTextCursor.KeepAnchor)
        self.blockSignals(True) # block recursion
        self.setTextCursor(cursor) # set selection
        self.blockSignals(False)


def main():
    app = QtGui.QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()