QML TextEdit get current cursor position

[Anonimista]

I am trying to get cursor row and column in the TextEdit control so I can put that information in the status bar (footer). I am trying to use QTextCursor as I would in Qt Widgets but in my Python slot (CharCounter.cursor.position) I always get 0, 0, as the position

view.qml

import QtQuick
import QtQuick.Controls
import QtQuick.Layouts

import examples.charcounter


ApplicationWindow {

    visible: true
    width: 400
    height:200
    title: "Template App"
    
    CharCounter {
        id: charCounter
    }

    RowLayout {
        
        anchors.fill: parent
            
        TextArea {
        
            id: textArea
        
            text: "Hello Qml!"

            Layout.fillWidth: true
            Layout.fillHeight: true
            
            onTextChanged: {
                charCounter.cursor_position(textDocument)
            }
        }
    }
    
    footer: RowLayout {
        Label {
            id: statusLabel
        }
    }
}

main.py

import sys

from PySide6.QtGui import QGuiApplication, QTextDocument, QTextCursor
from PySide6.QtQml import QQmlApplicationEngine, QmlElement
from PySide6.QtCore import QObject, Slot
from PySide6.QtQuick import QQuickTextDocument


QML_IMPORT_NAME = 'examples.charcounter'
QML_IMPORT_MAJOR_VERSION = 1

@QmlElement
class CharCounter(QObject):
    
    def __init__(self, parent=None):
        super().__init__(parent)
        
    @Slot(QQuickTextDocument)
    def cursor_position(self, textDocument):
        #print(textDocument.textDocument().toPlainText())
        cursor = QTextCursor(textDocument.textDocument())
        print(cursor.blockNumber(), cursor.columnNumber())


if __name__ == '__main__':

    app = QGuiApplication(sys.argv)
    
    engine = QQmlApplicationEngine()
    engine.quit.connect(app.quit)
    engine.load('view.qml')

    result = app.exec()
    del engine
    
    sys.exit(result)

[Bob64]

I see what you are trying to do but I think the issue is that you are creating a new cursor that, according to the documentation, will initialise itself at position (0, 0) of the document. There is no intrinsic cursor position stored in the document itself that the new cursor will acquire.

Meanwhile, presumably the internals of the QML code has its own cursor object that knows where it is within the document.

As for what you want to achieve, I'm afraid I don't see an obvious way to do it. But I am not an expert and maybe someone else will be able to suggest something.

[Anonimista]

@Bob64 Hey thanks! I actually got it to work using TextArea.cursorPosition. Turns out QTextCursor has a setPosition() method so I just set the cursor position immediately after creating it. On the Qml side I had to use onCursorPositionChanged instead of onTextChanged so the label is updated on cursor movement. Here is the full code for reference

main.py

import sys

from PySide6.QtGui import QGuiApplication, QTextCursor
from PySide6.QtQml import QQmlApplicationEngine, QmlElement
from PySide6.QtCore import QObject, Slot
from PySide6.QtQuick import QQuickTextDocument


QML_IMPORT_NAME = 'examples.charcounter'
QML_IMPORT_MAJOR_VERSION = 1

@QmlElement
class CharCounter(QObject):
    
    def __init__(self, parent=None):
        super().__init__(parent)
        
    @Slot(QQuickTextDocument, int, result=list)
    def cursor_position(self, textDocument, cursorPosition):

        cursor = QTextCursor(textDocument.textDocument())
        cursor.setPosition(cursorPosition)
        return (cursor.blockNumber(), cursor.columnNumber())


if __name__ == '__main__':

    app = QGuiApplication(sys.argv)
    
    engine = QQmlApplicationEngine()
    engine.quit.connect(app.quit)
    engine.load('view.qml')

    result = app.exec()
    del engine
    
    sys.exit(result)

view.qml

import QtQuick
import QtQuick.Controls
import QtQuick.Layouts

import examples.charcounter


ApplicationWindow {

    visible: true
    width: 400
    height:200
    title: "Template App"
    
    CharCounter {
        id: charCounter
    }

    RowLayout {
        
        anchors.fill: parent
            
        TextArea {
        
            id: textArea
        
            text: "Hello Qml!"

            Layout.fillWidth: true
            Layout.fillHeight: true
            
            onCursorPositionChanged: {
                let [row, col] =  charCounter.cursor_position(
                    textDocument, cursorPosition)
                statusLabel.text = "row: " + row + 
                    ", col: " + col
            }
        }
    }
    
    footer: RowLayout {
        Label {
            id: statusLabel
        }
    }
}

[Bob64]

I had seen the cursorPosition property but I couldn't see a way to translate that into a row and column position in the document. Your solution seems to do that. Nice!