CODEWITHSUNDEEP
pythonpyqtpyqt4
storm_to
storm_to

Reputation: 1595

pyqt4 QTextEdit - How to setMaxLength?

I have a multi-line QTextEdit that is tied to database VARCHAR(2048) field.

I want to limit the user entry length to max of 2048 chars

QTextEdit does not have a setMaxLength(int) method like QLineEdit does.

Anyone have any suggestions?

self.editBox = QTextEdit()

Thanks

Upvotes: 3

Views: 8923

Answers (3)

Reza
Reza

Reputation: 41

With thanks to nvd, to keep cursor position in right place:

self.description = QTextEdit()
self.description.textChanged.connect(partial(self.txtInputChanged, self.description, 200))
def txtInputChanged(self, txtInput, maxInputLen):
    text = txtInput.toPlainText()
    if len(text) > maxInputLen:
        cursor = txtInput.textCursor()
        pos = cursor.columnNumber()
        text = text[:pos-1] + text[pos:]
        txtInput.setPlainText(text)
        cursor.setPosition(pos - 1)
        txtInput.setTextCursor(cursor)

Upvotes: 1

nvd
nvd

Reputation: 3381

Using the slot "textChanged()":

txtInput = QPlainTextEdit()

QObject.connect(txtInput, SIGNAL("textChanged()"), txtInputChanged)

def txtInputChanged():
    if txtInput.toPlainText().length() > maxInputLen:
        text = txtInput.toPlainText()
        text = text[:maxInputLen]
        txtInput.setPlainText(text)

        cursor = txtInput.textCursor()
    cursor.setPosition(maxInputLen)
    txtInput.setTextCursor(cursor)

Another possibility is to derive from "QPlainTextEdit" and reimplement the "keyPress" event filtering keys when maximum length is reached or other keys are pressed whose input is not desired.

http://doc.qt.io/qt-5/qplaintextedit.html#keyPressEvent

Upvotes: 0

John Doe
John Doe

Reputation: 3516

I found this FAQ on the Qt Wiki:

There is no direct API to set/get a maximum length of a QTextEdit, but you can handle this yourself by connecting a slot to the contentsChanged() signal and then call toPlainText().length() to find out how big it is. If it is up to the limit then you can reimplement keyPressEvent() and keyReleaseEvent() to do nothing for normal characters.

You may also be interested in this post which has some code attached (hopefully it works for you):

#include <QtCore>
#include <QtGui>
#include "TextEdit.hpp"

TextEdit::TextEdit() : QPlainTextEdit() {
connect(this, SIGNAL(textChanged()), this, SLOT(myTextChanged()));
}

TextEdit::TextEdit(int maxChar) : QPlainTextEdit() {
this->maxChar = maxChar;
connect(this, SIGNAL(textChanged()), this, SLOT(myTextChanged()));
}

int TextEdit::getMaxChar() {
return maxChar;
}

void TextEdit::setMaxChar(int maxChar) {
this->maxChar = maxChar;
}

void TextEdit::myTextChanged() {
if (QPlainTextEdit::toPlainText().length()>maxChar) {
QPlainTextEdit::setPlainText(QPlainTextEdit::toPlainText().left(QPlainTextEdit::toPlainText().length()-1));
QPlainTextEdit::moveCursor(QTextCursor::End);
QMessageBox::information(NULL, QString::fromUtf8("Warning"),
QString::fromUtf8("Warning: no more then ") + QString::number(maxChar) + QString::fromUtf8(" characters in this field"),
QString::fromUtf8("Ok"));
}
}

Upvotes: 3

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