pyqt4 QTextEdit - 如何设置MaxLength? [英] pyqt4 QTextEdit - How to setMaxLength?

问题描述

我有一个与数据库 VARCHAR(2048) 字段相关联的多行 QTextEdit.

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

我想将用户条目长度限制为最多 2048 个字符

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

QTextEdit 没有像 QLineEdit 那样的 setMaxLength(int) 方法.

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

大家有什么建议吗?

self.editBox = QTextEdit()

谢谢

推荐答案

我发现了 thisQt Wiki 上的常见问题解答:

没有直接的 API 来设置/获取 QTextEdit 的最大长度，但您可以通过将插槽连接到 contentsChanged() 信号，然后调用 toPlainText().length() 找出它有多大.如果达到了限制，那么您可以重新实现 keyPressEvent()和 keyReleaseEvent() 对普通字符不做任何处理.

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.

您可能还对这篇文章感兴趣附有一些代码(希望它对你有用):

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"));
}
}

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