PyQt - sellectAll 然后退格键删除不起作用

Question

我有一个文本编辑器，可以将拉丁键盘按键转换为俄语字符。我重新实现了 QTextEdit 类：

class MyTextEdit(QTextEdit):
def __init__(self, *args):
    QTextEdit.__init__(self, *args)

leftMousePressedSignal = pyqtSignal(QPoint)
rightMousePressedSignal = pyqtSignal(QPoint, QEvent)
mouseMovedSignal = pyqtSignal(QPoint)
mouseDoubleClickedSignal = pyqtSignal(QPoint)
keyPressedSignal = pyqtSignal(QEvent)

def mousePressEvent(self, event):
    pos = event.pos()
    if event.button() == Qt.LeftButton:
        self.leftMousePressedSignal.emit(pos)
    elif event.button() == Qt.RightButton:
        self.rightMousePressedSignal.emit(pos, event)

def mouseMoveEvent(self, event):
    if event.buttons() & Qt.LeftButton:
        pos = event.pos()
        self.mouseMovedSignal.emit(pos)

def mouseDoubleClickEvent(self, event):
    if event.button() == Qt.LeftButton:
        pos = event.pos()
        self.mouseDoubleClickedSignal.emit(pos)

def keyPressEvent(self, event):
    if event.type() == QEvent.KeyPress:
        self.keyPressedSignal.emit(event)

然后将其与重新实现的 keyPressEvent 一起使用。因此，我还必须重新实现 Backspace 操作：

    self.textEdit = MyTextEdit(self)
    ...
    self.textEdit.keyPressedSignal.connect(self.OnKeyPressed)
    self.actionSelectAll.triggered.connect(self.textEdit.selectAll)
    ...

def OnKeyPressed(self, event):
    key = event.key()
    txt = str(event.text())
    if key == Qt.Key_Backspace:
        if self.cursor.hasSelection():
            self.cursor.movePosition(QTextCursor.NoMove, QTextCursor.KeepAnchor, self.cursor.selectionStart() - self.cursor.selectionStart())
        else:
            self.cursor.movePosition(QTextCursor.PreviousCharacter, QTextCursor.KeepAnchor, 1)
        self.textEdit.setTextCursor(self.cursor)
        self.textEdit.cut()
    elif key == Qt.Key_A and (event.modifiers() & Qt.ControlModifier):
        self.textEdit.selectAll()

现在，如果未选择任何内容并按 Backspace，它会删除光标左侧的单个字符。当用鼠标选择一个单词并按 Backspace 时，它​​会删除该单词。当用鼠标选择几个单词或整个文本并按 Backspace 时，它​​会删除整个选择。所以，它工作得很好。当我按下“全选”按钮（或 Ctrl+A）时，它会选择整个文本。但如果我随后按 Backspace，它只会删除光标左侧的 1 个字符，而不是整个文本。

如果您能告诉我我在这里做错了什么，我将不胜感激。谢谢。

Answer 1

为什么要重新实现选择和删除行为，以及为什么 MyTextEdit 中没有这样做？如果你只需要

将拉丁键盘按键转换为俄语字符

您只能执行此转换，并让 QTextEdit 进行其他工作（选择、删除、复制等）。

我会这样写：

class TransliterationEdit(QTextEdit):
    latin_alphabet = unicode(string.ascii_letters)  # or dict with transliteration table

    def translateLetter(self, letter):
        return u'Ъ'  # just example, you need translate letter somehow

    def keyPressEvent(self, event):
        text = unicode(event.text())
        if text and text in self.latin_alphabet:
            self.insertPlainText(self.translateLetter(text))
            event.ignore()
        else:
            QTextEdit.keyPressEvent(self, event)

更新

这是我对TextEdit的粗略实现，它将拉丁按键转换为俄语字符，希望它会有所帮助。

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys
from PyQt4.QtGui import *
from transliterator import SMTransliterator
# transliterator available at https://gist.github.com/1600988


class TransliterationEdit(QTextEdit):

    def __init__(self, *args, **kwargs):
        QTextEdit.__init__(self, *args, **kwargs)
        self._transliterator = SMTransliterator()

    def keyPressEvent(self, event):
        text = unicode(event.text())

        if not self._transliterator.add_letter(text):
            if text and self._transliterator.result:
                self.insertPlainText(self._transliterator.result)
            return QTextEdit.keyPressEvent(self, event)

        if self._transliterator.need_next:
            return  # skip it

        self.insertPlainText(self._transliterator.result)


if __name__ == '__main__':      
    app = QApplication(sys.argv)
    window = TransliterationEdit()
    window.show()
    sys.exit(app.exec_())

音译器位于 gist