QPlainTextEdit-搜索文档到底，然后从头开始

Question

我想在QPlainTextEdit中搜索从当前光标到末尾的字符串。如果什么都没有找到，我想从一开始就继续搜索。只有在这个阶段，如果什么都没找到，就会出现一条消息。这是代码：

void BasicEdit::findString(QString s, bool reverse, bool casesens, bool words) {
QTextDocument::FindFlags flag;
if (reverse) flag |= QTextDocument::FindBackward;
if (casesens) flag |= QTextDocument::FindCaseSensitively;
if (words) flag |= QTextDocument::FindWholeWords;
QTextCursor cursor = this->textCursor();
if (!find(s, flag)) {
//nothing is found | jump to start/end
cursor.movePosition(reverse?QTextCursor::End:QTextCursor::Start);
setTextCursor(cursor); //!!!!!!
if (!find(s, flag)) {
//no match in whole document
QMessageBox msgBox;
msgBox.setText(tr("String not found."));
msgBox.setStandardButtons(QMessageBox::Ok);
msgBox.setDefaultButton(QMessageBox::Ok);
msgBox.exec();
}
}
}

问题是线路setTextCursor(cursor);

• 如果没有此行，搜索将不会从头/尾继续
• 有了这一行，一切都很好，只是当找不到字符串时，光标位于文档的开头/末尾，并且用户在文档中的当前位置丢失了

如何在文档中搜索字符串，并且在没有找到字符串的情况下不更改当前位置？

---

更新

多亏了IAmInPLS，代码如下所示。我为垂直滚动条增加了保值功能。即便如此，当cursor.movePosition(reverse?QTextCursor::End:QTextCursor::Start);未生成任何内容时，仍会出现短暂闪烁

我们怎样才能摆脱它？怎么看起来像一个专业的编辑？创建另一个不可见的QPlainTextEdit元素在其中搜索是一个想法吗？

void BasicEdit::findString(QString s, bool reverse, bool casesens, bool words)
{
QTextDocument::FindFlags flag;
if (reverse) flag |= QTextDocument::FindBackward;
if (casesens) flag |= QTextDocument::FindCaseSensitively;
if (words) flag |= QTextDocument::FindWholeWords;
QTextCursor cursor = this->textCursor();
// here we save the cursor position and the verticalScrollBar value
QTextCursor cursorSaved = cursor;
int scroll = verticalScrollBar()->value();
if (!find(s, flag))
{
//nothing is found | jump to start/end
cursor.movePosition(reverse?QTextCursor::End:QTextCursor::Start);
setTextCursor(cursor);
if (!find(s, flag))
{
// word not found : we set the cursor back to its initial position and restore verticalScrollBar value
setTextCursor(cursorSaved);
verticalScrollBar()->setValue(scroll);
QMessageBox msgBox(this);
msgBox.setText(tr("String not found."));
msgBox.setStandardButtons(QMessageBox::Ok);
msgBox.setDefaultButton(QMessageBox::Ok);
msgBox.exec();
}
}
}

Answer 1

这个想法是在开始搜索单词之前，保持光标的位置。然后，在研究之后，您将把光标设置回您保存的位置。

void BasicEdit::findString(QString s, bool reverse, bool casesens, bool words) 
{
QTextDocument::FindFlags flag;
if (reverse) flag |= QTextDocument::FindBackward;
if (casesens) flag |= QTextDocument::FindCaseSensitively;
if (words) flag |= QTextDocument::FindWholeWords;
QTextCursor cursor = this->textCursor();
// here , you save the cursor position
QTextCursor cursorSaved = cursor;
if (!find(s, flag)) 
{
//nothing is found | jump to start/end
cursor.movePosition(reverse?QTextCursor::End:QTextCursor::Start);
/* following line :
- the cursor is set at the beginning/end of the document (if search is reverse or not)
- in the next "find", if the word is found, now you will change the cursor position
*/ 
setTextCursor(cursor);
if (!find(s, flag)) 
{
//no match in whole document
QMessageBox msgBox;
msgBox.setText(tr("String not found."));
msgBox.setStandardButtons(QMessageBox::Ok);
msgBox.setDefaultButton(QMessageBox::Ok);
msgBox.exec();
// word not found : we set the cursor back to its initial position
setTextCursor(cursorSaved);
}
}
}