QPlainTextEdit - 将文档搜索到末尾，然后从头开始再次搜索

Question

我想在 QPlainTextEdit 中搜索从当前光标到末尾的字符串。如果什么也没找到，我想从头开始继续寻找。仅在这个阶段，如果没有找到任何内容，则会出现一条消息。

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();
        }
    }
}

问题就在

setTextCursor(cursor);

:

• 没有这一行，搜索不会从头/尾继续。
• 使用这一行，一切都很好，除了当找不到字符串时，光标位于文档的开头/结尾，并且用户在文档中的当前位置丢失。

如何在文档中搜索字符串，并且如果没有找到则不更改当前位置？

---

基于这个答案，我为

verticalScrollBar

添加了保值功能。

即便如此，当没有发现任何东西时，也会出现短暂的闪烁：

cursor.movePosition(reverse?QTextCursor::End:QTextCursor::Start);

我们怎样才能摆脱它？创建另一个不可见的 QPlainTextEdit 元素来在其中进行搜索是一个想法吗？

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);
        }
    }
}