c++ - QPlainTextEdit - 搜索文档到最后，然后再从头开始

Question

我想在 QPlainTextEdit 中搜索从当前光标到末尾的字符串。如果什么都找不到，我想从头开始继续搜索。只有在这个阶段，如果什么都没有找到，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 setTextCursor(cursor);

• 没有这一行，搜索不会从头/尾继续
• 对于这一行，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。

如何在文档中搜索一个字符串，如果没有找到则不改变当前位置？

---

更新

感谢 IAmInPLS，代码如下所示。 我为 verticalScrollBar 添加了保值。 即便如此，当没有发现生成的内容时，会出现短暂的闪烁:cursor.movePosition(reverse?QTextCursor::End:QTextCursor::Start);

我们怎样才能摆脱它？ 怎样才能看起来像专业的编辑？ 创建另一个不可见的 QPlainTextEdit 元素以在其中进行搜索是一种想法吗？

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，您会将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);
        }
    }
}