Qt如何实现输入框@联系人的@检测的示例

#ifndef MYEDIT_H
#define MYEDIT_H

#include <QObject>
#include <QTextEdit>
#include <QKeyEvent>

class MyEdit : public QTextEdit
{
    Q_OBJECT
public:
    MyEdit(QWidget *parent);
    
protected:
    //按键事件
    void keyPressEvent(QKeyEvent *e);
};

#endif // MYEDIT_H

#include "myedit.h"
#include <QDebug>

MyEdit::MyEdit(QWidget *parent):
    QTextEdit (parent)
{

}

void MyEdit::keyPressEvent(QKeyEvent *e)
{
    if((e->modifiers() == Qt::ShiftModifier) && (e->key() == Qt::Key_At))
    {
        qDebug()<<"@at";
        append(QKeySequence(e->key()).toString());//或者使用append(e->text());                
        return;
    }
    else {
        QTextEdit::keyPressEvent(e);
    }
}

void MainWindow::on_textEdit_2_cursorPositionChanged()
{
    QTextCursor tc = ui->textEdit_2->textCursor();
    QTextBlock tb = tc.block();
    if(!tb.text().isEmpty())
    {
        QString tx = tb.text();
        if(tx.endsWith("@"))
        {
            qDebug()<<"@at";
        }
    }
}