/*文件帧发送定时器信号槽*/
FileSendTimer = new QTimer(this);
connect(FileSendTimer,SIGNAL(timeout()),this,SLOT(File_TimerSend()));

/*
    函   数：File_TimerSend
    描   述：发送文件定时器槽函数
    输   入：无
    输   出：无
*/
void Widget::File_TimerSend(void)
{
    if (FrameCount < FrameNumber)
    {
        serial->write(FileText.mid(FrameCount * FrameLen, FrameLen).toUtf8());
        FrameCount++;
        //更新进度条
        ui->progressBar->setValue(ProgressBarValue += ProgressBarStep);
    }
    else
    {
        if (LastFrameLen > 0)
        {
            serial->write(FileText.mid(FrameCount * FrameLen, LastFrameLen).toUtf8());
            ui->progressBar->setValue(100);
        }
        /*发送完毕*/
        FileSendTimer->stop();
        FrameCount = 0;
        ProgressBarValue = 0;
        FrameNumber = 0;
        LastFrameLen = 0;
        QMessageBox::information(this, "提示", "发送完成");
        ui->progressBar->setValue(0);
        ui->Send_Bt->setText("发送");
    }
}

QString QString::mid(int position, int n = -1) const

Returns a string that contains n characters of this string, starting at the specified position index.

Returns a null string if the position index exceeds the length of the string. If there are less than n characters available in the string starting at the given position, or if n is -1 (default), the function returns all characters that are available from the specified position.

Example:

 QString x = "Nine pineapples";
 QString y = x.mid(5, 4);            // y == "pine"
 QString z = x.mid(5);               // z == "pineapples"

2.5、数据保存

当保存数据按钮按下时，将接收框数据按文本方式进行保存：

/*
    函   数：on_SaveData_Button_clicked
    描   述：保存数据按钮点击槽函数
    输   入：无
    输   出：无
*/
void Widget::on_SaveData_Button_clicked()
{
    QString data = ui->Receive_TextEdit->toPlainText();

    if (data.isEmpty())
    {
        QMessageBox::information(this, "提示", "数据内容空");
        return;
    }

    QString curPath = QDir::currentPath();            //获取系统当前目录
    QString dlgTitle = "保存文件";                     //对话框标题
    QString filter = "文本文件(*.txt);;所有文件(*.*)";  //文件过滤器
    QString filename = QFileDialog::getSaveFileName(this,dlgTitle,curPath,filter);
    if (filename.isEmpty())
    {
        return;
    }
    QFile file(filename);
    if (!file.open(QIODevice::WriteOnly))
    {
        return;
    }

    /*保存文件*/
    QTextStream stream(&file);
    stream << data;
    file.close();
}

/*
    函   数：SerialPortReadyRead_slot
    描   述：readyRead()信号对应的数据接收槽函数
    输   入：无
    输   出：无
*/
void Widget::SerialPortReadyRead_slot()
{
    /*读取串口收到的数据*/
    QByteArray bytedata = serial->readAll();
    
    //......省略
    
    if(ui->HexDisp_checkBox->isChecked() == false)  //ascii显示
    {
        /* 判断编码 */
        QTextCodec::ConverterState state;
        //调用utf8转unicode的方式转码，获取转换结果
        QString asciidata = QTextCodec::codecForName("UTF-8")->toUnicode(bytedata.constData(),bytedata.size(),&state);
        //存在无效字符则是GBK，转码后返回
        if (state.invalidChars > 0) 
        {
            asciidata = QTextCodec::codecForName("GBK")->toUnicode(bytedata);
        } 
        else 
        {
            asciidata = QString(bytedata);
        }
        
        //......省略
    }
    
    //......省略
}