qt读取.bin文件，显示在textEdit上，显示速度特别慢

textEdit

->insertPlainText

(*tempStr);会等一会才显示。

void MainWindow::on_openFileButton_clicked()
{
    //get file name
    fileName = QFileDialog::getOpenFileName(this,"Open File",QDir::currentPath());
//    qDebug()<< "fileName is" << fileName;
    ui->filePathLineEdit->setText (fileName);
    if(fileName.isEmpty())
    {
        QMessageBox::information(this,"Error Message", "Please Select a Text File");
        return;
    }
    QFileInfo *pcsfileInfo = new QFileInfo(fileName);
    binSize = pcsfileInfo->size ();

    QFile* file = new QFile;
    file->setFileName(fileName);
    bool ok = file->open(QIODevice::ReadOnly);
    if(ok)
    {
//        QTextStream in(file);
//        ui->textEdit->setText(in.readAll());//read all context from the file
    }
    else
    {
        QMessageBox::information(this,"Error Message", "File Open Error" + file->errorString());
        return;
    }
    QDataStream in(file);
    char * binByte = new char[binSize];
    in.setVersion (QDataStream::Qt_5_9);

    ui->statusBar->showMessage(tr("准备读取数据"));
    in.readRawData (binByte, binSize);      //读出文件到缓存
    ui->statusBar->showMessage(tr("读取数据完毕"));

    tempByte = new QByteArray(binByte, binSize);                //格式转换
    delete[] binByte;
    QString *tempStr = new QString(tempByte->toHex ().toUpper ());
//    ui->textEdit->append(*tempStr);
//    int i;
//    for(i = 0; i < tempStr->size (); i++)
//    {
//        if(i%64 == 0)
//        {
//        QString str1 = tempStr->mid(i,i+64);
//        qDebug("i:%d i+64:%d",i,i+64);
//        ui->textEdit->append(str1);
//        }
//    }
    //显示文件内容
    qint8 cnt = 1;
    qint16 kcnt = 0;
    for(qint64 i = 2; i < tempStr->size ();)
    {
        tempStr->insert (i, ' ');//每个字节之间空一格
        i += 3;
        cnt++;
        if(cnt == 8)//每8个字节空2格
        {
            tempStr->insert (i, ' ');
            i += 1;
        }
        if(cnt == 16)//每16个字节空一格
        {
            cnt = 1;
            kcnt ++;
            if(kcnt == 64)//每64行，即1K数据，空一行
            {
                kcnt = 0;
                tempStr->insert (i, '\n');
                i++;
            }
            tempStr->insert (i, '\n');
            i += 3;         //避免换行后开头一个空格,换行相当于从新插入
        }

    }
    ui->statusBar->showMessage(tr("准备显示"));
    ui->textEdit->insertPlainText (*tempStr);//这句话执行非常慢
    ui->statusBar->showMessage(tr("显示完毕"));

    timer->start(10);

    delete tempStr;

    file->close ();
    delete file;