In Qt c QLabel::setText does not work but other fun can work

I wanted to display the specified content in the label (Client::saveData, a static variable),but I couldn't do it anyway. QMessageBox::information works, and qDebug() outputs the correct content, but it just doesn't show up on the label.

void S8524Widget::setTandHLabel()
{
    qDebug() << Client::saveData;

    QMessageBox::information(NULL,"OK","OK");
    ui->tempText->setAlignment(Qt::AlignCenter);
    QString tempdata(Client::saveData.left(2));
    ui->tempText->setText(tempdata);
    //ui->tempText->setProperty("text",tempdata);
    //ui->tempText->setStyleSheet("setProperty: TEST;");
    QString var = ui->tempText->text();

    QString humiditydata(Client::saveData.right(2));
    ui->humidityText->setText(humiditydata);
    QString vae = ui->humidityText->text();

    ui->ProgramNameText->setPlainText(tempdata);
    ui->TimeStatusText->setPlainText(tempdata);
    ui->StepStatusText->setPlainText(tempdata);

    qDebug() << var;
    qDebug() << vae;
}

Client::saveData prints correctly. If I put settext in the constructor, it works fine, but I need it to update the text dynamically. In this function, even setText (“Tempdata”) doesn't work. If you save Ui-> tempText as a variable, calling setText from the mainwindow won't work either.