QLineEdit can't update inside QStackedWidget

[lwz]

While a QStackedWidget adds several widgets , QLineEdit inside the QStackedWidget can't update .
Is that a QStackedWidget bug or I miss something ?
please help.

[anda_skoa]

What do you mean with "can't update"?

If you set a text it doesn't change?
You can't type into it?

Cheers,
_

[lwz]

I can type into it ,but it fail when I use setText().

[anda_skoa]

Very strange.

Just to be sure: you are calling setText() on the correct line edit, right? I.e. there is no other line edit than the one being displayed.

Can you create a minimal example that shows the problem?

Cheers,
_

[lwz]

It works well in a minimal example , but it doesn't within my code .
In my code , it is ok when the stackedwidget adds no more than 5 widgets.. When up to 6, 7,,it fails sometimes.
It definitely goes wrong with more than 8 widgets(Eache of these widgets contains about 20 qwidgets,llike button,qlineedit ,qdoublespinbox etc.).

[Lesiok]

How You recognize which QLineEdit should be updated ? Show some code.

[lwz]

Thansands of lines ,,,minimal example can't make it goes wrong.

[wysota]

Show us code where you initialize widgets in the stacked view and how you later try to call setText() on the proper line edit.

[lwz]

if I have initialized widgets in a wrong way , how can it work just fine when adding 3 or 4 widgets?

---

Added after 16 minutes:

This a slice of my code

QStackedWidget *TraceConfigDialog::buildStackedWidget()
{
    QStackedWidget *stackedWidget = new QStackedWidget();
    stackedWidget->addWidget(linearGroupBox());
 
    stackedWidget->addWidget(fillingGroupBox());
#if 1     // here if I put this "#if 1" on the 5th line , qlineedit can't update , actually all widgets inside the stacedwidget can't update.
    stackedWidget->addWidget(imageGroupBox());
    stackedWidget->addWidget(textGroupBox());
    stackedWidget->addWidget(logGroupBox());
    stackedWidget->addWidget(waveGroupBox());
    stackedWidget->addWidget(depthGroupBox());
    stackedWidget->addWidget(timeGroupBox());
    stackedWidget->addWidget(tadpoleGroupBox());
#endif 
   return stackedWidget;
}
 
void inti()
{
   vlayout=new QVBoxLayout();
    vlayout->addWidget(listWidget);
    vlayout->addWidget(curveStyleLabel);
    vlayout->addWidget(curveStyle);
 
 
    layout=new QHBoxLayout();
    layout->addLayout(vlayout);
 
    stackedWidget = buildStackedWidget();     // <----
    m_rightLayout = new QVBoxLayout();
    m_rightLayout->addWidget(stackedWidget,10);
 
    layout->addLayout(m_rightLayout);
    layout->addStretch();
 
    widget->setLayout(layout);
}
 
    QPushButton *recommendButton = new QPushButton(tr("Recommend Value"));
    connect(recommendButton,SIGNAL(clicked()),this,SLOT(handleRecommendValue()));
 
void TraceConfigDialog::handleRecommendValue()
{
 
        m_linearLeftValue->setText("testest); // <--- m_linearLeftValue is a QLineEdit
        m_linearLeftValue->update();
        stackedWidget->update();
}

QStackedWidget *TraceConfigDialog::buildStackedWidget()
{
    QStackedWidget *stackedWidget = new QStackedWidget();
    stackedWidget->addWidget(linearGroupBox());

    stackedWidget->addWidget(fillingGroupBox());
#if 1     // here if I put this "#if 1" on the 5th line , qlineedit can't update , actually all widgets inside the stacedwidget can't update.
    stackedWidget->addWidget(imageGroupBox());
    stackedWidget->addWidget(textGroupBox());
    stackedWidget->addWidget(logGroupBox());
    stackedWidget->addWidget(waveGroupBox());
    stackedWidget->addWidget(depthGroupBox());
    stackedWidget->addWidget(timeGroupBox());
    stackedWidget->addWidget(tadpoleGroupBox());
#endif 
   return stackedWidget;
}

void inti()
{
   vlayout=new QVBoxLayout();
    vlayout->addWidget(listWidget);
    vlayout->addWidget(curveStyleLabel);
    vlayout->addWidget(curveStyle);


    layout=new QHBoxLayout();
    layout->addLayout(vlayout);

    stackedWidget = buildStackedWidget();     // <----
    m_rightLayout = new QVBoxLayout();
    m_rightLayout->addWidget(stackedWidget,10);

    layout->addLayout(m_rightLayout);
    layout->addStretch();

    widget->setLayout(layout);
}

    QPushButton *recommendButton = new QPushButton(tr("Recommend Value"));
    connect(recommendButton,SIGNAL(clicked()),this,SLOT(handleRecommendValue()));

void TraceConfigDialog::handleRecommendValue()
{

        m_linearLeftValue->setText("testest); // <--- m_linearLeftValue is a QLineEdit
        m_linearLeftValue->update();
        stackedWidget->update();
}

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The QLineEdit is inside linearGroupBox() , which return a QGroupBox. And there is a QPushButton inside the linearGroupBox()

[Lesiok]

Where m_linearLeftValue is initialized ? I think that it is initialized many times.
P.S.
TraceConfigDialog::handleRecommendValue() should look like :

void TraceConfigDialog::handleRecommendValue()
{
m_linearLeftValue->setText("testest); //m_linearLeftValue is a QLineEdit
}

void TraceConfigDialog::handleRecommendValue()
{
m_linearLeftValue->setText("testest); //m_linearLeftValue is a QLineEdit
}

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[lwz]

I know the two lines in handleRecommendValue() is useless.

Speaking of initializing, I do have the stackedwidget initialized many times, because I found it couldn't update. However, I have not found this trick back then, it was related to stackedwidegt' adding widgets.

[anda_skoa]

Your comment for the #if 1 doesn't make sense, i.e. it doesn't matter where you put it because everything between it and #endif will be part of the compiled source code.

foo();
#if 1
bar();
#endif

foo();
#if 1
bar();
#endif

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and

#if 1
foo();
bar();
#endif

#if 1
foo();
bar();
#endif

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result in exactly the same code after preprocessing.

Cheers,
_

[lwz]

anda_skoa, thanks for your replay.
I get what you mean , it was #if 0 when I tested how many widgets to be added would cause that problem.

[ChrisW67]

Where is m_linearLeftValue initialised?