ui->addTab "index out of range" !?

[mrjj]

Hi
I assume you are doing other stuff in your app since it crashes.

Just to be sure, your Qt is not sick.
Can you try test project
https://www.dropbox.com/s/tpyxmww5t98i4um/untitled39.zip?dl=0

[Niagarer]

@Paul-Busovikov
Oh yes, I see, I'm sorry.

[Niagarer]

@mrjj
Yep, it works

Yes, I duplicated an old project. And now the MainWindow sould create a new tab in the tab widget called Graph with an object of my class GraphWidget (QGraphicsView). Nothing else (in the constructor).

[mrjj]

Ok, all good then (with your Qt) :)
It should be no different inserting a QGraphicsView subclass

[Niagarer]

@mrjj
I'm not sure if I understood that correctly...
In the old project GraphWidget is just a normal Widget. Here it is a QGraphicsView. Where is the mattering difference?

[mrjj]

@Niagarer

Its not. 100% the same.
class QGraphicsView : public QAbstractScrollArea
class QAbstractScrollArea : public QFrame
class QFrame : public QWidget

[Niagarer]

@mrjj
Ok... So it is because of the QGraphicsView
And what could I do to fix that?

[Paul Busovikov]

@Niagarer here I see that you add your Widget to vector after you are trying to get one from

//ui->allNodes_scrollArea->setWidget( allNodesWidgets[ui->Graph->currentIndex()] );     // !? PROBLEM !?
    allNodesWidgets.append(allNodesWidget);

[mrjj]

@Niagarer
No, its not due to QGraphicsView.
its something else.

[Niagarer]

@mrjj
Ok >.<
can you give me suggestions what else I could try?

[mrjj]

@Niagarer

Im not really sure "what is not working".
You seem to crash your list when no tab is active
ui->Graph->currentIndex() returns -1 in this case.

Other than that im not sure what you ask?

[Niagarer]

@mrjj
No, yes the list thing was a mistake but the actual problem is still that In this project I event can not do this:

    ui->Graph->addTab(new QPushButton("blobb"),"tab");

And I have no idea why
And exactely this is the line where it crashes
When I do this:

    qDebug() << "first";
    ui->Graph->addTab(new QPushButton("blobb"),"tab");
    qDebug() << "second";

I get is this:

first
ASSERT failure in QVector<T>::operator[]: "index out of range"

[mrjj]

@Niagarer

Is ui->Graph the tabWidget ?
You do call setupUI() in (mainwin) constructor ? to setup ui before use?

Also addTab is the build in func? you did NOT add a new function your self?

[Niagarer]

@mrjj
Yes, the constructor of MainWindow now looks like this:

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    qDebug() << "Start of MainWindow Constructor";

    ui->setupUi(this);

    tabCounter = 0;

    qDebug() << "first";
    ui->Graph->addTab(new QPushButton("blobb"),"tab");
    qDebug() << "second";

    qDebug() << "End of MainWindow Constructor";
}

No I did not build a new addTab()-function
Yes the ui->Graph is the TabGidget

[mrjj]

@Niagarer
Really strange then.
All seems ok.

If you zip and upload project , I can try and see if it crash here

[Niagarer]

@mrjj
Ok, thank you. Give me a minute

[Niagarer]

@mrjj
https://www.dropbox.com/s/so6z2p3otpti2mo/GraphicalProgrammer_3.zip?dl=0

[mrjj]

@Niagarer
Super. Found it

When you insert new tab. A signal is sent (currentChanged)

you catch signal ( its auto connected )
on_Graph_currentChanged(int index)
and then kill yourself with allNodesWidgets[index] as index is 100% surely out of bounds as nothing added to
allNodesWidgets yet.

void MainWindow::on_Graph_currentChanged(int index)
{
ui->allNodes_scrollArea->setWidget( allNodesWidgets[index] ); <<<< this gives the actual error
}

[Niagarer]

@mrjj
Pheww...
Yes, you are right, now it works.
Thanks A LOT man!
Now I can sleep again... >.<

[mrjj]

@Niagarer
:)
Super.
It took 10 secs with breakpoint to find.
If larger program, it would been one of the nasty ones. :)

Good sleep then ;)