find child control

sashapont

I create QTextEdit dynamically and what to get it next, but have app crash& Please told me where is error?

 QTextEdit *O1Date= new QTextEdit("10.06.2016");
 O1Date->setObjectName("O1Date");
 QGraphicsScene *scene = new QGraphicsScene;
              QGraphicsProxyWidget *proxy = new QGraphicsProxyWidget();
              proxy->setWidget(O1Date);
 scene->addItem(proxy);
 ui->graphicsView->setScene(scene);

And then
QTextEdit* O1Date1 = ui->graphicsView->findChild<QTextEdit*>("O1Date");

Joel Bodenmann

Where exactly crashes your application? Did you check the pointer returned by findChild() before you access/use it?

sashapont

Yes^ it is not accessible....

Joel Bodenmann

I just checked the documentation. I'm not an expert so please don't take what I'm saying for granted...
First of all, QGraphicsView::setScene() doesn't make the scene become a child of the QGraphicsView. Also, QGraphicsProxyWidget::setWidget() doesn't make the widget become a child of QGraphicsProxyWidget. Hence you will never find your widget by calling findChild() on your view.

So either you store a pointer to your QTextEdit widget yourself or you use QGraphicsProxyWidget::widget() to access it.

Again: I might be wrong and there might be a better/proper solution to this.

VRonin

The problem here is you do not give a parent to O1Date
QTextEdit *O1Date= new QTextEdit("10.06.2016");
should become
QTextEdit *O1Date= new QTextEdit("10.06.2016",ui->graphicsView);

Joel Bodenmann

@VRonin said:

The problem here is you do not give a parent to O1Date

Well, look at that. I missed the obvious solution...

sashapont

@VRonin said:

should become
QTextEdit *O1Date= new QTextEdit("10.06.2016",ui->graphicsView);

In this case i cannot rotate it in graphic view :(

kshegunov · should become QTextEdit *O1Date= new QTextEdit("10.06.2016",ui->graphicsView);

@sashapont
Tracing the inheritance tree, I'd look for the text edit in the scene, not in the view.

QTextEdit *O1Date= new QTextEdit("10.06.2016");
O1Date->setObjectName("O1Date");
QGraphicsScene *scene = new QGraphicsScene;
QGraphicsProxyWidget *proxy = new QGraphicsProxyWidget();
proxy->setWidget(O1Date);
scene->addItem(proxy);
 ui->graphicsView->setScene(scene);

Then:

ui->graphicsView->scene()->findChild<QTextEdit *>("O1Date");

In any case I'd think the most simplest solution is to just keep a pointer to your item. E.g.

QPointer<QTextEdit> O1Date; //< This goes into the header file

O1Date = new QTextEdit("10.06.2016"); //< This goes into the source file

EDIT:
Although the scene uses it's own child tree as can be seen here.

sashapont

@kshegunov said:

ui->graphicsView->scene()->findChild<QTextEdit *>("O1Date");

Not working :( app crashes

kshegunov

@sashapont

ui->graphicsView->scene()

Did you make sure this is not NULL?

sashapont

I see textedit, and that rotated^ that scene is not NULL

kshegunov

@sashapont
I'm sorry I don't follow. Do you mind uploading a screen shot and a stack trace of the crash. Also the exact type of the crash would be helpful.

sashapont

Thats all project
untitled

kshegunov

@sashapont
Your app crashes because you don't handle the case when the line edit is not found.

QTextEdit * O1Date1 = ui->graphicsView->scene()->findChild<QTextEdit *>("O1Date");

is NULL and you're directly calling:

O1Date1->setText("");

Which brings me to my original point - use a pointer to your widget instead of recursively searching through the object tree.

sashapont

@kshegunov said:

QPointer<QTextEdit> O1Date;

When I try to write that in header file i have error

implicit instantiation of undefined template 'QPointer<QTextEdit>'
QPointer<QTextEdit> O1Date;
^

I try to use static variables in header and it works thank you!

But i have new issue
Now i can set value to the text edit^ And in qDebug I see that it set, but in control i see old value... How i can redraw that?

kshegunov

@sashapont said:

implicit instantiation of undefined template 'QPointer<QTextEdit>'

Have you forgotten to include the appropriate header? That is:

#include <QPointer>

Now i can set value to the text edit^ And in qDebug I see that it set, but in control i see old value... How i can redraw that?

Issue an update request to the graphics view:

 ui->graphicsView->update();

Although, I believe it the change of data should be reflected automatically.