[SOLVED]Get mainwindows Widgets

toho71

I'm building a desktop application and from a widget that i placed in another widget, reach a label on the mainwindow to change text or color or something.

I've tried to send the ref from thet labelwidget thru the constructor but i cant do anything with it.

Is it the parentwidget etc etc or am I completly wrong.

fluca1978

Not clear what you want to achieve, but QWidget has a method to get its parent. However I don't see the problem on keeping a pointer/reference to the widget somewhere, e.g., in your main window class.

Also "QObject::children()":http://doc.qt.nokia.com/stable/qobject.html#children could be helpful for you.

[EDIT: merged two comments, please edit comments, do not double comment, Volker]

toho71

AFter i pressed a button on my shown widget i want to change the state of a label in the Mainclass.

And i tried to do this just like I do in Java but I got alot of errors in that case

goetz

You should NOT change the label from the button class. Use signal/slots mechanism to notify the main widget class of the requested change. The buttons provide a clicked() signal that you can connect to.

toho71

So this code is Compleatly wrong

Just a little pseudo

On the widgets Button click()
mainwindow->Label->setText("Text I want to setSet")

--

fluca1978

Steps are the following:

connect a signal from your button to a slot of yours
@connect( myButton, SIGNAL(clicked()), this, SLOT(updateLabelSlot()));@
in the slot perform the update of the text
@void MainWindow::updateLabelSlot(){
Label->setText("whatever you want");
}@

toho71

I'm very bad to explain my problem I think.
Bad english

My case

I got a mainwindow with some widgets .
Qlabel Qtab etc etc

On every tab i have diffrent widgets(Qtforms and Classes)
i Instance the Class when i open that tab
and show that widget.

for exampel
On one widget there are ex . 6 buttons with diffrent conditions and when i click a button i want the text on the Label on the mainwindow to append or change the text.

Is the post above the rigth way to handel this case?

I'll give it a try.
//Thomas

goetz

Hi Thomas,

in that case you would connect the buttons' clicked() signals to on or more internal slot(s) of your widget. In that you emit a newly defined signal, e.g. changeLabelText(QString). You then connect that signal to the main window's label.

eg.

@
// --- in the header file for your widgets in the tab
class MyWidget : public QWidget
{
Q_OBJECT

public:
// constructors etc.

signals:
void changeLabelText(const QString &text)

protected slots:
void onButton1Clicked();

};

// --- in the cpp file for your widgets in the tab

MyWidget::MyWidget(QWidget *parent)
: QWidget(parent)
{
// setup your usual stuff here
connect(ui->button1, SIGNAL(clicked()), this, SLOT(onButton1Clicked()));
}

MyWidget::onButton1Clicked()
{
emit changeLabelText("I have clicked on button 1!");
}

// --- in your main widget, where you setup or insert the widgets:

MainWidget::insertTab(MyWidget *widget)
{
tabWidet->addTab(widget, "my widget");
connect(widget, SIGNAL(changeLabelText(QString), label, SLOT(setText(QString)));
}
@

You can ease your life, if you create a base class MyTabContentWidget which does less more than define the signal changeLabelText and subclass your actual widgets from that. This way you have a nice interface to use in your main widget.

toho71

Nice.
I'll try this.
{
It works perfectly
}
Thanks to all