Beginners: how to show main widget after child exits

SherifOmran

Hello guys,

here is a beginner question. I made a widget X (QWidget) and when i click on a button, I create a new QWidget (y). However to save space on the screen, I hide the X window before I show y.

I need to show the x window after y exits. Any Idea?

thanks

JKSH

If y is deleted, you can connect the y's "destroyed()" to X's "show()" slot

SherifOmran

how can i do it?

inside y I wrote this
@
#include "x.h"

X t= new X;
connect(this,this->close(), x, x.show());

@
could you please help me to formulate it?
thanks

[Edit: Added @ formatting tags -- mlong]

JKSH

close() is a slot, not a signal. You want to connect this from outside y:
@
connect(y, SIGNAL(destroyed()), x, SLOT(show()));
@

... but that will only work if y is deleted when it's closed. That means, you need to set this attribute: Qt::WA_DeleteOnClose ...read http://qt-project.org/doc/qt-4.8/qwidget.html#close for more details.

Do you have experience with Qt signals and slots? If not, I recommend following a good beginner's tutorial, such as: http://doc.trolltech.com/4.3/tutorial.html This will help you learn much faster.

SherifOmran

My friend, I am newby but I know signals and slots.

Lets make the task simpler on two steps. When I click on a button in Y form,
I can not show x from inside y.

in y, I have the header #include "x.h"

Should I create a new instance of X
@
x *t = new x
x.show();
@

should I make parent child?

prabuqt

In show() method
this->setVisible(true);

SherifOmran

but this code will be in y and @this@ would refer to y.
Am I right?

To hide x before y loads, I used this.hide() in a x function.

JKSH

Let's make it clearer by calling the classes ParentWidget and ChildWidget.

[quote author="SherifOmran" date="1347214503"]Should I create a new instance of X[/quote]You can create a new instance of the ChildWidget, and destroy it when it closes.
@
ChildWidget *child = new ChildWidget();
child->setAttribute(Qt::WA_DeleteOnClose);
@

[quote author="SherifOmran" date="1347214503"]should I make parent child?[/quote]This is a good idea. If you delete the parent, then Qt will automatically delete the child also. This makes memory-management easier, and helps avoid memory leaks.
@
// Constructor
ChildWidget::ChildWidget(QWidget *parent)
: QWidget(parent)
{
// ...
}
@

@
// Creation, inside ParentWidget
ChildWidget *child = new ChildWidget(this); // Sets "this" as the parent
@

[quote author="SherifOmran" date="1347219741"]but this code will be in y and @this@ would refer to y.
Am I right?

To hide x before y loads, I used this.hide() in a x function.[/quote] You are right -- if your code is in y, "this" refers to y.

However, I would put the code in the parent, not the child. That's because the parent should manage the child; the child should not manage the parent.

I would put this code in ParentWidget:

@
void ParentWidget::createChild()
{
ChildWidget *child = new ChildWidget(this);
child->setAttribute(Qt::WA_DeleteOnClose);

connect(child, SIGNAL(destroyed()), this, SLOT(show()));

child->show();
this->hide();

}
@

SherifOmran

Thank you my friend, i will test and let you know.

SherifOmran

It does not work my friend. When I close the child, the parent is hidden and the software exists.

SherifOmran

I made a slot called reshow and connected the signal child destroyed to it. What i get is that

1- after closing the child window, it comes to the parent reshow slot, ignores the this.show command
2- goes to the parent destroyed function and destroy the parent

may be we need to drop event destroyed of the parent

SherifOmran

I found the solution guys

http://www.thedazzlersinc.com/source/2012/06/04/qt-show-child-window-from-parent-vice-versa/