[Solved] How to hide and show a mainwindow?

Leon · wrote on 12 Jun 2011, 13:26

So a dialog can be hide with hide(); and can been shown with show();
But what about if it is not a dialog but the mainwindow?
hide(); doesn't hide my mainwindow....

NarutoUzumakis · wrote on 12 Jun 2011, 16:39

why would you want to hide your mainwindow at all??can you be more specific

loladiro · wrote on 12 Jun 2011, 16:44

I just tried it out, hide() hides my MainWindow. Are you reimplementing the event() method?

sfilippidis · wrote on 12 Jun 2011, 18:57

[quote author="Leon" date="1307885217"]So a dialog can be hide with hide(); and can been shown with show();
But what about if it is not a dialog but the mainwindow?
hide(); doesn't hide my mainwindow....[/quote]

How (eg: by using a push button?) and why do you plan to hide the main window? How and why do you plan to re-display the main window?

Leon · wrote on 13 Jun 2011, 07:47

My app pops app a dialog and from there you can take a screenshot. And it has the ability to hide the dialog and after the screenshot has been take show it again. But i also want to hide the mainwindow..

So at the mainwindow hide(); doesn't hide the window.. What's wrong?

Eddy · wrote on 13 Jun 2011, 08:40

Using hide() should work on QMainwindow.

I just tested it to be sure since i never needed this.

So there must be something else going on
I suggest you make a minimal compilable example that reproduces your problem or show us the relevant code.

Leon · wrote on 13 Jun 2011, 09:12

It must be a bug of Ubuntu 11.04 again...

As for an example... Putting hide(); at the constructor of the mainwindow.cpp won't hide the window...

sfilippidis · wrote on 13 Jun 2011, 09:14

[quote author="Leon" date="1307951240"]My app pops app a dialog and from there you can take a screenshot. And it has the ability to hide the dialog and after the screenshot has been take show it again. But i also want to hide the mainwindow..

So at the mainwindow hide(); doesn't hide the window.. What's wrong?[/quote]

Just a guess: maybe you are calling hide() method/function of the wrong object (ie: not for the main window) by accident? Check it! ;-)

Eddy · wrote on 13 Jun 2011, 09:25

try to use hide in your main()

there you make an instance of your mainwindow class and you hide that instance.

jim_kaiser · wrote on 13 Jun 2011, 09:28

bq. As for an example… Putting hide(); at the constructor of the mainwindow.cpp won’t hide the window…

I suspected that's what you were doing. I don't think that should be expected to work. Although, the QMainWindow is constructed by then, i think you should try it after the construction of the MainWindow object is complete. Also, are you saying that the main window is shown without calling show()? Because you call hide() in the MainWindow constructor, where do you call show?

Eddy · wrote on 13 Jun 2011, 09:34

could you make an new widget based Qt project, choose a QMainwindow as class and use the following code in your main.

like this :
@int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();

QTimer timer;

timer.singleShot(1000, &w, SLOT(hide()));

return a.exec&#40;&#41;;

}@

normally this should work unless you have other issues.

Eddy · wrote on 13 Jun 2011, 09:38

@jim_kaiser
it is possible to use hide() in the constructor of a QMainwindow class.
I tested it using a singleshot timer too.

you're right asking where Leon uses his show() function, probably this one is called after the hide() function.

jim_kaiser · wrote on 13 Jun 2011, 09:54

@eddy

Thanks for the clarification about the hide() in the constructor. Assumed there might be events from the desktop which the main windows reacts to after the construction and just thought its a bit iffy.

giesbert · wrote on 13 Jun 2011, 10:33

Hi,

by default each widget is hiodden, unless it has a visible parent. So hide in the constructorn is not needed. But mostly, the main contains a show call, remove that and it is hidden.

Eddy · wrote on 13 Jun 2011, 10:49

Hi Gerolf,

You're right it's hidden unless you show it first.

But what Leon wants is to use a mainwindow and click a button to hide it. Hiding seems not to work on his system. That's why i suggested to use a minimal working example because we don't have code to look at.

Leon · wrote on 13 Jun 2011, 12:29

Ok so probably it was wrong to put hide(); at the constructor.. Putting it in a void function will work..
I made an example that hides both the dialog and the mainwindow :) ("Link":http://dl.dropbox.com/u/11379868/hideExample.zip)

Eddy · wrote on 13 Jun 2011, 13:20

so you have solved it?
if so, please add [Solved] in your title

Leon · wrote on 13 Jun 2011, 13:40

Done :)

Eddy · wrote on 13 Jun 2011, 16:44

Stripping down a problem to it's essential is a good way of discovering solutions, isn't it?

Have fun Qt programming

amin · wrote on 18 Aug 2012, 22:49

sorry but I can`t download the zip file you,Eddy,have posted ,if possible please paste the required code just right here!!!,Plz ;)