QStackedLayout / QStackedWidget

[morraine]

Hello Jacek, Thanks for your reply.

It sounds like a QStackedLayout / QStackedWidget Class with optional page load and delete, memory management needs developing and adding to the qt class libary.

Do you know how i would go about creating a manager which could add and delete pages on the fly from a stacked widget. Or even add and delete a stacked widget on the fly seeing as i can put unlimited children into a parent stacked widget?

this would be a great function as opening up all the GUI pages for a complex ERP application would just have the computer running like trying to run vista ultimate on a Pentium 2 especially if the end users will be using the cheapest and greenest commodity computer gear

[jacek]

It sounds like a QStackedLayout / QStackedWidget Class with optional page load and delete, memory management needs developing and adding to the qt class libary.

But Qt isn't going to know when to delete your page nor when and how to create new ones.

Do you know how i would go about creating a manager which could add and delete pages on the fly from a stacked widget.

First of all you have to know how your application is going to know when to create a new page, which page it should be and when to delete it. You should end up with an interface for the manager class. This is an architectural decision. You have to think it through and maybe even construct a simple prototype to know exactly how your GUI is going to work. It reminds me of SAP's screens and their codes.

Qt part of the implementation should be pretty easy, since Qt provides you with proper methods for inserting and removing pages, but the factory might be a bit tricky.

Or even add and delete a stacked widget on the fly seeing as i can put unlimited children into a parent stacked widget?

The question is: do you really need nested stacked widgets? Maybe you need the "managed" version only for top-level pages?

[morraine]

The question is: do you really need nested stacked widgets? Maybe you need the "managed" version only for top-level pages?

the reason i said if it was possible to add and remove QStacked Widgets is because architectural i could group pages together so that say guys in the sales department will have 5 pages they use all the time and the accounts department may have 6 different pages they use all the time.

OK when i said that there should be a Stacked widget class for adding and deleting pages on the fly i was referring to the methods that are in it all ready (or lack there of). because the remove Widget() method does not actually delete the widget from memory.

Unless you know of a method to Delete the Widget from memory not in this class?

programmatically in know that i have to tell qt to add and delete when its needed some time i probably would not delete the widget and leave it in memory. it just depends on the situation.

But im new to QT and i was not sure of a way to add and delete pages from Qstacked Widgets programmatically in the way i design the application.

Excuse my ignorance but what do you mean by a factory?

[jacek]

i could group pages together so that say guys in the sales department will have 5 pages they use all the time and the accounts department may have 6 different pages they use all the time.

OK. You can hardcode that or you can devise some mechanism that will allow users to choose what they need, but this really depends on how you plan to expand your application.

because the remove Widget() method does not actually delete the widget from memory.

Yes, removeWidget() just removes the widget from the layout. To delete it you have to use the delete operator.

Excuse my ignorance but what do you mean by a factory?

It's an object which knows how to create other objects. If you had a page factory, then if you would need to show some page, the manager class could check if such page exists and show it or ask the factory to create it.

[morraine]

Jacek thanks for your help on this mate. ive looked again at the QStackedWidget Class and thought about creating a management class to add widgets on the fly to one QStackedWidget stack, (i think your right as i will only need one stack if im adding and removing the pages on the fly) then remove them with the removeWidget () method and then delete them from memory with the QWidget destroy() method.

removing and destroying sounds quite easy but if i have a stack with one widget at load time when i start to addWidgets() on the fly will qt load that widget/object into memory with that method or do i need to first load that page/widget/object into memory some how with another method, then i can addWidget or insertwidget it to the Stack?

Im doing this in python as well with PYQT so im not sure if this would be a problem as i know with python you can create objects on the fly, but ive read you cant do that with c++ but as pyqt is essentially using c++ classes im not sure if it will fall foul of the same problem.

[jacek]

if i have a stack with one widget at load time when i start to addWidgets() on the fly will qt load that widget/object into memory with that method or do i need to first load that page/widget/object into memory some how with another method, then i can addWidget or insertwidget it to the Stack?

You can't add a widget to the stack without creating it first.

but ive read you cant do that with c++

It's not true. Where did you read that?

[morraine]

You can't add a widget to the stack without creating it first.

Ok so i cant add a widget to the stack without creating it first, so do you have any code examples in C++ or python (I'm not fused what language really as i can adapt it if incompatible) of how to create a widget into memory please.

It's not true. Where did you read that?

it was some other forum so that post was obviously wrong don't worry about it.

[jacek]

how to create a widget into memory

Simply create it:

SomeWidget *w = new SomeWidget();
// or
SomeWidget w;

SomeWidget *w = new SomeWidget();
// or
SomeWidget w;

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[morraine]

So do you mean just create a new object and assign that object to the widget which link the new page into the application and then addwidget or insertWidget() it to the stack?

(basically that simple)

or do you mean that is a class or function called someWidget() and that creates the page with some other code that i must come up with to load the page?

sorry i just need clarification but thanks for all your help!

[jacek]

So do you mean just create a new object and assign that object to the widget which link the new page into the application and then addwidget or insertWidget() it to the stack?

Yes .

[morraine]

thanks jacek for your help on this friend i had just been sorting out the theory on this problem as i have been creating pages with the designer and doing other things before i dive into creating my management class to create, track and remove pages on the fly.

Ive got the ammunition to do this now so thanks for the help.

[SiddhantR]

Can I know if its possible to make a page in QStackedWidget child of another page in the same stacked widget.
Also is it good to have a stacked widget on another stacked widget. I will be having 8 basic stackedwidgets on which I plan to add 8 more stacked widgets. Is it a good idea or should I try for QTabWidget or QMdiArea?
Thank You