Instantiating gui object issue
-
HI, sorry I tried to copy your messed up code here but it's almost impossible because it puts everything into one line and the quotations are also messed up etc.
If you put it in proper code tags or just zip and upload your project somewhere I will try finding your error, but not like this if I have to cleanup all the code just to recreate your whole project. :D
-
Hi Xander thanks for taking a look
I uploaded it to dropbox, hope that's ok?download link:
https://www.dropbox.com/s/i2hz6per5o78lry/Order-exercise.rar
-
Ok i had to add some stuff to the pro file and include QtWidgets in OrderForm.h to compile the project, I think you are using Qt 4 or why don't you need that?
Anyway I didn't change the code and it works!? lol
maybe a little weird to start the app with a menu only, but when i click on "Add Order" i see this:
!http://i.imgur.com/2ADRudL.png(order form)!
isn't that what you want, I am a little confused now because it seems to work or what is not working!?I noticed some other bugs, but i'm waiting for your response on this first.
-
are you sure your slot is working? how are you compiling your project?
because I had to modify your project file to get it to work :Dalso if you start learning Qt now and have the choice you should use Qt5 and not the old version, or is there any other reason you use Qt4?
maybe put a debug line in your slot to see if it's called, if you compile the project without qmake your signals and slots are not working I think.
@
void ordergui::add_order_clicked() {
qDebug("add_order_clicked");
//OrderForm* obj = new OrderForm;
setCentralWidget(new OrderForm(this));
}
@
I have the feeling your slot is never called..also the other bug in your slot:
@
void ordergui::view_orders_clicked() {
setCentralWidget(m_text);
}
@
that will crash the app because m_text has been deleted, check the doc of "setCentralWidget":http://qt-project.org/doc/qt-5/qmainwindow.html#setCentralWidget (Note: QMainWindow takes ownership of the widget pointer and deletes it at the appropriate time.)
that means if you set your ordner form as central widget it will delete the previous widget (your text).. -
i'm currently busy with a university course that uses QT 4 which is why I am using it. I just commented out the slots but still not getting a main window... I created a new project and added the order and OrderForm files to it and it ran with no issues... So i'm guessing there's also something wrong with my main window's constructor?
-
Oh yeah I thought it was supposed to be like that, that's why I said it is a little weird your app starts with a menu and not the main window, so that is a bug too?
comment out this line
@
orderMenu->exec();
@
in your ordergui::createMenu() function.
you should sometimes read the Qt doc, it tells you that QMenu::exec() "Executes this menu synchronously." which means it will block the thread until you close the menu (click an item) and only after that display the window. if you don't call "exec" it will just show the main window with your menu and your text widget (like it should?). -
I now have to add all orders to a list that gets displayed when view_orders_clicked is triggered.
What i've tried doing is create a function in OrderForm
QString addToList() { return m_order.toString(); }
then in my ordergui class I created a new varieable
QStringList OrderList;
So now the add_order_clicked slot looks like this:
@
void ordergui::add_order_clicked() {
OrderForm* obj;
setCentralWidget(obj);
OrderList.append(obj->addToList());
view_orders->setEnabled(true);;
}
@
when I click on add order the program crashes every time...Am I going about this the right way?
-
you have not allocated an object
@
OrderForm* obj;
@
is just a pointer to nothing (invalid memory), that is why your app is crashing.this should work:
@
OrderForm* obj = new OrderForm; // creates an object on the heap memory (you have to delete it yourself usually, use this)
OrderForm obj; // creates an object on the stack memory (will be deleted if the object leaves the current scope / end of function)
@ -
Thanks it works perfectly now:). when I try to add orders to the OrderList ad in my previous post and write it to a new instance of m_text when view_orders is triggered none of the m_order values gets read in. i'm guessing that happens because it immediately tries to call addToList in Orderform passing obj->m_Order before the ok button is clicked. How could I go about making sure that m_order gets converted to a QString and added to OrderList only after all the orderForm fields have been completed?
-
I am not sure what you want to achieve but you can try using "validators":http://qt-project.org/doc/qt-4.8/qvalidator.html for the form fields? e.g.
"QLineEdit::setValidator(const QValidator * v)":http://qt-project.org/doc/qt-4.8/qlineedit.html#setValidator
and then check if the input of all fields is valid before you add it to the list or show an error next if it isn't. that is the classic approach I would say. :) -
My current issue isn't validating the order input. I have to create a list of orders which should then get printed to m_text when view_orders is triggered.
What i've done is create a QListQList<Order> m_list in the orderForm class.
I added m_list.append() to the submit slot of OrderForm to add orders to the list every time the ok button is clicked. then I added another function to OrderForm
@
QString OrderForm::displayOrders() {
for (int i = 0; i < m_list.size(); ++i)
return m_list.at(i).toString();
}
@also I changed my add_order_clicked slot to
@
void ordergui::add_order_clicked() {
OrderForm *obj = new OrderForm;setCentralWidget(obj); OrderList.append(obj->displayOrders()); view_orders->setEnabled(true);}
@Then I changed my view_orders_clicked slot of ordergui to:
@
void ordergui::view_orders_clicked() {
m_text = new QTextEdit;
setCentralWidget(m_text);
for (int i = 0; i < OrderList.size(); ++i) {
m_text->append(OrderList.at(i));
}}
@whenever I add an order and then select view orders the program crashes... Any idea why that would happen?
-
Sounds a little chaotic to me, sorry :D
Your order form keeps a list of all orders and then your have a list of the string values of all orders in another class!?I would suggest using a list view, why are you using a QTextEdit for a list of orders? Ok i might be a little bit easier at first, but the proper way would be to use a ListView which holds a list model with all your orders and displays them as their string representation I think? You could also use a TableView but is more complicated.
Maybe take a look at these articles:
http://qt-project.org/doc/qt-4.8/modelview.html
http://qt-project.org/doc/qt-4.8/model-view-programming.htmlAlso your for loop is useless:
@
QString OrderForm::displayOrders() {
for (int i = 0; i < m_list.size(); ++i)
return m_list.at(i).toString();
}
@
the return expression will exit the function immediately, so that is the same as
@
QString OrderForm::displayOrders() {
return m_list.at(0).toString();
}
@
if you want to concatenate the values of all strings and return those you need to use QString::append or something else to build a string and return it at the end of the function.