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Instantiating gui object issue

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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #4

    Your class is not called orderForm but OrderForm, that's why it fails. Casing is important.

    Have look "here":http://qt-project.org/doc/qt-5/qwidget.html#QWidget to get an explanation about the parent of QWidget

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    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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    • D Offline
      D Offline
      Dn588
      wrote on last edited by
      #5

      Thanks SGaist stupid error on my side... What do you mean by the base constructor isn't called in the constructor? I get the program to run but there's no gui output

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      • SGaistS Offline
        SGaistS Offline
        SGaist
        Lifetime Qt Champion
        wrote on last edited by
        #6

        Since both are QWidget:

        Clean way:
        @
        OrderForm::OrderForm(QWidget *parent):
        QWidget(parent){

        }@

        Only if you don't expect to parent your widget in the constructor:
        @
        ordergui::ordergui() {
        }@

        Edit: corrected the wording

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        • D Offline
          D Offline
          Dn588
          wrote on last edited by
          #7

          Thanks again... So I obviously didn't understand the explanation on the previous link you posted. What I understood from there was that if QWidget* parent = 0; it will be a window otherwise it would be a widget on a window?

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          • D Offline
            D Offline
            Dn588
            wrote on last edited by
            #8

            When I do that I get an error saying QWidget is not a direct base type of ordergui...

            Also why was that not done in this example?

            http://qt-project.org/doc/qt-4.8/mainwindows-application.html

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            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #9

              I've updated the wording of my last post (was a bit tired)

              Since you have that error, it means that ordergui doesn't inherit from QWidget. It should inherit from QMainWindow.

              Since you don't see anything do you call show somewhere in you main.cpp ?

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              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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              • D Offline
                D Offline
                Dn588
                wrote on last edited by
                #10

                Yes I call show from main.cpp but for some reason I don't get any output, any idea what i'm doing wrong?

                main.cpp:

                @
                #include <QtGui>
                #include <QApplication>
                #include "ordergui.h"

                int main(int argc, char *argv[]) {
                QApplication app(argc, argv);
                ordergui order;

                order.show();
                return app.exec();
                

                }
                @

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                • mranger90M Offline
                  mranger90M Offline
                  mranger90
                  wrote on last edited by
                  #11

                  could it be becuase you orderForm is created on the stack before being sent to setCentralWidget ? It then goes out of scope and is not available.
                  You should allocate it off the heap with "new".

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                  • D Offline
                    D Offline
                    Dn588
                    wrote on last edited by
                    #12

                    I just tried that but still no luck...

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                    • X Offline
                      X Offline
                      Xander84
                      wrote on last edited by
                      #13

                      Just wondering, how can you even call setCentralWidget without a pointer to QWidget? :)
                      @
                      void QMainWindow::setCentralWidget(QWidget * widget)
                      @
                      you should get a compile error here:
                      @
                      orderForm obj;
                      setCentralWidget(obj);
                      @

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                      • D Offline
                        D Offline
                        Dn588
                        wrote on last edited by
                        #14

                        Hi Xander. Sorry yes I changed it to OrderForm* obj but for some reason there's no output. Also when I try to close the running program I have to force quit

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                        • X Offline
                          X Offline
                          Xander84
                          wrote on last edited by
                          #15

                          [quote author="Dn588" date="1397930234"]Hi Xander. Sorry yes I changed it to OrderForm* obj but for some reason there's no output. Also when I try to close the running program I have to force quit[/quote]
                          Then you have most like created another (invisible) top level windows, if you have to "kill" the app.
                          you can try setting the parent of your central widget, I though the setCentralWidget would reparent it, but maybe not:
                          @
                          setCentralWidget(new orderForm(this));
                          @
                          maybe that works.

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                          • D Offline
                            D Offline
                            Dn588
                            wrote on last edited by
                            #16

                            No still no visible output and I still have to force quit...

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                            • X Offline
                              X Offline
                              Xander84
                              wrote on last edited by
                              #17

                              Is it possible that you can upload your whole project code somewhere? I don't know if you can publish your code or how large your codebase is beside what you already posted, but an logic error like this is hard to debug over the forums.. :/

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                              • D Offline
                                D Offline
                                Dn588
                                wrote on last edited by
                                #18

                                My Code:

                                @
                                order.h

                                #ifndef ORDER_H
                                #define ORDER_H

                                #include <QString>
                                #include <QDate>

                                class Order {

                                public:
                                //getters
                                QString name() const {return m_name;}
                                QDate dateAdded() const { return m_added; }
                                int quantity() const {return m_quantity; }
                                double price() const {return m_price;}

                                //return a string representation of an order
                                QString toString() const;
                                
                                //setters
                                void setName(const QString &name) {m_name = name;}
                                void setDateAdded(const QDate &added) {m_added = added;}
                                void setQuantity(int qty) {m_quantity = qty;}
                                void setPrice(double unitPrice) {m_price = unitPrice;}
                                

                                private:
                                //data members
                                QString m_name;
                                QDate m_added;
                                int m_quantity;
                                double m_price;

                                };

                                #endif // #ifndef ORDER_H

                                order.cpp

                                #include "order.h"
                                #include <QString>

                                //returns the string representation of an order
                                QString Order::toString() const {
                                return QString("%1 %2 (%3)at $ %4 total: %5").arg(m_name)
                                .arg(m_added.toString("yyyyMMdd")).arg(m_quantity)
                                .arg(m_price).arg(m_quantity*m_price);
                                }

                                OrderForm.h
                                #ifndef ORDERFORM_H
                                #define ORDERFORM_H

                                #include <QtGui>
                                #include "order.h"

                                class OrderForm : public QWidget {
                                Q_OBJECT

                                public:
                                //constructor
                                OrderForm(QWidget* parent);
                                //view a given order
                                void setOrder(Order prod);

                                private slots:
                                //create a new order
                                void submit();
                                //calculate the cost of an order
                                void calculateCost();

                                private:
                                //private data members
                                QLineEdit* m_nameEdit;
                                QDateEdit* m_dateEdit;
                                QSpinBox* m_quantitySpin;
                                QDoubleSpinBox* m_priceSpin;
                                QLineEdit* m_totalEdit;
                                QPushButton* m_submitButton;
                                QPushButton* m_cancelButton;

                                Order m_Order;
                                
                                //to view an order
                                void viewOrder();
                                //sets up the GUI
                                void setUpGui();
                                

                                };

                                #endif // #ifndef ORDERFORM_H

                                OrderForm.cpp

                                #include "orderform.h"
                                #include "order.h"
                                #include <QFormLayout>

                                //constructor
                                OrderForm::OrderForm(QWidget *parent) : QWidget(parent) {
                                setUpGui();
                                }

                                //sets up the GUI
                                void OrderForm::setUpGui(){
                                m_nameEdit = new QLineEdit();
                                m_dateEdit = new QDateEdit();
                                m_quantitySpin = new QSpinBox();
                                m_quantitySpin->setRange(1,1000);
                                m_priceSpin = new QDoubleSpinBox();
                                m_priceSpin->setRange(1.0,1000.00);
                                m_totalEdit = new QLineEdit();
                                m_totalEdit->setReadOnly(true);
                                m_submitButton = new QPushButton("OK");
                                m_cancelButton = new QPushButton("Cancel");

                                QGridLayout* gridLayout = new QGridLayout();
                                gridLayout->addWidget(m_submitButton,0,0);
                                gridLayout->addWidget(m_cancelButton,0,1);
                                
                                QFormLayout *formLayout = new QFormLayout();
                                formLayout->addRow(tr("&Name"), m_nameEdit);
                                formLayout->addRow(tr("&Date Added"), m_dateEdit);
                                formLayout->addRow(tr("&Quantity"), m_quantitySpin);
                                formLayout->addRow(tr("&Unit Price"), m_priceSpin);
                                formLayout->addRow(tr("&Total Price"), m_totalEdit);
                                formLayout->addRow(gridLayout);
                                
                                connect(m_submitButton, SIGNAL(clicked()), this, SLOT(submit()));
                                connect(m_cancelButton, SIGNAL(clicked()), this, SLOT(close()));
                                connect(m_quantitySpin, SIGNAL(editingFinished()), this, SLOT(calculateCost()));
                                connect(m_priceSpin, SIGNAL(editingFinished()), this, SLOT(calculateCost()));
                                
                                this->setLayout(formLayout);
                                this->setWindowTitle("Manual Order Form");
                                

                                }

                                // sets an order
                                void OrderForm::setOrder(Order prod){
                                m_Order = prod;
                                viewOrder();
                                }

                                //create a new order
                                void OrderForm::submit(){
                                m_Order.setName(m_nameEdit->text());
                                m_Order.setDateAdded(m_dateEdit->date());
                                m_Order.setQuantity(m_quantitySpin->value());
                                m_Order.setPrice(m_priceSpin->value());
                                }

                                //view an order
                                void OrderForm::viewOrder(){
                                m_nameEdit->setText(m_Order.name());
                                m_dateEdit->setDate(m_Order.dateAdded());
                                m_quantitySpin->setValue(m_Order.quantity());
                                m_priceSpin->setValue(m_Order.price());
                                calculateCost();
                                }
                                //calculate the cost of an order
                                void OrderForm::calculateCost(){
                                double total = double(m_quantitySpin->value()* m_priceSpin->value());
                                m_totalEdit->setText(QString::number(total, 'f', 2));
                                }

                                ordergui.h

                                #ifndef ORDERGUI_H
                                #define ORDERGUI_H
                                #include <QMainWindow>
                                #include <QTextEdit>

                                class ordergui : public QMainWindow {
                                Q_OBJECT
                                public:
                                ordergui();
                                public slots:
                                void add_order_clicked();
                                void view_orders_clicked();
                                private:
                                void createMenu();
                                void createActions();
                                QTextEdit* m_text;
                                QMenu* orderMenu;
                                QAction* add_order;
                                QAction* view_orders;
                                };

                                #endif // ORDERGUI_H

                                ordergui.cpp

                                #include <QTGui>
                                #include "ordergui.h"
                                #include "OrderForm.h"

                                ordergui::ordergui() {
                                m_text = new QTextEdit;
                                setCentralWidget(m_text);
                                createActions();
                                createMenu();
                                }

                                void ordergui::createActions() {
                                add_order = new QAction(("Add Order"), this);
                                connect(add_order, SIGNAL(triggered()), this, SLOT(add_order_clicked()));

                                view_orders = new QAction(("View Order"), this);
                                connect(view_orders, SIGNAL(triggered()), this, SLOT(view_orders_clicked()));
                                

                                }

                                void ordergui::createMenu() {
                                orderMenu = menuBar()->addMenu("Order");
                                orderMenu->addAction(add_order);
                                orderMenu->addAction(view_orders);
                                orderMenu->exec();
                                }

                                void ordergui::add_order_clicked() {
                                //OrderForm* obj = new OrderForm;
                                setCentralWidget(new OrderForm(this));
                                }

                                void ordergui::view_orders_clicked() {
                                setCentralWidget(m_text);
                                }

                                main.cpp

                                #include <QtGui>
                                #include <QApplication>
                                #include "ordergui.h"

                                int main(int argc, char *argv[]) {
                                QApplication app(argc, argv);
                                ordergui order1;

                                order1.show();
                                return app.exec&#40;&#41;;
                                

                                }

                                @

                                [edit: modified the code to allow proper tagging SGaist]

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                                • X Offline
                                  X Offline
                                  Xander84
                                  wrote on last edited by
                                  #19

                                  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

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                                  • D Offline
                                    D Offline
                                    Dn588
                                    wrote on last edited by
                                    #20

                                    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

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                                    • X Offline
                                      X Offline
                                      Xander84
                                      wrote on last edited by
                                      #21

                                      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.

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                                      • D Offline
                                        D Offline
                                        Dn588
                                        wrote on last edited by
                                        #22

                                        Yes I am using QT 4

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                                        • D Offline
                                          D Offline
                                          Dn588
                                          wrote on last edited by
                                          #23

                                          no idea why it's not working for me... it is a little strange yes i'm busy working through "Design patterns in C++ with QT" and this is a varient of one of the exercises...

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