(C++) Answer of exercise: Qt hide and show #2

 

Answer of exercise: Qt hide and show #2 is the answer of the exercise Qt hide and show #2.

 

 

 

 

 

Solution

 

 

• Download the Qt Creator project 'CppExerciseQtHideAndShow2Answer' (zip)

 

 

 

 

 

Qt project file: CppExerciseQtHideAndShow2Answer.pro

 

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QT       += core gui TARGET = CppExerciseQtHideAndShow2Answer TEMPLATE = app SOURCES += \     main.cpp\     firstdialog.cpp \     seconddialog.cpp \     thirddialog.cpp HEADERS  +=  \     firstdialog.h \     seconddialog.h \     thirddialog.h FORMS    += \     firstdialog.ui \     seconddialog.ui \     thirddialog.ui

 

 

 

 

 

firstdialog.h

 

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#ifndef FIRSTDIALOG_H #define FIRSTDIALOG_H #include <QDialog> namespace Ui { class FirstDialog; } class FirstDialog : public QDialog {     Q_OBJECT      public:     explicit FirstDialog(QWidget *parent = 0);     ~FirstDialog();      private slots:     void close_child();     void on_pushButton_clicked(); private:     Ui::FirstDialog *ui;     bool m_show_child; }; #endif // FIRSTDIALOG_H

 

 

 

 

 

firstdialog.cpp

 

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#include "seconddialog.h" #include "firstdialog.h" #include "ui_firstdialog.h" FirstDialog::FirstDialog(QWidget *parent) :     QDialog(parent),     ui(new Ui::FirstDialog),     m_show_child(false) {   ui->setupUi(this); } FirstDialog::~FirstDialog() {     delete ui; } void FirstDialog::close_child() {   m_show_child = false; } void FirstDialog::on_pushButton_clicked() {   SecondDialog d;   this->hide();   QObject::connect(&d,SIGNAL(close_me()),this,SLOT(close_child()));   m_show_child = true;   while (m_show_child)   {     d.exec();   }   this->show(); }

 

 

 

 

 

main.cpp

 

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#include <QtGui/QApplication> #include "firstdialog.h" int main(int argc, char *argv[]) {   QApplication a(argc, argv);   FirstDialog w;   w.show();   a.exec(); }

 

 

 

 

 

seconddialog.h

 

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#ifndef SECONDDIALOG_H #define SECONDDIALOG_H #include <QDialog> namespace Ui { class SecondDialog; } class SecondDialog : public QDialog {     Q_OBJECT      public:     explicit SecondDialog(QWidget *parent = 0);     ~SecondDialog();      private slots:     void close_child();     void on_button_goto_third_clicked();     void on_button_back_to_first_clicked(); protected:     void closeEvent(QCloseEvent *); signals:     void close_me(); private:     Ui::SecondDialog *ui;     bool m_show_child; }; #endif // SECONDDIALOG_H

 

 

 

 

 

seconddialog.cpp

 

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#include <cassert> #include "seconddialog.h" #include "ui_seconddialog.h" #include "thirddialog.h" SecondDialog::SecondDialog(QWidget *parent) :     QDialog(parent),     ui(new Ui::SecondDialog),     m_show_child(false) {   ui->setupUi(this); } SecondDialog::~SecondDialog() {   delete ui; } void SecondDialog::close_child() {   m_show_child = false; } void SecondDialog::closeEvent(QCloseEvent *) {   emit close_me(); } void SecondDialog::on_button_back_to_first_clicked() {   close(); } void SecondDialog::on_button_goto_third_clicked() {   ThirdDialog d;   this->hide();   QObject::connect(&d,SIGNAL(close_me()),this,SLOT(close_child()));   m_show_child = true;   while (m_show_child)   {     d.exec();   }   if (d.m_back_to_which_dialog == 1)   {     this->close();   }   else   {     this->show();   } }

 

 

 

 

 

thirddialog.h

 

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#ifndef THIRDDIALOG_H #define THIRDDIALOG_H #include <QDialog> namespace Ui { class ThirdDialog; } class ThirdDialog : public QDialog {     Q_OBJECT      public:     explicit ThirdDialog(QWidget *parent = 0);     ~ThirdDialog();     int m_back_to_which_dialog; protected:     void closeEvent(QCloseEvent *); private slots:     void on_button_back_to_first_clicked();     void on_button_back_to_second_clicked(); signals:   void close_me(); private:     Ui::ThirdDialog *ui; }; #endif // THIRDDIALOG_H

 

 

 

 

 

thirddialog.cpp

 

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#include "thirddialog.h" #include "ui_thirddialog.h" ThirdDialog::ThirdDialog(QWidget *parent) :     QDialog(parent),     m_back_to_which_dialog(2), //When user closes the dialog, go back to the previous/second dialog     ui(new Ui::ThirdDialog) {   ui->setupUi(this); } ThirdDialog::~ThirdDialog() {   delete ui; } void ThirdDialog::closeEvent(QCloseEvent *) {   emit close_me(); } void ThirdDialog::on_button_back_to_first_clicked() {   m_back_to_which_dialog = 1;   close(); } void ThirdDialog::on_button_back_to_second_clicked() {   m_back_to_which_dialog = 2;   close(); }