Using 2 ui files in a project

[ben1996123]

I have a QDialog with a pushbutton on it, and when I click the pushbutton, I want another QDialog window in a separate ui file to open. I have a dialog class (with the pushbutton in), but I can't figure out how to use the other ui file to create the window. I've included settings.h (the file that's automatically generated when I compile the program) and added it to the Ui namespace, then tried to create a settings object with "Ui::settings foo;", but I keep getting the same compiler error:

"c:\programs\qt\sim\dialog.h:67: error: C2079: 'Dialog::foo' uses undefined class 'Ui::settings'"

[Santosh Reddy]

You may not have included the required ui file. See if this sample helps

#include "ui_OtherDialog.h"
 
void Dialog::on_pushButton_Clicked()
{
    QDialog * other_parent = new QDialog(this);
    Ui::OtherDialog other_ui;
 
    other_ui.setupUi(other_parent);
 
    other_parent.exec();    
}

#include "ui_OtherDialog.h"

void Dialog::on_pushButton_Clicked()
{
    QDialog * other_parent = new QDialog(this);
    Ui::OtherDialog other_ui;
    
    other_ui.setupUi(other_parent);
    
    other_parent.exec();    
}

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[ben1996123]

You may not have included the required ui file. See if this sample helps

#include "ui_OtherDialog.h"
 
void Dialog::on_pushButton_Clicked()
{
    QDialog * other_parent = new QDialog(this);
    Ui::OtherDialog other_ui;
 
    other_ui.setupUi(other_parent);
 
    other_parent.exec();    
}

#include "ui_OtherDialog.h"

void Dialog::on_pushButton_Clicked()
{
    QDialog * other_parent = new QDialog(this);
    Ui::OtherDialog other_ui;
    
    other_ui.setupUi(other_parent);
    
    other_parent.exec();    
}

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Hmm... Just tried that, but now I'm getting an error whenever I access a member of ui (in the dialog class):

dialog.cpp:

#include "dialog.h"
#include "ui_dialog.h"
 
Dialog::Dialog(QWidget *parent):
    QDialog(parent),
    ui(new Ui::Dialog),
{
    srand(time(0));
    ui->setupUi(this);
    ui->label->setVisible(false);
}
 
void Dialog::on_pushButton_clicked(){ //settings
    QDialog *parent = new QDialog(this);
    Ui::settings foo;
 
    foo.setupUi(parent);
    parent->exec();
}

#include "dialog.h"
#include "ui_dialog.h"

Dialog::Dialog(QWidget *parent):
    QDialog(parent),
    ui(new Ui::Dialog),
{
    srand(time(0));
    ui->setupUi(this);
    ui->label->setVisible(false);
}

void Dialog::on_pushButton_clicked(){ //settings
    QDialog *parent = new QDialog(this);
    Ui::settings foo;

    foo.setupUi(parent);
    parent->exec();
}

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dialog.h:

#ifndef DIALOG_H
#define DIALOG_H
 
#include <QDialog>
#include <QtCore>
#include <QtGui>
#include "settings.h"
#include "ui_settings.h"
 
namespace Ui {
class Dialog;
class settings;
}
 
class Dialog : public QDialog
{
    Q_OBJECT
 
public:
    Ui::Dialog *ui;
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();
 
private slots:
    void on_pushButton_clicked();
};
 
#endif // DIALOG_H

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QtCore>
#include <QtGui>
#include "settings.h"
#include "ui_settings.h"

namespace Ui {
class Dialog;
class settings;
}

class Dialog : public QDialog
{
    Q_OBJECT
    
public:
    Ui::Dialog *ui;
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();

private slots:
    void on_pushButton_clicked();
};

#endif // DIALOG_H

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Now, I get errors whenever I have "ui->" in my code.

[Santosh Reddy]

Can you post the error?

[ben1996123]

Can you post the error?

C:\programs\Qt\sim-build-desktop-Qt_4_8_1_for_Desktop_-_MSVC2010__Qt_SDK__Release\..\sim\dialog.cpp:21: error: C2027: use of undefined type 'Ui::Dialog'
C:\programs\Qt\sim-build-desktop-Qt_4_8_1_for_Desktop_-_MSVC2010__Qt_SDK__Release\..\sim\dialog.cpp:21: error: C2227: left of '->setupUi' must point to class/struct/union/generic type

[d_stranz]

@ben: I think you are totally confused about how to go about what you want to do. You should not need to access the ui pointer in your other dialog at all. Ui pointers are meant to be hidden inside the widget classes that define them, so that they can access the signals, slots, and properties of the widgets defined in the ui file.

To invoke a second dialog as a response to a button click in the first dialog, all you need to do is something like this:

// Dialog1.cpp:
#include "Dialog1.h"
#include "Dialog2.h"
 
Dialog1::Dialog1( QWidget * parent )
:  QDialog( parent )
,  ui( new Ui::Dialog1 )
{
    ui->setupUi( this );
 
    connect( ui->someButton, SIGNAL( clicked() ), this, SLOT( showDialog2() ) );
}
 
void Dialog1::showDialog2()
{
   Dialog2 dlg2( this );
   dlg2->exec();
}

// Dialog1.cpp:
#include "Dialog1.h"
#include "Dialog2.h"

Dialog1::Dialog1( QWidget * parent )
:  QDialog( parent )
,  ui( new Ui::Dialog1 )
{
    ui->setupUi( this );

    connect( ui->someButton, SIGNAL( clicked() ), this, SLOT( showDialog2() ) );
}

void Dialog1::showDialog2()
{
   Dialog2 dlg2( this );
   dlg2->exec();
}

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where of course, you have defined the showDialog2 slot correctly in the Dialog1.h header. The "ui" pointers in the Dialog1 and Dialog2 classes should be declared as private, since there is absolutely no reason to access them from outside of the class the uses them.

If there are any signals or slots in Dialog2 that need to be "watched" from inside of Dialog1, then set up the connections in showDialog2(). These will automatically be disconnected when dlg2 goes out of scope at the end of showDialog2().

[ben1996123]

@ben: I think you are totally confused about how to go about what you want to do. You should not need to access the ui pointer in your other dialog at all. Ui pointers are meant to be hidden inside the widget classes that define them, so that they can access the signals, slots, and properties of the widgets defined in the ui file.

To invoke a second dialog as a response to a button click in the first dialog, all you need to do is something like this:

// Dialog1.cpp:
#include "Dialog1.h"
#include "Dialog2.h"
 
Dialog1::Dialog1( QWidget * parent )
:  QDialog( parent )
,  ui( new Ui::Dialog1 )
{
    ui->setupUi( this );
 
    connect( ui->someButton, SIGNAL( clicked() ), this, SLOT( showDialog2() ) );
}
 
void Dialog1::showDialog2()
{
   Dialog2 dlg2( this );
   dlg2->exec();
}

// Dialog1.cpp:
#include "Dialog1.h"
#include "Dialog2.h"

Dialog1::Dialog1( QWidget * parent )
:  QDialog( parent )
,  ui( new Ui::Dialog1 )
{
    ui->setupUi( this );

    connect( ui->someButton, SIGNAL( clicked() ), this, SLOT( showDialog2() ) );
}

void Dialog1::showDialog2()
{
   Dialog2 dlg2( this );
   dlg2->exec();
}

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where of course, you have defined the showDialog2 slot correctly in the Dialog1.h header. The "ui" pointers in the Dialog1 and Dialog2 classes should be declared as private, since there is absolutely no reason to access them from outside of the class the uses them.

If there are any signals or slots in Dialog2 that need to be "watched" from inside of Dialog1, then set up the connections in showDialog2(). These will automatically be disconnected when dlg2 goes out of scope at the end of showDialog2().

That's similar to what I originally tried, but I was getting linker errors...

dialog.obj:-1: error: LNK2019: unresolved external symbol "public: virtual __thiscall settings::~settings(void)" (??1settings@@UAE@XZ) referenced in function "public: void __thiscall Dialog::showSettings(void)" (?showSettings@Dialog@@QAEXXZ)

dialog.obj:-1: error: LNK2019: unresolved external symbol "public: __thiscall settings::settings(class QWidget *)" (??0settings@@QAE@PAVQWidget@@@Z) referenced in function "public: void __thiscall Dialog::showSettings(void)" (?showSettings@Dialog@@QAEXXZ)

release\sim.exe:-1: error: LNK1120: 2 unresolved externals

[d_stranz]

That's because you are trying to access some "Ui::settings" object. I have no clue what that is, and it is probably a bad design to try to access it in the way that you are doing, whatever it is.

What is it that you really want to do?

[ben1996123]

That's because you are trying to access some "Ui::settings" object. I have no clue what that is, and it is probably a bad design to try to access it in the way that you are doing, whatever it is.

What is it that you really want to do?

Click a pushbutton and have it create a window from the ui file.

I basically copied the code that you posted, and I got the errors I posted before:

#ifndef DIALOG_H
#define DIALOG_H
 
#include <QDialog>
#include <QtCore>
#include <QtGui>
#include "settings.h"
 
namespace Ui {
class Dialog;
}
 
class Dialog : public QDialog
{
    Q_OBJECT
 
public:
    Ui::Dialog *ui;
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();
 
private slots:
    void on_pushButton_clicked();
};
 
#endif // DIALOG_H

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QtCore>
#include <QtGui>
#include "settings.h"

namespace Ui {
class Dialog;
}

class Dialog : public QDialog
{
    Q_OBJECT
    
public:
    Ui::Dialog *ui;
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();

private slots:
    void on_pushButton_clicked();
};

#endif // DIALOG_H

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#include "dialog.h"
#include "ui_dialog.h"
#include "settings.h"
 
Dialog::Dialog(QWidget *parent):
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);
}
 
void Dialog::on_pushButton_clicked(){ //settings
    settings a(this);
    a.exec();
}

#include "dialog.h"
#include "ui_dialog.h"
#include "settings.h"

Dialog::Dialog(QWidget *parent):
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);
}

void Dialog::on_pushButton_clicked(){ //settings
    settings a(this);
    a.exec();
}

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[d_stranz]

create a window from the ui file

I don't know what that means. The moc compiler converts the XML definition in the .ui file into C++ code, which is then compiled and linked into your executable. At run-time the Qt meta-object system executes that compiled code and instantiates QWidgets and layouts, sets their properties, and establishes connections between signals and slots. That's what the "ui->setupUi( this )" line does behind the scenes.

As far as I know, the only way to replicate this functionality at run-time (e.g. go from uncompiled XML code in a .ui file to running QWidget instances) is to use the QUiLoader or QFormBuilder classes.

void Dialog::on_pushButton_clicked()
{ //settings
  settings a(this);
  a.exec();
}

void Dialog::on_pushButton_clicked()
{ //settings
  settings a(this);
  a.exec();
}

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What is this "settings" class you are trying to create and exec()? Is that the name of your second dialog class? If it is, there is probably something wrong with the way it has been declared or implemented, but since you don't show the code for "settings.h" or "settings.cpp", there's no way to tell.

What happens if you use QFileDialog instead of "settings"?

#include <QFileDialog>
 
void Dialog::on_pushButton_clicked()
{ //settings
  QFileDialog a(this);
  a.exec();
}

#include <QFileDialog>

void Dialog::on_pushButton_clicked()
{ //settings
  QFileDialog a(this);
  a.exec();
}

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[ben1996123]

void Dialog::on_pushButton_clicked()
{ //settings
  settings a(this);
  a.exec();
}

void Dialog::on_pushButton_clicked()
{ //settings
  settings a(this);
  a.exec();
}

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What is this "settings" class you are trying to create and exec()? Is that the name of your second dialog class? If it is, there is probably something wrong with the way it has been declared or implemented, but since you don't show the code for "settings.h" or "settings.cpp", there's no way to tell.

What happens if you use QFileDialog instead of "settings"?

#include <QFileDialog>
 
void Dialog::on_pushButton_clicked()
{ //settings
  QFileDialog a(this);
  a.exec();
}

#include <QFileDialog>

void Dialog::on_pushButton_clicked()
{ //settings
  QFileDialog a(this);
  a.exec();
}

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The settings class is the second dialog class. I added the settings.h and settings.cpp files and straight away it wouldn't compile, even with the default code. Using QFileDialog compiles and works fine.

settings.h:

#ifndef SETTINGS_H
#define SETTINGS_H
 
#include <QDialog>
 
namespace Ui {
class settings;
}
 
class settings : public QDialog
{
    Q_OBJECT
 
public:
    explicit settings(QWidget *parent = 0);
    ~settings();
    Ui::settings *ui;
 
private:
};
 
#endif // SETTINGS_H

#ifndef SETTINGS_H
#define SETTINGS_H

#include <QDialog>

namespace Ui {
class settings;
}

class settings : public QDialog
{
    Q_OBJECT
    
public:
    explicit settings(QWidget *parent = 0);
    ~settings();
    Ui::settings *ui;
    
private:
};

#endif // SETTINGS_H

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settings.cpp:

#include "settings.h"
#include "ui_settings.h"
 
settings::settings(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::settings) //error: C2512: 'Ui::settings' : no appropriate default constructor available
{
}
 
settings::~settings(){
    delete ui;
}

#include "settings.h"
#include "ui_settings.h"

settings::settings(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::settings) //error: C2512: 'Ui::settings' : no appropriate default constructor available
{
}

settings::~settings(){
    delete ui;
}

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