I don't get it.
loginview.h
#ifndef LOGINVIEW_H
#define LOGINVIEW_H
#include <QMainWindow>
#include <QDebug>
#include <QPushButton>
class LoginView : public QWidget
{
public:
QWidget *LoginViewSetup(QWidget * wdgMain);
public slots:
virtual void LogInUser();
virtual void CreateUser();
public:
QPushButton *logInBtn;
QPushButton *createBtn;
};
#endif // LOGINVIEW_H
loginview.cpp
#include "loginview.h"
QWidget *LoginView::LoginViewSetup(QWidget * wdgMain)
{
//some code
return wdgCenter;
}
void LoginView::LogInUser()
{
//some code
}
void LoginView::CreateUser()
{
//some code
}
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QDebug>
#include <loginview.h>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
QWidget * wdgMain;
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
wdgMain = new QWidget(this);
LoginView LoginViewObj;
QWidget *wdgCenter = LoginViewObj.LoginViewSetup(wdgMain);
setCentralWidget( wdgMain );
connect(LoginViewObj.createBtn, SIGNAL (released()), &LoginViewObj, SLOT (CreateUser()));
}
MainWindow::~MainWindow()
{
delete ui;
}
Problem:
QObject::connect: No such slot QWidget::CreateUser() in
../proj/mainwindow.cpp:16
I tried to add Q_OBJECT to the loginview.h and then rebuild project with QMAKE. After that there is no warning about slot, but buttons still not active. Program don't jump to handle of the button in debug mode.
Please, help me to understand what's wrong? I have an object of another class LoginView and I pass this object as a reciever for a slot. Why it passes through my class and searches slot in QWidget?
Related
I try to switch between two different Widgets in QT5.
The first problem was that my first window was visible in the background of my second window. I solve this with a check in "autoFillBackground". Now i can switch between them, but if i resize them it only resize the Main content.
Both Widgets have a grid layout.
Resize Problem
Im new at QT5, so is there a better way to make a switching between 2 widgets without this problem?
I try it with wMessages = new Messages(); and hide() but then my program crash after going back.
Code:
mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "messages.h"
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
private slots:
void on_btnMessages_clicked();
private:
Ui::MainWindow *ui;
Messages *wMessages;
};
#endif // MAINWINDOW_H
mainwindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_btnMessages_clicked()
{
wMessages = new Messages(this);
wMessages->show();
}
messages.h:
#ifndef MESSAGES_H
#define MESSAGES_H
#include <QWidget>
namespace Ui {
class Messages;
}
class Messages : public QWidget
{
Q_OBJECT
public:
explicit Messages(QWidget *parent = nullptr);
~Messages();
QString NewsGenerator();
private slots:
void on_bBack_clicked();
void on_pushButton_clicked();
private:
Ui::Messages *ui;
};
#endif // MESSAGES_H
messages.cpp:
#include "messages.h"
#include "ui_messages.h"
Messages::Messages(QWidget *parent) :
QWidget(parent),
ui(new Ui::Messages)
{
ui->setupUi(this);
}
Messages::~Messages()
{
delete ui;
}
void Messages::on_bBack_clicked()
{
this->close();
QWidget *parent = this->parentWidget();
parent->show();
}
Edit 1 - working Main Window Button (from G.M.´s answer):
void MainWindow::on_btnMessages_clicked()
{
wPlaner = new Planer();
QMainWindow::setCentralWidget(wPlaner);
}
Update (based on the comments):
The best solution was to use the QStackedWidget to navigate between the views.
Docu: https://doc.qt.io/qt-5/qstackedwidget.html#details
Example-Code for Button:
// return back to first view
void MainWindow::on_btnret_clicked()
{
ui->stackedWidget->setCurrentIndex(0);
}
I have a problem. I created two classes in my Qt project. One as the main window, and second as the settings dialog. My idea is to send the values from "Settings" to "MainWindow" (like from one TextEdit to another) but unfortunately, I have no idea how to do it. It's confusing me. I have read similar topics on the internet but none of them gives me a clear answer. Can someone help me understand the way how can I do it via example?
I have no useful code to place it here, so I will put the part of the source code and headers of mine.
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
[...]
}
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "settings.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = nullptr);
~MainWindow()
[...]
private:
Ui::MainWindow *ui;
[...]
};
#endif // MAINWINDOW_H
settings.cpp
#include "settings.h"
#include "ui_settings.h"
#include "mainwindow.h"
#include "ui_mainwindow.h"
Settings::Settings(QWidget *parent) :
QDialog(parent),
ui(new Ui::Settings)
{
ui->setupUi(this);
}
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 = nullptr);
~Settings();
[...]
private:
Ui::Settings *ui;
[...]
};
#endif // SETTINGS_H
main.cpp
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
Use signals/slots mechanism to share values between two QObject.
For example:
The following code allows yout to send the value in a QLineEdit to another widget by clicking on a button:
class Widget1: public QWidget
{
Q_OBJECT
public:
Widget1(): QWidget(),
message(new QLineEdit())
{
QPushButton* button = new QPushButton("Send msg", this);
connect(button, &QPushButton::clicked, this, [=]() { emit this->sendMsg(message->text());}); // When you click on the button, it will emit the signal sendMsg
QVBoxLayout* layout = new QVBoxLayout(this);
layout->addWidget(message);
layout->addWidget(button);
}
private:
QLineEdit* message;
signals:
void sendMsg(QString const& msg);
};
class Widget2: public QWidget
{
Q_OBJECT
public:
Widget2(): QWidget(),
display(new QLabel("Nothing to display", this))
{
QVBoxLayout* layout = new QVBoxLayout(this);
layout->addWidget(display);
}
private:
QLabel* display;
public slots:
void receive(QString const& message)
{
display->setText(message); // When called, display the message in the label
}
};
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QWidget* mainWidget = new QWidget();
QHBoxLayout* layout = new QHBoxLayout(mainWidget);
Widget1* w1 = new Widget1();
Widget2* w2 = new Widget2();
layout->addWidget(w1);
layout->addWidget(w2);
// When the signal sendMsg is emitted, call the slot receive
QObject::connect(w1, &Widget1::sendMsg, w2, &Widget2::receive);
mainWidget->show();
return app.exec();
}
There are multiple ways to achieve this.
For example you can provide the public Getter Methods in your dialog for provide value to the public and use them directly in the MainWindow to read those.
Or you can use Signals/Slots as stated above.
One example with Signal/Slots:
The SettingsWindow emits textEdit(QString) signal if Dialog Accepted, and MainWindow receives this signal via on_textEdit(QString) slot and writes it to its own text field:
SettingsWindow reading text input and emitting signal textEdit(QString):
MainWindow receiving signal via slot on_textEdit(QString):
And this is the code:
maindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = nullptr);
~MainWindow();
private slots:
void on_pushButton_clicked();
void on_textEdited(QString txt);
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "settingsdialog.h"
#include <memory>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_pushButton_clicked()
{
auto dlg = new SettingsDialog{this};
connect(dlg, &SettingsDialog::textEdit, this, &MainWindow::on_textEdited);
dlg->setAttribute(Qt::WA_DeleteOnClose);
dlg->show();
}
void MainWindow::on_textEdited(QString txt)
{
ui->textEdit->setText(txt);
}
settingsdialog.h
#ifndef SETTINGSDIALOG_H
#define SETTINGSDIALOG_H
#include <QDialog>
namespace Ui {
class SettingsDialog;
}
class SettingsDialog : public QDialog
{
Q_OBJECT
public:
explicit SettingsDialog(QWidget *parent = nullptr);
~SettingsDialog();
signals:
void textEdit(QString txt);
private slots:
void on_buttonBox_accepted();
private:
Ui::SettingsDialog *ui;
};
#endif // SETTINGSDIALOG_H
settingsdialog.cpp
#include "settingsdialog.h"
#include "ui_settingsdialog.h"
SettingsDialog::SettingsDialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::SettingsDialog)
{
ui->setupUi(this);
}
SettingsDialog::~SettingsDialog()
{
delete ui;
}
void SettingsDialog::on_buttonBox_accepted()
{
emit textEdit(ui->textEdit->toPlainText());
}
More about Signal/Slots
I am trying to connect a signal from a second QMainWindow to the mainwindow. It doesn't say anything about a problem connection when the program is launched, but It doesn't work. I am not very familiar with C++ and Qt so maybe is something simple.
My code consists on a Mainwindow used as a SCADA with Start, stop, On, off buttons. In the second qmainwindow I created a terminal where you can type, start,stop... There, I would like to emit a signal to my MainWindow which is in charge of controlling the multiple threads and windows. The problem is that I cannot connect to my slot. I present here a simple overview of this two pieces of code.
Terminal. h
#ifndef TERMINAL__H
#define TERMINAL__H
#include <QMainWindow>
#include <QTextEdit>
#include <QLineEdit>
#include <QObject>
namespace Ui {
class Terminal_;
}
class Terminal_ : public QMainWindow
{
Q_OBJECT
public:
explicit Terminal_(QWidget *parent = 0);
~Terminal_();
signals:
void turnonPLC_terminal();
public slots:
void newline();
private:
Ui::Terminal_ *ui;
QTextEdit* mTerminal;
QLineEdit* mInput;
};
#endif // TERMINAL__H
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "terminal_.h"
#include "terminal_help.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
Terminal_ *terminal;
public slots:
void turnon_terminal();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
Mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "terminal_.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
terminal = new Terminal_(this);
connect(terminal, SIGNAL(turnonPLC_terminal()), this, SLOT(turnon_terminal()));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::turnon_terminal(){
turnonPLC=1;
}
terminal_.cpp
#include "terminal_.h"
#include "ui_terminal_.h"
#include <QDockWidget>
#include <QWidget>
#include <QLineEdit>
QString on=("on");
Terminal_::Terminal_(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::Terminal_)
{
ui->setupUi(this);
mTerminal = new QTextEdit();
setCentralWidget(mTerminal);
mInput = new QLineEdit();
QDockWidget* qdw = new QDockWidget;
qdw->setWidget(mInput);
addDockWidget(Qt::BottomDockWidgetArea, qdw);
connect (mInput, SIGNAL(returnPressed()),
this, SLOT(newline()));
}
Terminal_::~Terminal_()
{
delete ui;
}
void Terminal_::newline(){
QString command = mInput->text();
if (command==on){
emit turnonPLC_terminal();
}
}
Thanks
The signal-slots part in the code works perfectly. (compiled and tested with some small modifications)
After entering "on" (not On as written in question)
Terminal_::newline() slot called, turnonPLC_terminal() is fired and finally
void MainWindow::turnon_terminal() is called.
However, there are some small details the header file is called terminal_.h, not Terminal.h turnonPLC is not defined. terminal is created by not displayed (no show-call).
I guess, there are simply some many small logic errors. Try to use debugger or trace the chain of expected calls with qDebug.
I am using Qt in my project and facing some difficulty in accessing ui label from other class,I have mainwindow and Yar class as shown below.
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "yar.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
Yar b;
private:
Ui::MainWindow *ui;
public slots:
void dispal();
private slots:
void on_pushButton_clicked();
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
QObject::connect(ui->pushButton,SIGNAL(clicked()),&b,SLOT(lll()));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::dispal(){
ui->label->setText("hello");
}
Yar.h
#ifndef YAR_H
#define YAR_H
#include <QObject>
class Yar : public QObject
{
Q_OBJECT
public:
explicit Yar(QObject *parent = 0);
public slots:
void lll();
};
#endif // YAR_H
void MainWindow::on_pushButton_clicked()
{//ui->label->setText("hello");
//b.wrrrot();
//dispal();
}
Yar.cpp
#include "yar.h"
#include <iostream>
Yar::Yar(QObject *parent) :
QObject(parent)
{
//setupUi(this);
//QObject::connect(&a, SIGNAL(dis), &a, SLOT(dispal()));
//emit wrrrot();
}
void Yar::lll(){
//emit wrrrot();
std::cout<<"gfggdf"<<std::endl;
}
In my gui i have one push button and one label, I have connected push button with lll() function of class Yar and when I click push button it is displaying gfggdf in console but I want to display this text in ui label, could you please help me how can I display my data in ui label from function lll();
One possible solution is to emit signal from Yar::lll() i.e.
emit updateLabelText("your text");
And connect this signal to the slot that handles GUI (changes label with given text) in the MainWindow.
hi how to add widget inside widget
i created main widget, and for the main widget headerbar come from another widget.
here the code below
main.cpp
#include <QApplication>
#include "mainwindow.h"
int main(int argl,char *argv[])
{
QApplication test(argl,argv);
mainWindow *window=new mainWindow();
window->setWindowState(Qt::WindowFullScreen);
window->show();
return test.exec();
}
mainwindow.cpp
#include "mainwindow.h"
#include <QtGui>
#include "headerbar.h"
#include <QGridLayout>
mainWindow::mainWindow(QWidget *parent) : QWidget(parent)
{
QGridLayout *layout;
headerBar *Header=new headerBar(this);
layout->addWidget(Header,0,0);
this->setLayout(layout);
}
mainWindow::~mainWindow()
{
}
headerbar.cpp
#include "headerbar.h"
headerBar::headerBar(QWidget *parent) : QWidget(parent)
{
this->setMaximumHeight(24);
}
headerBar::~headerBar()
{
}
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QWidget>
class mainWindow : public QWidget
{
Q_OBJECT
public:
mainWindow(QWidget *parent = 0);
~mainWindow();
signals:
public slots:
};
#endif // MAINWINDOW_H
headerbar.h
#ifndef HEADERBAR_H
#define HEADERBAR_H
#include <QWidget>
class headerBar : public QWidget
{
Q_OBJECT
public:
headerBar(QWidget *parent = 0);
~headerBar();
signals:
public slots:
};
#endif // HEADERBAR_H
while compile this code no errors. but when i am trying to run it's through error "exited with code -1073741819"
please help me to fix this issue
While you use layout, you have never created and assigned an instance to it:
QGridLayout *layout; // no initialization here
headerBar *Header = new headerBar(this);
layout->addWidget(Header,0,0); // layout is uninitialized and probably garbage
You should create it first before using it:
QGridLayout *layout = new QGridLayout(this);