Everytime i click my QPushButton which I have added with the UI Designer, the button stays clicked and the application crashes. When I remove the slot which the 'clicked()' signal of the button is connected to, I can click the button and the application behaves normal.
This is the header of the class that uses the UI:
#ifndef DARLEHENSRECHNER_H
#define DARLEHENSRECHNER_H
#include <QMainWindow>
#include "Darlehensgeber.h"
namespace Ui {
class Darlehensrechner;
}
class Darlehensrechner : public QMainWindow
{
Q_OBJECT
public:
explicit Darlehensrechner(QWidget *parent = 0);
~Darlehensrechner();
private slots:
void on_berechnenButton_clicked();
private:
Ui::Darlehensrechner *ui;
Darlehensgeber dg;
};
#endif // DARLEHENSRECHNER_H
And this is the cpp:
#include "darlehensrechner.h"
#include "ui_darlehensrechner.h"
Darlehensrechner::Darlehensrechner(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::Darlehensrechner),
dg()
{
ui->setupUi(this);
}
Darlehensrechner::~Darlehensrechner()
{
delete ui;
}
void Darlehensrechner::on_berechnenButton_clicked()
{
dg.takeLoan(ui->kreditEdit->text().toFloat(),
ui->ratenEdit->text().toFloat(),
ui->zinsEdit->text().toFloat());
ui->dauerLabel_2->setText(QString::number(dg.getAmountOfInstallments()));
ui->betragLabel_2->setText(QString::number(dg.getAmount()));
}
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'm new to QtCreator and created a button on the mainwindow that opens a dialog. In the dialog i added QLineEdit and a button. When i click on this button, i want the input text to be displayed on a Qlabel in the mainwindow.
I found another question which is basicly the same, but for me it has to work the other way around.
So In the header of MainWindow.h i have added to public:
void setLabelText(QString str);
I created the getter/setter function and added it to MainWindow.cpp:
void MainWindow::setLabelText(QString str)
{
ui->label->setText(str);//it is label dialog
}
And in the windowdialog.cpp i have added under button click() slot:
void WindowDialog::on_pushButton_clicked()
{
QString str = ui->lineEdit->text();
MainWindow MainWindow;
MainWindow.setLabelText(str);
}
It compiles without errors. Yet when i click on the button in the dialog, it won't print the results in the mainwindow... I have been trying to find another examples about how to do this, but couldn't really find one yet. So what am i missing? Or how do i make this work?
You can use signals and slots for this. https://doc.qt.io/qt-5/signalsandslots.html
you would need to connect the signal to a slot by using this command
connect(dlg,&DialogWindow::transmit,this,&MainWindow::update);
anytime you want to call the update function you would just need to emit the signal.
emit transmit(ui->lineEdit->text());
I created a dialog window class in this example.
Dialog.h
#ifndef DIALOGWINDOW_H
#define DIALOGWINDOW_H
#include <QDialog>
QT_BEGIN_NAMESPACE
namespace Ui { class Dialog; }
QT_END_NAMESPACE
class DialogWindow : public QDialog
{
Q_OBJECT
public:
DialogWindow(QWidget *parent = nullptr);
~DialogWindow();
signals:
void transmit(QString txt);
private slots:
void on_buttonBox_accepted();
private:
Ui::Dialog *ui;
};
#endif // DIALOGWINDOW_H
Dialog.cpp
#include "dialog.h"
#include "ui_dialog.h"
DialogWindow::DialogWindow(QWidget *parent)
: QDialog(parent),
ui(new Ui::Dialog)
{
ui->setupUi(this);
}
DialogWindow::~DialogWindow()
{
}
void DialogWindow::on_buttonBox_accepted()
{
emit transmit(ui->lineEdit->text());
}
MainWindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "dialog.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_pushButton_clicked();
void update(QString txt);
private:
Ui::MainWindow *ui;
DialogWindow *dlg;
};
#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);
dlg = new DialogWindow(NULL);
connect(dlg,&DialogWindow::transmit,this,&MainWindow::update);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_pushButton_clicked()
{
dlg->show();
}
void MainWindow::update(QString txt)
{
ui->label->setText(txt);
}
In this line MainWindow MainWindow;, you create a new MainWindow, but you want to set the text on your existing MainWindow.
Instead you might want to pass a reference or pointer to the MainWindow to the dialog, once you create it.
If you pass your MainWindow as the parent of the QDialog, you could do it this way:
void WindowDialog::on_pushButton_clicked()
{
QString str = ui->lineEdit->text();
static_cast<MainWindow*>(parent())->setLabelText(str);
}
A safer version using dynamic_cast:
void WindowDialog::on_pushButton_clicked()
{
QString str = ui->lineEdit->text();
MainWindow* window = dynamic_cast<MainWindow*>(parent());
if (!window) {
throw std::runtime_error{"Parent was not a MainWindow"};
}
window->setLabelText(str);
}
Welcome, I have a question about Qt's windows operations. I have a simple app which contains 2 windows:
MainWindow - includes push button, can't be resizeable,
AdminWindow - includes label, can be resizeable.
When I click push button, it should open AdminWindow and hide MainWindow. I made the app and it seems to work but when I open the AdminWindow, the application icon which is located in windows's bottom bar is missing. How can I fix it?
Icon is showed when MainWindow is opened:
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "adminwindow.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
void on_pushButtonOpenAdmin_clicked();
private:
Ui::MainWindow *ui;
AdminWindow *adminWindow;
};
#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;
}
// hides MainWindow and show AdminWindow
void MainWindow::on_pushButtonOpenAdmin_clicked()
{
hide();
adminWindow = new AdminWindow(this);
adminWindow->show();
}
adminwindow.h
#ifndef ADMINWINDOW_H
#define ADMINWINDOW_H
#include <QMainWindow>
namespace Ui {
class AdminWindow;
}
class AdminWindow : public QMainWindow
{
Q_OBJECT
public:
explicit AdminWindow(QWidget *parent = 0);
~AdminWindow();
private:
Ui::AdminWindow *ui;
};
#endif // ADMINWINDOW_H
adminwindow.cpp
#include "adminwindow.h"
#include "ui_adminwindow.h"
AdminWindow::AdminWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::AdminWindow)
{
ui->setupUi(this);
}
AdminWindow::~AdminWindow()
{
delete ui;
}
I've set up a basic Qt-Widgets-Application (Qt 5.5 community) with a simple QWidget "MainWindow" and an additinal QWidget "SettingsScreen".
Within the "MainWindow", touchscreen-events (handled by OS) are working as expected, but after opening the "SettingsScreen" all touch-events are executed on the desktop until I close the "SettingsScreen" using mouse or keyboard.
Environment:
Ubuntu Studio 14.04.03
Qt 5.5 Open Source Edition
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QWidget>
#include <settingsscreen.h>
namespace Ui {
class MainWindow;
}
class MainWindow : public QWidget
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
void on_btnExit_clicked();
void on_btnSettings_clicked();
private:
Ui::MainWindow *ui;
SettingsScreen *wSettingsScreen;
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "settingsscreen.h"
#include "ui_settingsscreen.h"
MainWindow::MainWindow(QWidget *parent) : QWidget(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_btnExit_clicked()
{
this->close();
}
void MainWindow::on_btnSettings_clicked()
{
wSettingsScreen = new SettingsScreen(parentWidget());
wSettingsScreen->show();
}
settingsscreen.h
#ifndef SETTINGSSCREEN_H
#define SETTINGSSCREEN_H
#include <QWidget>
namespace Ui {
class SettingsScreen;
}
class SettingsScreen : public QWidget
{
Q_OBJECT
public:
explicit SettingsScreen(QWidget *parent = 0);
~SettingsScreen();
private slots:
void on_pushButton_clicked();
void on_btnBack_clicked();
private:
Ui::SettingsScreen *ui;
};
#endif // SETTINGSSCREEN_H
settingsscreen.cpp
#include "settingsscreen.h"
#include "ui_settingsscreen.h"
SettingsScreen::SettingsScreen(QWidget *parent) :
QWidget(parent),
ui(new Ui::SettingsScreen)
{
ui->setupUi(this);
}
SettingsScreen::~SettingsScreen()
{
delete ui;
}
void SettingsScreen::on_btnBack_clicked()
{
this->close();
}
I've just started developing with Qt, so please forgive me if I'm missing something essential :)
Any help would by highly appreciated!!
Thank you in advance!
Actually the thing is QMainwindow or any base Widget of your application is able to properly synthesize the Unhandled touch screen events to Mouse events. So whenever you are creating a dialog/widget, make sure to set Mainwindow as there parent and in the constructor of the child widget use setParent(parent). Even I was facing this kind of Issue and this worked for me.
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.