On windows 7 pro x64 with Qt 5.6.1 this line alone is bringing my CPU up to 10-15%:
QWebEnginePage *page = new QWebEnginePage(this);
Deleting the page later (even immediately) does not help in reducing the usage back to 0-1% as usual for my apps. Any ideas what to do?
Full code causing the problem:
problem.pro
QT += core gui webenginewidgets
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = problem
TEMPLATE = app
SOURCES += main.cpp\
MainWindow.cpp
HEADERS += MainWindow.h
FORMS += MainWindow.ui
problem.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QWebEnginePage>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
problem.cpp
#include "MainWindow.h"
#include "ui_MainWindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
// Comment the next line to reduce CPU usage back to normal
QWebEnginePage *page = new QWebEnginePage(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
With QNetworkAccessManager I was able to achieve the same result as with the QWebEnginePage, but without the unnecesarry raised CPU usage.
Related
I have a QT application and I'm trying to have a button in one of my windows open another window.
The way I have done my window objects so far in the main is like this:
Website control;
control.show();
This displays my first window fine and if I declare my other window in a similar way that also displays at runtime, although this is not what I want
Then in a separate header file:
class Website: public QWidget, public Ui::Website
{
public:
Website();
}
Then in the corresponding Cpp file I have:
Website::Website()
{
setupUi(this);
}
Now all this works and have added a custom slot so that when I click a button it triggers a slot in my other cpp file. The issue is I'm not sure how to show my other window as I declare them in my main so can't access them to do .show()?
Any help would be appreciated, I'm fairly new to C++ and QT
It's not clear to me what you want to do. But i might understand your struggle as I had one myself the first time approaching this framework.
So let's say you have a MainWindow class that controls the main Window view. Than you want to create a second window controlled by Website class.
You then want to connect the two classes so that when you click a button on the Website window something happens in the MainWindow.
I made a simple example for you that is also on GitHub:
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "website.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
public slots:
void changeText();
private slots:
void on_openButton_clicked();
private:
Ui::MainWindow *ui;
//You want to keep a pointer to a new Website window
Website* webWindow;
};
#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::changeText()
{
ui->text->setText("New Text");
delete webWindow;
}
void MainWindow::on_openButton_clicked()
{
webWindow = new Website();
QObject::connect(webWindow, SIGNAL(buttonPressed()), this, SLOT(changeText()));
webWindow->show();
}
website.h
#ifndef WEBSITE_H
#define WEBSITE_H
#include <QDialog>
namespace Ui {
class Website;
}
class Website : public QDialog
{
Q_OBJECT
public:
explicit Website(QWidget *parent = 0);
~Website();
signals:
void buttonPressed();
private slots:
void on_changeButton_clicked();
private:
Ui::Website *ui;
};
#endif // WEBSITE_H
website.cpp
#include "website.h"
#include "ui_website.h"
Website::Website(QWidget *parent) :
QDialog(parent),
ui(new Ui::Website)
{
ui->setupUi(this);
}
Website::~Website()
{
delete ui;
}
void Website::on_changeButton_clicked()
{
emit buttonPressed();
}
Project composed:
SOURCES += main.cpp\
mainwindow.cpp \
website.cpp
HEADERS += mainwindow.h \
website.h
FORMS += mainwindow.ui \
website.ui
Consider the Uis to be composed:
Main Window: a label called "text" and a button called "openButton"
Website Window: a button called "changeButton"
So the keypoints are the connections between signals and slots and the management of windows pointers or references.
I've created my own class in QT 5.4 with header and source file, then I've implemented there a video player. The problem is, that it's working fine when I'm placing it in the center of the main window or when I'm showing it in a separate window, but when I'm trying to create a Widget container in the main window and promote widget to it, it gives me some errors:
'videowindow' does not name a type
'widget' was not declared in this scope
expected type-specifier before 'videowindow'
So, here is the code:
videowindow.h - header of my implemented class
#ifndef VIDEOWINDOW_H
#define VIDEOWINDOW_H
#include "mainwindow.h"
class videoWindow
{
private:
QMediaPlayer *player;
QMediaPlaylist *playlist;
public:
videoWindow();
void video_enable();
void widget();
};
#endif // VIDEOWINDOW_H
videowindow.cpp - source
#include "videowindow.h"
#include "mainwindow.h"
videoWindow::videoWindow()
{
}
void videoWindow::video_enable()
{
player = new QMediaPlayer;
playlist = new QMediaPlaylist;
playlist->addMedia(QUrl::fromLocalFile("D:\\фото\\video\\P1150277.MOV"));
QVideoWidget *videoWid = new QVideoWidget;
player->setVideoOutput(videoWid);
videoWid->show();
player->setPlaylist(playlist);
playlist->setCurrentIndex(1); // start from a first video in the playlist
player->play();
}
mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QtMultimedia>
#include <QtMultimediaWidgets>
#include <QtDebug>
#include <string>
#include <QGraphicsVideoItem>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "videowindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
main.cpp
#include "mainwindow.h"
#include "videowindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
InstantPlayer.pro - .pro file of the project
#-------------------------------------------------
#
# Project created by QtCreator 2016-06-24T11:37:26
#
#-------------------------------------------------
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = InstantPlayers
TEMPLATE = app
#
QT += multimedia
QT += multimediawidgets
#
SOURCES += main.cpp\
mainwindow.cpp \
videowindow.cpp \
playerbase.cpp
HEADERS += mainwindow.h \
videowindow.h \
playerbase.h
FORMS += mainwindow.ui \
playerbase.ui
I would like to make a simple QT mainwindow with the button to open a second window or dialog. I followed literally the step from the QT link "Using a Designer UI File in Your Application" and following the single inheritance example.
But QT gives 4 errors , which you will see a snapshot of below.
Now, what I did is I created a mainwindow in Qt designer, then I added a second form to the project , which will be the second dialog window when a button clicked. Because I created the form manually "mydialog.ui", I added class "mydialog.h and mydialog.cpp" and put the header of "ui-mydialog" in the source file "mydialog.cpp".
I' not sure what am I missing ?
Below is the code :
- mydialog.h
#ifndef MYDIALOG_H
#define MYDIALOG_H
#include<QWidget>
class mydialog ;
namespace Ui {
class mydialog;
}
class mydialog : public QWidget
{
Q_OBJECT
public:
explicit mydialog(QWidget *parent = 0);
virtual ~mydialog();
private :
Ui::mydialog *ui;
};
#endif // MYDIALOG_H
- mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QtCore/QtGlobal>
#include <QMainWindow>
QT_USE_NAMESPACE
QT_BEGIN_NAMESPACE
namespace Ui {
class MainWindow;
}
QT_END_NAMESPACE
class mydialog;
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
void on_Start_clicked();
private:
Ui::MainWindow *ui;
mydialog *dialog1;
};
#endif // MAINWINDOW_H
- mydialog.cpp
#include"mydialog.h"
#include "ui_mydialog.h"
mydialog::mydialog(QWidget *parent) : QWidget(parent), ui(new Ui::mydialog)
{
ui->setupUi(this);
}
mydialog::~mydialog()
{
delete ui;
}
- mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include"mydialog.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
dialog1 = new mydialog ;
}
MainWindow::~MainWindow()
{
delete ui;
delete dialog1;
}
void MainWindow::on_Start_clicked()
{
}
- main.cpp
#include"mainwindow.h"
#include<QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
- The .pro file
#-------------------------------------------------
#
# Project created by QtCreator 2015-12-17T00:10:58
#
#-------------------------------------------------
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = TestTool
TEMPLATE = app
SOURCES += main.cpp\
mainwindow.cpp \
mydialog.cpp
HEADERS += mainwindow.h \
mydialog.h
FORMS += mainwindow.ui \
mydialog.ui
RESOURCES += \
misc.qrc
- Qt compilation output error
Compilation error
The generated file Ui_mydialog.h is :
#ifndef UI_MYDIALOG_H
#define UI_MYDIALOG_H
#include <QtCore/QVariant>
#include <QtWidgets/QAction>
#include <QtWidgets/QApplication>
#include <QtWidgets/QButtonGroup>
#include <QtWidgets/QDialog>
#include <QtWidgets/QDialogButtonBox>
#include <QtWidgets/QHeaderView>
QT_BEGIN_NAMESPACE
class Ui_Dialog
{
public:
QDialogButtonBox *buttonBox;
void setupUi(QDialog *Dialog)
{
if (Dialog->objectName().isEmpty())
Dialog->setObjectName(QStringLiteral("Dialog"));
Dialog->resize(400, 300);
buttonBox = new QDialogButtonBox(Dialog);
buttonBox->setObjectName(QStringLiteral("buttonBox"));
buttonBox->setGeometry(QRect(30, 240, 341, 32));
buttonBox->setOrientation(Qt::Horizontal);
buttonBox->setStandardButtons(QDialogButtonBox::Cancel|QDialogButtonBox::Ok);
retranslateUi(Dialog);
QObject::connect(buttonBox, SIGNAL(accepted()), Dialog, SLOT(accept()));
QObject::connect(buttonBox, SIGNAL(rejected()), Dialog, SLOT(reject()));
QMetaObject::connectSlotsByName(Dialog);
} // setupUi
void retranslateUi(QDialog *Dialog)
{
Dialog->setWindowTitle(QApplication::translate("Dialog", "Dialog", 0));
} // retranslateUi
};
namespace Ui {
class Dialog: public Ui_Dialog {};
} // namespace Ui
QT_END_NAMESPACE
#endif // UI_MYDIALOG_H
This is because of the diferences between the names in your UI- und C++sourcecode files.
For example if in your UI-sourcecode file you have a name like "StatusBarPart"
but the name of your class in the C++ file is "StatusBar"
<class>StatusBarPart</class>
<widget class="QWidget" name="StatusBarPart">
StatusBar::StatusBar(QWidget *parent)
: PartBase(parent),
ui(new Ui::StatusBar)
then you you get these error message you see.
Solution:
You can edit the UI file in some external editor and make the names equal. Save changes. Compile your app. Be happy ;-)
You are mixing the name of the ui file with the name of the Ui class (objectName of the top level widget in QtDesigner).
For example, if QtDesigner looks like that:
You'll get a class names Ui::CalculatorForm, whatever the .ui file name is.
Replace Ui::mydialog by Ui::Dialog (or whatever the class name is in your generated ui_mydialog.h file)
I'm new to Qt and am trying to figure out how to add a custom widget I've created to my main window.
The widget is pretty simple - I just used Qt Designer to create the default widget (I'm calling it Editor) and then added a button to it. Next I included the header of my custom widget in mainwindow.h and added a pointer to it in my MainWindow class. So far, so good. But when I try to create a new instance of Editor, I get the error:
mainwindow.obj:-1: error: LNK2019: unresolved external symbol "public: __cdecl Editor::Editor(class QWidget *)" (??0Editor##QEAA#PEAVQWidget###Z) referenced in function "public: __cdecl MainWindow::MainWindow(class QWidget *)" (??0MainWindow##QEAA#PEAVQWidget###Z)
What do I need to do to be able to link my code?
mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "editor.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
Editor *editor;
};
#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);
editor = new Editor(0);
}
MainWindow::~MainWindow()
{
delete ui;
delete editor;
}
editor.h:
#ifndef EDITOR_H
#define EDITOR_H
#include <QWidget>
namespace Ui {
class Editor;
}
class Editor : public QWidget
{
Q_OBJECT
public:
explicit Editor(QWidget *parent = 0);
~Editor();
private:
Ui::Editor *ui;
};
#endif // EDITOR_H
editor.cpp:
#include "editor.h"
#include "ui_editor.h"
Editor::Editor(QWidget *parent) :
QWidget(parent),
ui(new Ui::Editor)
{
ui->setupUi(this);
}
Editor::~Editor()
{
delete ui;
}
CustomWidgetTest.pro:
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = CustomWidgetTest
TEMPLATE = app
SOURCES += main.cpp\
mainwindow.cpp \
editor.cpp
HEADERS += mainwindow.h \
editor.h
FORMS += mainwindow.ui \
editor.ui
So I've been developing a small ACARS (plane tracking system) for the VATSIM network and apart of this entails using the FSUIPC library to interact with Flight Sim X. I have the program working beautifully in VS2010 but when I attempt to use any functions from FSUIPC I get the error:
"mainwindow.obj:-1: error: LNK2019: unresolved external symbol FSUIPC_Open referenced in **function "public: void __cdecl MainWindow::connectFSUIPC(void)" (?connectFSUIPC#MainWindow##QEAAXXZ)"**
From some research I've learnt that this is a library load error and for the life of me I can't figure out how to get it working. Below is the code for all files I am using.
AcarsTest.pro
#-------------------------------------------------
#
# Project created by QtCreator 2013-12-16T23:56:06
#
#-------------------------------------------------
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = AcarsTest
TEMPLATE = app
SOURCES += main.cpp\
mainwindow.cpp
HEADERS += mainwindow.h
FORMS += mainwindow.ui
INCLUDEPATH += "D:/Windows/QT/Tools/QtCreator/bin/AcarsTest/"
LIBS += -LD:/Windows/QT/Tools/QtCreator/bin/AcarsTest/ -lFSUIPC_User
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <Windows.h>
#include <FSUIPC_User.h>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
void connectFSUIPC();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
main.cpp
#include <Windows.h>
#include "mainwindow.h"
#include <QApplication>
#include "FSUIPC_User.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
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::connectFSUIPC()
{
DWORD dwResult;
if(FSUIPC_Open(SIM_ANY, &dwResult))
{
}
}
try change code like this
your code:
LIBS += -LD:/Windows/QT/Tools/QtCreator/bin/AcarsTest/ -lFSUIPC_User
replace by
win32:LIBS += "D:/Windows/QT/Tools/QtCreator/bin/AcarsTest/FSUIPC_User.lib"