In a recent project, I tried to draw points on a scene after clicking on the corresponding location within GraphicsView, but nothing happend. I tracked the error down to a missing call of ClickableMap::mousePressEvent(const QMouseEvent&).
In this minimal example, nothing is printed after a mouse click on the white Widget, but a message should be printed. I will load an image into the scene, if needed.
What goes wrong here? Many thanks in advance!
ClickableMap.h:
#ifndef CLICKABLEMAP_H
#define CLICKABLEMAP_H
#include <QMouseEvent>
#include <QGraphicsView>
#include <QPoint>
class ClickableMap: public QGraphicsView {
Q_OBJECT
public:
using QGraphicsView::QGraphicsView; // seit C++ 11, benötigt wird mindestens GCC 4.8
// Destruktor entfällt, da argumentlos
void mousePressEvent(const QMouseEvent& event);
signals:
void mousePressed(const QPoint&);
};
#endif // CLICKABLEMAP_H
MainWindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QDebug>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
public slots:
void erster_klick(const QPoint& punkt);
};
#endif // MAINWINDOW_H
ClickableMap.cpp:
#include <QMouseEvent>
#include <QPoint>
#include "ClickableMap.h"
#include <QDebug>
#include <QMessageBox>
void ClickableMap::mousePressEvent(const QMouseEvent& event){
const QPoint& punkt = event.pos();
qDebug() << "Maus gepresst";
QMessageBox::information(this, tr("Dialog"), "Detected click in Drawspace");
emit mousePressed(punkt);
}
main.cpp:
#include "mainwindow.h"
#include <QApplication>
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);
connect(ui->graphicsView, &ClickableMap::mousePressed, this, erster_klick);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::erster_klick(const QPoint& punkt){
qDebug() << "Ich bin nun im Slot";
qDebug() << punkt;
}
mainwindow.ui:
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>300</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralWidget">
<widget class="ClickableMap" name="graphicsView">
<property name="geometry">
<rect>
<x>80</x>
<y>20</y>
<width>256</width>
<height>192</height>
</rect>
</property>
<property name="mouseTracking">
<bool>true</bool>
</property>
</widget>
</widget>
<widget class="QMenuBar" name="menuBar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>26</height>
</rect>
</property>
</widget>
<widget class="QToolBar" name="mainToolBar">
<attribute name="toolBarArea">
<enum>TopToolBarArea</enum>
</attribute>
<attribute name="toolBarBreak">
<bool>false</bool>
</attribute>
</widget>
<widget class="QStatusBar" name="statusBar"/>
</widget>
<layoutdefault spacing="6" margin="11"/>
<customwidgets>
<customwidget>
<class>ClickableMap</class>
<extends>QGraphicsView</extends>
<header>clickablemap.h</header>
</customwidget>
</customwidgets>
<resources/>
<connections/>
</ui>
Testanwendung.pro:
#-------------------------------------------------
#
# Project created by QtCreator 2017-09-18T19:53:12
#
#-------------------------------------------------
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = Testanwendung
TEMPLATE = app
# The following define makes your compiler emit warnings if you use
# any feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += \
main.cpp \
mainwindow.cpp \
clickablemap.cpp
HEADERS += \
mainwindow.h \
clickablemap.h
FORMS += \
mainwindow.ui
When overriding parent methods it is necessary to copy the names exactly as they were written to the parent, according to the docs:
void QGraphicsView::mousePressEvent(QMouseEvent *event)
That is to say it receives as a parameter a pointer and not a reference, in your case you must make the following changes:
*.h
void mousePressEvent(QMouseEvent *event);
*.cpp
void ClickableMap::mousePressEvent(QMouseEvent *event){
const QPoint& punkt = event->pos();
qDebug() << "Maus gepresst";
QMessageBox::information(this, tr("Dialog"), "Detected click in Drawspace");
emit mousePressed(punkt);
}
You should also change the following:
connect(ui->graphicsView, &ClickableMap::mousePressed, this, erster_klick);
to:
connect(ui->graphicsView, &ClickableMap::mousePressed, this, &MainWindow::erster_klick);
Related
This took me awhile to figure out... but whenever I try to use a QWidget's move() (or even setGeometry) function that has a child QWidgit with a QGraphicsOpacityEffect assigned to it, it causes the QWidgit to have a black border along the right and bottom sides.
The border is exactly the size of the amount of pixels that I moved. If I increase the amount I move the widget, the border increases also...
If I remove the move() call, the problem is fixed... If I use 0.99 instead of 1.0 in the setOpacity() call, it fixes the problem...
Here's a picture of the issue...
Does anyone know how to avoid/fix this...?
Here's my code.
mainwindow.ui
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>560</width>
<height>351</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralWidget">
<widget class="QWidget" name="TestHolder2" native="true">
<property name="geometry">
<rect>
<x>200</x>
<y>90</y>
<width>120</width>
<height>80</height>
</rect>
</property>
</widget>
</widget>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
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
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
ui->TestHolder2->resize(450, 250);
ui->TestHolder2->move(11, 11);
ui->TestHolder2->setStyleSheet("background-color: black;");
QWidget* new_widget = new QWidget(ui->TestHolder2);
new_widget->setStyleSheet("background-color:red;");
new_widget->resize(450, 250);
QGraphicsOpacityEffect* opacity_effect = new QGraphicsOpacityEffect(new_widget);
new_widget->setGraphicsEffect(opacity_effect);
opacity_effect->setOpacity(1);
}
MainWindow::~MainWindow()
{
delete ui;
}
main.cpp
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
I have a serial comport data read write program. Data is being read from the comport 4 (Eg: 1022), but when I'm trying to do a mathematical calculation of the data 1022/2 then its give me output as 0.5 5.0 51.00 511.0 means its not taking the whole 1022 as a single number for the mathematical calculation. Its take 1 first then divide 1/2=0.5 then once 0 digit receive it take as 10/2=5 and so on. But I want 1022 as a single digit number like (eg: 1022/2=511)
I have tried to convert the QByteArray into Double for the calculation.
void MainWindow::readData()
{
QByteArray data = serial->readAll();
bool ok;
QByteArray cata= QByteArray::number(data.toDouble(&ok)/2);
console->putData(cata);
}
So here an example of a TCP client/server in Qt. the server sends 1022.72, and the client receives it and shows the result value divided by 2. (run the server then the client:
Server Code:
test.pro:
#-------------------------------------------------
#
# Project created by QtCreator 2017-06-26T12:49:54
#
#-------------------------------------------------
QT += core gui network
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = test
TEMPLATE = app
# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += main.cpp\
mainwindow.cpp
HEADERS += mainwindow.h
FORMS += mainwindow.ui
main.cpp:
#include "mainwindow.h"
#include <QApplication>
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"
#include <QDebug>
#include <QHostAddress>
#include <QAbstractSocket>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow),
_server(this)
{
ui->setupUi(this);
_server.listen(QHostAddress::Any, 4242);
connect(&_server, SIGNAL(newConnection()), this, SLOT(onNewConnection()));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::onNewConnection()
{
QTcpSocket *clientSocket = _server.nextPendingConnection();
connect(clientSocket, SIGNAL(readyRead()), this, SLOT(onReadyRead()));
connect(clientSocket, SIGNAL(stateChanged(QAbstractSocket::SocketState)), this, SLOT(onSocketStateChanged(QAbstractSocket::SocketState)));
_sockets.push_back(clientSocket);
for (QTcpSocket* socket : _sockets) {
double data = 1022.72;
// socket->write(QByteArray::fromStdString(clientSocket->peerAddress().toString().toStdString() + " connected to server !\n"));
socket->write(QByteArray::fromStdString(QVariant(data).toString().toStdString()));
}
}
void MainWindow::onSocketStateChanged(QAbstractSocket::SocketState socketState)
{
if (socketState == QAbstractSocket::UnconnectedState)
{
QTcpSocket* sender = static_cast<QTcpSocket*>(QObject::sender());
_sockets.removeOne(sender);
}
}
void MainWindow::onReadyRead()
{
QTcpSocket* sender = static_cast<QTcpSocket*>(QObject::sender());
QByteArray datas = sender->readAll();
for (QTcpSocket* socket : _sockets) {
if (socket != sender)
socket->write(QByteArray::fromStdString(sender->peerAddress().toString().toStdString() + ": " + datas.toStdString()));
}
}
mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QTcpServer>
#include <QTcpSocket>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
public slots:
void onNewConnection();
void onSocketStateChanged(QAbstractSocket::SocketState socketState);
void onReadyRead();
private:
Ui::MainWindow *ui;
QTcpServer _server;
QList<QTcpSocket*> _sockets;
};
#endif // MAINWINDOW_H
mainwindow.ui: (empty)
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>300</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralWidget">
<layout class="QVBoxLayout" name="verticalLayout_2">
<item>
<layout class="QVBoxLayout" name="verticalLayout"/>
</item>
</layout>
</widget>
<widget class="QMenuBar" name="menuBar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>25</height>
</rect>
</property>
</widget>
<widget class="QToolBar" name="mainToolBar">
<attribute name="toolBarArea">
<enum>TopToolBarArea</enum>
</attribute>
<attribute name="toolBarBreak">
<bool>false</bool>
</attribute>
</widget>
<widget class="QStatusBar" name="statusBar"/>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>
Client code:
test2.pro:
#-------------------------------------------------
#
# Project created by QtCreator 2017-06-26T14:34:11
#
#-------------------------------------------------
QT += core gui network
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = test2
TEMPLATE = app
# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += main.cpp\
mainwindow.cpp
HEADERS += mainwindow.h
FORMS += mainwindow.ui
main.cpp:
#include "mainwindow.h"
#include <QApplication>
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"
#include <QDebug>
#include <QHostAddress>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow),
_socket(this)
{
ui->setupUi(this);
_socket.connectToHost(QHostAddress("127.0.0.1"), 4242);
connect(&_socket, SIGNAL(readyRead()), this, SLOT(onReadyRead()));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::onReadyRead()
{
QByteArray datas = _socket.readAll();
qDebug() << QVariant(datas).toDouble() / 2;
ui->label->setText(QVariant(QVariant(datas).toDouble() / 2).toString());
_socket.write(QByteArray("ok !\n"));
}
mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QTcpSocket>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
public slots:
void onReadyRead();
private:
Ui::MainWindow *ui;
QTcpSocket _socket;
};
#endif // MAINWINDOW_H
mainwindow.ui: (result written here and also with qDebug)
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>300</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralWidget">
<layout class="QVBoxLayout" name="verticalLayout_2">
<item>
<layout class="QVBoxLayout" name="verticalLayout">
<item>
<widget class="QLabel" name="label">
<property name="text">
<string/>
</property>
</widget>
</item>
</layout>
</item>
</layout>
</widget>
<widget class="QMenuBar" name="menuBar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>25</height>
</rect>
</property>
</widget>
<widget class="QToolBar" name="mainToolBar">
<attribute name="toolBarArea">
<enum>TopToolBarArea</enum>
</attribute>
<attribute name="toolBarBreak">
<bool>false</bool>
</attribute>
</widget>
<widget class="QStatusBar" name="statusBar"/>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>
My open file dialog in Qt5 is being cut off and it doesn't respond to any mouse clicks. I'm using an OpenGLWindow (per http://doc.qt.io/qt-5/qtgui-openglwindow-example.html) inside the central widget of the QMainWindow (per http://blog.qt.io/blog/2013/02/19/introducing-qwidgetcreatewindowcontainer/). If I don't set the central widget to my OpenGLWindow, then the open file dialog works, but once I use the OpenGLWindow in the central widget, then this problem occurs. See the screenshot below. Any ideas on how to fix this or debug it?
main.cpp:
...
QApplication app(argc, argv);
QSurfaceFormat format;
format.setSamples(16);
MainWindow mainWin;
MyOpenGLWindow window();
window.setFormat(format);
window.setAnimating(true);
QWidget *container = QWidget::createWindowContainer(&window);
mainWin.setCentralWidget(container);
#if defined(Q_OS_SYMBIAN)
mainWin.showMaximized();
#else
mainWin.show();
#endif
....
mainwindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QFileDialog>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_actionOpen_File_triggered()
{
QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"), "/home");
}
mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
private slots:
void on_actionOpen_File_triggered();
};
#endif // MAINWINDOW_H
mainwindow.ui:
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>800</width>
<height>600</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralwidget"/>
<widget class="QMenuBar" name="menubar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>800</width>
<height>25</height>
</rect>
</property>
<widget class="QMenu" name="menuTest_Window">
<property name="title">
<string>File</string>
</property>
<addaction name="actionOpen_File"/>
</widget>
<addaction name="menuTest_Window"/>
</widget>
<widget class="QStatusBar" name="statusbar"/>
<action name="actionOpen_File">
<property name="text">
<string>Open File</string>
</property>
</action>
</widget>
<resources/>
<connections/>
</ui>
It seems that the way to solve this is to use an QOpenGLWidget (per https://blog.qt.io/blog/2014/09/10/qt-weekly-19-qopenglwidget/). The QWindow approach to using OpenGL doesn't seem to mix well with other QWidgets. I successfully transferred my application to use a QOpenGLWidget now and it works!
I want to use my global qss stylesheet with a derived class. I understand I have to override the paintEvent (style sheet reference , or here).
void CustomWidget::paintEvent(QPaintEvent *) {
QStyleOption opt;
opt.init(this); // tried initFrom too, same result=>not working
QPainter p(this);
style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);
}
However, it does not seem to work. With CDerived:QWidget and the following style sheet lines I face:
CDerived { background-color: black; } // no effect
QWidget { background-color: black; } // works
CDerived implements paintEvent as above. Anything else I need to do?
-- Edit / Solution --
Thanks to JK's hint I have figured it out. My above example is actually not correctly reflecting my scenario. My real class resides in a C++ namespace (my mistake I have missed that). So I have to write MyNamespace--CDerived in the qss. See "Widgets inside C++ namespaces"
After I have tried JK's simple example here, I suddenly realized my mistake!
Correct one:
MyNamespace--CDerived { background-color: black; } // works, use -- for ::
Remarks: Relateds SO question (a,b), but with no answer to this particular question. My derived class resides in a C++ namespace.
It is strange....it works fine for me:
untitled.pro:
#-------------------------------------------------
#
# Project created by QtCreator 2014-10-07T11:34:54
#
#-------------------------------------------------
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = untitled
TEMPLATE = app
SOURCES += main.cpp\
mainwindow.cpp \
mywidget.cpp
HEADERS += mainwindow.h \
mywidget.h
FORMS += mainwindow.ui
mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
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"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
mainwindow.ui:
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>300</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<property name="styleSheet">
<string notr="true"/>
</property>
<widget class="QWidget" name="centralWidget">
<widget class="MyWidget" name="widget" native="true">
<property name="geometry">
<rect>
<x>70</x>
<y>30</y>
<width>201</width>
<height>121</height>
</rect>
</property>
<property name="styleSheet">
<string notr="true"/>
</property>
<widget class="QPushButton" name="pushButton">
<property name="geometry">
<rect>
<x>30</x>
<y>20</y>
<width>75</width>
<height>23</height>
</rect>
</property>
<property name="text">
<string>PushButton</string>
</property>
</widget>
</widget>
</widget>
<widget class="QMenuBar" name="menuBar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>21</height>
</rect>
</property>
</widget>
<widget class="QToolBar" name="mainToolBar">
<attribute name="toolBarArea">
<enum>TopToolBarArea</enum>
</attribute>
<attribute name="toolBarBreak">
<bool>false</bool>
</attribute>
</widget>
<widget class="QStatusBar" name="statusBar"/>
</widget>
<layoutdefault spacing="6" margin="11"/>
<customwidgets>
<customwidget>
<class>MyWidget</class>
<extends>QWidget</extends>
<header>mywidget.h</header>
<container>1</container>
</customwidget>
</customwidgets>
<resources/>
<connections/>
</ui>
mywidget.h:
#ifndef MYWIDGET_H
#define MYWIDGET_H
#include <QWidget>
class MyWidget : public QWidget
{
Q_OBJECT
public:
explicit MyWidget(QWidget *parent = 0);
protected:
void paintEvent(QPaintEvent *e);
};
#endif // MYWIDGET_H
mywidget.cpp:
#include "mywidget.h"
#include <QStyleOption>
#include <QPainter>
MyWidget::MyWidget(QWidget *parent) :
QWidget(parent)
{
}
void MyWidget::paintEvent(QPaintEvent *e)
{
Q_UNUSED(e)
QStyleOption opt;
opt.init(this); // tried initFrom too, same result=>not working
QPainter p(this);
style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);
}
main.cpp:
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
a.setStyleSheet("MyWidget { background-color: red; }");
MainWindow w;
w.show();
return a.exec();
}
I've been using Qt5 on MS Windows 7 for a while. All of the sudden I cannot compile even the default scaffold for a GUI (Forms) application. I get the following error:
main.cpp
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
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"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
project.pro
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = RagnSells3
TEMPLATE = app
SOURCES += main.cpp\
mainwindow.cpp
HEADERS += mainwindow.h
FORMS += mainwindow.ui
mainwindow.ui
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow" >
<property name="geometry" >
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>300</height>
</rect>
</property>
<property name="windowTitle" >
<string>MainWindow</string>
</property>
<widget class="QMenuBar" name="menuBar" />
<widget class="QToolBar" name="mainToolBar" />
<widget class="QWidget" name="centralWidget" />
<widget class="QStatusBar" name="statusBar" />
</widget>
<layoutDefault spacing="6" margin="11" />
<pixmapfunction></pixmapfunction>
<resources/>
<connections/>
</ui>