A QDialog can't be exited on Windows, but not on MacOS/ - c++

I have a dialog in Qt5(C++). You can see that the dialog just creates some widgets (VisGLWidget from QOpenGLWidget) and keeps updating it.
#include "visualizationdlg.h"
#include "ui_visualizationdlg.h"
VisualizationDlg::VisualizationDlg(QWidget *parent, NewtonSpace *data) :
QDialog(parent),
ui(new Ui::VisualizationDlg)
{
ui->setupUi(this);
this->setFixedSize(600,600);
this->data = data;
this->visualizationGL = new VisGLWidget(this, this->data);
this->visualizationGL->setObjectName(QString::fromUtf8("visualizationGL"));
this->visualizationGL->setGeometry(QRect(10, 50, 581, 541));
this->visualizationGL->repaint();
this->rePaintTimer = startTimer(1);
}
VisualizationDlg::~VisualizationDlg()
{
delete ui;
}
void VisualizationDlg::timerEvent(QTimerEvent *event)
{
if(event->timerId() == this->rePaintTimer) {
this->data->update(ui->GInput->value(), ui->updateSpdInput->value());
this->visualizationGL->repaint();
this->rePaintTimer = startTimer(1);
}
}
The question is, I can quit this dialog by clicking the cross on MacOS, but not on Windows. What's wrong with it?

In your VisualizationDlg constructor you have...
this->rePaintTimer = startTimer(1);
That will result in a QTimerEvent being sent to your VisualizationDlg instance once every millisecond (potentially).
Now consider the code that handles timer events...
void VisualizationDlg::timerEvent (QTimerEvent *event)
{
if(event->timerId() == this->rePaintTimer) {
this->data->update(ui->GInput->value(), ui->updateSpdInput->value());
this->visualizationGL->repaint();
this->rePaintTimer = startTimer(1);
}
}
The first time this is invoked the id associated with the timer event will match rePaintTimer. Hence repaint will be called. But you then start a new timer and assign its id to rePaintTimer without stopping the original timer. You now have two timers each generating events at 1KHz but your event handler only ever acts on events from the most recently created timer.
Now think what this will become after even a few seconds. You could potentially have thousands of timers each generating events at 1KHz.
Remove the line...
this->rePaintTimer = startTimer(1);
from your event handler to make it...
void VisualizationDlg::timerEvent (QTimerEvent *event)
{
if(event->timerId() == this->rePaintTimer) {
this->data->update(ui->GInput->value(), ui->updateSpdInput->value());
this->visualizationGL->repaint();
}
}

Related

How to show a QToolTip on mouse press event and leave it popped up for some time? Qt

Trying to show a tool tip on mouse press event and make it popped up for some time. For now it shows only if a mouse button is pressed.
void ::mousePressEvent(QMouseEvent* e)
{
if (!m_isLinkingAvailable)
{
QToolTip::showText(e->screenPos().toPoint(),
tr("Symbol Linking\navailable only for Price"), this);
}
}
According to the Qt Docs, looks like there's an alternate method for this function:
void QToolTip::showText(const QPoint &pos, const QString &text, QWidget *w, const QRect &rect, int msecDisplayTime)
You should be able to specify a time for how long to display the tooltip.
EDIT:
Okay so seems like this method doesn't work as expected with a mousePress event, so here's an alternative using a QTimer:
Add these to your class:
MyConstructor(...params...)
, m_tooltipTimer(new QTimer(this)) // don't forget this line
{
connect(m_tooltipTimer, SIGNAL(timeout()), this, SLOT(updateTooltip()));
setAcceptedMouseButtons(Qt::AllButtons);
}
...
public slots:
void mousePressEvent(QMouseEvent *event) override;
void updateTooltip();
...
private:
QPoint m_tooltipPos;
qint64 m_tooltipTimerStart;
QTimer *m_tooltipTimer;
And then implement these in your .cpp
void ::mousePressEvent(QMouseEvent *event) {
m_tooltipTimer->start(200); // 5x per second, automatically resets timer if already started
m_tooltipTimerStart = QDateTime::currentMSecsSinceEpoch();
m_tooltipPos = event->globalPos();
event->accept();
}
void ::updateTooltip() {
auto howLongShown = QDateTime::currentMSecsSinceEpoch() - m_tooltipTimerStart; // startTime here is the moment of first showing of the tooltip
qDebug() << howLongShown;
if (howLongShown < 1000) { // 1 sec
QToolTip::showText(m_tooltipPos, tr("Test Tooltip")); // Replace this with your own
} else {
QToolTip::hideText();
m_tooltipTimer->stop();
}
}
Thanks to #Ian Burns's answer I have manged to create own approach:
void ::mousePressEvent(QMouseEvent*)
{
QTimer::singleShot(200, [this]()
{
QToolTip::showText(mapToGlobal({}),
tr("Symbol Linking\navailable only for Price"), this);
});
}
Somehow if I show a tooltip inside mousePressEvent method it disappears immediately after I unpress the mouse button. QTimer delays the pop up call and it stays popped for reasonable time.

Qt - Why can't I trigger mousePressEvent for my custom button in MainWindow

This is my first time to ask on Stack Overflow. If any suggestion about asking question, please let me know.
I am very new to Qt, and have some problems while using event. Hope someone can provide any thoughts.
Background:
I have my custom pushButton, which is rxPushButton in rx.h and rx.cpp. I use on_rxPushButton_clicked to change the image and it works pretty well.
In MainWindow, I need to use some rx so I include the class rx and I want to detect if I press left button of the mouse, I need to know which rx has been pressed and record its id in int rxId in MainWindow.
Problem:
I tried two ways to achieve my goal, including mousePressEvent and eventFilter. I found that I can't detect the mouse pressed signal on any rx, but I can detect it outside rx in other places in Mainwindow. I wonder if the events will conflict, but when I comment on_rxPushButton_clicked in rx.cpp, MainWindow still doesn't work for the problem. So I presume that maybe the space in the screen occupied by rx will not be in control of MainWindow (I can get Debug message "test1" but not "test2" in my code, check below).
How should I do to solve this problem if I need both things (change image in rx and modify one variable in MainWindow)? Or maybe it's just something wrong with my code and how to modify?
I hope to separate them if possible because I still need to include many objects in MainWindow in the future.
Here are some of my related codes:
rx.cpp
void rx::on_rxPushButton_clicked(void)
{
startLoading();
}
void rx::startLoading(void)
{
state = 1;
connect(timer, SIGNAL(timeout()), this, SLOT(loading1()));
timer->start(LOADING_INTERVAL);
}
void rx::loading1(void)
{
if(state == 1)
{
state = 2;
ui->rxPushButton->setStyleSheet("border-image: url(:/images/Rx/Rxloading1.png);");
disconnect(timer, SIGNAL(timeout()), this, SLOT(loading1()));
}
}
mainwindow.cpp
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
for(int i = 0 ; i < rxSize ; i++)
{
rxList << new rx(this);
int j = i/rxHorizontalCount;
rxList[i]->setGeometry(500+(i-j*8)*110,10+j*90,100,90);
}
//rxList[0]->installEventFilter(this);
}
void MainWindow::mousePressEvent(QMouseEvent *event)
{
if(event->buttons() & Qt::LeftButton)
{
qDebug() << "test1";
if(rxList[0]->rect().contains(event->x(), event->y()))
qDebug() << "test2";
}
}
Change image in rx
Use QSignalMapper class that bundles signals from QWidgets (class rx) and re-emits them with widget (class rx) parameters corresponding to the object that sent the signal.
We connect each button's clicked() signal to the signal mapper's map() slot, and create a mapping in the signal mapper from each button to the button itself.
Finally we connect the signal mapper's mapped() signal to the custom widget's(rx object) clicked() signal. When the user clicks a button, the custom widget(rx object) will emit a single clicked() signal whose argument is the button (rx object) the user clicked.
Handle the button clicked event in MainWindow::slotButtonsClicked(QWidget *p) function.
Modify n variable in MainWindow:
You can update variable of MainWindow in mousePressEvent function
class MainWindow : public QWidget
{
public :
MainWindow (QWidget *parent);
QSignalMapper * mapper;
slots:
void slotButtonsClicked(QWidget *);
// ...
}
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
mapper = new QSignalMapper(this);
for(int i = 0 ; i < rxSize ; i++)
{
rxList << new rx(this);
int j = i/rxHorizontalCount;
rxList[i]->setGeometry(500+(i-j*8)*110,10+j*90,100,90);
QObject::connect(rxList[i], SIGNAL(clicked()),mapper,SLOT(map()));
//Adds a mapping so that when map() is signalled from the sender, the signal mapped(widget ) is emitted.
mapper->setMapping(rxList[i], rxList[i]);
}
QObject::connect(mapper,SIGNAL(mapped(QWidget *)),this,SLOT(slotButtonsClicked(QWidget *)));
}
void MainWindow::mousePressEvent(QMouseEvent *event)
{
if(event->buttons() & Qt::LeftButton)
{
qDebug() << "Clicked outside the button";
//Now you can modify n variable in MainWindow
}
MainWindow::mousePressEvent(event);
}
void MainWindow::slotButtonsClicked(QWidget *p)
{
rx *button = dynamic_cast<rx *>(p);
button->on_rxPushButton_clicked();
qDebug() << button <<" clicked on button";
//Now you can change image in rx
}
Hope this works :)
Event propagating prevent you to do it. When mouse is over Button, event sends to button, not to the MainWindow, thats why you never see test2 in debug output.
Since I don't know what do you need it's hard to say what you should do. You can process event in Button and send some signals or whatever, or set event filter and check if target object is your button, and so on.
Any way, read Qt event system docs for better understanding.

My Qt eventFilter() doesn't stop events as it should

Something is fundamentally wrong with my eventFilter, as it lets every single event through, while I want to stop everything. I've read lots of documentation on QEvent, eventFilter() and so on, but obviously I'm missing something big. Essentially, I'm trying to create my own modal-functionality for my popup-window class based on QDialog. I want to implement my own since the built-in setModal(true) includes a lot of features, e.g. playing QApplication::Beep(), that I want to exclude. Basically, I want to discard all events going to the QWidget (window) that created my popup. What I have so far is,
// popupdialog.h
#ifndef POPUPDIALOG_H
#define POPUPDIALOG_H
#include <QDialog>
#include <QString>
namespace Ui {class PopupDialog;}
class PopupDialog : public QDialog
{
Q_OBJECT
public:
explicit PopupDialog(QWidget *window=0, QString messageText="");
~PopupDialog();
private:
Ui::PopupDialog *ui;
QString messageText;
QWidget window; // the window that caused/created the popup
void mouseReleaseEvent(QMouseEvent*); // popup closes when clicked on
bool eventFilter(QObject *, QEvent*);
};
...
// popupdialog.cpp
#include "popupdialog.h"
#include "ui_popupdialog.h"
PopupDialog::PopupDialog(QWidget *window, QString messageText) :
QDialog(NULL), // parentless
ui(new Ui::PopupDialog),
messageText(messageText),
window(window)
{
ui->setupUi(this);
setAttribute(Qt::WA_DeleteOnClose, true); // Prevents memory leak
setWindowFlags(Qt::Window | Qt::FramelessWindowHint);
ui->message_text_display->setText(messageText);
window->installEventFilter(this);
//this->installEventFilter(window); // tried this also, just to be sure ..
}
PopupDialog::~PopupDialog()
{
window->removeEventFilter(this);
delete ui;
}
// popup closes when clicked on
void PopupDialog::mouseReleaseEvent(QMouseEvent *e)
{
close();
}
Here's the problem, the filter doesn't work. Note that if I write a std::cout
inside the if(...), I see that it does trigger whenever events are sent to window, it just doesn't stop them.
bool PopupDialog::eventFilter(QObject *obj, QEvent *e)
{
if( obj == window )
return true; //should discard the signal (?)
else
return false; // I tried setting this to 'true' also without success
}
When the user interacts with the main program, a PopupDialog can be created like this:
PopupDialog *popup_msg = new PopupDialog(ptr_to_source_window, "some text message");
popup_msg->show();
// I understand that naming the source 'window' might be a little confusing.
// I apologise for that. The source can in fact be any 'QWidget'.
Everything else works as expected. Only the event filter fails. I want the filter to remove events sent to the window that created the popup; like mouse clicking and key pressing, until the popup is closed. I'm expecting to be extremely embarrassed when someone points out a trivial fix in my code.
You have to ignore all events that arrive in the widget tree of the window. Therefore, you need to install the eventFilter application-wide and check, if the object you are filtering on is a descendant of window. In other words: Replace
window->installEventFilter(this);
by
QCoreApplication::instance()->installEventFilter(this);
and implement the event filter function this way:
bool PopupDialog::eventFilter(QObject *obj, QEvent *e)
{
if ( !dynamic_cast<QInputEvent*>( event ) )
return false;
while ( obj != NULL )
{
if( obj == window )
return true;
obj = obj->parent();
}
return false;
}
I tried it, tested it and it worked for me.
Note: Using event filters in Qt is a bit messy in my experience, since it is not quite transparent what is happening. Expect bugs to pop up from time to time. You may consider disabling the main window instead, if you and your clients don't have a problem with the grayed-out main window as a consequence.
After the massive amount of responses, feedback, suggestions and time ivested in extensive research I've finally found what I believe to be the optimal, and safest solution. I wish to express my sincere gratidtude to everyone for their aid to what Kuba Ober describes as "(...) not as simple of a problem as you think".
We want to filter out all certain events from a widget, including its children. This is difficult, because events may be caught in the childrens default eventfilters and responded to, before they are caught and filtered by the the parent's custom filter for which the programmer implements. The following code solves this problem by installing the filter on all children upon their creation. This example assumes the use of Qt Creator UI-forms and is based on the following blog post: How to install eventfilters for all children.
// The widget class (based on QMainWindow, but could be anything) for
// which you want to install the event filter on, includings its children
class WidgetClassToBeFiltered : public QMainWindow
{
Q_OBJECT
public:
explicit WidgetClassToBeFiltered(QWidget *parent = 0);
~WidgetClassToBeFiltered();
private:
bool eventFilter(QObject*, QEvent*);
Ui::WidgetClassToBeFiltered *ui;
};
...
WidgetClassToBeFiltered::WidgetClassToBeFiltered(QWidget *parent) :
QMainWindow(parent), // Base Class constructor
ui(new Ui::WidgetClassToBeFiltered)
{
installEventFilter(this); // install filter BEFORE setupUI.
ui->setupUi(this);
}
...
bool WidgetClassToBeFiltered::eventFilter(QObject *obj, QEvent* e)
{
if( e->type() == QEvent::ChildAdded ) // install eventfilter on children
{
QChildEvent *ce = static_cast<QChildEvent*>(e);
ce->child()->installEventFilter(this);
}
else if( e->type() == QEvent::ChildRemoved ) // remove eventfilter from children
{
QChildEvent *ce = static_cast<QChildEvent*>(e);
ce->child()->removeEventFilter(this);
}
else if( (e->type() == QEvent::MouseButtonRelease) ) // e.g. filter out Mouse Buttons Relases
{
// do whatever ..
return true; // filter these events out
}
return QWidget::eventFilter( obj, e ); // apply default filter
}
Note that this works, because the eventfilter installs itself on added children! Hence, it should also work without the use of UI-forms.
Refer this code to filter out specific event:-
class MainWindow : public QMainWindow
{
public:
MainWindow();
protected:
bool eventFilter(QObject *obj, QEvent *ev);
private:
QTextEdit *textEdit;
};
MainWindow::MainWindow()
{
textEdit = new QTextEdit;
setCentralWidget(textEdit);
textEdit->installEventFilter(this);
}
bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
if (obj == textEdit) {
if (event->type() == QEvent::KeyPress) {
QKeyEvent *keyEvent = static_cast<QKeyEvent*>(event);
qDebug() << "Ate key press" << keyEvent->key();
return true;
} else {
return false;
}
} else {
// pass the event on to the parent class
return QMainWindow::eventFilter(obj, event);
}
}
If you want to set more specific event filter on multiple widgets you can refer following code:
class KeyPressEater : public QObject
{
Q_OBJECT
protected:
bool eventFilter(QObject *obj, QEvent *event);
};
bool KeyPressEater::eventFilter(QObject *obj, QEvent *event)
{
if (event->type() == QEvent::KeyPress) {
QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
qDebug("Ate key press %d", keyEvent->key());
return true;
} else {
// standard event processing
return QObject::eventFilter(obj, event);
}
}
KeyPressEater *keyPressEater = new KeyPressEater(this);
QPushButton *pushButton = new QPushButton(this);
pushButton->installEventFilter(keyPressEater);

Qt Browser stack when dropping link to QMainWindow

I have simple drag and drop functions implemented in QmainWindow the reference taken from here and here
all i want to do is to accept valid url and open QDialog when the url dropped .
but when the url drooped and the QDialog poped up the browser is stocked in the background until i close the QDialog . this is wrong the browser should be free all the time.
here is my code :
void MainWindow::dragMoveEvent(QDragMoveEvent *event)
{
if (event->mimeData()->hasFormat("text/html"))
{
event->acceptProposedAction();
}
else
{
event->ignore();
}
}
void MainWindow::dragEnterEvent(QDragEnterEvent *event)
{
// accept just text/uri-list mime format
if (event->mimeData()->hasFormat("text/html"))
{
event->acceptProposedAction();
}
else
{
event->ignore();
}
}
void MainWindow::dragLeaveEvent(QDragLeaveEvent *event)
{
event->accept();
}
void MainWindow::dropEvent(QDropEvent *event)
{
QList<QUrl> urlList;
QString fName;
QStringList pathList;
QFileInfo info;
QString suffix;
if (event->mimeData()->hasFormat("text/html"))
{
urlList = event->mimeData()->urls(); // returns list of QUrls
// if just text was dropped, urlList is empty (size == 0)
if ( urlList.size() > 0) // if at least one QUrl is present in list
{
QString url = urlList.at(0).toString();
event->acceptProposedAction();
openDialog(url); // THIS IS THE FUNCTION THAT I OPEN THE QDIALOG window
}
}
//event->acceptProposedAction();
}
void MainWindow::openDialog(QString& slink)
{
QHash<QString,QVariant> DataMap;
QString link = slink;
DataMap.insert("m_webpage",link);
PublishToDialog* pPublishToDialog = new PublishToDialog(this);
pPublishToDialog->Init(DataMap);
if(pPublishToDialog->exec() != QDialog::Accepted)
{
}
}
when i remove the call to the QDialog , so every thing is working fine .
and the browser doesn't stuck. i even tryed as suggested using signal/slot put again
when i start the QDialog when drop invoked the browser stucked!
What exactly is PublishToDialog? I would assume that it is a custom dialog implementation of yours that inherits QDialog. And given this line:
pPublishToDialog->exec() != QDialog::Accepted
This opens the dialog as a modal dialog. A modal dialog is blocking and will block the execution of the current thread until some action is performed on the dialog. Instead of using a modal dialog, you should use a non-modal dialog. Since I am still not sure if PublishToDialog inherits QDialog or what else, I am just going to assume it is. Here is what you could do:
PublishToDialog* pPublishToDialog = new PublishToDialog(this);
// Make it a non-modal dialog
pPublishDialog->setModal(false);
// Connect it to a slot to handle whenever the user performs some action on it
QObject::connect(pPublishDialog, SIGNAL(finished()), this, SLOT(handleDialogAction());
pPublishDialog.show();
You will have to implement handleDialogAction in your code. At the same time, you may want to make pPublishDialog a class-member as you will need it to access QDialog::reuslt in handleDialogAction.

Qt progressBar getting Unhandled exception how detect when parent widget is done loading

im using Qt QProgressBar and place it in the statusBar on my main window
Like this in the constructor :
pb = new QProgressBar(statusBar());
pb->setTextVisible(false);
pb->hide();
statusBar()->addPermanentWidget(pb);
then im running procsses (web page loadding in this case )
and trying to show the progress with :
connect(ui.webView, SIGNAL(loadProgress(int)), SLOT(setProgress (int)));
void myMainWindow:: setProgress(int progress)
{
pb->show();
pb->setRange(0,100);
pb->setValue(progress);
}
But im getting Unhandled exception when it comes to pb->show()
I guess it has to do something with loading the parent main windows and then the progress bar
I was reading about the QAbstractEventDispatcher and processEvents but not understood how to implement it .
i did small test and put the pb->show() function call in button click signal/slut
that means im triggering the pb->show() after the web page and the mainwindows fully loaded and its working fine without the exception. that make me belive there is problem
with the event processing.
here is the class :
class MainWindowMainWindowContainer : public QMainWindow
{
Q_OBJECT
public:
MainWindowContainer(QWidget *parent = 0);
public slots:
void adjustLocation();
void changeLocation();
void adjustTitle();
void setProgress(int p);
void finishLoading(bool);
void finishedSlot(QNetworkReply* reply);
private:
Ui::OnLineBack_mainWindow ui;
int progress;
void createWebViewActions();
QProgressBar *pb;
void setprogressBar(int progress,bool show);
};
MainWindowContainer::MainWindowContainer(QWidget* parent) :
QMainWindow(parent),
{
ui.setupUi(this);
progress = 0;
createWebViewActions();
ui.webView->load(QUrl("www.cnnnn.com"));
ui.webView->show();
pb = new QProgressBar(statusBar());
pb->setTextVisible(false);
pb->hide();
statusBar()->addPermanentWidget(pb);
}
void MainWindowContainer::createWebViewActions()
{
connect(ui.webView, SIGNAL(loadFinished(bool)), SLOT(adjustLocation()));
connect(ui.webView, SIGNAL(titleChanged(QString)), SLOT(adjustTitle()));
connect(ui.webView, SIGNAL(loadProgress(int)), SLOT(setProgress(int)));
connect(ui.webView, SIGNAL(loadFinished(bool)), SLOT(finishLoading(bool)));
connect(ui.webView, SIGNAL(linkClicked(const QUrl&)),this, SLOT(linkClicked(const QUrl&)));
}
void MainWindowContainer::setProgress(int p)
{
progress = p;
adjustTitle();
}
void MainWindowContainer::adjustTitle()
{
qApp->processEvents();
pb->show();
if (progress <= 0 || progress >= 100)
{
QString titl = ui.webView->title();
statusBar()->showMessage(titl);
setprogressBar(-1,false);
}
else
{
statusBar()->showMessage(QString("%1 (%2%)").arg(ui.webView->title()).arg(progress));
setprogressBar(progress,true);
}
}
void MainWindowContainer::finishLoading(bool)
{
progress = 100;
adjustTitle();
}
void MainWindowContainer::setprogressBar(int progress,bool show)
{
if(show)
{
pb->show();
pb->setRange(0,100);
pb->setValue(progress);
}
else
{
pb->hide();
}
}
In your createWebViewActions() function you connect the signals to their respective slots. (One small remark, the connect for the titleChanged(QString) signal and adjustTitle() slot fails because they have different signatures)
Among others you are connecting the signal loadProgress(int) to slot setProgress(int). In this slot you call adjustTitle() where the instruction pb->show() is being executed.
Notice that you are calling the createWebViewActions() function before the call to QProgressBar constructor
(...)
createWebViewActions(); <------ here you establish the signal->slot connections
ui.webView->load(QUrl("www.cnnnn.com"));
ui.webView->show();
pb = new QProgressBar(statusBar()); <------ here you call the QProgressBar constructor
pb->setTextVisible(false);
pb->hide();
statusBar()->addPermanentWidget(pb);
(...)
I think that maybe this slot (setProgress()) is being called before the QProgressBar is constructed which triggers the Unhandled exception you are getting.
You could try and move the call to the QProgressBar constructor so that it is created before the slots connection.