I was able to simulate the Right-Click event by subclassing the QTableWidget:
header file:
#ifndef QRIGHCLICKTABLE_H
#define QRIGHCLICKTABLE_H
#include <QTableWidget>
#include <QMouseEvent>
class QRightClickTable : public QTableWidget
{
Q_OBJECT
public:
explicit QRightClickTable(QWidget *parent = 0);
private slots:
void mousePressEvent(QMouseEvent *e);
signals:
void rightClicked();
public slots:
};
#endif // QRIGHCLICKTABLE_H
cpp file
QRightClickTable::QRightClickTable(QWidget *parent) :
QPushButton(parent)
{
}
void QRightClickTable::mousePressEvent(QMouseEvent *e)
{
if(e->button()==Qt::RightButton)
emit rightClicked();
}
QRightClickTable *button = new QRightClickTable(this);
ui->gridLayout->addWidget(button);
connect(button, SIGNAL(rightClicked()), this, SLOT(onRightClicked()));
void MainWindow::onRightClicked()
{
qDebug() << "User right clicked me";
}
Now, right-click works correctly, but there are other problems with QTableWidget: all other mouse events, such as the left click to select a cell, no longer work.
Can you help me? I know I need to call the base class implementation in my override of mousePressEvent, you could show me how with a little piece of code?
Change your event handler like this :
void QRightClickTable::mousePressEvent(QMouseEvent *e) {
if(e->button()==Qt::RightButton) {
emit rightClicked();
} else {
QTableWidget::mousePressEvent(e);
}
}
Related
I wish derived class from QComboBox with following additional feature:
When user clicks to QLiineEdit of this combo box, the effect have to be the same as click to arrow on the right side of combo box (showPopup() method).
My attemption is:
File lineedit.h
#ifndef LINEEDIT_H
#define LINEEDIT_H
#include <QLineEdit>
class LineEdit : public QLineEdit {
Q_OBJECT
public:
LineEdit(QWidget *parent = nullptr);
signals:
void pressed();
protected:
void mousePressEvent(QMouseEvent *event) override;
};
#endif // LINEEDIT_H
File lineedit.cpp
#include "lineedit.h"
#include <QMouseEvent>
LineEdit::LineEdit(QWidget *parent) : QLineEdit(parent) {}
void LineEdit::mousePressEvent(QMouseEvent *event) {
QLineEdit::mousePressEvent(event);
emit pressed();
event->accept();
}
File combobox.h
#ifndef COMBOBOX_H
#define COMBOBOX_H
#include <QComboBox>
class ComboBox : public QComboBox {
Q_OBJECT
public:
ComboBox(QWidget *parent = nullptr);
private slots:
void lineEditPressed();
};
#endif // COMBOBOX_H
File combobox.cpp
#include "combobox.h"
#include "lineedit.h"
ComboBox::ComboBox(QWidget *parent) : QComboBox(parent) {
setLineEdit(new LineEdit);
connect(lineEdit(), SIGNAL(pressed()), this, SLOT(lineEditPressed()));
}
void ComboBox::lineEditPressed() { showPopup(); }
But, when I press lineEdit, it shows popup, but after releasing mouse button it vanishes.
Please, revise the documentation of the event handler. As you show pop-up menu in this function, then the release event will conflict hastily. I can't predict your implementation of showPopup(), but please don't create a pop-up menu inside it. You may show, hide, assign, but NEVER create.
I have created following dialog using QT designer form class
#ifndef DLG_GAMMA_H
#define DLG_GAMMA_H
#include <QDialog>
namespace Ui {
class Dlg_Gamma;
}
class Dlg_Gamma : public QDialog
{
Q_OBJECT
public:
explicit Dlg_Gamma(QWidget *parent = nullptr);
~Dlg_Gamma() override;
private slots:
void on_horizontalSlider_valueChanged(int value);
void on_saveButton_clicked();
void on_discardButton_clicked();
void on_resetButton_clicked();
signals:
void savechanges(QString filter);
void discardchanges();
void reset();
private:
Ui::Dlg_Gamma *ui;
bool eventFilter(QObject *target, QEvent *event) override;
void closeEvent(QCloseEvent *dlg) override;
bool close_X;
};
#endif // DLG_GAMMA_H
.cpp
bool Dlg_Gamma::eventFilter(QObject *target, QEvent *event)
{
qDebug() << event->type();
}
However, clicking on help button, does not trigger any event.
Has anybody faced this issue before ?
Does anybody know solution ?
bool MyDialog::event(QEvent *e)
{
// reimplement event processing
if(e->type()==QEvent::WhatsThisClicked)
{
QWhatsThisClickedEvent ce = static_cast<QWhatsThisClickedEvent>(e);
....
return true;
}
return QDialog::event(e);
}
This is the event catcher.
To use event filter you need to install it:
installEventFilter(this) in the constructor of the Dialog.
You need to install eventFilter on your 'help button' when using eventFilter.
You need to insert kind of code below in the constructor of the 'Dlg_Gamma'
ui->helpButton->installEventFilter(this)
For more information, Please refer to the information below.
https://doc.qt.io/qt-5/eventsandfilters.html
Using Qt to create an application that accepts a file drop. I have an area on my UI that I want to drop the file into, using a Qlabel. I have the function of dragging and dropping the file into the UI working, however I can drop it anywhere on the window, and not just into the Qlabel area.
I thought using
ui->label_drag->setAcceptDrops(true);
would work, however this just removed the functionality all together. What is the best way of handling this? if possible at all.
Thanks
The best way to do this is to override the QLabel class. In the dragEnterEvent be sure to call acceptProposedAction to process the move and leave events. If you don't do that, only the dragEnter event will fire.
Sample code follows. To use this in your project, add the source to your project and then right click on the label on the form and promote the item to QLabelDragDrop.
#ifndef QLABELDRAGDROP_H
#define QLABELDRAGDROP_H
#include <QLabel>
class QLabelDragDrop : public QLabel
{
Q_OBJECT
public:
explicit QLabelDragDrop(QWidget *parent = nullptr);
protected:
void dragEnterEvent(QDragEnterEvent *event);
void dragLeaveEvent(QDragLeaveEvent *event);
void dragMoveEvent(QDragMoveEvent *event);
signals:
public slots:
};
#endif // QLABELDRAGDROP_H
#include "qlabeldragdrop.h"
#include <QDebug>
#include <QDragEnterEvent>
#include <QDropEvent>
QLabelDragDrop::QLabelDragDrop(QWidget *parent) : QLabel(parent)
{
setAcceptDrops(true);
setMouseTracking(true);
}
void QLabelDragDrop::dragEnterEvent(QDragEnterEvent *event)
{
qDebug() << "dragEnterEvent";
event->acceptProposedAction();
}
void QLabelDragDrop::dragLeaveEvent(QDragLeaveEvent *event)
{
qDebug() << "dragLeaveEvent";
releaseMouse();
}
void QLabelDragDrop::dragMoveEvent(QDragMoveEvent *event)
{
qDebug() << "dragMoveEvent";
}
void QLabelDragDrop::dropEvent(QDropEvent *event)
{
qDebug() << "dropEvent";
}
A widget derived from QListWidget is the only widget on a window. Function "setAcceptDrops(true);" is used in its constructor, and "event->accept();" is called in its "dragEnterEvent". However, its "dropEvent" could not be triggered. Please check the whole source code (created using Qt 5.12.0) at
github.com/jianz-github/dropevent.
I have asked a question at Qt Drop event not firing. This situation is supposed to be the same, but it is not. Weird.
Thanks in advance for any help.
In this case, the solution is to overwrite the dragMoveEvent() method as well.
listbox.h
#ifndef LISTBOX_H
#define LISTBOX_H
#include <QListWidget>
#include <QDropEvent>
#include <QDragEnterEvent>
class ListBox : public QListWidget
{
public:
ListBox(QWidget *parent = nullptr);
protected:
void dropEvent(QDropEvent *event) override;
void dragEnterEvent(QDragEnterEvent *event) override;
void dragMoveEvent(QDragMoveEvent *event) override;
};
#endif // LISTBOX_H
listbox.cpp
#include "listbox.h"
#include <QDebug>
ListBox::ListBox(QWidget *parent) : QListWidget (parent)
{
setAcceptDrops(true);
}
void ListBox::dropEvent(QDropEvent *event)
{
qDebug() << "dropEvent"<<event;
}
void ListBox::dragEnterEvent(QDragEnterEvent *event)
{
event->acceptProposedAction();
}
void ListBox::dragMoveEvent(QDragMoveEvent *event)
{
event->acceptProposedAction();
}
I've tried to emit a custom signal login() from my loginmanager class to the mainwindow. The signal is fired on the loginButtonClicked slot, and to my understand on the signal/slot mechanism, it should be able to capture any signal fired event and "look" for the corresponding slot to be execute. But it doesn't work as what I've think.
The connect function returns 1, which means it is able to be implemented in the moc file, and it DOES work if i run the m_LoginManager->setLogin() which fires the login() signal.
But what I prefer is the signal is emitted by the loginButton, and pass to the mainwindow to be process (in this case, init()).
Please correct me if I'm wrong.
Below are the code.
loginmanager.cpp
LoginManager::LoginManager(QWidget * parent) : QWidget(parent)
{
ui.setupUi(this);
connect(ui.loginButton, SIGNAL(clicked()), this, SLOT(loginButtonClicked());
}
LoginManager::~LoginManager()
{
}
void LoginManager::setLogin()
{
emit login();
}
void LoginManager::loginButtonClicked()
{
setLogin();
}
loginmanager.hpp
#include <QWidget>
#include "ui_loginmanager.h"
class DatabaseManager;
class SettingManager;
class LoginManager : public QWidget
{
Q_OBJECT
public:
LoginManager(QWidget * parent = Q_NULLPTR);
~LoginManager();
void setLogin();
signals:
void login();
public slots:
void loginButtonClicked();
private:
Ui::LoginManager ui;
};
mainwindow.hpp
#include <QtWidgets/QMainWindow>
#include "ui_safeboxmanager.h"
class SafeboxManager : public QMainWindow
{
Q_OBJECT
public:
SafeboxManager(QWidget *parent = 0);
~SafeboxManager();
public slots:
void init();
private:
Ui::SafeboxManagerClass ui;
LoginManager* m_LoginManager;
};
#endif // SAFEBOXMANAGER_H
mainwindow.cpp
#include "safeboxmanager.hpp"
#include "loginmanager.hpp"
SafeboxManager::SafeboxManager(QWidget *parent)
: QMainWindow(parent)
{
ui.setupUi(this);
m_LoginManager = new LoginManager();
ui.mainToolBar->setEnabled(false);
ui.tableWidget->setEnabled(false);
connect(m_LoginManager, SIGNAL(login()), this, SLOT(init()));
//m_LoginManager->setLogin() << this work
}
SafeboxManager::~SafeboxManager()
{
}
void SafeboxManager::init()
{
ui.mainToolBar->setEnabled(true);
ui.tableWidget->setEnabled(true);
}
SafeboxManager and LoginManager objects must live long enough. Check life times.