I am working on implementing a right-click context menu on a QWidget. I was wondering if there is a way to make this menu inherit, copy or in some way show the elements in the MainWindow's ui->menubar.
Qt Documentation -> Menus Example: In particular, implementing a right-click context menu on a QWidget
The main part of the code:
void MainWindow::contextMenuEvent(QContextMenuEvent *event)
{
QMenu menu(this);
menu.addAction(cutAct);
menu.addAction(copyAct);
menu.addAction(pasteAct);
menu.exec(event->globalPos());
}
I have an answer now that properly does what I want. Could be better, but is fairly efficient and condensed:
void MainWindow::customContextMenu(const QPoint &posa) {
QMenu contextMenu;
QPoint globalPos = ui->widget->mapToGlobal(posa);
QList<QMenu*> list = ui->menubar->findChildren<QMenu*>();
for (int i=0; i<list.size(); i++) {
contextMenu.addMenu(list.at(i));
}
contextMenu.exec(globalPos);
}
Related
I have a QGraphicsView which contains many QGraphicsItem. If I click mouse right click on any QGraphicsItem, the item should get select and right menu options should appear and then I will choose one of the options among them.To do that I have installed eventFilter and through it, I am using ContextMenu to create right click menu. Right click menu are getting cretaed properly. But propblem is I am not getting how to connect them to some function so that I can write logic for it.
It means if I clicked on save option that particular QGraphicsItem should get select and I should be able to go to some function where I will write logic for saving.
bool myClass::eventFilter(QObject *watched, QEvent *event)
{
switch(event->type())
{
case QEvent::ContextMenu:
{
QMouseEvent *mouseEvent = static_cast<QMouseEvent*> (event);
menu = new QMenu(this);
option = menu->addMenu("CopyOption");
option->addAction("save");
menu->exec(mouseEvent->globalPos());
break;
}
default:
break;
}
}
In your approach you show a context menu when you have no information if any item is selected. It is rather bad idea. You don't want to show the context menu in any location of view. You have to check if a cursor mouse is over an item.
Why not to derive from QGraphicsItem and just overload mousePressEvent method. Inside this method check if right button of mouse is clicked. If so, show context menu and test which action is clicked. Minimal code would be:
class TItem : public QGraphicsItem
{
bool _selected = false;
public:
TItem(QGraphicsItem* parent = nullptr) : QGraphicsItem(parent) {}
QRectF boundingRect() const override { return QRectF(0,0,20,20); }
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) override {
painter->fillRect(QRectF(0,0,20,20),_selected ? QColor(0,255,255) : QColor(255,255,0));
}
void mousePressEvent(QGraphicsSceneMouseEvent* e) override {
QGraphicsItem::mousePressEvent(e);
if (e->button() & Qt::RightButton) {
QMenu menu;
QAction* a1 = menu.addAction(QString("test1"));
QAction* a2 = menu.addAction(QString("test2"));
if(a2 == menu.exec(e->screenPos())) {
test2();
_selected = true;
update();
}
}
}
void test2() {
QMessageBox::information(nullptr,"test2","test2");
}
};
All the job with checking is an item is under mouse is done by QT, mousePressEvent is invoked only if it is necessary.
Another approach would be override mousePressEvent on QGraphicsView. Inside which:
get all items belonging to the scene
iterate over them, checking if an item is under mouse -> QGraphicsItem has isUnderMouse method
if any item is under mouse, create QMenu and show it
check selected QAction, if it is save call a proper method which doing the save and mark the item as selected
I want to show a menu in Qt with the following functionality: clicking anywhere outside of the menu will close it, but the click will be processed by the receiving widget. As far as I know, this rules out using setWindowFlag(Qt::Popup) because the click that closed the popup will be 'eaten' and not processed any further. I'd love to know if there is a way around this.
For the time being, I'm overriding focusOutEvent like so:
class Menu : public QWidget
{
Q_OBJECT
public:
Menu(QWidget* parent = nullptr)
: QWidget(parent){
setWindowFlags(Qt::FramelessWindowHint);
resize(200, 100);
}
public slots:
void showMenu(QPoint point)
{
move(point);
show();
setFocus(); // so that focusOutEvent will be trigerred
}
protected:
void focusOutEvent(QFocusEvent *event) override
{
hide();
}
};
And I'm using it like this:
class Window : public QMainWindow
{
Q_OBJECT
public:
Window(): m_menu()
{
auto* list = new QListWidget();
list->addItems(QStringList() << "item1" << "item2" << "item3");
connect(list, &QListWidget::itemClicked, [this](){
m_menu.showMenu(QCursor::pos());
});
// Layout stuff
auto central_widget = new QWidget();
auto layout = new QVBoxLayout(central_widget);
layout->addWidget(list);
layout->addItem(new QSpacerItem(20,200, QSizePolicy::Minimum, QSizePolicy::Expanding));
setCentralWidget(central_widget);
}
public:
~Window(){}
private:
Menu m_menu;
};
Single clicking on any of the items in the list will show the menu and clicking anywhere on the grey background will close the menu.
The issue I'm facing is that when the menu is shown, focus is lost from the main window (photo on the right, the titlebar buttons and selected item are greyed out). Focus is lost because of calling setFocus on the menu but if I don't use it then the QFocusOutEvents are not trigerred and the menu doesn't close.
The same happens if I use setAttribute(Qt::WA_ShowWithoutActivating) on the menu.
So here are my questions:
Is there a way to use Qt::Popup without the 'eaten' clicks issue?
If not, is there a way to show the menu without losing the focus from the main window but still trigger the focusOutEvents as necessary?
Using Qt 5.15.1 on MacOS 11.2.3. Thanks for reading through my long post!
I want to generate the right click menu from the entry of a QTreeView. Currently I tried this, but I don't want the whole treeView to generate the right click and then me to filter the position on which the mouse is. I want that the signal to be generated from the entry.
connect(mtreeView, SIGNAL(customContextMenuRequested(const QPoint&)),
this, SLOT(showContextMenu(const QPoint&)));
Thanks!
Method 1
It is better to use the ContextMenuEvent rather than MouseReleaseEvent as it is a more portable way to trigger the context menu, will support accessibility on certain platforms, etc... The right click is not the only way to open a context menu.
If you do not want to subclass QTreeView , install an event handler from the main window:
ui->myTreeView->installEventFilter(this);
Then handle the event in the main window filterEvent
bool MainWindow::eventFilter(QObject *target, QEvent *event)
{
if (target == ui->myTreeView)
{
QContextMenuEvent* m = dynamic_cast<QContextMenuEvent*>(event);
if (event->type() == QEvent::ContextMenu && e!=0)
{
//Create context menu here
return true;
}
}
return false;
}
Method 2
Change the context menu mode to a signal:
ui->myTreeView->setContextMenuPolicy(Qt::CustomContextMenu);
connect(ui->myTreeView, SIGNAL(customContextMenuRequested(QPoint)),
this, SLOT(treeCustomMenu(QPoint)));
Then implement your slot:
void MainWindow::treeCustomMenu(const QPoint & pos)
{
//Implement your menu here using myTreeView->itemAt(pos);
}
What I do is to override mouseReleaseEvent and check manually.
void MyTreeView::mouseReleaseEvent(QMouseEvent *e) {
if (e->button() == Qt::RightButton) {
QTreeWidgetItem *item = itemAt(e->pos());
if (item) {
QMenu m;
m.addAction("hello");
m.addAction("world");
QAction *selected = m.exec(mapToGlobal(e->pos()));
if (selected) {
qDebug() << "selected" << selected->text();
}
}
} else {
QTreeView::mouseReleaseEvent(e);
}
}
What you mean by the entry is not represented by a QObject in Qt. Only the item model is a QObject, but the individual tree nodes are not QObjects in Qt item/view system.
Therefore, they cannot emit any signal
I have grid of QFrames in QGridLayout and a popup menu with some actions, which are targeted on the cell where mouse right click happens. On the implementation of ContextMenuEvent I get clicked QPoint using common event->pos() but how I get access to my correct cell object by that point? Or is there some better alternative solution path for this purpose?
void X::contextMenuEvent(QContextMenuEvent* event)
{ // QPoint target = event->pos();
// TODO: m_gridLayout-> ...
// myDerivedCell->setSomething();
}
There are a bunch of solutions here. The simplest is to go through your widgets, calling bool QWidget::underMouse () const. My favorite is this:
frame_i->setContextMenuPolicy(Qt::CustomContextMenu);
connect(frame_i, SIGNAL(customContextMenuRequested(QPoint))
, SLOT(onContextMenu(QPoint)));
...
void X::onContextMenu(const QPoint &pos)
{
QFrame *w = qobject_cast < QFrame * >(sender());
...
}
I've been looking for ways to implement the "Edit" menu of Qt application. The "Edit" menu contains items such as "Copy", "Cut", "Paste", etc. and which need to forward to the currently active widget.
I can't seem to find a standard or elegant way to do this. According to this question, it's not possible:
How to implement the "Edit" menu with "Undo", "Cut", "Paste" and "Copy"?
I recently had the idea to trigger a context menu event on the current active widget when the "Edit" menu is shown, via:
// create menus in MainWindow constructor
...
edit_menu = menuBar()->addMenu(tr("&Edit"));
connect(edit_menu, SIGNAL(aboutToShow()), this, SLOT(showEditMenu()));
...
// custom slot to handle the edit menu
void MainWindow::showEditMenu()
{
QWidget* w = QApplication::focusWidget();
// show the context menu of current focus widget in the menubar spot
QPoint global_pos = edit_menu->mapToGlobal(edit_menu->rect().bottomLeft());
QPoint pos = w->mapFromGlobal(global_pos);
QApplication::sendEvent(w, new QContextMenuEvent(QContextMenuEvent::Keyboard, pos, global_pos));
}
This shows the a context menu for the current widget great, but has some problems. For example, it takes focus away from the menubar, or if you click a different menubar item first, the menubar has focus, etc.
One partial solution would be to grab the context menu from the widget and copy it's items into the edit menu dynamically. Is there a way to do this?
Is there a better way build the edit menu in Qt?
Thanks for your help.
well, if you just need to create menu, you can always take actions from actions of a widget. To create edit actions for widgets, you can do something like this:
void MainWindow::addActions (QWidget* widget)
{
QAction * copyAction = new QAction("copy",widget);
if(connect(copyAction,SIGNAL(triggered()),widget,SLOT(copy())))
{
widget->addAction(copyAction);
qDebug()<<"success connection";
}
}
and
foreach (QObject * obj, centralWidget()->children())
{
QWidget * w = dynamic_cast<QWidget*>(obj);
if (w)
addActions(w);
}
then you always can update actions of edit menu with focused widget's actions
This may be not elegant, but it better, than imporssible. The main bad assumption in example is that copy slot is named copy
An elegant solution I guess would be to have a base class for the widgets you need to have copy/paste/... functionality, and have them register themselves with some parent class upon becoming active and unregistering when being deactivated. The actions can then just be connected to slots in the main window, which forwards them to the registered widget. You could even gray out the menu items if no widget is currently registered (e.g. because the active widget does not have the required functionality).
An example for registering/unregistering (untested):
class ActionWidget;
class ActionWidgetManager
{
public:
ActionWidgetManager() : actionWidget_(0){}
void registerWidget(ActionWidget* widget){ actionWidget_ = widget; }
void unregisterWidget(ActionWidget* widget)
{ if (actionWidget_ == widget) actionWidget_ = 0; }
bool hasActiveWidget() const{ return actionWidget_ != 0; }
ActionWidget* getActiveWidget(){ return actionWidget_; }
private:
ActionWidget* actionWidget_;
};
class ActionWidget : public QWidget
{
public:
ActionWidget(ActionWidgetManager* manager, QWidget* parent=0)
: manager_(manager), QWidget(parent) {}
~ActionWidget(){ manager_->unregisterWidget(this); }
void Widget::changeEvent(QEvent *event)
{
QWidget::changeEvent(event);
if(event->type() == QEvent::ActivationChange){
if(isActiveWindow()) {
manager_->registerWidget(this);
}
else {
manager_->unregisterWidget(this);
}
}
}
virtual void doCopy() = 0;
virtual void doPaste() = 0;
virtual void doUndo() = 0;
virtual void doCut() = 0;
private:
ActionWidgetManager* manager_;
};
Or something equivalent using signals and slots.