Is there a way to know exactly when an expand operation begins when a user, lets say clicks the expand arrow in a QTreeView?
For the case when he double clicks I can catch the double-click event.
I tried reimplementing this slot void expand(const QModelIndex &index); from QTreeView but it doesn't seem to work.
There is a signal called void expanded(const QModelIndex &index); in QTreeView but it seems to be sent after the expansion happened.
I am using QT 4.8.2
This is what I did to get the functionality I needed:
I reimplemented the mousePressEvent from QTreeView like this
void MyTreeView::mousePressEvent(QMouseEvent *event)
{
QModelIndex clickedIndex = indexAt(event->pos());
if(clickedIndex.isValid())
{
QRect vrect = visualRect(clickedIndex);
int itemIdentation = vrect.x() - visualRect(rootIndex()).x();
if(event->pos().x() < itemIdentation)
{
if(!isExpanded(clickedIndex))
{
//do stuff
}
}
}
}
I check to see if the mouse press is left to the text label of the item(meaning on the expand arrow)
This combined with the double click event gives me what I needed.
You could try to this by implementing a method for a change event:
void YourTreeView::changeEvent(QEvent *e)
{
QFrame::changeEvent(e);
switch (e->type()) {
case QEvent::QGraphicsSceneResizeEvent
//do want you want to do
break;
default:
break;
}
}
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
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.
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
The problem is the following: I want to redefine (get rid of hovering effect of the button) the default Qt button style's behaviour. I only need 1 and 3 as shown on the picture under. The 2nd look comes when the button is focused.
Hovering effect: appears when you hover the button; remains painted when you press the button and move the cursor outside the space of the button.
What I've tried:
Redefining the events:
How do I implement QHoverEvent in Qt?
Here I simply redefined some of the events like Move, Hover etc. and made them non-functional.
Example Code:
class TestButton : public QToolButton
{
Q_OBJECT
public:
TestButton (QWidget *parent = 0) :
QToolButton(parent)
{}
bool event(QEvent * e)
{
this->clearFocus();
this->clearMask();
switch (e->type())
{
case QEvent::GraphicsSceneHoverEnter:
case QEvent::GraphicsSceneHoverLeave:
case QEvent::GraphicsSceneHoverMove:
case QEvent::HoverEnter:
case QEvent::HoverLeave:
case QEvent::HoverMove:
return true;
default:
return QWidget::event(e);
}
}
};
Some minor hacks:
btn->setFocusPolicy(Qt::NoFocus);
If you accept only HoverEnter events then after releasing the button the hover effect will go off as soon as you move mouse away. So you need to pretend moving mouse away by sending a corresponding event.
bool event(QEvent * e)
{
switch (e->type()) {
case QEvent::HoverEnter:
return true;
case QEvent::MouseButtonRelease: {
QEvent event(QEvent::Leave);
QApplication::sendEvent(this, &event);
}
default:
return QWidget::event(e);
}
}
By default the cell in QTableView starts being edited after double click. How to change this behavior. I need it to start editing after one click.
I have set combo-box delegate to the cell. When clicking the cell it only selects it. When double clicking on the cell the QComboBox editor is activated but not expanded. I want it to expand after just one click as if I added QComboBox by setCellWidget function of QTableWidget. I need the same effect by using model-view-delegate.
You can just set edit trigger use this function setEditTriggers
C++
yourView->setEditTriggers(QAbstractItemView::AllEditTriggers)
Python:
yourView.setEditTriggers(QAbstractItemView.AllEditTriggers)
enum QAbstractItemView::EditTrigger
flags QAbstractItemView::EditTriggers
This enum describes actions which will initiate item editing.
Constant Value Description
QAbstractItemView::NoEditTriggers 0 No editing possible.
QAbstractItemView::CurrentChanged 1 Editing start whenever current item changes.
QAbstractItemView::DoubleClicked 2 Editing starts when an item is double clicked.
QAbstractItemView::SelectedClicked 4 Editing starts when clicking on an already selected item.
QAbstractItemView::EditKeyPressed 8 Editing starts when the platform edit key has been pressed over an item.
QAbstractItemView::AnyKeyPressed 16 Editing starts when any key is pressed over an item.
QAbstractItemView::AllEditTriggers 31 Editing starts for all above actions.
The EditTriggers type is a typedef for QFlags. It stores an OR combination of EditTrigger values.
Edit after one click
You can reimplement mousePressEvent in view you are using
void YourView::mousePressEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton) {
QModelIndex index = indexAt(event->pos());
if (index.column() == 0) { // column you want to use for one click
edit(index);
}
}
QTreeView::mousePressEvent(event);
}
Expanded QCombobox when edit
You should imlement setEditorData in your subclass of QItemDelegate and at the end call showPopup.
But it has some unexpected behaviour. QComboBox disappears when mouse leave its area. But for me it is advantage.
I can select different item with single click and release.
void IconDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
Q_UNUSED(index);
QComboBox *comboBox = qobject_cast<QComboBox*>(editor);
// Add data
comboBox->addItem(QIcon(":/icons/information16.png"), "info");
comboBox->addItem(QIcon(":/icons/warning16.png"), "warning");
comboBox->addItem(QIcon(":/icons/send16.png"), "send");
comboBox->addItem(QIcon(":/icons/select16.png"), "select");
comboBox->showPopup(); // <<<< Show popup here
}
Together it works fast way. Click and hold to choose item and commit data on release ( Just one click and release )
If you want click to show expanded qcombobox and next click to choose/hide, I do not know solution for now.
Based on the idea provided by Jason, I came up with this solution.
To launch the editor on single click, I connected QAbstractItemView::clicked(const QModelIndex &index) signal of my view, to QAbstractItemView::edit(const QModelIndex &index) slot of that same view.
If you use Qt4, you need to create a slot in your delegate. Pass your combobox as an argument to this slot. In this slot you call QComboBox::showPopup. So it will look like this:
void MyDelegate::popUpComboBox(QComboBox *cb)
{
cb->showPopup();
}
But first we need to register the QComboBox* type. You can call this in the constructor of your delegate:
qRegisterMetaType<QComboBox*>("QComboBox*");
The reason we need this slot, is because we can't show the pop up straight away in MyDelegate::createEditor, because the position and the rect of the list view are unknown. So what we do is in MyDelegate::createEditor, we call this slot with a queued connection:
QComboBox *cb = new QComboBox(parent);
// populate your combobox...
QMetaObject::invokeMethod(const_cast<MyDelegate*>(this), "popUpComboBox", Qt::QueuedConnection, Q_ARG(QComboBox*, cb));
This will show the list view of the combobox correctly when the editor is activated.
Now if you are using Qt5, the slot is not needed. All you do is call QComboBox::showPopup with a queued connection from MyDelegate::createEditor. The easiest way to do this is with a QTimer:
QTimer::singleShot(0, cb, &QComboBox::showPopup);
For some extra information, this is how you can paint the combobox so it is shown all the time, not only when the editor is shown:
void MyDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
if(index.column() == 1) // show combobox only in the second column
{
QStyleOptionComboBox box;
box.state = option.state;
box.rect = option.rect;
box.currentText = index.data(Qt::EditRole).toString();
QApplication::style()->drawComplexControl(QStyle::CC_ComboBox, &box, painter, 0);
QApplication::style()->drawControl(QStyle::CE_ComboBoxLabel, &box, painter, 0);
return;
}
QStyledItemDelegate::paint(painter, option, index);
}
This solution works perfeclty for me. Single click on a cell, and the combo pops up.
class GFQtComboEnumItemDelegate : public QStyledItemDelegate
{
void setEditorData(QWidget *editor, const QModelIndex &index) const
{
QComboBox* pE = qobject_cast<QComboBox*>(editor);
... // init the combo here
if(m_must_open_box)
{
m_must_open_box = false;
pE->showPopup();
}
}
bool editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index)
{
if (event->type() == QEvent::MouseButtonRelease)
{
QMouseEvent* pME = static_cast<QMouseEvent*>(event);
if(pME->button() == Qt::LeftButton)
{
QAbstractItemView* pView = qobject_cast<QAbstractItemView*>( const_cast<QWidget*>(option.widget) );
if(pView != nullptr)
{
emit pView->setCurrentIndex(index);
m_must_open_box = true;
emit pView->edit(index);
}
return true;
}
}
return QStyledItemDelegate::editorEvent(event, model, option, index);
}
mutable bool m_must_open_box;
};
If you override QStyledItemDelegate::createEditor() then you can expand the combo box after it is created.