I'm using Qt 4.8.3 (32 bit) on Windows 7 Ultimate x64.
In a constructor of a QGraphicsScene subclass, I have:
QGraphicsItemGroup *point_table = new QGraphicsItemGroup;
addItem(point_table);
Later in the constructor:
QPushButton *button = new QPushButton("Call++");
QGraphicsProxyWidget *inc_button = addWidget(button);
connect(button, SIGNAL(clicked()), this, SLOT(onCallIncrease()));
onCallIncrease() gets called whenever the button is clicked. However, if I add inc_button to point_table, onCallIncrease() doesn't get called.
QPushButton *button = new QPushButton("Call++");
QGraphicsProxyWidget *inc_button = addWidget(button);
point_table->addToGroup(inc_button);
connect(button, SIGNAL(clicked()), this, SLOT(onCallIncrease())); // doesn't work
Even if I manually set to accept left mouse button:
QPushButton *button = new QPushButton("Call++");
QGraphicsProxyWidget *inc_button = addWidget(button);
inc_button->setAcceptedMouseButtons(Qt::LeftButton);
point_table->setAcceptedMouseButtons(Qt::LeftButton);
point_table->addToGroup(inc_button);
connect(button, SIGNAL(clicked()), this, SLOT(onCallIncrease())); // doesn't work
onCallIncrease() doesn't get called on left mouse click. Why is this happening?
Related
I am trying to create an expandable Qt dialog application. The main layout is a QVBoxLayout. The top part has two views and a QPushButtonbutton. Clicking button will unfold the bottom widget which is initially hidden. In the bottom widget, there is another push button, which could fold (hide) the bottom widget. When the bottom widget fold/unfold, I expect the size of the dialog size to change as well.
But for some reason, the dialog size only increases when the bottom widget is unfolded. And never shrink back to (200, 100). Is there anything I missed?
Environment: Qt Creator 3.6.1; Based on Qt5.6.0 (MSVC2013 32bit); build on Mar 14 2016; revision d502727b2c
The code I am using :
Dialog::Dialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::Dialog)
{
ui->setupUi(this);
QTreeView *tree = new QTreeView;
QTableView *table = new QTableView;
QPushButton *button_show = new QPushButton;
button_show->setText(tr("Show hidden panel"));
QHBoxLayout *layout_top = new QHBoxLayout;
layout_top->addWidget(tree);
layout_top->addWidget(table);
layout_top->addWidget(button_show);
QHBoxLayout *layout_bottom = new QHBoxLayout;
QTextEdit *editor = new QTextEdit;
QPushButton *button_hide = new QPushButton;
button_hide->setText(tr("Hide the bottom panel"));
g_pEditor = editor;
layout_bottom->addWidget(editor);
layout_bottom->addWidget(button_hide);
QWidget *panel = new QWidget;
panel->setLayout(layout_bottom);
QVBoxLayout *layout_main = new QVBoxLayout;
layout_main->addLayout(layout_top);
layout_main->addWidget(panel);
setLayout(layout_main);
panel->hide();
connect(button_show, &QPushButton::clicked
, panel
, [=]()
{
panel->setVisible(true);
button_show->setEnabled(false);
resize(200, 200);// not really working, the dialog size is able to increase without calling resize()
});
connect(button_hide, &QPushButton::clicked, panel, [=]()
{
panel->hide();
button_show->setEnabled(true);
resize(200,100);// does not shrink the dialog size*
});
resize(200,100);
}
Thanks for your help :)
Your should try setFixedSize(w, h) instead. This sets both, the minimum and the maximum size to (w, h). "This will override the default size constraints set by QLayout."
In a QWidget like QLabel, how can we set a "?" button, such that when clicked (or hovered) it should show some help text.
Also you can use QMenu instead of QPushButton + QLabel.
// Constructor
setContextMenuPolicy(Qt::CustomContextMenu);
connect(this, SIGNAL(customContextMenuRequested(QPoint)), this, SLOT(slotCustomMenu(QPoint)));
// slotCustomMenu(QPoint)
QMenu menu(this);
menu.addAction(this->toolTip());
menu.addAction(this->whatsThis());
menu.exec(QCursor::pos());
Easiest way to show help when hover QWidget: setToolTip(QString) and setToolTipDuration(int).
If you want a "?" button, just implement your own QWidget. Then via ui designer or directly in your code add QPushButton and QLabel on layout, and show your QLabel with help text in position of cursor when clicked(). Something like this:
{
// Constructor
...
m_mainLabel = new QLabel("Main text");
m_button = new QPushButton("?");
m_helpLabel = new QLabel("Help text");
connect(m_button, SIGNAL(clicked(bool)),
this, SLOT(slotShowOrHideHelpLabel(bool)));
QHBoxLayout *hBoxLayout = new QHBoxLayout;
hBoxLayout->addWidget(m_mainLabel);
hBoxLayout->addWidget(m_button);
setLayout(hBoxLayout);
}
void slotShowOrHideHelpLabel(bool showHelpLabel)
{
if (showHelpLabel)
{
m_helpLabel->show();
m_helpLabel->move(QCursor::pos());
}
else
{
m_helpLabel->hide();
}
}
I have QWidget with button. When button is pressed, show new smaller window (Qwidget too). I want then new window is centered horizontal and veritcal on main window. Code which display new window is:
QWidget *wdg = new QWidget;
QPushButton *closeBtn = new QPushButton("Close");
QHBoxLayout *layout = new QHBoxLayout;
layout->addWidget(closeBtn);
wdg->setLayout(layout);
wdg->show();
wdg->resize(400,200);
Use the move slot. For example:
QPoint centerPoint = oldWidget->geometry()->center();
newWidget->adjustSize();
newWidget->move(centerPoint.x() - newWidget->width()/2, centerPoint.y() - newWidget->height()/2);
You may consider using frameGeometry() instead of geometry().
http://qt-project.org/doc/qt-5/application-windows.html#window-geometry
Hope that helps.
I created a this->setWindowFlags(Qt::FramelessWindowHint); and so there is no title bar. Therefore, I am implementing my own. I wanted to know, however, before I continue whether there is a standard way to add the close, minimize, and maximize buttons in a native-os looking way (i.e. on windows it should look like the windows close buttons and the same for osx and linux).
QStyle take a lot of standard icons base on OS style. You can get this icon from current OS style and then draw it by your self.
This is a simple implementation for reference.
class TitleBar : public QWidget
{
Q_OBJECT
public:
explicit TitleBar(QWidget *parent = 0)
:QWidget(parent)
{
QStyle *style = qApp->style();
QIcon closeIcon = style->standardIcon(QStyle::SP_TitleBarCloseButton);
QIcon maxIcon = style->standardIcon(QStyle::SP_TitleBarMaxButton);
QIcon minIcon = style->standardIcon(QStyle::SP_TitleBarMinButton);
QPushButton *min = new QPushButton(this);
QPushButton *max = new QPushButton(this);
QPushButton *close = new QPushButton(this);
min->setIcon(minIcon);
max->setIcon(maxIcon);
close->setIcon(closeIcon);
QHBoxLayout *layout = new QHBoxLayout(this);
layout->setSpacing(0);
layout->addWidget(min);
layout->addWidget(max);
layout->addWidget(close);
setLayout(layout);
}
};
Basically I have a QTabWidget. At first it has a form widget, widget1. After that form is done being interacted with, the new widget2 form should take over that same tab.
I thought tabWidget->setCurrentWidget(new widget2()); would work, but it's basically an overload for setCurrentIndex(int).
Does anyone know of a way to do this?
You can use a QStackedWidget for this type of thing, in a tab or elsewhere.
Put all the widgets you'll want to display in that tab inside a single QStackedWidget, and place that stacked widget in a tab.
Here's a quick'n'dirty demo:
#include <QtGui>
class W: public QWidget
{
Q_OBJECT
public:
W(QWidget *parent=0): QWidget(parent)
{
// stacked widget displays one of its "children" at a time
QStackedWidget *sw = new QStackedWidget;
QPushButton *b1 = new QPushButton("hello");
sw->addWidget(b1);
QPushButton *b2 = new QPushButton("world");
sw->addWidget(b2);
// tab widget and simplistic layout
QTabWidget *tw = new QTabWidget(this);
tw->addTab(sw, "tab");
QHBoxLayout *l = new QHBoxLayout;
l->addWidget(tw);
setLayout(l);
// signal mapper to demo the widget switching
QSignalMapper *m = new QSignalMapper(this);
connect(b1, SIGNAL(clicked()), m, SLOT(map()));
m->setMapping(b1, 1);
connect(b2, SIGNAL(clicked()), m, SLOT(map()));
m->setMapping(b2, 0);
connect(m, SIGNAL(mapped(int)), sw, SLOT(setCurrentIndex(int)));
}
};