I want to make a scrollbar that fades in and out depending on usage. I subclassed QScrollBar and got the look that I want. The problem is that the scrollbar is placed next to the content. How do I instead make it go on top of the content?
I created a new QScrollbar which I connected to the original via signals and then used widget->setParent and then widget->setGeometry() to paint it on top
I quicker solution is to reparent the QScrollBars that the QScrollArea creates and add it to a new QLayout to position it how you want.
QScrollArea *scrollArea = new QScrollArea();
QScrollBar *scrollBar = scrollArea->horizontalScrollBar();
scrollBar->setParent(scrollArea);
scrollBar->setFixedHeight(20);//required for later
QVBoxLayout *scrollAreaLayout = new QVBoxLayout(scrollArea);
scrollAreaLayout->setContentsMargins(0, 0, 0, 10);//use whatever margins you want
scrollAreaLayout->addStretch(1);
scrollAreaLayout->addWidget(scrollBar);
This gets the basic functionality working, however the QScrollArea still adds space where the scrollbar would have been. To remove this, subclass QProxyStyle and override pixelMetric().
#include <QProxyStyle>
class StyleFixes : public QProxyStyle
{
public:
int pixelMetric(PixelMetric metric, const QStyleOption *option = Q_NULLPTR, const QWidget *widget = Q_NULLPTR) const override
{
if(metric == PM_ScrollBarExtent)
{
return 0;
}
return QProxyStyle::pixelMetric(metric, option, widget);
}
};
Then just apply it in main.cpp
QApplication::setStyle(new StyleFixes);
This will remove the arrows on the scrollbar however so you'll need to style it yourself.
Related
I have one QWidget which contains a multiple sliders. All sliders resized to main QWidget size. As result all sliders share same draw rectangle. For sliders I overload paintEvent method, so it draw only required stuff. Here is an example code:
class MySlider : public QSlider
{
void paintEvent(QPaintEvent *event) {
...
}
}
class MyWidget : public QWidget
{
MyWidget() : QWidget() {
slider1 = new MySlider(this);
slider2 = new MySlider(this);
slider1->resize(rect().width(), rect().height());
slider2->resize(rect().width(), rect().height());
}
MySlider * slider1;
MySlider * slider2;
}
adsf
Groove is not seen with this solution (because we don't call QSlider::paintEvent), but it still exist. For this widget it is possible to use only the last created slider (slider2). The rest are visible, but they are not available.
Is it possible to overlay multiple widgets on each other and still be able to access all of them with mouse event?
Overlapping widgets isn't a good idea, expect only one is visible at the same time. What is the purpose for that overlapping?
You can set QWidget::setAttribute(Qt::WA_TransparentForMouseEvents) to not generate any mouse events for that particular widget so that only one slider will get that events. Then you are able to redirect that messages to your other sliders.
I have a QDockWidget class and a QMainWindow:
// docker.hpp
class Docker : public QDockWidget
{
Q_OBJECT
public:
Docker(QString title, QWidget* parent = 0);
}
// docker.cpp
Docker::Docker(QString title, QWidget* parent): QDockWidget(title, parent)
{
QWidget* widget = new QWidget(this);
widget.setMinimumSize(200, 200);
setWidget(widget);
widget->setStyleSheet("border:5px solid gray;");
setAllowedAreas(Qt::AllDockWidgetAreas);
}
// mainwindow.hpp
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget* parent);
private slots:
void createDockers();
};
// mainwindow.cpp
MainWindow::MainWindow(QWidget* parent): QMainWindow(parent)
{
setDockOptions(dockOptions() |
QMainWindow::AllowTabbedDocks |
QMainWindow::GroupedDragging);
// The following line of code does not change the situation.
// setTabPosition(Qt::RightDockWidgetArea, QTabWidget::East);
// There are some other codes which connect a button to the void createDockers() method
}
void createDockers()
{
Docker* dock = new Docker("Docker", this);
dock->setFloating(true);
dock->show();
}
I am able to create two Dockers with clicks of the button mentioned above.
However, when I drag one QDockWidget onto the other, the border disappears and no tabs show up:
I am expecting the following to happen: (Achieved by spawning several QDockWidgets)
I am also noticing that one of the QDockWidgets did not vanish. Instead, it merged back to the MainWindow. This only happens if they are the "first two" QDockWidgets.
What caused this problem and how to solve it? I am trying to mimic this project.
I guess it's linked to the QMainWindow::GroupedDragging option. I'm pretty sure it should work well without it (I mean for the not showing tab issue). Do you have restrictions on dock position somewhere else? The documentation implies it could create issues: http://doc.qt.io/qt-5/qmainwindow.html#DockOption-enum
For the style issue, you may need to redefine it on tab event, because once tabbed, the widget may inherit the tab style instead of the dock widget style you defined (not certified at all ^^)
Last guess/thing you can try, is to start with the dock tabbed and not floating to see if you have any new bahaviour, it was what I was doing in a previous project and it was working pretty well.
Sorry but no other ideas for the moment.
I'm fighting for hours with following problem.
Widget A is container with QHBoxLayout for QLabel objects. I want to put such widget in other widget, with constant height equal to A's height, and minimum width equal to A's width (but width can be changed).
In A constructor I have following code:
QHBoxLayout* mLayout = new QHBoxLayout();
for (auto e : wordsList)
mLayout->addWidget(e);
mLayout->setSpacing(0);
mLayout->setMargin(0);
mLayout->setSizeConstraint(QLayout::SetFixedSize);
setLayout(mLayout);
And there is the body of B:
class B : public QWidget
{
Q_OBJECT
public:
explicit B(A *a0, QWidget *parent = 0)
: QWidget(parent),
a(a0)
{
a->setParent(this);
setSizePolicy(QSizePolicy());
setFixedSize(sizeHint());
}
QSize minimumSize() const
{
return a->size();
}
QSize sizeHint() const
{
return minimumSize();
}
private:
A *a;
};
In main() I call show() on B's instance. In effect, I get big, fully resizeable window, bigger than A. A is frozen, doesn't resize with B.
I want B to start with the same size as A and to be resizeable only horizontally (but with minimum width equal to A).
How can I achieve this?
And why setSizePolicy() and setFixedSize(), minimumSize() and even sizeHint() don't work?
Can this be because I use B as a main window?
If I use layout in B, this probably should be another QHBoxLayout. But when he has too much space, he fits his component, so I would need to use QSpacerItem and resize him always, when B is resizing. But I don't know order, in which widgets are receiving QResizeEvent: if B gets it before my spacer, I will do nothing. I probably could use eventFilter, but still, this is too complicated (behaviour I need is pretty simple!).
I think there is no need to inherit B you can just add a layout in B and add A to the layout:
QWidget * widgetB = new WhateverWidgetYouWant();
QHBoxLayout* layoutForB = new QHBoxLayout();
widgetB->setLayout(mLayout);
layoutForB->addWidget(pointerToA);
What you need is to change the size policy of A to Expanding or Preffered or experiment with some other policies. You can test this in the designer and when you are satisfied with the results you can get the right properties and set them in your code.
I have a class MyListWidget derrived from QWidget. I passed parent and flags to the base class QWidget constructor (tried both Qt::Dialog and Qt::Popup in tests) but the custom widget is shown in the center of the screen instead centered to its parent.
MyListWidget* myListWidget = new MyListWidget(this, Qt::Dialog);
This is the constructor:
MyListWidget::MyListWidget(QWidget* parent, Qt::WindowFlags flags)
: QWidget(parent, flags),
ui(std::auto_ptr<Ui::MyListWidget>(new Ui::MyListWidget))
{
ui->setupUi(this);
}
If I put this widget into a separate dialog, anything works as expected. But why?
Wrapping works:
QDialog* popup = new QDialog(this, Qt::Popup);
QVBoxLayout* hLayout = new QVBoxLayout(popup);
// ... doing list creation like above
hLayout->addWidget(mmyListWidget);
popup->setLayout(hLayout);
const int width = mapListWidget->width();
const int height = mapListWidget->height();
popup->resize(width, height);
Any ideas what could happend here?
QWidget is not shown on center by default, so you need to center it manually (you can do that in the constructor):
MyListWidget::MyListWidget(QWidget* parent, Qt::WindowFlags flags)
: QWidget(parent, flags),
ui(std::auto_ptr<Ui::MyListWidget>(new Ui::MyListWidget))
{
ui->setupUi(this);
move(
parent->window()->frameGeometry().topLeft() +
parent->window()->rect().center() - rect().center()
);
}
P.S. Beware of std::auto_ptr, you probably want to use std::unique_ptr these days.
I'm not quite sure what you're trying to achieve but I have the feeling you should derive MyListWidget from QDialog.
Regards,
Ben
I have found this: Getting the size of a QGraphicsView
But I can't figure out what does it mean to "move my initialization code to showEvent" and I can't comment on that answer.
I am want to resize a QPixmap so it could fit my QGraphicsView. I've placed my graphicsview in Designer and set GridLayout for my main window. In a MainWindow constructor I have written the following code:
ui->setupUi(this);
// Get GView size
g_sizeX = ui->mapView->width();
g_sizeY = ui->mapView->height();
// Init scene
scene = new QGraphicsScene(this);
// Init MAP pixmap and add it to scene
mapImage = new QPixmap(":/Map/europe.jpg");
QPixmap newmapImage = mapImage->scaled(g_sizeX, g_sizeY);
scene->addPixmap(newmapImage);
// Display scene in gview.
ui->mapView->setScene(scene);
But I always get size of 100x30. If I break the gridLayout, I get the correct size.
So, how should I deal with this?
Thank you.
The QGraphicsView will be resized by the QGridLayout after the widget is shown, and can be also resized later when the window is itself resized.
So you should change the size of the pixmap as a result of a QResizeEvent, either by subclassing QGraphicsView to redefine resizeEvent(), and then promoting your view object to your new class in the designer to use it instead of QGraphicsView, or by installing your MainWindow object as an event filter for the view to handle to the resize event from the MainWindow::eventFilter function.
You probably don't want to change the pixmap size in the scene, but rather adjust the view matrix so that your QGraphicsPixmapItem fits perfectly inside the view, with QGraphicsView::fitInView.
For example:
/* QGraphicsPixmapItem *pixmapItem; as a MainWindow member */
pixmapItem = scene->addPixmap(newmapImage);
/* Either always disable or enable the scrollbars (see fitInView doc) */
ui->mapView->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
ui->mapView->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
ui->mapView->installEventFilter(this);
...
bool MainWindow::eventFilter(QObject *obj, QEvent *evt) {
if(obj == ui->mapView && evt->type() == QEvent::Resize) {
ui->mapView->fitInView(pixmapItem, Qt::KeepAspectRatioByExpanding);
}
// Call the base class implementation
return QMainWindow::eventFilter(obj, evt);
}
I believe that what is happening is that Qt only applies layouts and sets widget sizes when the widget is first displayed.
One way to work that is to override QWidget::showEvent(), and put your sizing code in there.
However, one simpler way, that often works in constructors, is to ask the widget for its sizeHint(), rather than for its not-yet-layed-out size.
In your case, that would mean changing two lines of code to:
g_sizeX = ui->mapView->sizeHint().width();
g_sizeY = ui->mapView->sizeHint().height();
If your layout isn't too complicated, and if you haven't overridden the default size policies, this may well fix things for you.