A nice simple example would be nice. For my part, I wish to do something like this:
myLayout->addWidget(myButton1);
myLayout->addWidget(myButton2);
myButtonList<QToolButtons*>->append(myLayout->findChildren(QToolButtons));
myButtonList->at(1)->setText("This is 'myButton2'");
Use QList along with using findChildren with QWidget because QLayout does not show QWidgets as its children and a QWidget have a parent QWidget only. Refer this
QWidget w;
QPushButton *p1= new QPushButton;
QPushButton *p2= new QPushButton;
QHBoxLayout l;
l.addWidget(p1);
l.addWidget(p2);
w.setLayout(&l);
QList<QPushButton*> buttons = w.findChildren<QPushButton*>();
buttons.at(0)->setText("Hello I am P1");
buttons.at(1)->setText("Hello I am P2");
w.show();
A lot easier would be the approach to first fill the list and afterwards the layout:
QList<QToolButton *> list;
list.append(new QToolButton);
list.last().setText("1");
myLayout->addWidget(list.last());
This could then also be easily looped for a higher amount of buttons.
You can still use
ParentWidget->findChildren<QToolButtons *>();
edited given vahancho hint for parent is always a widget, not the layout
Related
I'm beginning with Qt and I do not understand something. Here is my code:
#include <QApplication>
#include <QtWebKitWidgets/QWebView>
#include <QMainWindow>
#include <QPushButton>
QApplication a(argc, argv);
QMainWindow *mWin = new QMainWindow();
QPushButton *button = new QPushButton("Button");
button->setGeometry(0,0,128,56);
button->show();
mWin->setGeometry(QRect(300,300,1024,640));
mWin->setWindowFlags(Qt::CustomizeWindowHint | Qt::WindowMinimizeButtonHint | Qt::WindowCloseButtonHint);
mWin->show();
return a.exec();
When I launch the program, it makes a pushbutton, but not on the main GUI. It instead makes it in the upper lefthand corner of my scoeen. How do I make the pushbutton part of the main GUI?
Both QMainWindow and QPushButton derive from QWidget and generally, QWidgets can display themselves independently, so don't need to be attached to a parent, though it's likely you'll want to group and organise the widgets you're presenting to the user.
For a beginner, I think that QMainWindow is a bit misleading as you don't actually need it to display widgets. If, for example, you wanted to just display the button, you only need create the QPushButton and call show: -
QPushButton pButton = new QPushButton("Test");
pButton->show();
Though it's rare that you'll actually want to do this. In actuality, though it appears pointless, you can even just create a QWidget and display that: -
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QWidget w;
w.show();
return a.exec();
}
The QWidget can now be the parent to all other widgets, still without you defining a QMainWindow.
It is likely that you will want other widgets to display and Qt uses a parent / child hierarchy system of linking them together. Amongst other things, an advantage here is that you don't need to keep track of the different widgets in order to release their memory. When you're finished, you just delete the top level item, which may be a QMainWidget, or QDialog or other QWidget based object. In the case of Windows, all you need to do is close them and their children are cleaned up too.
Adding Widgets to a QMainWindow can be done in different ways, depending upon what you're trying to achieve. Eventually, you'll likely want to use layouts that allow grouping of widgets in logical arrangements, but to start with, if you look at the constructor of the QPushButton, you'll see that it takes an optional parameter of QWidget* : -
QPushButton(QWidget * parent = 0)
This allows you to attach the widget you're creating (QPushButton in this case) to a parent. Therefore, create the QMainWindow and then pass its pointer to the QPushButton.
QMainWindow* pWindow = new QMainWindow; // create the main window
QPushButton pButton = new QPushButton(pWindow); // create the push button
pWindow->show(); // Display the main window and its children.
You're creating a button and a window, but you're not associating them together. Therefore, the button is not part of the main UI. In order to add the button to the main window, you should add the following line-
mWin->setCentralWidget(button);
When creating user interfaces with Qt, it's better to avoid setting the geometry explicitly. Here is a nice page which describes the layouting in Qt.
Also, you seem to be missing a main function.
You are not setting parent child relationship, you need QPushbutton as a child of QMainwindow. Then you can see QPushbutton on QMainwindow.
Please try this, I am not sure what exactly you want to achive..but below code will give some hind about how to proceed..
QApplication a(argc, argv);
QMainWindow *mWin = new QMainWindow();
QPushButton *button = new QPushButton(mWin); // setting parent as QMainwindow
button->setGeometry(0,0,128,56);
// button->show();
//mWin->setCentralWidget( button );
mWin->setGeometry(QRect(300,300,1024,640));
mWin->setWindowFlags(Qt::CustomizeWindowHint | Qt::WindowMinimizeButtonHint | Qt::WindowCloseButtonHint);
mWin->show()
;
Create a central widget for the main window and then use a layout to place the push button on the central widget. For example:
QMainWindow *mWin = new QMainWindow();
// Place the button in a layout
QHBoxLayout *layout = new QHBoxLayout;
QPushButton *button = new QPushButton("Button");
layout->addWidget(button);
// Set up a central widget for the main window
QWidget *centralWidget = new QWidget();
centralWidget->setLayout(layout);
mWin->setCentralWidget(centralWidget);
If you've placed your button into a layout this way (or as a central widget itself, as one of the other answers has indicated), you don't need to set the geometry on the button, nor do you need to call setVisible or show on the button explicitly (but you still need to on the main window).
Consider looking through some of Qt's examples, such as the application example for more information.
Ok, so basically I have a simple table with a QWidget and two buttons as shown below:
QGridLayout *layout = new QGridLayout;
layout->addWidget(viewcontainer,0,0,1,2);
layout->addWidget(reset,1,0);
layout->addWidget(done,1,1);
This is basically what I want, where "reset" and "done" are buttons. Essentially it's a QWidget, viewcontainer, which resizes as the window size is changed by the user while the buttons' heights remains the same. But, the default for the gridlayout is to align the contents to the left. If I change this with:
layout->addWidget(viewcontainer,0,0,1,2, Qt::AlignCenter);
It does sort of what I want, but the graphicsscene no longer resizes (remains a small constant size). I'd like to retain the resizing while just aligning the widget to the center. Thanks.
I think the easiest solution which provides a clean solution is to nest 2 layouts.
Your 'outer' (parent) layout should be a QHBoxLayout and you can add your QGridLayout into it as an 'inner' (child) layout with addLayout().
Based on my experience you should avoid to set Qt::Alignment every time you can. It can really mess up your layout. For simple layouts it can work but for more complex ones you should avoid it. And you never know that you should extend your layout in the future or not so my suggestion is to use nested layouts.
Of course you can create a QWidget for the 'outer' layout and for the 'innser' layout as well but most of the times it should be fine to just nest 2 layouts.
Also you can use QSpacerItem to fine-tune your layout.
Have a look at this example code, I think it does what you want:
#include <QApplication>
#include <QPushButton>
#include <QGraphicsView>
#include <QGridLayout>
#include <QPalette>
class MyWidget : public QWidget
{
public:
MyWidget()
{
QGridLayout * layout = new QGridLayout(this);
QGraphicsView * gv = new QGraphicsView;
layout->addWidget(gv, 0,0, 1,2);
layout->setRowStretch(0, 1); // make the top row get more space than the second row
layout->addWidget(new QPushButton("reset"), 1,0);
layout->addWidget(new QPushButton("done"), 1,1);
}
};
int main(int argc, char ** argv)
{
QApplication app(argc, argv);
MyWidget w;
w.show();
return app.exec();
}
I would like to make a QToolButton where the text is the left of its icon. I've tried to find related information, and tried things with:
button->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
but this sets the text to the right side of the button. I've looked into trying stylesheets, but text-alignment is only for push buttons. Is there any way to do this?
My highest-level goal is to make an interface bar which looks like this:
with a text label and image right beside it. Currently I'm using a toolbar with checkable toolbuttons because of the style (no border unless moused-over, still has the indent with checkable, contains text and an icon...). It's entirely possible that I'm using the wrong type widgets, so if I can't change the layout of this, is there any way to emulate this style?
This is what I currently have:
.
You can use QWidget::setLayoutDirection:
toolbar->setLayoutDirection(Qt::RightToLeft);
Your best bet is probably to create this functionality yourself in a QWidget. It should have a QLabel and a QToolButton (or QPushButton) arranged in a QHBoxLayout. Then you can add this custom widget to the toolbar using QToolBar::addWidget() or QToolBar::insertWidget().
Here's an example of a widget you could use:
#include <QtGui>
class CoolButton : public QWidget
{
public:
CoolButton(QWidget *parent = 0) : QWidget(parent)
{
QLabel *label = new QLabel("Hi!", this);
QToolButton *button = new QToolButton(this);
QHBoxLayout *layout = new QHBoxLayout;
layout->addWidget(label);
layout->addWidget(button);
setLayout(layout);
}
};
How to Add QListView/QListWidget to QGraphicsScene and add Widgets to ListView
When i Try to add QLisView to QGraphicsScene mouse scroll affects goes from Scene.
I want to add QPushButtons as ListView Items in QgraphicsScene with mouse scroll affect.
Thanks.
What about QGraphicsProxyWidget?
QListView *listView = new QListView;
QGraphicsProxyWidget *proxy = scene.addWidget(listView);
Then (or before that) you can populate the list with anything you want. QPushButton can be added to the list using setIndexWidget(). Also you might rethink the whole idea of having a QListView, and give it a try with QScrollArea and a linear layout containing buttons. That would require a bit more logic to organize items within the scroll area, but it should be more lightweight that QListView with custom widgets.
I second the answer above: ProxyWidget is the answer.
Here is my working code,
Header:
class CenterScreen{
private:
QListWidget* nameListWidget;
QGraphicsProxyWidget* nameProxyWidget;
...
C++ source:
void CenterScreen::addListView()
{
QGraphicsScene* scene = ui.centerGraphicsView->scene();
nameListWidget = new QListWidget();
nameProxyWidget = scene->addWidget(nameListWidget);
...
nameProxyWidget->hide(); // you can control your widget as you like
in qdesigner_workbench.cpp, how can I add a widget (say QLabel) into a FormWindow by code?
Since methods like createWidget()...etc are all abstract, how do I properly use the internal mechanics to add QLabel into the active FormWindow?
EDIT:
In qdesigner_workbench.cpp, this is currently what I have:
QDesignerFormWindowManagerInterface* fwm = core()->formWindowManager();
QDesignerFormWindowInterface* fw = fwm->activeFormWindow();
QWidget* mw = fw->mainContainer();
QLabel* label = new QLabel(mw); //can be added correctly but not in the right hierarchy
label->setText("I am a good girl.");
The mw (obtained from fw->mainContainer()) is actually a MainWindow, however the real data I need is in:
mw -> children[2] (which is a QDesignerWidget) -> children
There are 9 widgets in the designer, and you can see there's 9 arrays in children mentioned above; see this link (an image) for illustration.
http://img24.imagevenue.com/img.php?image=98871_a_122_476lo.jpg
So... how can I correctly add the QLabel widget?
Tried both
QLabel* label = new QLabel(fw); // will be a sibling of MainContainer, which is the QMainWindow (mw) in this case
QLabel* label = new QLabel(mw); // will be a sibling of QDesignerWidget
and apprarently either of the works.
If you want just to display a widget on a form, you can set your QMainWindow or QDialog to be the widget parent:
QLabel *l = new QLabel(this);
l->setText("My long string");
Where this is a pointer pointing to your current QDialog or QMainWindow.
Otherwise as ufukgun pointed out, you can use setCentralWidget if you need your widget to occupy the center of the QMainWindow.
You should add any QWidget to the QLayout of the form.This will put it into the display strategy of the form when resizing it.
form->ui->layout->add(yourQWidget);
Depending of the QLayout you are using, parameters of the add function will not be the same.
create a widget and add it to your main window as it is your central widget
mainWindow->setCentralWidget(centralWidget);
if you want to add a label, you can add it to this central widget