How to build a simple custom widget with Qt? The widget is very simple with just 2 line edit QLineEdit' in a vertical box layoutQVBoxLayout`. How to do it? I read Qt's examples on custom widget generation. They reimplement paint event to rendering the custom widget. However, mine is so simple that I cannot find a solution in Qt's reference.
Well to do it all programatically it would look something like this:
class MyWidget : public QWidget {
public:
MyWidget(QWidget *parent=0) : QWidget(parent) {
QVboxLayout *layout = new QVboxLayout();
setLayout(layout);
layout->addWidget(new QLineEdit());
layout->addWidget(new QLineEdit());
}
};
Depending on your needs you could make the line edits member variables and manipulate them as you see fit.
Related
I need material styled replacements of standard widgets and it's kind of hard to implement them by using custom widgets. I was wondering if there's any way to include widgets from quick control module and use them as regular widgets?
If your application is Qt5.1 and above, the answer is yes you can.
You have to use the QQuickView object and pass it to static function createWindowContainer of QWidget, which takes QWindow as in paramater.
QQuickView derived from QQuickWindow which is derived from QWindow.
So you can pass a QQuickView as an input to the createWindowContainer.
Below is some rough code.
//CREATE A QQuickView OBJECT.
QQuickView *view = new QQuickView();
//ADD THE QQuickView OBJECT TO QWidget::createWindowContainer
QWidget *container = QWidget::createWindowContainer(view, this);
//ADD SOURCE
view->setSource(QUrl("your.qml"));
//ADD THE CONTAINER TO YOUR LAYOUT.
ui->verticalLayout->addWidget(container);
You can use QQuickWidget if you want to insert your QML view in a layout :
//CREATE THE QQuickWidget
QQuickWidget *quickWidget = new QQuickWidget(this);
//ADD SOURCE
view->setSource(QUrl("your.qml"));
//ADD THE QQuickWidget TO YOUR LAYOUT.
ui->verticalLayout->addWidget(quickWidget);
I adapted #katamarayudu's code to use QQuickWidget instead of QQuickView.
I need a QMainWindow layout to change depending on the number of cores.
Therefore I set it manually (not using the Design mode).
My question is:
After this layout was created, how can I refer to the widgets it contains?
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
//...
buildLayout();
//...
// Now I'd like to use something like this:
// ui->threadingTable->...
// However, it's not the member of ui
}
void MainWindow::buildLayout()
{
QWidget *window = new QWidget(this);
QTableView *threadingTable = new QTableView(window);
//...
QGridLayout *layout = new QGridLayout(window);
layout->addWidget(threadingTable, 0, 0);
//...
window->setLayout(layout);
this->setCentralWidget(window);
}
I can get the QLayoutItem out of this->centralWidget().
Or I can make all widgets in layout members of MainWindow class and access them directly.
However, I feel that neither of these is the right way.
Is there a way to pass the widgets to ui?
So that I could access them by calling
ui->threadingTable
Both options are fine. It is possible to get pointer to threadingTable from the main class member or directly from the objects hierarchy:
qDebug() << qobject_cast<QGridLayout *>(this->centralWidget()->layout())->itemAtPosition(0, 0)->widget();
qDebug() << this->centralWidget()->layout()->itemAt(0)->widget();
Of course, null verification may be required. You can also check this question QGridLayout: Getting the list of QWidget added.
The class Ui::MainWindow is automatically generated from the .ui xml form that can be generated in the Design mode: "Using a Designer UI File in Your Application"
Since the layout is constructed manually the .ui file and the ui instance is not needed at all. You can remove them from your project.
On the other hand, it is possible to use custom widgets even in the Design mode in .ui forms.
So, if you need some tricky object you can build the entire form in handy Design mode and then, for example, the standard QTableView may be promoted to your CustomTableView that is inherited from QTableView. That custom class may implement some special behavior.
I needed to read widget classnames, names etc from gui loaded via QUiloader.
And I got answer here that I needed to subclass QUiloader and reimplement its method.
I have MainWindow, and via menu/toolbar I load the file, and show it. And when I load I want to know what elements are in that gui to work further with them.
The code I got from a user here:
class UiLoader : public QUiLoader
{
Q_OBJECT
public:
QStringList *wlist;
UiLoader(QObject *parent = 0) : QUiLoader(parent) {}
virtual QWidget* createWidget(const QString &className, QWidget *parent =0, const QString &name = QString())
{
QWidget* widget = QUiLoader::createWidget(className, parent, name);
//here do my stuff with className, parent, name
return widget;
}
};
I used Uiloader to load my file. And it is working.
My question now is how I intercept createWidget before returning widget, I want to get the list of widget and then return Widgets.
I do not know how what is the efficient way to create a list as simple as this one:
0=>TextBox, 1=>Button, ...
I really do not care about the structure I just need to know which one comes first and what it is.
Thanks.
I wouldn't reimplement class loader at all honestly.. May be only if you need to 'inject' something into existing code which use QUiLoader a lot.. but in general only thing you need:
pWidget = ...->createWidget(...);
QList<QWidget *> widgets = pWidget->findChildren<QWidget *>();
here you go, your widgets contains list of all form components..
I was wondering if it were possible to create my own shortcut key to a QTabWidget. So if I put an ampersand infront of the letter, that means that ALT+'letter' will display that tab; however, I want it so that CTRL+'letter' will display that tab (not ALT).
Is there an easy way to do this in Qt Designer? If not, is there a simple way to do it in code? QTabWidget doesn't seem to have any direct methods for setting shortcuts.
I don't know of a way to do this via the Designer, not familiar with that. You could do it with QShortcut fairly easily in code though.
Here's a dummy widget to illustrate that. Press Ctrl+a / Ctrl+b to switch between tabs.
#include <QtGui>
class W: public QWidget
{
Q_OBJECT
public:
W(QWidget *parent=0): QWidget(parent)
{
// Create a dummy tab widget thing
QTabWidget *tw = new QTabWidget(this);
QLabel *l1 = new QLabel("hello");
QLabel *l2 = new QLabel("world");
tw->addTab(l1, "one");
tw->addTab(l2, "two");
QHBoxLayout *l = new QHBoxLayout;
l->addWidget(tw);
setLayout(l);
// Setup a signal mapper to avoid creating custom slots for each tab
QSignalMapper *m = new QSignalMapper(this);
// Setup the shortcut for the first tab
QShortcut *s1 = new QShortcut(QKeySequence("Ctrl+a"), this);
connect(s1, SIGNAL(activated()), m, SLOT(map()));
m->setMapping(s1, 0);
// Setup the shortcut for the second tab
QShortcut *s2 = new QShortcut(QKeySequence("Ctrl+b"), this);
connect(s2, SIGNAL(activated()), m, SLOT(map()));
m->setMapping(s2, 1);
// Wire the signal mapper to the tab widget index change slot
connect(m, SIGNAL(mapped(int)), tw, SLOT(setCurrentIndex(int)));
}
};
This isn't meant as an example of widget layout best practices... just to illustrate one way to wire a shortcut sequence to a tab change.
I have a browser made in Qt and a I have a tabwidget with one tab (which has a label, lineedit and a webview). I want to add others that look like the first one (have label, lineedit and webview).
How can I do this?
I don't know of any way to "clone" or duplicate an existing tab or widget, so I believe you'll need to code the tab contents yourself (i.e. not through the designer).
If all you need are a QLabel, a QLineEdit and a QWebView, that's not very complex. The idea would be to:
create a custom widget (inheriting from QWidget directly, or from QFrame)
lay out the contained widgets in the fashion you want in its constructor
add as many tabs as you want, when you want them, via the QTabWidget.addTab function.
The Tab Dialog example has everything you need - it's actually more complex than what you need because it uses different widgets for each tab. You can get away with a single widget.
If you wonder how to do the layout, and you're satisfied with what you got from the designer, you can inspect the generated (.moc) files. You'll see what layouts it uses, and you can replicate that in your own code.
Skeleton widget:
class BrowserTab : public QWidet
{
Q_OBJECT
public:
BrowserTab(QUrl const& home, QWidget *parent = 0);
void setUrl(QUrl const& url);
private:
QWebView *web;
QLabel *title;
QLineEdit *urlEdit;
};
BrowserTab::BrowserTab(QUrl const& home, QWidget *parent)
: QWidget(parent)
{
urlEdit = new QLineEdit(this);
title = new QLabel(this);
web = new QWebView(this);
QVBoxLayout *vl = new QVBoxLayout;
vl->addLayout(title);
vl->addLayout(urlEdit);
vl->addLayout(web);
setLayout(vl);
setUrl(home);
}
void BrowserTab::setUrl(QUrl const& url)
{
web->load(url);
// update label & urlEdit here
}
You'll need to do a bit more to make it a proper browser (setUrl should probably be a slot too), but this should get you started.