I want to have some sequential actions; for example press a QPushButton and then delete the layout that is running and run another layout in the "SAME WINDOW"
In fact, I don't know what exactly layouts and widgets are!
Are they an object? an instance of object or what?
I found the bellow code in the Internet, I don't know how to change it to make it useful for me
#include <QApplication>
#include <QPushButton>
int main(int argc, char *argv[]) {
QApplication app(argc, argv);
QWidget *window = new Qwidget;
QPushButton *button1 = new QPushButton("One");
QPushButton *button2 = new QPushButton("Two"); QPushButton *button3 = new QpushButton("Three");
QHBoxLayout *layout = new QHBoxLayout;
layout->addWidget(button1);
layout->addWidget(button2);
layout->addWidget(button3);
window->setLayout(layout);
window->show();
return app.exec();
}
A better way than deleting layout and setting a new one would be to use a QStackedWidget (docs) and the concept of pages. Using QStackedWidget you can show and hide pages as you wish.
Related
I am trying to draw various shapes like rectangle, ellipse, text etc uisng QGraphicsView and QGraphicsScene. For that I am trying to create an interface where there will be a vertical layout and besides that there will be few buttons. On clicking those buttons, I can show various QGraphicsItem's on screen. I want to create this interface programatically but not using ui.
I tried and ended up this way.
I wanted buttons on the right side and verticalLayout on the left side and both should filled up the whole screen.
Here is my current implementation :
Widget::Widget(QWidget *parent)
: QWidget(parent)
, ui(new Ui::Widget)
{
ui->setupUi(this);
QGraphicsScene* scene = new QGraphicsScene(this);
QGraphicsView* view = new QGraphicsView(this);
view->setScene(scene);
QWidget* mainWidget = new QWidget(this);
QHBoxLayout *mainLayout = new QHBoxLayout();
QVBoxLayout *buttonLayout = new QVBoxLayout();
QVBoxLayout *vlayout2 = new QVBoxLayout();
vlayout2->addWidget(view);
QPushButton *btn1 = new QPushButton("Rectangle");
btn1->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Preferred );
QPushButton *btn2 = new QPushButton("Ellipse");
btn2->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Preferred );
QPushButton *btn3 = new QPushButton("Text");
btn3->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Preferred );
buttonLayout->addWidget(btn1);
buttonLayout->addWidget(btn2);
buttonLayout->addWidget(btn3);
buttonLayout->addStretch();
mainLayout->addLayout(buttonLayout);
mainLayout->addLayout(vlayout2);
mainWidget->setLayout(mainLayout);
}
Can anyone guide me ?
Actually, it should work with the hints given in my comments.
I made an MCVE to convince myself:
#include <QtWidgets>
int main(int argc, char **argv)
{
qDebug() << "Qt Version:" << QT_VERSION_STR;
QApplication app(argc, argv);
// setup GUI
QWidget qMain;
qMain.setWindowTitle("Test Box Layout");
qMain.resize(640, 320);
QHBoxLayout qHBox;
QVBoxLayout qVBoxBtns;
QPushButton qBtnRect("Rectangle");
qVBoxBtns.addWidget(&qBtnRect);
QPushButton qBtnCirc("Circle");
qVBoxBtns.addWidget(&qBtnCirc);
QPushButton qBtnText("Text");
qVBoxBtns.addWidget(&qBtnText);
qVBoxBtns.addStretch();
qHBox.addLayout(&qVBoxBtns);
QVBoxLayout qVBoxView;
QGraphicsView qView;
qVBoxView.addWidget(&qView, 1);
qHBox.addLayout(&qVBoxView, 1);
qMain.setLayout(&qHBox);
qMain.show();
// runtime loop
return app.exec();
}
Output:
Thus, there must be something else in OP's code…
Unfortunately, OP didn't expose an MCVE.
Thus, it's not clear how OP's Widget is instanced. Is it the widget which becomes the main window? Is there another widget where the Widget's instance becomes child of?
It's just guessing but the latter would explain what OP described.
To confirm my guess, I modified the above code a bit:
// setup GUI
QWidget qMain0; // main window widget
QWidget qMain(&qMain0); // child widget of main window widget
⋮
qMain.setLayout(&qHBox);
qMain0.show();
// runtime loop
return app.exec();
Please, note that qMain is now a child of qMain0 but there is no layout which adjusts the size of qMain when qMain0 is resized.
Hence, the size of view stays the initial size while the window is resized.
I am currently learning to use Qt. So I am trying to create an application that uses QtWidgets. However, when I ran my program and resize manually the window obtained, the texts displayed are trimmed (see image)
.
The code I am using is shown below:
#include <QApplication>
#include "FenPrincipale.h"
using namespace std;
int main(int argc, char *argv[])
{
QApplication app(argc,argv);
FenPrincipale fenetre;
fenetre.show();
return app.exec();
}
and the FenPrincipale contains:
FenPrincipale::FenPrincipale()
{
QWidget mainFen;
QGroupBox *groupbox1 = new QGroupBox("Class definition", &mainFen);
QLineEdit *className = new QLineEdit;
QLineEdit *mother_className = new QLineEdit;
QFormLayout *class_def = new QFormLayout;
class_def->addRow("Class name", className);
class_def->addRow("Mother Class", mother_className);
groupbox1->setLayout(class_def);
QGroupBox *groupbox2 = new QGroupBox("Options", &mainFen);
QCheckBox *header_protect = new QCheckBox("Protect header against mutiple inclusions");
QCheckBox *constr_gen= new QCheckBox("Generate default constructor");
QCheckBox *destruct_gen= new QCheckBox("Generate a destructor");
QVBoxLayout *options_layout = new QVBoxLayout;
options_layout->addWidget(header_protect);
options_layout->addWidget(constr_gen);
options_layout->addWidget(destruct_gen);
groupbox2->setLayout(options_layout);
QVBoxLayout *main_layout = new QVBoxLayout;
main_layout->addWidget(groupbox1);
main_layout->addWidget(groupbox2);
this->setLayout(main_layout);
this->setWindowTitle("Zero Class Generator");
this->resize(400,450);
}
I don't have any idea how to fix this problem. Can anyone help me?
QWidget::setMinimumSize
should make the job
https://doc.qt.io/qt-5/qwidget.html#setMinimumSize-1
I have a custom widget with some standard child widgets inside. If I make a separate test project and redefine my custom widget to inherit QMainWindow, everything is fine. However, if my custom widget inherits QWidget, the window opens, but there are no child widgets inside.
This is the code:
controls.h:
#include <QtGui>
#include <QVBoxLayout>
#include <QLineEdit>
#include <QPushButton>
class Controls : public QWidget
{
Q_OBJECT
public:
Controls();
private slots:
void render();
private:
QWidget *frame;
QWidget *renderFrame;
QVBoxLayout *layout;
QLineEdit *rayleigh;
QLineEdit *mie;
QLineEdit *angle;
QPushButton *renderButton;
};
controls.cpp:
#include "controls.h"
Controls::Controls()
{
frame = new QWidget;
layout = new QVBoxLayout(frame);
rayleigh = new QLineEdit;
mie = new QLineEdit;
angle = new QLineEdit;
renderButton = new QPushButton(tr("Render"));
layout->addWidget(rayleigh);
layout->addWidget(mie);
layout->addWidget(angle);
layout->addWidget(renderButton);
frame->setLayout(layout);
setFixedSize(200, 400);
connect(renderButton, SIGNAL(clicked()), this, SLOT(render()));
}
main.cpp:
#include <QApplication>
#include "controls.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
Controls *controls = new Controls();
controls->show();
return app.exec();
}
This opens up a window with correct dimensions, but with no content inside.
Bear in mind this is my first day using Qt. I need to make this work without inheriting QMainWindow because later on I need to put this on a QMainWindow.
You're missing a top level layout:
Controls::Controls()
{
... (yoour code)
QVBoxLayout* topLevel = new QVBoxLayout(this);
topLevel->addWidget( frame );
}
Or, if frame is not used anywhere else, directly:
Controls::Controls()
{
layout = new QVBoxLayout(this);
rayleigh = new QLineEdit;
mie = new QLineEdit;
angle = new QLineEdit;
renderButton = new QPushButton(tr("Render"));
layout->addWidget(rayleigh);
layout->addWidget(mie);
layout->addWidget(angle);
layout->addWidget(renderButton);
setFixedSize(200, 400);
connect(renderButton, SIGNAL(clicked()), this, SLOT(render()));
}
Note that setLayout is done automatically when QLayout is created (using parent widget)
You'll want to set a layout on your Controls class for managing its child sizes. I'd recommend removing your frame widget.
controls.cpp
Controls::Controls()
{
layout = new QVBoxLayout(this);
.
.
.
}
main.cpp
int main(int argc, char* argv[])
{
QApplication app(argc, argv);
MainWindow w;
w.show();
return app.exec();
}
How do I create a simple widget that would contain a first, middle and last name field and add it to the main window class?
I ask because I cant figure out why is this simple widget attempt below is not working, what have I missed?
main
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
mainWindow class
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent){
QMainWindow *mainView = new QMainWindow;
setCentralWidget(mainView);
CardUI *card = new CardUI;
QHBoxLayout *hCard = new QHBoxLayout;
hCard->addWidget(card);
mainView->setLayout(hCard);
mainView->show();
}
cardui class
CardUI::CardUI(QWidget *parent) : QWidget(parent){
QLineEdit *fnText = new QLineEdit;
QLineEdit *miText = new QLineEdit;
QLineEdit *lnText = new QLineEdit;
QHBoxLayout *name = new QHBoxLayout;
name->addWidget(fnText);
name->addWidget(miText);
name->addWidget(lnText);
setLayout(name);
}
QMainWindow *mainView = new QMainWindow;
//....
mainView->setLayout(hCard);
You should not change layout of QMainWindow. Use setCentralWidget or add toolbars/docks using given API instead.
In this particular case you shouldn't create mainView as QMainWindow (you cannot have two main windows in one application, right?). You can change mainView type to QWidget, but you can even don't create any proxy widgets, and just
MainWindow::MainWindow(QWidget *parent); : QMainWindow(parent){
card = new CardUI;
setCentralWidget(card);
}
I am having trouble getting a QGraphicsView to show up in a QVBoxLayout object and I have no idea what is wrong. My code compiles so no errors are being thrown. Here is my simple code. (I am a Qt and C++ newb). At the bottom, I add a QPushButton widget to the layout and that shows up fine. Thanks for your help in advance!
QGraphicsScene scene;
QGraphicsView view(&scene);
view.setBackgroundBrush(QImage(":/images/bg/tile.png"));
view.setCacheMode(QGraphicsView::CacheBackground);
QPixmap pixmap("images/icons/dsp.gif");
QGraphicsPixmapItem* dsp = scene.addPixmap(pixmap);
view.show();
vlayout->addWidget(&view);
vlayout->addWidget(new QPushButton("some button here"));
Not enough context, so I can't tell what's happening exactly. But, if those are in a function, then you are declaring local variables that are gone once the function exits. If you are in the main, you're code should look something like this, but it will probably crash:
QApplication app(argc, argv);
QGraphicsScene scene;
QGraphicsView view(&scene);
QWidget widget;
view.setBackgroundBrush(Qt::red);
QVBoxLayout vlayout;
widget.setLayout(&vlayout);
vlayout.addWidget(&view);
vlayout.addWidget(new QPushButton("some button here"));
widget.show();
I recommend dynamically allocating objects:
int main(int argc, char* argv[]){
QApplication app(argc, argv);
QGraphicsScene* scene = new QGraphicsScene;
QGraphicsView* view = new QGraphicsView(scene);
QWidget *widget = new QWidget;
view->setBackgroundBrush(Qt::red);
QVBoxLayout* vlayout = new QVBoxLayout(widget);
vlayout->addWidget(view);
vlayout->addWidget(new QPushButton("some button here"));
widget->show();
return app.exec();
}
Don't forget to delete the parent object so it doesn't leak memory.