I'm building a simple application, the main window have to shows two widgets (QTreeView on the right, QTabWidget on the left), to perform this i use a QHBoxLayout.
This is the code i've written(constructor of MainWindow):
MainWindow::MainWindow()
{
mainLayout = new QHBoxLayout(this);
tabber = new QTabWidget(this);
analysisTreeView = new QTreeView(this);
tabber->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
mainLayout->addWidget(tabber, 0);
mainLayout->addWidget(analysisTreeView, 0);
createActions();
createMenus();
createToolBars();
connect(tabber, SIGNAL(currentChanged(int)), this, SLOT(currentTabChanged(int)));
setLayout(mainLayout);
}
But when i run the application the main window shows no widgets. Why?
On request, i add some code:
Once a button in the mainwindows's toolbar is clicked a new tab is added to tabber:
void MainWindow::newSheet()
{
GraphicsScene *newScene = new GraphicsScene(itemMenu,this);
QGraphicsView *newView = new QGraphicsView(this);
newScene->setSceneRect(-200, -200, 400, 400);
newView->scale(1.5,1.5);
newView->setCacheMode(QGraphicsView::CacheBackground);
newView->setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate);
newView->setRenderHint(QPainter::Antialiasing);
newView->setTransformationAnchor(QGraphicsView::AnchorUnderMouse);
newView->setScene(newScene);
sheetList.append(newView);
tabber->addTab(newView,"PNC");
connect(newScene, SIGNAL(itemInserted(PItem*)), this, SLOT(itemInserted(PItem*)));
connect(newScene, SIGNAL(requestUpdateGUI(GraphicsScene*)), this, SLOT(updateGUI(GraphicsScene*)));
}
My main.cpp:
#include <QApplication>
#include "mainwindow.h"
int main(int argc, char *argv[])
{
Q_INIT_RESOURCE(application);
QApplication a(argc, argv);
MainWindow window;
window.showMaximized();
return a.exec();
}
I suppose your class specializes QMainWindow. If so, it needs a centralWidget to be set:
MainWindow::MainWindow()
{
// added by jpo38
QWidget* mainWidget = new QWidget( this );
setCentralWidget( mainWidget );
// end added by jpo38
mainLayout = new QHBoxLayout(mainWidget);
tabber = new QTabWidget(mainWidget);
analysisTreeView = new QTreeView(mainWidget);
tabber->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
mainLayout->addWidget(tabber, 0);
mainLayout->addWidget(analysisTreeView, 0);
createActions();
createMenus();
createToolBars();
connect(tabber, SIGNAL(currentChanged(int)), this, SLOT(currentTabChanged(int)));
setLayout(mainLayout);
}
Related
I'm new to Qt programming and I want to align a QLabel with a custom QGraphicsItem i created. Here's inside my custom item constructor:
QGraphicsProxyWidget* pMyProxy = new QGraphicsProxyWidget(this);
QLabel *label = new QLabel();
label->setText("Some Text");
pMyProxy->setWidget(label);
label->setAlignment(Qt::AlignLeft);
the last line seems to have no effect whether its AlignLeft, Center, or Right.
myItem is a custom rectangle, and I'd like the label to be centered inside the rectangle, as it is the first word of label is being centered at the rectangle instead of the center of the label.
Please help
When you add a widget through a proxy, the proxy is the child of the initial item so its position will be relative to it and by default the position is (0, 0), so you see that although you set an alignment does not change, what you must do to place it in the center through setPos():
#include <QApplication>
#include <QGraphicsProxyWidget>
#include <QGraphicsView>
#include <QLabel>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QGraphicsView w;
QGraphicsScene *scene = new QGraphicsScene;
QGraphicsRectItem *item = new QGraphicsRectItem;
item->setRect(QRect(0, 0, 200, 200));
item->setBrush(Qt::red);
scene->addItem(item);
QGraphicsProxyWidget *pMyProxy = new QGraphicsProxyWidget(item);
QLabel *label = new QLabel();
label->setText("Some Text");
pMyProxy->setWidget(label);
pMyProxy->setPos(item->boundingRect().center()-label->rect().center());
w.setScene(scene);
w.show();
return a.exec();
}
Assuming this is the item, you should do the following:
QGraphicsProxyWidget *pMyProxy = new QGraphicsProxyWidget(this);
QLabel *label = new QLabel();
label->setText("Some Text");
pMyProxy->setWidget(label);
pMyProxy->setPos(boundingRect().center()-label->rect().center());
If you want to access the widget regarding the item you must follow the children tree:
QGraphiscScene
└── QGraphiscItem
└── (children)
QGraphicsProxyWidget
└── (widget)
QLabel
Example:
main.cpp
#include <QApplication>
#include <QGraphicsProxyWidget>
#include <QGraphicsView>
#include <QLabel>
#include <QTimer>
#include <QDebug>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QGraphicsView w;
QGraphicsScene *scene = new QGraphicsScene;
QGraphicsRectItem *item = new QGraphicsRectItem;
item->setRect(QRect(0, 0, 200, 200));
item->setBrush(Qt::red);
scene->addItem(item);
item->setFlag(QGraphicsItem::ItemIsSelectable, true);
item->setFlag(QGraphicsItem::ItemIsMovable, true);
QGraphicsProxyWidget *pMyProxy = new QGraphicsProxyWidget(item);
QLabel *label = new QLabel();
label->setText("Some Text");
pMyProxy->setWidget(label);
pMyProxy->setPos(item->boundingRect().center()-label->rect().center());
w.setScene(scene);
QTimer timer;
QObject::connect(&timer, &QTimer::timeout, [&](){
if(!scene->selectedItems().isEmpty()){
auto *item = scene->selectedItems().first();
if(!item->childItems().isEmpty()){
auto proxy = static_cast<QGraphicsProxyWidget *>(item->childItems().first());
if(proxy){
auto label = qobject_cast<QLabel *>(proxy->widget());
if(label){
label->setText(QString("x: %1, y: %2").arg(item->pos().x()).arg(item->pos().y()));
}
}
}
}
});
timer.start(100);
w.show();
return a.exec();
}
I am trying to overlay a few buttons over my video player.
I have added a new class called overlay.cpp that subclassed a QWidget for the overlay purpose.
What I did in my code is to overlay button onto the video. In my centralWidget I have added a verticalLayout and morph it into a QWidget. The video was added into this verticalLayout. Upon program is running, the video is playing well. However, what's not working is the overlay of the button. The background doesn't seem to appear transparent even though it was set. I am not sure what is causing it to not appear transparent.
My code is as follows:
main.cpp
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[]){
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent):QMainWindow(parent),
ui(new Ui::MainWindow){
ui->setupUI(this);
initializeVideo();
initializeButton();
}
MainWindow::~MainWindow(){
delete ui;
}
void MainWindow::initializeVideo(){
QVideoWidget *v_widget = new QVideoWidget;
QMediaPlayer *m_player = new QMediaPlayer;
m_player->setMedia(QUrl::fromLocalFile("C:/user/Desktop/video.wmv"));
m_player->setVideoOutput(v_widget);
ui->verticalLayout->addWidget(v_widget);
m_player->player();
v_widget->show();
}
void MainWindow::initializeButton(){
QFrame *b_frame = new QFrame;
QGridLayout *grid = new QGridLayout;
b_frame->setLayout(grid);
b_frame->setAttribute(Qt::WA_TranslucentBackground, true);
QPushButton *buttonStop = new QPushButton;
buttonStop->setText("STOP");
grid->addWidget(buttonStop, 0, 0, Qt::AlignTop);
overlay *overlay_1 = new overlay;
QGridLayout *gridLayout = new QGridLayout;
gridLayout->addWidget(b_frame);
overlay_1->setLayout(gridLayout);
overlay_1->setParent(ui->verticalWidget);
overlay_1->show();
b_frame->show();
}
overlay.cpp
#include "overlay.h"
overlay::overlay(QWidget *parent): QWidget(parent){
this->setAttribute(Qt::WA_TranslucentBackground, true);
}
Move declaration of QVideoWidget *v_widget and QMediaPlayer *m_player to mainwindow.h like this:
private:
Ui::MainWindow *ui;
QVideoWidget *v_widget;
QMediaPlayer *m_player;
In mainwindow.cpp:
void MainWindow::initializeVideo()
{
v_widget = new QVideoWidget(this);
m_player = new QMediaPlayer(this);
m_player->setMedia(QUrl::fromLocalFile("C:/user/Desktop/video.wmv"));
m_player->setVideoOutput(v_widget);
ui->verticalLayout->addWidget(v_widget);
m_player->play();
}
void MainWindow::initializeButton()
{
QGridLayout *grid = new QGridLayout(v_widget);
QPushButton *buttonStop = new QPushButton(this);
buttonStop->setText("STOP");
grid->addWidget(buttonStop, 0, 0, Qt::AlignTop);
}
This will add "STOP" button on top of QVideoWidget.
Specify widget's parent when crating it. new QVideoWidget(this) will create new QVideoWidget as child of current MainWindow widget. If you are creating child of already visible widget you do not need to call show() on it.
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();
}
Shortly: when I dragging the mouse over the QPushButton in MS Windows7 (64bit) my app eats some memory.
But if I close the widget where the buttons are then memory will be returned.
I'm using qt5 beta 2 and VC++ with crtdbg.h.
Here is my test app (Launch, open widget2 and drag mouse over the buttons on it. At the same time see task manager.)
//-- widget1.h
class Widget1 : public QWidget
{
Q_OBJECT
private:
void callWidget2();
public:
Widget1(QWidget* parent = 0);
~Widget1() {}
};
//-- widget1.cpp
Widget1::Widget1(QWidget* parent)
:QWidget(parent)
{
QPushButton* btn = new QPushButton(this);
btn->setText("show widget2");
connect(btn, &QPushButton::clicked, this, &Widget1::callWidget2);
this->resize(100, 100);
this->show();
}
void Widget1::callWidget2()
{
new Widget2();
}
//-- widget2.h
class Widget2 : public QWidget
{
Q_OBJECT
private:
public:
Widget2(QWidget* parent = 0);
~Widget2() {}
};
//-- widget2.cpp
Widget2::Widget2(QWidget* parent)
:QWidget(parent)
{
this->setAttribute(Qt::WA_DeleteOnClose);
this->resize(300, 300);
QPushButton* button = new QPushButton(this);
button->setText("btn1");
button = new QPushButton(this);
button->setText("btn2");
button->move(0, 20);
button = new QPushButton(this);
button->setText("btn3");
button->move(0, 40);
button = new QPushButton(this);
button->setText("btn4");
button->move(0, 60);
button = new QPushButton(this);
button->setText("btn5");
button->move(0, 80);
this->show();
}
//-- main.cpp
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
new Widget1;
return a.exec();
}
This is the result of 5 minutes dragging.
I can't repeat this on windows XP 32bit.
What is this?
Greetings all,
Is there any widget to separate two QWidgets and also give full focus to a one widget.
As shown in following figure ?
Thanks in advance,
umanga
How about QSplitter?
QWidget 1, for exmaple, QListView. QWidget 2 is a combination of QWidgets (the left part is simple QPushButton with show/hide caption, and the right part another widget)... All you have to do, is to hide your QWidget2 when user clicked on QPushButton...
If you need an example, I may post it.
Updated
main.cpp
#include "splitter.h"
#include <QtGui/QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
splitter w;
w.show();
return a.exec();
}
splitter.h
#ifndef SPLITTER_H
#define SPLITTER_H
#include <QtGui/QDialog>
class splitter : public QDialog
{
Q_OBJECT;
QWidget* widget1;
QWidget* widget2;
QPushButton* button;
public:
splitter(QWidget *parent = 0, Qt::WFlags flags = 0);
~splitter();
private slots:
void showHide(void);
};
#endif // SPLITTER_H
splitter.cpp
#include <QtGui>
#include "splitter.h"
splitter::splitter(QWidget *parent, Qt::WFlags flags)
: QDialog(parent, flags)
{
QApplication::setStyle("plastique");
QListView* listView = new QListView;
QTableView* tableView = new QTableView;
button = new QPushButton("Hide >");
widget1 = new QWidget;
QHBoxLayout* w1Layout = new QHBoxLayout;
w1Layout->addWidget(listView);
w1Layout->addWidget(button);
widget1->setLayout(w1Layout);
widget2 = new QWidget;
QHBoxLayout* w2Layout = new QHBoxLayout;
w2Layout->addWidget(tableView);
widget2->setLayout(w2Layout);
QSplitter *mainSplitter = new QSplitter(this);
mainSplitter->addWidget(widget1);
mainSplitter->addWidget(widget2);
connect(button, SIGNAL(clicked()), this, SLOT(showHide()));
QVBoxLayout *mainLayout = new QVBoxLayout;
mainLayout->addWidget(mainSplitter);
setLayout(mainLayout);
}
splitter::~splitter()
{}
void splitter::showHide(void)
{
if (widget2->isVisible())
{ // hide
widget2->setVisible(false);
button->setText("< Show");
}
else
{ // show
widget2->setVisible(true);
button->setText("Hide >");
}
}