How to display QLabel inside qwidget from active QMdiAreaSubwindow in statusbar? - c++

I have a app that uses QMdiArea.
I want the text in the statusbar to update when another QMdiAreaSubwindow becomes active.
So the text in the statusbar should become the same as the Qlabel text inside the QWidget which is been displayed inside the QMdiAreaSubwindow.
But i can't find a way to do this. Right now the statusbar only shows the text from latest created QMdiAreaSubwindow. But it won't update the text in the statusbar(With qlabel from the qwidget) when another QMdiAreaSubwindow is selected.
As you can see in the screenshot, the text in the statusbar keeps saying "test2", but I want it to change to "text" from the active QMdiAreaSubwindow.
mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QMdiArea>
#include <QMdiSubWindow>
#include <newwindow.h>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = nullptr);
~MainWindow();
void NewSubWindow(QString name);
void createStatusBar(QString name);
private slots:
void on_actionNew_triggered();
void on_mdiArea_subWindowActivated(QMdiSubWindow *arg1);
private:
Ui::MainWindow *ui;
NewWindow *nDialog;
};
#endif // MAINWINDOW_H
mainwindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "mdisubwidget.h"
#include "newwindow.h"
#include <QDebug>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
nDialog = new NewWindow();
connect(nDialog,&NewWindow::transmit,this,&MainWindow::NewSubWindow);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::NewSubWindow(QString name) {
// new Widget to add to mdiareasubwindow
mdisubwidget *mdiwidget = new mdisubwidget();
mdiwidget->addName(name);
mdiwidget->setWindowTitle(name);
// Create new mdiAreaSubWindow
ui->mdiArea->addSubWindow(mdiwidget);
// Show mdiArea
mdiwidget->show();
}
void MainWindow::on_actionNew_triggered()
{
nDialog->show();
}
void MainWindow::on_mdiArea_subWindowActivated(QMdiSubWindow *arg1)
{
mdisubwidget *mdiwidget = new mdisubwidget(arg1->widget());
qDebug() << "name" << mdiwidget->returnName();
createStatusBar(mdiwidget->returnName());
}
void MainWindow::createStatusBar(QString name)
{
statusBar()->showMessage("chart = "+name);
}
mdisubwidget.h
#ifndef MDISUBWIDGET_H
#define MDISUBWIDGET_H
#include <QWidget>
namespace Ui {
class mdisubwidget;
}
class mdisubwidget : public QWidget
{
Q_OBJECT
public:
explicit mdisubwidget(QWidget *parent = nullptr);
void addName(QString name);
QString returnName();
~mdisubwidget();
private:
Ui::mdisubwidget *ui;
};
#endif // MDISUBWIDGET_H
mdisubwidget.cpp
#include "mdisubwidget.h"
#include "ui_mdisubwidget.h"
#include "mainwindow.h"
QString currentName;
mdisubwidget::mdisubwidget(QWidget *parent) :
QWidget(parent),
ui(new Ui::mdisubwidget)
{
ui->setupUi(this);
}
void mdisubwidget::addName(QString name) {
ui->label_2->setText(name);
currentName = name;
}
QString mdisubwidget::returnName() {
return currentName;
}
mdisubwidget::~mdisubwidget()
{
delete ui;
}
NewWindow.h:
#ifndef NEWWINDOW_H
#define NEWWINDOW_H
#include <QWidget>
namespace Ui {
class NewWindow;
}
class NewWindow : public QWidget
{
Q_OBJECT
public:
explicit NewWindow(QWidget *parent = nullptr);
~NewWindow();
signals:
void transmit(QString name);
private slots:
void on_pushButton_clicked();
private:
Ui::NewWindow *ui;
};
#endif // NEWWINDOW_H
NewWindow.cpp:
#include "newwindow.h"
#include "ui_newwindow.h"
#include "mainwindow.h"
NewWindow::NewWindow(QWidget *parent) :
QWidget(parent),
ui(new Ui::NewWindow)
{
ui->setupUi(this);
}
NewWindow::~NewWindow()
{
delete ui;
}
void NewWindow::on_pushButton_clicked()
{
QString name = ui->lineEdit->text();
emit transmit(name);
}

ok you're using Qt Designer to connect the signal of subWindowActivated to the slot of on_mdiArea_subWindowActivated of your MainWindow, double check with qDebug in your on_mdiArea_subWindowActivated function if the name of your selected sub window appears on the console as you tried to change your current mdi sub window so follow my code snippets to find your way:
connect(ui->mdiArea, &QMdiArea::subWindowActivated, this, &DesignerWindow::activeViewChanged);
activeViewChanged():
void DesignerWindow::activeViewChanged(QMdiSubWindow *activeSubWindow)
{
// checks if there is no active sub window defined or the number of subwindows
// are zero then return
if (!activeSubWindow)
return;
if (ui->mdiArea->subWindowList().count() == 0) {
ui->itemsTree->clear();
return;
}
// defines the current Midi, View and graphical Scene when current sub window changes
currentMidi = reinterpret_cast<MidiWindow*>(activeSubWindow->widget());
currentView = reinterpret_cast<HMIView*>(currentMidi->internalView());
currentScene = reinterpret_cast<HMIScene*>(currentMidi->internalScene());
ItemsToolBar::ItemType currentType = currentScene->itemType();
itemsToolBar->selectItemType(currentType);
// updates the widgets and labels in status bar related to current midi sub window
updateScale(currentView->zoomFactor() * 100);
updateSelected();
updateItemsTree();
updateRendererType();
}
for example for updating the label in the status bar that holds the zooming factor of the current mdiSubWindow I wrote the updateScale procedure as below:
void DesignerWindow::updateScale(double _scale)
{
scale = static_cast<int>(_scale);
scaleLbl->setText(QString("%1%").arg(scale));
}
and finally I've noticed that your creating a label in status bar every time that you try to update the text in it, please avoid such a procedure and create a QLabel object and add it to your status bar as a permanent widget like below:
scaleLbl = new QLabel(this);
scaleLbl->setFrameStyle(QFrame::Sunken | QFrame::Panel);
scaleLbl->setMinimumWidth(50);
statusBar()->addPermanentWidget(scaleLbl);

Related

menu bar functionalities aren't working in Qt

so i am writing a simple video player program and i did the same steps as the lesson i am taking but when i run the program and click on functionalities like end (which is close()) and open (open file) they dont work, i used the slot triggering as per the lesson although i saw different ways of using the menubar here but i must follow this format, here is my code:
header:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QPushButton>
#include <QVideoWidget>
#include <QStyle>
#include <QMediaPlayer>
#include <QFileDialog >
namespace Ui {
class videoWidget;
}
class videoWidget : public QMainWindow
{
Q_OBJECT
QMediaPlayer *meinPlayer;
QPushButton *playButton;
QPushButton *stopButton;
public:
explicit videoWidget(QWidget *parent = 0);
~videoWidget();
private slots:
void listeUndTitelAktualisieren();
void on_action_End_triggered();
void on_action_ffnen_triggered();
void on_action_Stop_triggered();
void on_action_PlayBack_triggered();
void on_action_Pause_triggered();
private:
Ui::videoWidget *ui;
};
#endif // MAINWINDOW_H
cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"
videoWidget::videoWidget(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::videoWidget)
{
ui->setupUi(this);
meinPlayer = new QMediaPlayer(this);
meinPlayer->setMedia(QUrl::fromLocalFile("/beispiele/topologien.wmv"));
meinPlayer->play();
}
void videoWidget::listeUndTitelAktualisieren()
{
QString titel = meinPlayer->media().canonicalUrl().toLocalFile();
ui->listWidget->addItem(titel);
this->setWindowTitle("Multimedia-Player – " + titel);
connect(meinPlayer, SIGNAL(mediaChanged(QMediaContent)), this, SLOT(listeUndTitelAktualisieren()));
}
void videoWidget::on_action_End_triggered()
{
this->close();
}
void videoWidget::on_action_ffnen_triggered()
{
QFileDialog *meinDialog = new QFileDialog(this);
meinDialog->setAcceptMode(QFileDialog::AcceptOpen);
meinDialog->setWindowTitle("Datei öffnen");
meinDialog->setNameFilters(QStringList() << "Videos (*.mp4 *.wmv)" << "Audios (*.mp3)" << "Alle Dateien (*.*)");
meinDialog->setDirectory(QDir::currentPath());
meinDialog->setFileMode(QFileDialog::ExistingFile);
if (meinDialog->exec() == QDialog::Accepted) {
QString datei = meinDialog->selectedFiles().first();
meinPlayer->setMedia(QUrl::fromLocalFile(datei));
/*QString fileName = QFileDialog::getOpenFileName(this,
tr("Open Image"), "/home/jana", tr("Video & Audio Files (*.mp3 *.mp4 *.wmv)"));
*/
meinPlayer->play();
}
}
void videoWidget::on_action_Stop_triggered()
{
meinPlayer->pause();
}
void videoWidget::on_action_PlayBack_triggered()
{
meinPlayer->play();
}
void videoWidget::on_action_Pause_triggered()
{
meinPlayer->pause();
}
am pretty sure this instruction here:
connect(meinPlayer, SIGNAL(mediaChanged(QMediaContent)), this, SLOT(listeUndTitelAktualisieren()));
is not located where it should coz you are connecting the signal toa slot INSIDE of the SLOT implementation....
try moving that to the constructor of dein videoWidget

How to send message from child widget to parent window in Qt?

How do I send a message from a child widget to a parent window in qt?
I tried sending a signal from the child widget to the parent window in qt. When I call the function test in subwidget.cpp, the signal is sent but the mainwindow slot does not execute. How can I send the message?
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QStackedWidget>
#include <QPushButton>
#include <QProcess>
#include <QDebug>
#include <subwidget.h>
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
void check_adb_exists();
private:
Ui::MainWindow *ui;
QStackedWidget *stack;
QPushButton *start_btn;
SubWidget *f2;
private slots:
void StartApplication();
void ReceiveCustomMessage(const QString &msg);
};
#endif // MAINWINDOW_H
subwidget.h
#define SUBWIDGET_H
#include <QWidget>
namespace Ui {
class SubWidget;
}
class SubWidget : public QWidget
{
Q_OBJECT
public:
explicit SubWidget(QWidget *parent);
~SubWidget();
void test();
private:
Ui::SubWidget *ui;
signals:
void SendCustomMessage(const QString& msg);
};
#endif // SUBWIDGET_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
// #include <formcustomnew.h>
#include <subwidget.h>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
stack = MainWindow::findChild<QStackedWidget *>("stackedWidget");
start_btn = MainWindow::findChild<QPushButton *>("start_btn");
stack->setCurrentIndex(0);
connect(start_btn,SIGNAL(released()),this,SLOT(StartApplication()));
f2 = new SubWidget(this);
//connect(f2,SIGNAL(SendCustomMessage(QString)),this,SLOT(ReceiveCustomMessage(QString)));
//f2->test();
//auto f1 = new FormCustomNew(this);
//connect(f1,SIGNAL(sendMessageNewMessage(QString)),this,SLOT(receiveMessage(QString)));
//f1->test();
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::StartApplication(){
//check_adb_exists();
f2->test();
}
void MainWindow::ReceiveCustomMessage(const QString &msg){
qDebug("Recieved message from child");
qDebug("Message: " + msg.toLatin1());
}
void MainWindow::check_adb_exists(){
QProcess *p = new QProcess();
connect(p,&QProcess::readyReadStandardOutput,[&](){
auto data = p->readAllStandardOutput();
qDebug("Stdout: " + data);
});
connect(p,&QProcess::readyReadStandardError,[&](){
auto data = p->readAllStandardError();
qDebug("Error: " + data);
if(data.toStdString().compare("File Not Found")){
qDebug("File Not Found is the error");
}
});
QStringList args;
args << "/c dir C:\\Users\\%USERNAME%\\AppData\\Local\\Android\\Sdk";
p->setArguments(args);
p->setProgram("C:\\Windows\\System32\\cmd.exe");
p->start();
}
subwidget.cpp
#include "subwidget.h"
#include "ui_subwidget.h"
SubWidget::SubWidget(QWidget *parent) :
QWidget(parent),
ui(new Ui::SubWidget)
{
ui->setupUi(this);
qDebug("parent: " + parent->objectName().toLatin1());
connect(this,SIGNAL(SendCustomMessage(QString)),parent,SLOT(ReceiveCustomMessage(QString)));
}
SubWidget::~SubWidget()
{
delete ui;
}
void SubWidget::test(){
emit SendCustomMessage("trial message");
}
void SubWidget::SendCustomMessage(const QString &msg){
qDebug("Sending Message: " + msg.toLatin1());
}
Signals must not be defined in Qt.
From the Qt wiki on Signal & Slots:
Signals are automatically generated by the moc and must not be implemented in the .cpp file
Remove your implementation and this should work. However you should not be binding the signal within subclass as that reduces encapsulation and reusability (parent must have a ReceiveCustomMessage(QString) slot). Instead bind it outside, as you have in your commented out code.

How to get QString from one window to another window, via pressing a button in a 3rd window

New to C++ and Qt as part of a research project (biology) and have been struggling with presumably some quite simple stuff. I'd really appreciate someone's help.
I'm working with a GUI for a pre-existing programme and I'm trying to transfer a QString variable from the QLineEdit of one of the windows (inputform), to the QLineEdit of a second window (output form).
The bit I'm stuck with is that I need the output form to appear, with it's LineEdit pre-populated, when I click a button on a third window (filedialog).
Problem:
At start up --> two windows appear: filedialog and inputform.
User enters data into inputform's QLineEdit
User presses 'transferButton' on filedialog window
On button press --> outputform appears, with a QLineEdit pre-populated with the user's data (from the inputform).
I assume the problem is of the getter/setter variety and my variable is probably going out of scope, but I've tried following lots of similar examples but can't make it work.
Thanks in advance.
Here's my code:
Main.cpp
#include "filedialog.h"
#include "inputform.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
FileDialog w;
InputForm w2;
w.show();
w2.show();
return a.exec();
}
filedialog.h
#ifndef FILEDIALOG_H
#define FILEDIALOG_H
#include <QDialog>
namespace Ui {
class FileDialog;
}
class FileDialog : public QDialog
{
Q_OBJECT
public:
explicit FileDialog(QWidget *parent = nullptr);
~FileDialog();
void setFileName();
QString getFileName();
private slots:
void on_transferButton_clicked();
private:
Ui::FileDialog *ui;
QString fileName;
};
#endif // FILEDIALOG_H
filedialog.ccp
#include "filedialog.h"
#include "ui_filedialog.h"
#include "inputform.h"
#include "ui_inputform.h"
#include "outputform.h"
#include "ui_outputform.h"
FileDialog::FileDialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::FileDialog)
{
ui->setupUi(this);
}
FileDialog::~FileDialog()
{
delete ui;
}
void FileDialog::setFileName()
{
InputForm *inputform = new InputForm;
fileName = inputform->ui->inputLineEdit->text();
}
QString FileDialog::getFileName()
{
return fileName;
}
void FileDialog::on_transferButton_clicked()
{
setFileName();
OutPutForm *outputform = new OutPutForm;
outputform->ui->outputLineEdit->setText(getFileName());
outputform->show();
}
inputform.h
#ifndef INPUTFORM_H
#define INPUTFORM_H
#include <QWidget>
namespace Ui {
class InputForm;
}
class InputForm : public QWidget
{
Q_OBJECT
public:
explicit InputForm(QWidget *parent = nullptr);
~InputForm();
Ui::InputForm *ui;
};
#endif // INPUTFORM_H
inputform.ccp
#include "inputform.h"
#include "ui_inputform.h"
InputForm::InputForm(QWidget *parent) :
QWidget(parent),
ui(new Ui::InputForm)
{
ui->setupUi(this);
}
InputForm::~InputForm()
{
delete ui;
}
outputform.h
#ifndef OUTPUTFORM_H
#define OUTPUTFORM_H
#include <QWidget>
namespace Ui {
class OutPutForm;
}
class OutPutForm : public QWidget
{
Q_OBJECT
public:
explicit OutPutForm(QWidget *parent = nullptr);
~OutPutForm();
Ui::OutPutForm *ui;
};
#endif // OUTPUTFORM_H
outputform.ccp
#include "outputform.h"
#include "ui_outputform.h"
OutPutForm::OutPutForm(QWidget *parent) :
QWidget(parent),
ui(new Ui::OutPutForm)
{
ui->setupUi(this);
}
OutPutForm::~OutPutForm()
{
delete ui;
}
Thank you for your brief pointer.
After some playing around:
Setup mainwindow (or in my case main dialog window). Generate inputform instance, connect button to inputform.
FileDialog::FileDialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::FileDialog)
{
ui->setupUi(this);
InputForm *inputForm = new InputForm;
connect(ui->transferButton,SIGNAL(clicked()),inputForm,SLOT(getLineEditTextFunc()));
inputForm->show();
}
FileDialog::~FileDialog()
{
delete ui;
}
void FileDialog::on_transferButton_clicked()
{
}
Then from the input form:
Define a function to get the input form's LineEdit text (fileName); and then also generate an output form and populate it's LineEdit with the fileName variable.
InputForm::InputForm(QWidget *parent) :
QWidget(parent),
ui(new Ui::InputForm)
{
ui->setupUi(this);
}
InputForm::~InputForm()
{
delete ui;
}
void InputForm::getLineEditTextFunc()
{
fileName = this->ui->inputLineEdit->text();
OutPutForm *outputform = new OutPutForm;
outputform->ui->outputLineEdit->setText(fileName);
outputform->show();
}

Using QPainter to draw a line between QWidgets

I'm working on an application where I need to be able to draw a line between two QWidget objects. I have tried quite a few things, but my current attempt (which I think is in the right direction I just think I'm missing something) is to have the containing widget (which I called DrawWidget and which holds the QGridLayout that the QWidget objects are added to) override the paintEvent method and call the QPainter::drawLine() function.
The issues I'm having are that:
No matter how I try to get the position of the widgets, the endpoints of the line are always in the wrong place
Whenever I try to draw a second line, the first line that I drew gets erased.
Here is the paintEvent function of the containing widget:
void paintEvent(QPaintEvent *)
{
if (!drewSinceUpdate){
drewSinceUpdate = true;
QPainter painter(this);
painter.setPen(QPen(Qt::black));
painter.drawLine(start->geometry().center(), end->geometry().center());
}
}
I have tried many different ways to get the correct position of the widgets in the last line of paintEvent, which I will post some of the ways (I can't remember all of them):
painter.drawLine(start->pos(), end->pos());
painter.drawLine(start->mapToGlobal(start->geometry().center()), end->mapToGlobal(end->geometry().center()));
painter.drawLine(this->mapToGlobal(start->geometry().center()), this->mapToGlobal(end->geometry().center()));
painter.drawLine(start->mapTo(this, start->pos()), end->mapTo(this, end->pos()));
painter.drawLine(this->mapFrom(start, start->pos()), this->mapFrom(end, end->pos()));
And just to make my question clear, here is an example of what I am looking for, taken from QT Diagram Scene Example:
But this is what I end up getting:
Thank you for any help you can provide.
NOTE:
-start and end are both QWidget objects which I passed in using another method
-The hierarchy relevant to DrawWidget is:
QMainWindow
->QScrollArea
->DrawWidget
->QGridLayout
->Items <-- These are the things I want to connect
EDIT: To make a Complete and Verifiable example, here is the entirety of the relevant code.
MainWindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QHBoxLayout>
#include <QVBoxLayout>
#include <QTextEdit>
#include <QPushButton>
#include <QScrollBar>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
// Setting up the relevant hierarchy
ui->setupUi(this);
scrollArea = new QScrollArea();
setCentralWidget(scrollArea);
drawWidget = new DrawWidget();
gridLayout = new QGridLayout();
gridLayout->setSpacing(300);
drawWidget->setLayout(gridLayout);
scrollArea->setWidget(drawWidget);
scrollArea->setWidgetResizable(true);
AddItemSlot();
QApplication::connect(scrollArea->horizontalScrollBar(), SIGNAL(rangeChanged(int,int)), this, SLOT(scrollHorizontal()));
}
// This is just creating a single one of the example widgets which I want to connect
QWidget* MainWindow::CreateNewItem(){
QWidget* itemWidget = new QWidget();
itemWidget->setStyleSheet("background-color: lightgray");
QHBoxLayout* singleItemLayout = new QHBoxLayout();
itemWidget->setLayout(singleItemLayout);
QTextEdit* textEdit = new QTextEdit(std::to_string(counter++).c_str());
textEdit->setStyleSheet("background-color:white;");
singleItemLayout->addWidget(textEdit);
QVBoxLayout* rightSidePanel = new QVBoxLayout();
rightSidePanel->setAlignment(Qt::AlignTop);
QPushButton* button1 = new QPushButton("Top Button");
QApplication::connect(button1, SIGNAL(clicked(bool)), this, SLOT(AddItemSlot()));
rightSidePanel->addWidget(button1);
QWidget* rightPanelWidget = new QWidget();
rightSidePanel->setMargin(0);
rightPanelWidget->setLayout(rightSidePanel);
singleItemLayout->addWidget(rightPanelWidget);
itemWidget->setLayout(singleItemLayout);
itemWidget->setMinimumWidth(400);
itemWidget->setFixedSize(400,200);
return itemWidget;
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::scrollHorizontal()
{
scrollArea->ensureWidgetVisible(noteItems.back());
}
void MainWindow::AddItemSlot()
{
QWidget* w = CreateNewItem();
gridLayout->addWidget(w,currRow, currCol++);
if (!noteItems.empty()){
drawWidget->updateEndpoints(noteItems.back(), w);
}
noteItems.push_back(w);
}
MainWindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QGridLayout>
#include <QWidget>
#include <QMainWindow>
#include <QScrollArea>
#include <drawwidget.h>
#include "drawscrollarea.h"
#include <vector>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
public slots:
void scrollHorizontal();
void AddItemSlot();
private:
Ui::MainWindow *ui;
QWidget* CreateNewItem();
int counter = 0, currCol = 0, currRow = 0;
std::vector<QWidget*> noteItems;
QScrollArea* scrollArea;
DrawWidget* drawWidget;
QGridLayout* gridLayout;
};
#endif // MAINWINDOW_H
DrawWidget.cpp:
#include "drawwidget.h"
#include <QDebug>
#include <QRect>
DrawWidget::DrawWidget(QWidget *parent) : QWidget(parent)
{
}
void DrawWidget::paintEvent(QPaintEvent *)
{
if (!drewSinceUpdate){
drewSinceUpdate = true;
QPainter painter(this);
painter.setPen(QPen(Qt::black));
for (ConnectedPair pair : items){
const QWidget* from = pair.from;
const QWidget* to =pair.to;
QPoint start = from->mapToGlobal(from->rect().topRight() + QPoint(0, from->height()/2));
QPoint end = to->mapToGlobal(to->rect().topLeft() + QPoint(0, to->height()/2));
painter.drawLine(mapFromGlobal(start), mapFromGlobal(end));
}
}
}
void DrawWidget::updateEndpoints(QWidget* startIn, QWidget* endIn){
drewSinceUpdate = false;
items.push_back(ConnectedPair{startIn, endIn});
}
DrawWidget.h
#ifndef DRAWWIDGET_H
#define DRAWWIDGET_H
#include <QWidget>
#include <QPainter>
#include <QtCore>
#include <vector>
class DrawWidget : public QWidget
{
Q_OBJECT
public:
explicit DrawWidget(QWidget *parent = nullptr);
void updateEndpoints(QWidget* startIn, QWidget* endIn);
virtual void paintEvent(QPaintEvent *);
signals:
private:
struct ConnectedPair {
const QWidget* from;
const QWidget* to;
};
std::vector<ConnectedPair> items;
bool drewSinceUpdate = true;
};
#endif // DRAWWIDGET_H
For this case we use the function mapToGlobal() and mapfromGlobal(), since pos() returns a position with respect to the parent and this can cause problems if the widget has different parents.
drawwidget.h
#ifndef DRAWWIDGET_H
#define DRAWWIDGET_H
#include <QWidget>
class DrawWidget : public QWidget
{
Q_OBJECT
public:
explicit DrawWidget(QWidget *parent = nullptr);
void addWidgets(const QWidget *from, const QWidget *to);
protected:
void paintEvent(QPaintEvent *);
private:
struct WidgetsConnected {
const QWidget* from;
const QWidget* to;
};
QList<WidgetsConnected> list;
};
#endif // DRAWWIDGET_H
drawwidget.cpp
#include "drawwidget.h"
#include <QPainter>
DrawWidget::DrawWidget(QWidget *parent) : QWidget(parent)
{
}
void DrawWidget::addWidgets(const QWidget * from, const QWidget * to)
{
list.append(WidgetsConnected{from , to});
update();
}
void DrawWidget::paintEvent(QPaintEvent *)
{
QPainter painter(this);
for(const WidgetsConnected el: list){
const QWidget* from = el.from;
const QWidget* to = el.to;
QPoint start = from->mapToGlobal(from->rect().topRight() + QPoint(0, from->height()/2));
QPoint end = to->mapToGlobal(to->rect().topLeft() + QPoint(0, to->height()/2));
painter.drawLine(mapFromGlobal(start), mapFromGlobal(end));
}
}
The complete example can be found here.

c++ qt Dialog 'OK' button after Mainwindow set image

I want new form from 'OK' click after
From Mainwindow label Set image
image path : ./org/org.jpg
addim.h
private slots:
void on_buttonBox_accepted(); <---- 'OK' button
addim.cpp
void AddIm::on_ADdimg_cliekd()
system("raspistill -w 480 -h 360 -q 20 -o aaa.jpg -t 2");
QPixmap pix("./org/org.jpg);
ui2->QWidjet_org->setPixmap(pix); <--- QWidjet_org this label
I managed to do a minimal code that works:
MainWindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "dialog.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
public slots:
//This will change the image in the main window
void buttonHere();
//This will change the image in the dialog box
void buttonDialog();
private:
Ui::MainWindow *ui;
Dialog dialog;
//We need to save the image in QImage so it doesn't disappear
QImage image;
};
#endif // MAINWINDOW_H
MainWindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
QObject::connect(ui->pushButton_here, SIGNAL(clicked(bool)), SLOT(buttonHere()));
QObject::connect(ui->pushButton_dialog, SIGNAL(clicked(bool)), SLOT(buttonDialog()));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::buttonHere()
{
//We load the image
image.load(ui->label->text());
//We set the label image
ui->label_2->setPixmap(QPixmap::fromImage(image));
}
void MainWindow::buttonDialog()
{
//We call the function that changes the dialog image
dialog.setImage(ui->label->text());
//We show the dialog
dialog.show();
}
Dialog.h
#ifndef DIALOG_H
#define DIALOG_H
#include <QDialog>
namespace Ui {
class Dialog;
}
class Dialog : public QDialog
{
Q_OBJECT
public:
explicit Dialog(QWidget *parent = 0);
~Dialog();
//This function changes the image
void setImage(QString path);
private:
Ui::Dialog *ui;
//We need to save the image in QImage so it doesn't disappear
QImage image;
};
#endif // DIALOG_H
Dialog.cpp
#include "dialog.h"
#include "ui_dialog.h"
Dialog::Dialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::Dialog)
{
ui->setupUi(this);
}
Dialog::~Dialog()
{
delete ui;
}
void Dialog::setImage(QString path)
{
//We load the image
image.load(path);
//We set the label image
ui->label->setPixmap(QPixmap::fromImage(image));
}
You get this result
http://i.imgur.com/sguOqLS.png
http://i.imgur.com/p2rCK9f.png
You should create a resource file, import your picture in it and then use the following example code:
QPixmap pixmap_btn_hw(":/new/myPrefix/btn_hardware.png");
QIcon ButtonIcon_hw(pixmap_btn_hw);
ui->hardware_btn->setIcon(ButtonIcon_hw);
ui->hardware_btn->setIconSize(pixmap_btn_hw.rect().size());
ui->hardware_btn->setFocusPolicy(Qt::NoFocus);
To start an external program, "sytem()" is a bad idea. The following is much better:
QProcess *prpr = new QProcess();
prpr->setProcessChannelMode(QProcess::MergedChannels);
prpr->start("raspistill -w 480 -h 360 -q 20 -o aaa.jpg -t 2");
if (!prpr->waitForFinished())
{
// there was an error
}
else
{
// command worked!
}