I am trying to run some code when I select a new index in a QTreeView
In RoverPlanner.h
namespace Ui {
class RoverPlanner;
}
class RoverPlanner : public QWidget
{
Q_OBJECT
public:
explicit RoverPlanner(QWidget *parent = nullptr);
void save_paths_from_tree(QTreeView* treeView);
void load_paths_into_tree(QTreeView* treeView);
std::vector<cuarl_path::Path> get_paths(const char* filename) const;
void update_segment_editor();
cuarl_path::Segment* addSegment();
~RoverPlanner();
private Q_SLOTS:
void treeSelectionChanged(const QModelIndex& prevIndex, const QModelIndex& nextIndex);
private:
Ui::RoverPlanner *ui;
};
In RoverPlanner.cpp
RoverPlanner::RoverPlanner(QWidget *parent) :
QWidget(parent),
ui(new Ui::RoverPlanner)
{
ui->setupUi(this);
QPushButton* btnLoadPaths = this->findChild<QPushButton*>("btn_load_paths");
QPushButton* btnSavePaths = this->findChild<QPushButton*>("btn_save_paths");
QPushButton* btnExecutePath = this->findChild<QPushButton*>("btn_execute_path" );
QPushButton* btnAddSegment = this->findChild<QPushButton*>("btn_add_to_path");
QTreeView* treeView = this->findChild<QTreeView*>("tree_paths");
connect(btnLoadPaths, &QPushButton::clicked, this, [=]() { load_paths_into_tree(treeView); });
connect(treeView->selectionModel(), &QItemSelectionModel::currentChanged, this, &RoverPlanner::treeSelectionChanged); // This does not seem to properly bind the index chan
}
void RoverPlanner::treeSelectionChanged(const QModelIndex &prevIndex, const QModelIndex &nextIndex) {
std::cout << "Test" << std::endl;
}
//other functions
When I click on the items, it does not output anything in the console
I'm confused because this seems to be the way to correctly connect the treeview selected index changed. What did I do wrong?
selectionModel gets replaced each time a new model is set for QTreeView.
void QAbstractItemView::setModel(QAbstractItemModel *model):
This function will create and set a new selection model, replacing any model that was previously set with setSelectionModel().
That means you need to reconnect the &QItemSelectionModel::currentChanged signal each time you set a new model.
I have a custom SpinBox class that extends a functionality of QSpinBox. I'm trying to show a tooltip when the input is correct, that is, show a tooltip in overriden QSpinBox::validate(QString &text, int &pos). But when I do the mouse click on the tooltip the program crashes.
The crash occures in QApplicationPrivate::notifyActiveWindowChange(QWindow *previous), it looks like Qt tries to set QTipLabel (which has already been destroyed) as an active window.
Here is the minimal code to reproduce the crash:
// spinbox.h
#include <QSpinBox>
#include <QToolTip>
class SpinBox : public QSpinBox
{
Q_OBJECT
public:
explicit SpinBox(QWidget *parent = nullptr)
: QSpinBox(parent)
{}
~SpinBox() override = default;
QValidator::State validate(QString &input, int &pos) const override
{
Q_UNUSED(pos);
int x = input.toInt();
auto mn = minimum();
auto mx = maximum();
if(x >= mn && x <= mx)
{
QToolTip::showText(mapToGlobal({0, 0}), QString("Your value fits the range!!!"));
return QValidator::State::Acceptable;
}
else
{
QToolTip::hideText();
}
return QValidator::State::Invalid;
}
};
// constructor of the default mainwindow created by qt creator
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent)
{
Ui::MainWindow ui;
ui.setupUi(this);
auto spin_box = new SpinBox(this);
spin_box->setRange(1, 200);
}
Here is a gif that illustrates the crash:
Thanks in advance!
UPD.
I've found that after clicking on the tooltip, the qtooltip_labelWindow gets focus.
UPD2.
I haven't found the reason of the crash yet, but a workaround that helps me is to install the following event filter to qApp:
bool eventFilter(QObject* obj, QEvent* e) override
{
if(obj->objectName().contains("tooltip") && e->type() == QEvent::FocusIn)
{
if (auto window = qobject_cast<QWindow*>(obj))
window->show();
}
return QObject::eventFilter(obj, e);
}
I got two windows(two classes), one window that opens another when i click a button.
then the user inputs something into the newly opened window and then transfer that information to the first window when a button is clicked
The problem is I can't seem to send something to the second window so i can send the user input back to the main window. I read a few places that I should use Q_object but not really sure how that works
I should mention that I am new to Qt and didn't know about the designer there is in qt creator before i was way to ahead with the program.
Hope you have some ideas to how I can do this
edit1:
I should show the relevant code i have
Mainwindow.cpp
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent)
{
//alot of stuff not relevant right now creating different stuff
changeProfile= new QPushButton("ændre valgte profil",this);
profileList = new QComboBox(this);
cProfile = new CreateProfile;
connect(changeProfile,SIGNAL(clicked()),this,SLOT(ProfileChange()));
}
void MainWindow::ProfileChange()
{
file pfile(profileList->currentText().toStdString());
string tempName = pfile.read(light);
cProfile->setValue(light,tempName);
cPr
ofile->show();
}
void MainWindow::setProfileList(QString Pname_)
{
bool found = 0;
for (int i = 0;i<5;i++)
{
if (Pname_ ==profileList->itemText(i))
found = 1;
}
if (found !=1)
profileList->addItem(Pname_);
}
createProfile.cpp
CreateProfile::CreateProfile(QWidget *parent)
:QMainWindow(parent)
{
//alot of other irrelevant stuff here
saveP = new QPushButton("Save",this);
connect(saveP,SIGNAL(clicked()),this,SLOT(saveProfile()));
}
void CreateProfile::saveProfile()
{
temp = pName->text();
file pFile(temp.toStdString());
bool lights[2] = {light1->checkState(),light2->checkState()};
if (temp.length() == 0)
{
MessageBox(NULL,"Du har ikke skrevet noget navn ind\n Prov igen","Error",MB_ICONWARNING+MB_SETFOREGROUND);
}
else
{
pFile.save(lights);
//call function setProfileList
this->hide();
}
}
If that makes sence, If you need the .h file too i can show them also
I need to call setProfileList from the mainwindow in the function saveprofile(there is in createprofile window) or if there is a way i can change the combobox in the wainwindow from the createprofile window?
edit 2:
mainwindow.h
#include "createprofile.h"
class MainWindow : public QMainWindow
{
Q_OBJECT
public slots:
void ProfileChange();
//some other button clicks
public:
CreateProfile *cProfile;
void setProfileList(QString Pname_);
//other irelevant stuff
private:
// and some private members
};
createProfile.h
class CreateProfile : public QMainWindow
{
Q_OBJECT
public slots:
void saveProfile();
public:
explicit CreateProfile(QWidget *parent = 0);
~CreateProfile();
//and other stuff there isnt relevant
};
You are looking for the Qt signal-slot mechanism, namely:
class SecondWindow : public QMainWindow
{
Q_OBJECT
public:
SecondWindow(QWidget *parent = Q_NULLPTR) : QObject(Q_NULLPTR)
{
// ...
connect(secondWindowButton, SIGNAL(clicked(bool)), SLOT(handleClicked()));
// ...
}
public slots:
void SecondWindow::handleClicked()
{
// Gather information from the UI as you wish
firstWindow->foo();
}
// ...
}
or, if you have a container class for the windows, you could handle it in there, too, as follows:
connect(secondWindow->myButton, SIGNAL(clicked(bool)), SLOT(handleClicked()));
I found a very different way to do this, so I have made a QComboBox in the constructor of createProfile.cpp and then I have access to the profileList this way.
I have a custom QDialog with a set of custom sliders (i.e., QWidgets each consisting of a slider and an associated label) on it. In essence, this dialog is used to change the coordinates of an object in a 3D scene by adjusting the sliders for each dimension.
Currently, the QDialog itself stores a pointer to the scene object it modifies. Thus, the slot that takes care of object movement when a slider emits valueChanged is also part of the QDialog class. Since it has no way of knowing which slider was moved, the movement function (rather inefficiently) just loops through all of the sliders on the dialog, gathers their values, and assigns a new configuration to the 3D object.
Ideally, only the dimension that changed would have to be re-assigned when a slider is moved. So I tried using QSignalMapper to identify each slider with a numerical index. This would require the ability to send a valueChanged signal with two parameters: one identifying the sender slider, and one giving the new value itself. Unfortunately, as I learned here, QSignalMapper can't do this.
Another way to get the functionality I want would perhaps be to use the sender() method. But, according to the documentation, that's bad practice--it violates the principle of modularity.
I can think of a couple of other solutions: allow the custom slider class to store its parent dialog (seems bad in the same say that sender() is bad), or maybe even store the movable object itself as a static member of the custom slider class instead of (non-statically/as it is now) in the overall dialog.
Which of these approaches, if any, would be the best way to go here? What alternatives should I consider?
Possible solution is connect QSlider signal sliderReleased(), emitted when the user releases the slider with the mouse, with QSignalMapper map() and store sliders id with pointer on some list. When value has hanged, QDialog could emit another signal with information of slider id and new value.
QSignalMapper *mapper = new QSignalMapper(this);
connect(slider_0, SIGNAL(sliderReleased()), mapper, SLOT(map()));
mapper->setMapping(slider_0, 0);
tab_s[0] = slider_0;
connect(slider_1, SIGNAL(sliderReleased()), mapper, SLOT(map()));
mapper->setMapping(slider_1, 1);
tab_s[1] = slider_1;
connect(slider_2, SIGNAL(sliderReleased()), mapper, SLOT(map()));
mapper->setMapping(slider_2, 2);
tab_s[2] = slider_2;
connect(mapper, SIGNAL(mapped(int)),
this, SLOT(checkSlider(int)));
and in some slot:
void SomeDialog::checkSlider(int id)
{
emit valueChanged(id, tab_s[id]->value());
}
The ideal solution would be to subclass QSlider and re-emit the valueChanged() signal with added parameters (x/y/z axis). Let's say MySlider which constructs with given axis index (0/1/2):
class MySlider : public QSlider
{
Q_OBJECT
public:
MySlider(int axis, QWidget *parent);
signals:
void valueChanged(int axis, int value);
private slots:
void reemitValueChanged(int value);
private:
int m_axis;
};
MySlider::MySlider(int axis, QWidget *parent)
: QSlider(parent)
{
m_axis = axis;
connect(this, SIGNAL(valueChanged(int)),
this, SLOT(reemitValueChanged(int)));
}
void MySlider::reemitValueChanged(int value)
{
emit valueChanged(m_axis, value);
}
MySlider intercepts valueChanged(int) signal from QSlider, and emits its own signal valueChanged(int,int) with the axis index (0/1/2). You can use MySlider in the application now:
for (int i=0; i<3; i++) {
sliders[i] = new MySlider(i, this);
connect(sliders[i], SIGNAL(valueChanged(int,int)),
this, SIGNAL(updateScene(int,int)));
}
Of course, you'll have to arrange these sliders in a layout or something. Here's the source of this approach.
I think using the sender() method is fine.
I'd write something like this:
enum Axes
{
axisX,
axisY,
axisZ
}
class MyDialog : public QDialog
{
...
signals:
void valueChanged(int value, int type);
}
MyDialog::MyDialog(QWidget *parent) :
QDialog(parent)
{
...
connect(xSlider, SIGNAL(valueChanged(int)),
this, SLOT(onSliderChange(int));
connect(ySlider, SIGNAL(valueChanged(int)),
this, SLOT(onSliderChange(int));
connect(zSlider, SIGNAL(valueChanged(int)),
this, SLOT(onSliderChange(int));
}
void MyDialog::onSliderChange(int value)
{
int axis = -1;
QSlider *slider = dynamic_cast<QSlider*>(sender());
if (slider == xSlider)
{
axis = axisX;
}
else if (slider == ySlider)
{
axis = axisY;
}
else if (slider == zSlider)
{
axis = axisZ;
}
else
{
qWarning() << "Wrong sender";
}
if (axis != -1)
{
emit valueChanged(value, axis);
}
}
//signalMapper.h
//--------------
#ifndef SIGNALMAPPER_H
#define SIGNALMAPPER_H
#include <QWidget>
#include <QGridLayout>
#include <QSlider>
#include <QLabel>
class Widget : public QWidget
{
Q_OBJECT
public:
Widget(QWidget *parent = 0);
~Widget();
private:
QGridLayout* m_pGridLayoutMain;
QLabel* m_pLabel;
private slots:
void setLabelText(QWidget *pWidget);
};
#endif // SIGNALMAPPER_H
//signalMapper.cpp
//----------------
#include "signalMapper.h"
#include <QSignalMapper>
#include <QString>
Widget::Widget(QWidget *parent)
: QWidget(parent)
{
setMinimumSize(400, 200);
QSignalMapper* pSignalMapper = new QSignalMapper(this);
m_pGridLayoutMain = new QGridLayout(this);
m_pGridLayoutMain->setContentsMargins(10, 10, 10, 10);
m_pGridLayoutMain->setSpacing(10);
m_pLabel = new QLabel(this);
m_pLabel->setMinimumSize(150, 20);
m_pLabel->setAlignment(Qt::AlignCenter);
m_pLabel->setFrameStyle(QFrame::Box | QFrame::Sunken);
m_pGridLayoutMain->addWidget(m_pLabel, 0, 0);
for(int i=1; i < 10; i++)
{
QSlider* pSlider = new QSlider(this);
QString strObjName = "Slider " + QString().setNum(i);
pSlider->setObjectName(strObjName);
pSlider->setMinimum(0);
pSlider->setMaximum(100);
pSlider->setSingleStep(1);
pSlider->setOrientation(Qt::Horizontal);
pSlider->setValue(35);
connect(pSlider, SIGNAL(valueChanged(int)), pSignalMapper, SLOT(map()));
pSignalMapper->setMapping(pSlider, pSlider);
m_pGridLayoutMain->addWidget(pSlider, i, 0);
}
connect(pSignalMapper, SIGNAL(mapped(QWidget*)), this, SLOT(setLabelText(QWidget*)));
}
Widget::~Widget()
{
}
void Widget::setLabelText(QWidget *pWidget)
{
QSlider* pSlider = dynamic_cast<QSlider*>(pWidget);
if(pSlider)
{
qDebug("Success");
m_pLabel->setText(pSlider->objectName()+" value changed to "+QString().setNum(pSlider->value()));
}
else
{
qDebug("Failure");
}
}
I was wondering if anybody could tell me whats actually going on here. I have included the header and implementation file for a simple config dialog. The problem is in the updateAutoSaveGroupBox slot I cannot access or change any properties of my widgets on the page. I.E. I want to make some widgets disabled if a check box has not been checked but when I try to set them I get a read access violation. Any help with this matter would be greatly appreciated. The problems exsist in these two lines(commented out so it will run for now without throwing an exception).
//autoSaveLabel->setDisabled(autoSaveIsEnabled);
//autoSaveSpinBox->setDisabled(getAutoSaveIsEnabled());
configWidget.h
class EnigmaConfigGeneralEnvironmentWidget : public QWidget
{
Q_OBJECT
public:
explicit EnigmaConfigGeneralEnvironmentWidget(QWidget *parent = 0);
~EnigmaConfigGeneralEnvironmentWidget();
signals:
void setAutoSaveIsEnabledSignal(bool autoSaveIsEnabled);
public slots:
void setAutoSaveIsEnabled(bool autoSaveIsEnabled){_AutoSaveIsenabled = autoSaveIsEnabled;}
bool getAutoSaveIsEnabled(){return _AutoSaveIsenabled;}
void updateAutoSaveGroupBox(bool autoSaveIsEnabled);
private:
void makeConnections();
void readSettings();
void writeSettings();
void createMainWidget();
QGroupBox *uiGroupBox;
QStringList localList;
QLabel *localLabel;
QComboBox *localeComboBox;
QHBoxLayout *localSelectionHLayout;
QGroupBox *systemGroupBox;
QCheckBox *autoSaveCheckBox;
QLabel *autoSaveLabel;
QSpinBox *autoSaveSpinBox;
QHBoxLayout *autoSaveHLayout;
bool _AutoSaveIsenabled;
};
ConfigWidget.cpp
#include "enigmaconfiggeneralenvironmentwidget.h"
#include <QtWidgets>
EnigmaConfigGeneralEnvironmentWidget::EnigmaConfigGeneralEnvironmentWidget(QWidget *parent) :
QWidget(parent)
{
makeConnections();
readSettings();
createMainWidget();
}
EnigmaConfigGeneralEnvironmentWidget::~EnigmaConfigGeneralEnvironmentWidget()
{
writeSettings();
}
void EnigmaConfigGeneralEnvironmentWidget::makeConnections()
{connect(this,SIGNAL(setAutoSaveIsEnabledSignal(bool)),this,SLOT(setAutoSaveIsEnabled(bool)) );
connect(this,SIGNAL(setAutoSaveIsEnabledSignal(bool)),this,SLOT(updateAutoSaveGroupBox(bool)) );
}
void EnigmaConfigGeneralEnvironmentWidget::readSettings()
{
QSettings settings;
settings.beginGroup(tr("UI.Config.Environment.General"));
bool autoSaveIsEnabled = settings.value("autoSaveIsEnabled",bool(true)).toBool();
setAutoSaveIsEnabledSignal(autoSaveIsEnabled);
settings.endGroup();
}
void EnigmaConfigGeneralEnvironmentWidget::writeSettings()
{
QSettings settings;
settings.beginGroup(tr("UI.Config.Environment.General"));
settings.setValue("autoSaveIsEnabled",getAutoSaveIsEnabled());
settings.endGroup();
}
void EnigmaConfigGeneralEnvironmentWidget::createMainWidget()
{
localList.append(tr("Danish - ???"));
localList.append(tr("English - Australia"));
localList.append(tr("English - Canada"));
localList.append(tr("English - USA"));
localList.append(tr("English - UK"));
localList.append(tr("Finnish - Finland"));
localList.append(tr("French - Canada"));
localList.append(tr("French - France"));
localList.append(tr("Norwegian - ???"));
localList.append(tr("Swedish - ???"));
uiGroupBox = new QGroupBox();
uiGroupBox->setTitle(tr("UI Settings"));
localLabel= new QLabel();
localLabel->setText(tr("Select a language: "));
localeComboBox = new QComboBox();
localeComboBox->addItems(localList);
localSelectionHLayout = new QHBoxLayout(uiGroupBox);
localSelectionHLayout->addWidget(localLabel);
localSelectionHLayout->addWidget(localeComboBox);
systemGroupBox = new QGroupBox();
systemGroupBox->setTitle(tr("System Settigns"));
autoSaveCheckBox = new QCheckBox();
autoSaveCheckBox->setText(tr("Auto-Save Enabled: "));
autoSaveCheckBox->setChecked(getAutoSaveIsEnabled());
connect(autoSaveCheckBox,SIGNAL(clicked(bool)),this,SIGNAL(setAutoSaveIsEnabledSignal(bool)));
autoSaveLabel = new QLabel(this);
autoSaveLabel->setText(tr("Auto-Save Interval is Every: "));
autoSaveSpinBox = new QSpinBox();
autoSaveSpinBox->setSuffix(tr("Mins."));
autoSaveSpinBox->setAccelerated(true);
autoSaveHLayout = new QHBoxLayout(systemGroupBox);
autoSaveHLayout->addWidget(autoSaveCheckBox);
autoSaveHLayout->addWidget(autoSaveLabel);
autoSaveHLayout->addWidget(autoSaveSpinBox);
QVBoxLayout *vLayout = new QVBoxLayout(this);
vLayout->addWidget(uiGroupBox);
vLayout->addWidget(systemGroupBox);
}
void EnigmaConfigGeneralEnvironmentWidget::updateAutoSaveGroupBox(bool autoSaveIsEnabled)
{
qDebug() << "debug " << autoSaveIsEnabled;
//autoSaveLabel->setDisabled(autoSaveIsEnabled);
//autoSaveSpinBox->setDisabled(getAutoSaveIsEnabled());
}
Spotted it:
void EnigmaConfigGeneralEnvironmentWidget::readSettings()
{
QSettings settings;
settings.beginGroup(tr("UI.Config.Environment.General"));
bool autoSaveIsEnabled = settings.value("autoSaveIsEnabled",bool(true)).toBool();
setAutoSaveIsEnabledSignal(autoSaveIsEnabled);
settings.endGroup();
}
You are calling void setAutoSaveIsEnabledSignal(bool) here (the signal), not void setAutoSaveIsEnabled(bool) (the actual setter). Hence the member variable is still uninitialized.
Reminder for yourself: Don't name signals as if they were setters, use e.g. void autoSaveIsEnabledChanged(bool)