Question with QTreeWidgetItem

[denumbaone]

I still can't figure out how to do something like that; I've never had to do anything like that to manipulate a signal. Can you show me a way that you can catch a signal emitted from QTreeWidget with this code:

QTreeWidgetItem *cities = new QTreeWidgetItem(treeWidget);
 cities->setText(0, tr("Places"));
 cities->setCheckState(0, Qt::Checked);

QTreeWidgetItem *cities = new QTreeWidgetItem(treeWidget);
 cities->setText(0, tr("Places"));
 cities->setCheckState(0, Qt::Checked);

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Whenever the checkbox for cities is toggled, I want to send a signal. Thank you very much for your help.

[Berryblue031]

After you create your QTreeWidgetItem you need to add it to a selectable QTreeWidget

mTreeWidget->setSelectionMode(QAbstractItemView::MultiSelection);
...
mTreeWidget->addTopLevelItem(cities);

mTreeWidget->setSelectionMode(QAbstractItemView::MultiSelection);
...
mTreeWidget->addTopLevelItem(cities);

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Whenever any item in the tree is selected the tree emits an itemClicked signal which you connect to like

QObject::connect(mTreeWidget, SIGNAL(itemClicked(QTreeWidgetItem*, int)), this, SLOT(onClicked(QTreeWidgetItem*, int)));
 
onClicked(QTreeWidgetItem* item, int column)
{
 //Do whatever you want to the item here
}

QObject::connect(mTreeWidget, SIGNAL(itemClicked(QTreeWidgetItem*, int)), this, SLOT(onClicked(QTreeWidgetItem*, int)));

onClicked(QTreeWidgetItem* item, int column)
{
 //Do whatever you want to the item here
}

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You actually shouldn't need to set you objects checked state manually the tree will do that automatically

[denumbaone]

I've tried the code that you have provided. It compiles but it doesn't seem to jump to the slot. I have provided my code below.

in treeview.h:

private slots:
    void setChecked(QTreeWidgetItem *, int);

private slots:
    void setChecked(QTreeWidgetItem *, int);

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in treeview.cpp:

QTreeWidgetItem *cities = new QTreeWidgetItem(treeWidget);
cities->setText(0, tr("Places"));
cities->setCheckState(0, Qt::Checked);
 
mTreeWidget->setSelectionMode(QAbstractItemView::MultiSelection);
mTreeWidget->addTopLevelItem(cities);
 
QObject::connect(mTreeWidget, SIGNAL(itemClicked(QTreeWidgetItem*,int)), this, SLOT(setChecked(QTreeWidgetItem*,int)));
 
void TreeView::setChecked(QTreeWidgetItem *item, int)
{
    qDebug ("Cities Clicked");
    cout << "Cities Clicked" << endl;
}

QTreeWidgetItem *cities = new QTreeWidgetItem(treeWidget);
cities->setText(0, tr("Places"));
cities->setCheckState(0, Qt::Checked);

mTreeWidget->setSelectionMode(QAbstractItemView::MultiSelection);
mTreeWidget->addTopLevelItem(cities);

QObject::connect(mTreeWidget, SIGNAL(itemClicked(QTreeWidgetItem*,int)), this, SLOT(setChecked(QTreeWidgetItem*,int)));

void TreeView::setChecked(QTreeWidgetItem *item, int)
{
    qDebug ("Cities Clicked");
    cout << "Cities Clicked" << endl;
}

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As you can see, I've added a simple cout and qDebug to signify if the slot has been reached and it does not. Any suggestions?

[Berryblue031]

So your tree displays properly with the cities item in it and when you click the item in the gui the signal is not being triggered?

Double check you are not getting any error messages other then that it's hard to debug your program with only code snippets

[denumbaone]

Here is my code for the treeview. Everything compiles, and I only get a warning for an unused parameter "item."

treeview.h

#ifndef TREEVIEW_H
#define TREEVIEW_H
 
#include <QMainWindow>
 
class QAction;
class QTreeWidget;
class QTreeWidgetItem;
class QCheckBox;
 
namespace Ui {
    class TreeView;
}
 
class TreeView : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit TreeView(QWidget *parent = 0);
    ~TreeView();
 
private slots:
    void setChecked(QTreeWidgetItem *, int);
 
private:
    Ui::TreeView *ui;
    void setupTreeItems();
   // void manageTreeItems();
 
    TreeView * treeView;
    //TreeView * check;
 
    QAction *ascendingAction;
    QTreeWidget *treeWidget;
    QTreeWidget *mTreeWidget;
};
 
#endif // TREEVIEW_H

#ifndef TREEVIEW_H
#define TREEVIEW_H

#include <QMainWindow>

class QAction;
class QTreeWidget;
class QTreeWidgetItem;
class QCheckBox;

namespace Ui {
    class TreeView;
}

class TreeView : public QMainWindow
{
    Q_OBJECT

public:
    explicit TreeView(QWidget *parent = 0);
    ~TreeView();

private slots:
    void setChecked(QTreeWidgetItem *, int);

private:
    Ui::TreeView *ui;
    void setupTreeItems();
   // void manageTreeItems();

    TreeView * treeView;
    //TreeView * check;

    QAction *ascendingAction;
    QTreeWidget *treeWidget;
    QTreeWidget *mTreeWidget;
};

#endif // TREEVIEW_H

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treeview.cpp

#include "treeview.h"
//#include "ui_treeview.h"
 //#include "dialog.h"
 
#include <iostream>
#include <QTreeWidget>
#include <QInputDialog>
#include <QCheckBox>
#include <QStandardItem>
#include <Qt>
#include <iostream>
 
using namespace std;
 
TreeView::TreeView(QWidget *parent) :
    QMainWindow(parent)
    //ui(new Ui::TreeView)
{
    //ui->setupUi(this);
 
    treeWidget = new QTreeWidget(/*this*/);
    mTreeWidget = new QTreeWidget;
 
    treeWidget->setColumnCount(1);
 
    QStringList headers;
    headers << tr("Legend");
    treeWidget->setHeaderLabels(headers);
 
    setupTreeItems();
 
    setCentralWidget(treeWidget);
    setWindowTitle(tr("Tree Widget"));
}
 
TreeView::~TreeView()
{
    //delete ui;
}
 
void TreeView::setupTreeItems()
{
 
 
    QTreeWidgetItem *cities = new QTreeWidgetItem(treeWidget);
    cities->setText(0, tr("Places"));
    cities->setCheckState(0, Qt::Checked);
 
    QTreeWidgetItem *citiesChild = new QTreeWidgetItem();
    cities->insertChild(0, citiesChild);
    citiesChild->setText(0, tr("USA Cities"));
    citiesChild->setCheckState(0, Qt::Checked);
 
    mTreeWidget->setSelectionMode(QAbstractItemView::MultiSelection);
    mTreeWidget->addTopLevelItem(cities);
 
    QObject::connect(mTreeWidget, SIGNAL(itemClicked(QTreeWidgetItem*,int)), this, SLOT(setChecked(QTreeWidgetItem*,int)));
}
 
void TreeView::setChecked(QTreeWidgetItem *item, int)
{
    cout << "Cities Clicked" << endl;
    qDebug("Cities Clicked");
}

#include "treeview.h"
//#include "ui_treeview.h"
 //#include "dialog.h"

#include <iostream>
#include <QTreeWidget>
#include <QInputDialog>
#include <QCheckBox>
#include <QStandardItem>
#include <Qt>
#include <iostream>

using namespace std;

TreeView::TreeView(QWidget *parent) :
    QMainWindow(parent)
    //ui(new Ui::TreeView)
{
    //ui->setupUi(this);

    treeWidget = new QTreeWidget(/*this*/);
    mTreeWidget = new QTreeWidget;

    treeWidget->setColumnCount(1);

    QStringList headers;
    headers << tr("Legend");
    treeWidget->setHeaderLabels(headers);

    setupTreeItems();

    setCentralWidget(treeWidget);
    setWindowTitle(tr("Tree Widget"));
}

TreeView::~TreeView()
{
    //delete ui;
}

void TreeView::setupTreeItems()
{
    

    QTreeWidgetItem *cities = new QTreeWidgetItem(treeWidget);
    cities->setText(0, tr("Places"));
    cities->setCheckState(0, Qt::Checked);

    QTreeWidgetItem *citiesChild = new QTreeWidgetItem();
    cities->insertChild(0, citiesChild);
    citiesChild->setText(0, tr("USA Cities"));
    citiesChild->setCheckState(0, Qt::Checked);

    mTreeWidget->setSelectionMode(QAbstractItemView::MultiSelection);
    mTreeWidget->addTopLevelItem(cities);

    QObject::connect(mTreeWidget, SIGNAL(itemClicked(QTreeWidgetItem*,int)), this, SLOT(setChecked(QTreeWidgetItem*,int)));
}

void TreeView::setChecked(QTreeWidgetItem *item, int)
{
    cout << "Cities Clicked" << endl;
    qDebug("Cities Clicked");
}

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Sorry for the lengthy post, I'm just really having trouble with this problem. When I do anything with the checkbox, it doesn't seem to jump to the slot. Do you have any suggestions?

[Berryblue031]

Ok I think one of the big problems you have is in the code you listed you declare 3 QTreeWidgets, one in the ui file, then one named "treewidget" and one named "mTreeWidget". The tree widget you actually see when you run the program is the one you declared in the ui file so you need to only use that one in your code.

#ifndef TREEVIEW_H
#define TREEVIEW_H
 
#include <QMainWindow>
 
class QAction;
class QTreeWidget;
class QTreeWidgetItem;
class QCheckBox;
 
#include "ui_treeview.h"
 
class TreeView : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit TreeView(QWidget *parent = 0);
    virtual ~TreeView(); //In general always make destructors virtual
 
private slots:
    void setChecked(QTreeWidgetItem *, int);
 
private:
    Ui::TreeView ui;
    void setupTreeItems();
    QTreeWidget* getTreeWidget(){ return ui.whatever_the_widgets_name_is_in_the_ui_file; }
    QAction *ascendingAction;
};
 
#endif // TREEVIEW_H

#ifndef TREEVIEW_H
#define TREEVIEW_H

#include <QMainWindow>

class QAction;
class QTreeWidget;
class QTreeWidgetItem;
class QCheckBox;

#include "ui_treeview.h"

class TreeView : public QMainWindow
{
    Q_OBJECT

public:
    explicit TreeView(QWidget *parent = 0);
    virtual ~TreeView(); //In general always make destructors virtual

private slots:
    void setChecked(QTreeWidgetItem *, int);

private:
    Ui::TreeView ui;
    void setupTreeItems();
    QTreeWidget* getTreeWidget(){ return ui.whatever_the_widgets_name_is_in_the_ui_file; }
    QAction *ascendingAction;
};

#endif // TREEVIEW_H

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#include "treeview.h"
 
 //#include "dialog.h"
 
#include <QDebug>
#include <QTreeWidget>
#include <QInputDialog>
#include <QCheckBox>
#include <QStandardItem>
#include <Qt>
 
TreeView::TreeView(QWidget *parent) :
    QMainWindow(parent)
{
    ui.setupUi(this);
 
	//can be done in ui file
    getTreeWidget()->setSelectionMode(QAbstractItemView::MultiSelection); 
 
	//Connecting the tree widgets slot only needs to be done once, not for every item
	QObject::connect(getTreeWidget(), SIGNAL(itemClicked(QTreeWidgetItem*,int)), this, SLOT(setChecked(QTreeWidgetItem*,int)));
 
    QStringList headers;
    qDebug() << "Legend: " << headers;
    getTreeWidget()->setHeaderLabels(headers);
 
    setupTreeItems();
}
 
TreeView::~TreeView()
{
}
 
void TreeView::setupTreeItems()
{
    QTreeWidgetItem *cities = new QTreeWidgetItem(getTreeWidget(),  QTreeWidgetItem::UserType + 1);
    cities->setText(0, tr("Places"));
 
    QTreeWidgetItem *citiesChild = new QTreeWidgetItem();
    cities->addChild(citiesChild);
    citiesChild->setText(0, tr("USA Cities"));
 
    getTreeWidget()->addTopLevelItem(cities);
}
 
void TreeView::setChecked(QTreeWidgetItem *item, int)
{
    if(item->type() ==  QTreeWidgetItem::UserType + 1)
	{
		qDebug() << "cities clicked";
	}
	else
	{
		qDebug() << "cities child clicked";
	}
}

#include "treeview.h"

 //#include "dialog.h"

#include <QDebug>
#include <QTreeWidget>
#include <QInputDialog>
#include <QCheckBox>
#include <QStandardItem>
#include <Qt>

TreeView::TreeView(QWidget *parent) :
    QMainWindow(parent)
{
    ui.setupUi(this);
	
	//can be done in ui file
    getTreeWidget()->setSelectionMode(QAbstractItemView::MultiSelection); 
	
	//Connecting the tree widgets slot only needs to be done once, not for every item
	QObject::connect(getTreeWidget(), SIGNAL(itemClicked(QTreeWidgetItem*,int)), this, SLOT(setChecked(QTreeWidgetItem*,int)));
		
    QStringList headers;
    qDebug() << "Legend: " << headers;
    getTreeWidget()->setHeaderLabels(headers);

    setupTreeItems();
}

TreeView::~TreeView()
{
}

void TreeView::setupTreeItems()
{
    QTreeWidgetItem *cities = new QTreeWidgetItem(getTreeWidget(),  QTreeWidgetItem::UserType + 1);
    cities->setText(0, tr("Places"));

    QTreeWidgetItem *citiesChild = new QTreeWidgetItem();
    cities->addChild(citiesChild);
    citiesChild->setText(0, tr("USA Cities"));

    getTreeWidget()->addTopLevelItem(cities);
}

void TreeView::setChecked(QTreeWidgetItem *item, int)
{
    if(item->type() ==  QTreeWidgetItem::UserType + 1)
	{
		qDebug() << "cities clicked";
	}
	else
	{
		qDebug() << "cities child clicked";
	}
}

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I hope that helps.