[SOLVED] signal and slot between two classes

[frankiefrank]

Isn't this supposed to be
@table->clear();@
?

I'm sorry but I won't be able to remotely assist you through every compile step of code. Maybe you should start out by working with some basic Qt sample.

[ecmanja]

sorry ,here is my code i'm getting error if i try to discard so please do help.
@#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QListWidget>
#include <QMouseEvent>
#include <QMimeData>
#include <QDrag>
#include <QDebug>
#include <QTabWidget>
#include <QTableWidget>
#include <QMimeType>
#include <QTcpSocket>
#include <QMessageBox>

namespace Ui {
class MainWindow;
}
class ProjectListWidget :public QTableWidget
{
Q_OBJECT

public:
ProjectListWidget(QWidget *parent = 0);

protected:
void mousePressEvent(QMouseEvent *event);
void mouseMoveEvent(QMouseEvent *event);
void dragEnterEvent(QDragEnterEvent *event);
void dragMoveEvent(QDragMoveEvent *event);
void dropEvent(QDropEvent *event);

private:
void performDrag();
QPoint startPos;

};
class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
ProjectListWidget *table4,*table5;
~MainWindow();

private:
Ui::MainWindow *ui;
public slots:
void on_item1_changed();

};

#endif // MAINWINDOW_H
@

[ecmanja]

@#include "mainwindow.h"
#include "ui_mainwindow.h"

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

ProjectListWidget *table=new ProjectListWidget(ui->widget);
table->setGeometry(0,0,750,580);
table->setColumnCount(1);
table->setRowCount(1);
table->horizontalHeader()->setDefaultSectionSize(750);
table->verticalHeader()->setDefaultSectionSize(580);
table->verticalHeader()->hide();
table->horizontalHeader()->hide();
table->setAcceptDrops(true);
setAcceptDrops(true);
table->setItem(0,0,new QTableWidgetItem("ITEM 1"));

ProjectListWidget *table2=new ProjectListWidget(ui->widget_3);
table2->setGeometry(0,0,750,580);
table2->setColumnCount(1);
table2->setRowCount(1);
table2->horizontalHeader()->setDefaultSectionSize(750);
table2->verticalHeader()->setDefaultSectionSize(580);
table2->verticalHeader()->hide();
table2->horizontalHeader()->hide();
table2->setAcceptDrops(true);
setAcceptDrops(true);
table2->setItem(0,0,new QTableWidgetItem("ITEM 2"));

ProjectListWidget *table3=new ProjectListWidget(ui->widget_4);
table3->setGeometry(0,0,750,580);
table3->setColumnCount(1);
table3->setRowCount(1);
table3->horizontalHeader()->setDefaultSectionSize(750);
table3->verticalHeader()->setDefaultSectionSize(580);
table3->verticalHeader()->hide();
table3->horizontalHeader()->hide();
table3->setAcceptDrops(true);
setAcceptDrops(true);
table3->setItem(0,0,new QTableWidgetItem("ITEM 3"));

ProjectListWidget table4=new ProjectListWidget(ui->widget_2);
//table2->setGeometry(1000,40,270,161);
table4->setColumnCount(1);
table4->setRowCount(1);
table4->verticalHeader()->setDefaultSectionSize(200);
table4->horizontalHeader()->setDefaultSectionSize(350);
table4->horizontalHeader()->hide();
table4->verticalHeader()->hide();
table4->setAcceptDrops(true);
setAcceptDrops(true);
connect(table4,SIGNAL(itemChanged(QTableWidgetItem)),this,SLOT(on_item1_changed()));

ProjectListWidget *table5=new ProjectListWidget(ui->widget_5);
//table2->setGeometry(1000,40,270,161);
table5->setColumnCount(1);
table5->setRowCount(1);
table5->verticalHeader()->setDefaultSectionSize(200);
table5->horizontalHeader()->setDefaultSectionSize(350);
table5->horizontalHeader()->hide();
table5->verticalHeader()->hide();
table5->setAcceptDrops(true);
setAcceptDrops(true);
ProjectListWidget *table6=new ProjectListWidget(ui->widget_6);
//table2->setGeometry(1000,40,270,161);
table6->setColumnCount(1);
table6->setRowCount(1);
table6->verticalHeader()->setDefaultSectionSize(200);
table6->horizontalHeader()->setDefaultSectionSize(350);
table6->horizontalHeader()->hide();
table6->verticalHeader()->hide();
table6->setAcceptDrops(true);
setAcceptDrops(true);
}

ProjectListWidget::ProjectListWidget(QWidget *parent)
: QTableWidget(parent)
{
setAcceptDrops(true);
}
void ProjectListWidget::mousePressEvent(QMouseEvent *event)
{

qDebug()<<"mouse press";
QWidget::mousePressEvent(event);
    if(event->button() == Qt::LeftButton)
    {
    }

}
void ProjectListWidget::mouseMoveEvent(QMouseEvent *event)
{
qDebug()<<"mouse move event";
if (event->buttons() & Qt::LeftButton) {
int distance = (event->pos() - startPos).manhattanLength();
if (distance >= QApplication::startDragDistance())
performDrag();
}
QTableWidget::mouseMoveEvent(event);
}
void ProjectListWidget::performDrag()
{
qDebug()<<"perform drag";
QTableWidgetItem *item = currentItem();
if (item) {
QMimeData *mimeData = new QMimeData;
mimeData->setText(item->text());

    QDrag *drag = new QDrag(this);
    drag->setMimeData(mimeData);
    QString fileName = "C:/Users/teclever/Desktop/qt-logo.jpg";
    QPixmap pic (fileName);
    drag->setPixmap(pic);
    if (drag->exec(Qt::CopyAction) == Qt::CopyAction)
    {
    }
}

}
void ProjectListWidget::dragEnterEvent(QDragEnterEvent *event)
{
qDebug()<<"drag enter";
ProjectListWidget *source =
qobject_cast<ProjectListWidget *>(event->source());
if (source && source != this) {
event->setDropAction(Qt::CopyAction);
event->accept();
}
}
void ProjectListWidget::dragMoveEvent(QDragMoveEvent *event)
{
qDebug()<<"drag move event";
ProjectListWidget *source =
qobject_cast<ProjectListWidget *>(event->source());
if (source && source != this) {
event->setDropAction(Qt::MoveAction);
setAcceptDrops(true);
event->acceptProposedAction();
}
}
@ continue

[ecmanja]

@#if 1
void ProjectListWidget::dropEvent(QDropEvent *event)
{

 qDebug()<<"drop event";
ProjectListWidget *source =
        qobject_cast<ProjectListWidget *>(event->source());
if (source && source != this) {
    QString str=event->mimeData()->text();
    qDebug()<<"str=="<<str;
    QTableWidgetItem *it=new QTableWidgetItem;
    setItem(0,0,new QTableWidgetItem(str));
  //  insertRow(rowCount());
    event->setDropAction(Qt::MoveAction);
    event->accept();
    event->acceptProposedAction();
    QTableWidget::dropEvent(event);

}
QTableWidget::dropEvent(event);
}
#endif
void MainWindow::on_item1_changed()
{
qDebug()<<"changed";

QMessageBox msgBox;
msgBox.setText("The document has been modified.");
msgBox.setInformativeText("Do you want to save your changes?");
msgBox.setStandardButtons(QMessageBox::Save | QMessageBox::Discard );
msgBox.setDefaultButton(QMessageBox::Save);
int ret = msgBox.exec();
switch (ret) {
  case QMessageBox::Save:
      qDebug()<<"Save was clicked";
      break;
  case QMessageBox::Discard:
      qDebug()<<" Don't Save was clicked";
        table4->clear();
      break;
  case QMessageBox::Cancel:
      // Cancel was clicked
      break;
  default:
      // should never be reached
      break;
}

}

MainWindow::~MainWindow()
{
delete ui;

}
@

[frankiefrank]

What is the exact error you get and when do you get it (when you compile? when you run?)

[ecmanja]

thanks for giving your time. In on_item1_changed() loop i have used qmessage box so that when item changes it ask for save and discard ,i want to clear the table if i press discard so i included
@table4->clear();@
but after running this code when i press discard i'm getting .exe not working. actually i cant able to perform any actions on table4.

[ecmanja]

thank you very much frankiefrank i solved the issue :)

[goblin]

What was the issue?

[ecmanja]

i have declared it twice so got that error i.e we must use only "table4" instead of "projectlistwidget *table4" in .cpp because it is already declared in .h

[frankiefrank]

OK, good to know.

By the way, when changing the post topic to solved, it's best to add [SOLVED] in the beginning of the title, not at the end.