Signal between 2 class

Reply to Signal between 2 class on Thu, 21 Jul 2016 22:16:48 GMT

Yacinoben — Thu, 21 Jul 2016 22:16:48 GMT

Thanks !

Reply to Signal between 2 class on Thu, 21 Jul 2016 20:43:01 GMT

Chris Kawa — Thu, 21 Jul 2016 20:43:01 GMT

It's easier and shorter to just create it on the stack:

History history(this);
connect(&history,&History::selectHistory, this, [ ]{ qDebug("test"); } );
history.exec();

Reply to Signal between 2 class on Thu, 21 Jul 2016 17:44:08 GMT

Yacinoben — Thu, 21 Jul 2016 17:44:08 GMT

Yes, you are right, when i call history, the object doesn't deletes, the use of the memory increases.
but now, its work !!

   History *history=new History(this);
   history->setAttribute(Qt::WA_DeleteOnClose);
   connect(history,&History::selectHistory,this,[ ] () {qDebug("test");});
   history->exec();

Thank's

Reply to Signal between 2 class on Wed, 20 Jul 2016 21:16:37 GMT

SGaist — Wed, 20 Jul 2016 21:16:37 GMT

Hi,

You're doing your connection after exec which means that it will happen after you close your history dialog thus you won't see any message.

On a side note, you are leaking memory since you don't delete history. The objects will get destroyed when MainWindow is since you give it a parent but the memory will fill up more each time you call showHistory.

Reply to Signal between 2 class on Wed, 20 Jul 2016 11:35:13 GMT

miho — Wed, 20 Jul 2016 11:35:13 GMT

http://easy-qt.blogspot.ru/2012/10/1.html

p.s. russian site

Reply to Signal between 2 class on Wed, 20 Jul 2016 11:34:28 GMT

Yacinoben — Wed, 20 Jul 2016 11:34:28 GMT

It doesn't work .
this is my code :

class History : public QDialog
{
    Q_OBJECT
public:
    explicit History(QWidget *parent = 0);

signals:
    void selectHistory();
};

History::History(QWidget *parent) : QDialog(parent)
{
/*
...
*/
     connect(view,&QListView::clicked,this,&History::selectHistory);
}

void MainWindow::showHistory()
{
    History *history=new History(this);
    history->exec();
    connect(history,&History::selectHistory,this,[ ] () {qDebug("test);});
}

The QListView contains a history of browser, i would like when i click in a index, i open a new tab in my navigator with a fonction addTab in Mainwindow, but the signal doesn't work

Reply to Signal between 2 class on Wed, 20 Jul 2016 07:58:06 GMT

micland — Wed, 20 Jul 2016 07:58:06 GMT

@Yacinoben
Why using lambda in the first connect statement? You can directly connect signals with signals:

connect(view, &QListView::clicked, this, &A::newSignal);

Reply to Signal between 2 class on Wed, 20 Jul 2016 07:28:38 GMT

praveen0991kr — Wed, 20 Jul 2016 07:28:38 GMT

connect(this->view,&QListView::clicked, this,[=]{
emit this->newSignal();
});

Reply to Signal between 2 class on Tue, 19 Jul 2016 21:03:00 GMT

Chris Kawa — Tue, 19 Jul 2016 21:03:00 GMT

Please post the actual code. This won't even compile.
[ ](){emit newSignal();} this lambda does not capture this so it would be a compilation error to try and call newSignal() from it.
()[ ]{qDebug("test");} the parenthesis are all backwards.
How and where is newSignal declared? Do you have a Q_OBJECT macro in you A class declaration?