Accessing from one form to another
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If you want a signal-slot connection (I thought that you understood that you don't need one), then you make such a connection at the place where you have references to both the involved objects. The most logical place in this case would be the place in your mainWindow code where you create the dialog. So, not in the constructor of the dialog. Something like this:
@
EditDialog* editDialog = new EditDialog(this);
//set your values
connect(editDialog, SIGNAL(triggerRefresh()), this, SLOT(refresh()));
editDialog.exec();
//...
@To make your dialog actually emit the signal, you may do something like this in the constructor of your dialog:
@
connect(ui->pushButtonSave, SIGNAL(clicked()), this, SIGNAL(triggerRefresh()));
@Note that it seems that you did not use QDialog as the base of your dialog. Perhaps you should re-evaluate that choice. QDialog gives you the option to use standard buttons, including a save button, that have the appropriate roles pre-defined. The nice thing is, is that they will order themselves in the order that is defined by the platform your application runs on, so the user is never suprised by what button will cancel and what button will accept.
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I think I don't really understand the idea of slots/signals and triggers too :/, so I better learn more basics:). My last experience with GUI was C++ Builder, and Qt is something completly new for me. in Builde what i have to do was include header file of second form and it was just all. Thanks for reply.
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I can't do it. Could somebody show me an example of accessing one form from another?
My test code
from mainwindow.h
@public slots:
void test();
void trigger();private slots:
void on_pushButtonMainWindow_clicked();@
mainwindow.cpp
@void MainWindow::on_pushButtonMainWindow_clicked()
{
Dialog dialog(this);
connect(this, SIGNAL(trigger()), &dialog, SLOT(test()));
dialog.exec();
}void MainWindow::test()
{
ui->lineEdit->setText("efgh");
}
void MainWindow::trigger()
{
ui->lineEdit->setText("this is a test");
}@
from dialog.cpp
@ connect(ui->pushButtonDialog, SIGNAL(clicked()), this, SLOT(MainWindow::trigger()));@
And it gives me:
@Object::connect: No such slot Dialog::MainWindow::trigger() in ..\slots\dialog.cpp:9
Object::connect: (sender name: 'pushButtonDialog')
Object::connect: (receiver name: 'Dialog')
Object::connect: No such signal MainWindow::trigger() in ..\slots\mainwindow.cpp:20
Object::connect: (sender name: 'MainWindow')
Object::connect: (receiver name: 'Dialog')@
Sorry for double post -
Signals are sent from the objects that define them. Your main window has no signal trigger - that's what the debug console tells you literally :-)
In your case, you probably want to connect a signal of a button or an action to the slot.
If you define your own signal triggered, it does not need an implementation in the cpp file (actually you must not provide any!). And if you have that your signal must be emit somewhere to have the connection be called in the end.
Did you read the "Signals & Slots":http://doc.qt.nokia.com/4.7/signalsandslots.html docs already?
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I've briefly read this doc and C++ GUI Programming with Qt 4 By Jasmin Blanchette, Mark Summerfield too (about signals and slots).
More, in project I'm actually working with, I have 2implementations of signals & slots, and they are working fine. But they both signals and slots in mainwindow area.
@ connect(ui->tableViewHouses, SIGNAL(clicked(const QModelIndex&)), this, SLOT(clickedRow(const QModelIndex&)));
connect(ui->tableViewInhabitants, SIGNAL(doubleClicked(const QModelIndex&)),
this, SLOT(doubleClickedRow(const QModelIndex&)));
@
I have a problem to connecting from main to dialog. I know that problem is my lack of knowledge, but i have no idea howto do it between different windows -
Does your edit dialog have a signal defined called trigger (that is, does it have a line in the header file that looks like this)?
@
signals:
void trigger();
@On top of that, do you have this line in the header of that dialog?
@
Q_OBJECT // this line is usually the first line inside the actual class definition
@Your error message suggests that you don't.
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Define the signal in one form, emit when you have something to tell to the other form.
Connect in the other form. Or connect in some managing code - it depends.
Other possibility is to give the form a pointer to the other form and call a method directly.
Or do it like Andre suggested:
Call exec() on a "QDialog":http://doc.qt.nokia.com/4.7/qdialog.html subclass and get the data from a method of this dialog and put it into the widgets of the main form, if the exec returns with Accepted.I personally would go with the last approach.
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[quote author="Andre" date="1299516055"]Does your edit dialog have a signal defined called trigger (that is, does it have a line in the header file that looks like this)?
@
signals:
void trigger();
@On top of that, do you have this line in the header of that dialog?
@
Q_OBJECT // this line is usually the first line inside the actual class definition
@Your error message suggests that you don't.[/quote]
Yes, I haven't get signal, I've added trigger now, but still it doesn't work properly.
"pastebin":http://pastebin.com/nAA2X3d8//edit
Its to much for me. Im quiting with this. Thanks for Your replies and Your time. Maybe some other time I'll try to understand slots and signals between forms. -
What you do is: Have the main window emit a signal that the dialog reacts on. You most probably want it the other way round!
Good luck with your projects so far. If you only read the docs briefly you'll be stuck in similar situations here and then in the future again... be warned!
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It works:) Thank You both for help. I've do it nor in signals&slots but in the way which Andre suggested with dialog set on Accepted
@void MainWindow::on_pushButton_clicked()
{
Dialog *dlg = new Dialog(this);
if(dlg->exec() == QDialog::Accepted) ui->lineEdit->setText("Accepted");
}@
This works perfectly for me, altough i know that i will have to learn slots&signals in future.
Thanks again for Your suggestions.
Best regards. -
nicely explained, here...