How to open dialog box on top of the application if two screen are connected?

[Yash001]

@mrjj

I don't know. what is different but now it is work. i did not make any change except setting the property

before:
QDialog *dialog = new QDialog(parent, Qt::SplashScreen);

now :

QDialog* dialog = new QDialog();
dialog->setWindowFlags(Qt::SplashScreen);
dialog->setParent(m_mainWindow);

[mrjj]

@Yash001
ok, im not sure either. seems the same :)

[Yash001]

I found the different.

it is work fine.

dialog->setWindowFlags(Qt::SplashScreen);
dialog->setParent(m_mainWindow);

it is not work.

dialog->setParent(m_mainWindow);
dialog->setWindowFlags(Qt::SplashScreen);

[mrjj]

@Yash001
Ok so Qt::SplashScreen does something with parent.

[Yash001]

@mrjj May be. It is qt default function.

[mrjj]

@Yash001
yeah its a windows flag.

[Yash001]

@mrjj

dialog->setWindowFlags(Qt::SplashScreen);
dialog->setParent(m_mainWindow);
In this case I got dialog box on top of the screen but it is make another issue

dialog->exec(); is not work as per expectation. without responding the to Dialog user access the other page also.

In other word, user can access both screen Main application as well as Dialog box. how to block access on other widget until get response from the user in dialog box?

[mrjj]

Hi
Im not 100% sure Qt::SplashScreen is compatiple with Qt::Dialog flag

Qt::SplashScreen 0x0000000e | Window Indicates that the window is a splash screen. This is the default type for QSplashScreen.

Normally used with QSplashScreen widget.

[mrjj]

maybe try with
dialog->setWindowFlags(Qt::Dialog | Qt::SplashScreen);

[Yash001]

@mrjj it is create previous issue.

[mrjj]

@Yash001
but why you need Qt::SplashScreen ?
and modal dialog ?
cant you just use the dialog ?

[JonB]

@Yash001
Similarly to @mrjj , have you considered using QSplashScreen (http://doc.qt.io/qt-5/qsplashscreen.html), maybe it doesn't have these problems?

[Yash001]

I am using Qt::SplashScreen because of I wanted show dialog on the top of all screen. This dialog is show whenever specific signal is generated from Hardware Connection. if hardware is connected with PC before opening our Software then dialog will open after Software Open. and control need to transfer on dialog box. (at this time user should not access any other page).

I have not idea what is model Dialog.

[mrjj]

@Yash001
Modal dialog means user cannot click on mainwindow behind dialog.
Sometimes also called blocking.
comes when using exec() versus show().

[Yash001]

@mrjj understood. thank you.