Qt主窗口失去焦点并意外进入背景

Question

Going up the learning curve and everything has been making sense so far except for this one:

I have a main window from where I call one or more dialog like this:

d->setWindowFlags(Qt::CustomizeWindowHint | Qt::Window | Qt::FramelessWindowHint);
d->setGeometry(etc...
d->show();

The dialogs are not bound to the main window, and they are actually set to be displayed right beside the main window looking like an extension.

To close the dialogs I use a mouse 'enterEvent' on the mainwindow to send a close signal to the dialog(s) which will use hide().

void MainWidget::enterEvent(QEvent *event)
{
emit signal_related_close();
}

This works but randomly this causes a very annoying issue. When the signal is sent to close the dialogs, the main window would loose focus and go in the background (behind whatever application that is on the screen). Note that it does not minimize but only goes in the background and like I said it is random (about one out of 3 times I do it). I can't seem to get a pattern.

I initially thought the signal was messed up and instead used a dialog::leaveEvent() but that didn't help. I also tried using dialog::mouseMoveEvent and using that to hide the dialog but that would still randomly loose focus on the application.

The only method that doesn't loose focus is using a push button on each dialog that will initiate the same hide commands but that's not great for my UI. So it would seem that using the mouse enterEvent/leaveEvent,mouseMoveEvent will cause that random issue.

Anyone experienced this issue before? Any idea what could be wrong? Thx.

Answer 1

I can't explain why but this problem occurred when using QEvent or any mouse related event together with recursive children widgets. For example take this code in the parent widget constructor:

ChildWidget c1 = new ChildWidget (this);  
ChildWidget c2 = new ChildWidget (c1);
Childwidget c3 = new ChildWidget (c2);

Using QEvent in the parent widget will randomly make the window go to the background and loose focus.

Setting all the ChildWidget to the same parent stopped the problem.