showing parent while closing child form

rahulvishwakarma

hi to all, I'm using qt 5.7 in centos7.5 linux. i want to show parent form while closing current child window. i am doing like this :-

void DialogAddModifyMemberRecords::on_pushButtonOK_clicked()
{
    this->hide();

    this->parentWidget()->show();
    //this->close();

}

but shows error

```Starting /opt/projects/Qt/computerized billing sysem/cbs/build-cbs-Desktop_Qt_5_7_0_GCC_64bit-Debug/cbs...
The program has unexpectedly finished.
/opt/projects/Qt/computerized billing sysem/cbs/build-cbs-Desktop_Qt_5_7_0_GCC_64bit-Debug/cbs crashed.

how to get rid of this.

JonB

@rahulvishwakarma
Step through your code in debugger to determine exact cause (stack trace on crash). This is standard debugging technique before you ask question like this. One possibility: if your program is on default "quit after last window not visible", and child is only visible window, and you close before showing parent, I don't know if that could be a problem. Try showing parent before hiding child, just in case.

Also, if this child is a QDialog, how is parent calling/showing it (exec(), or is it modal/modeless??), and why is child hide()-ing itself, dialogs often go via accept/reject/done()?

It's not always best design to have child show parent. Might be nicer to have parent notified of child closure so that it can re-show itself.

rahulvishwakarma

i used all choices you suggested(accept, reject ,done) and also setAttribute(Qt::WA_DeleteOnClose); in child and parent form.
but having same error :- The program has unexpectedly finished.

jsulm

@rahulvishwakarma said in showing parent while closing child form:

The program has unexpectedly finished

use debugger as already suggested

rahulvishwakarma

in debugger this showed following window at point of crash.

Signal name : SIGSEGV
Signal meaning : Segmentation fault

jsulm

@rahulvishwakarma You have to look at the stack trace (or post it here).

Pl45m4

@rahulvishwakarma

Does your this widget even have any parent? You don't check for nullptr.