Some errors if I don't click on QMessageBox button

[jpn]

A quick and dirty fix is to make installFile() a slot and in httpRequestFinished() invoke the slot with help of timer (to allow control to return to QHttp, where the signal was emitted from):

if (error) {
    ...
} else {
    //installFile();
    QTimer::singleShot(0, this, SLOT(installFile()));
}
 
//delete file;
//file = 0;

if (error) {
    ...
} else {
    //installFile();
    QTimer::singleShot(0, this, SLOT(installFile()));
}

//delete file;
//file = 0;

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Notice also that you can't either delete the file here because you will later use it in installFile().

[jpn]

Yet another (easier and more elegant) way would be to simply force a queued connection:

connect(http, SIGNAL(requestFinished(int, bool)),
    this, SLOT(httpRequestFinished(int, bool)), Qt::QueuedConnection);

connect(http, SIGNAL(requestFinished(int, bool)),
    this, SLOT(httpRequestFinished(int, bool)), Qt::QueuedConnection);

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In this case you wouldn't need modifications represented in my last message.

[jiveaxe]

Great code, jpn. Now the program runs very fine.

A thousand thanks.