Signal and Slot connection not working

[isan]

When I press the pushButton to save data, on_Recording () is called, but in this function the signal and slot connection does not work. Why?

//define in Saving.h
std::unordered_map<QString,DataStream>          _RecordData;
std::unordered_map<QString,ServerStream>        _RecordProcessor;


void Saving::on_Recording()
{
  _NewRecordId =  QDateTime::currentDateTime().toString("yyyy.MM.dd-hh.mm.ss.zzz");

  QObject::connect(&_RecordData[_NewRecordId], &DataStream::onDataReceived, this, &Saving::onRecordingData, Qt::UniqueConnection);
  QObject::connect(&_RecordProcessor[_NewRecordId], &ServerStream::onDataReceived, this, &Saving::onRecordingData, Qt::UniqueConnection);
}


void Saving::onRecordingData(QByteArray data) {
  QFile _File = QFile(dir.filePath(_NewRecordId + ".txt"));
  if (_File.open(QIODevice::WriteOnly | QIODevice::Append)) {
    _File.write(data);
    _File.flush();
    _File.close();
  }
}

[SGaist]

Hi,

What exactly are you expecting to happen ?
If you think the connection is failing, you should check the return value of your connect calls.

[JonB]

@isan
_RecordData[_NewRecordId]

What do you think this is? _NewRecordId = QDateTime::currentDateTime().toString("yyyy.MM.dd-hh.mm.ss.zzz"); is a unique new string, so what's going on?

[SGaist]

And to add to @JonB how did you declare your classes ?
QObject based classes cannot be copied, so there's also likely something fishy going on there.

[JoeCFD]

@isan said in Signal and Slot connection not working:

_NewRecordId = QDateTime::currentDateTime().toString("yyyy.MM.dd-hh.mm.ss.zzz");

QObject::connect(&_RecordData[_NewRecordId]

JonB is right.
_NewRecordId = QDateTime::currentDateTime().toString("yyyy.MM.dd-hh.mm.ss.zzz");
brand new time. _RecordData[_NewRecordId] does not exist yet and can not be used to connect.
QObject::connect(&_RecordData[_NewRecordId]

[isan]

@JonB For handle multiple record I define like this

[isan]

@JoeCFD The QObject::connect(&_RecordData[_NewRecordId],... run before
_NewRecordId = QDateTime::currentDateTime().toString("yyyy.MM.dd-hh.mm.ss.zzz"); ?

[JonB]

@isan
As @SGaist said earlier, the connect()s return a value to indicate whether the connection was made successfully. Print that out/test it.

[mchinand]

When and how are things being added to _RecordData? You can't have the key be a datetime string derived from a call to the QDateTime::currentDateTime() and then try to retrieve a value from the map later on by calling QDateTime::currentDateTime() a subsequent time to use as the search key. How would a value exist in it with a key of the current DateTime?

[isan]

@mchinand said in Signal and Slot connection not working:

You can't have the key be a datetime string derived from a call to the QDateTime::currentDateTime() and then try to retrieve a value from the map later on by calling QDateTime::currentDateTime() a subsequent time to use as the search key.

How can I fix it? Can I convert QDateTime::currentDateTime() to something else then use it for map?

[isan]

@JonB

const bool connected =   QObject::connect(&_RecordData[_NewRecordId], &DataStream::onDataReceived, this, &Saving::onRecordingData, Qt::UniqueConnection);
 qDebug() << "Connection established?" << connected;

Return true;

[JonB]

@isan
OK, fair enough. So the connect() works, but I don't understand how you will actually have any useful object at _RecordData[_NewRecordId] which you will actually use later to raise the signal?

Read what @mchinand says above, which is what I have been saying from the start:

When and how are things being added to _RecordData? You can't have the key be a datetime string derived from a call to the QDateTime::currentDateTime() and then try to retrieve a value from the map later on by calling QDateTime::currentDateTime() a subsequent time to use as the search key. How would a value exist in it with a key of the current DateTime?

I don't know how to express it any clearer than that.