[Kdenlive-devel] Problems with signals and slots

[Marco Gittler]

Hi

I used the new (your) signals with QVector and rewrote the audiosignal.cpp (commited to svn)

regards marco

Am 24.11.2010 um 11:10 schrieb Simon Eugster:

> Well, the «old» signal (using volume) _does_ work, but I cannot explain why.
> When I try to do the same with my new signal, it does not work.
> 
> Simon
> 
> 2010/11/24 Marco Gittler <marco at gitma.de>:
>> Hi
>> 
>> I'll change this, to get it working (first on the "old" audiosignal)
>> You can use this then for your audiospectrum.
>> 
>> 
>> regards marco
>> 
>> Am 24.11.2010 um 09:42 schrieb Simon Eugster:
>> 
>>> Good Morning,
>>> 
>>> I'm battling around with Qt's signals and slots. In r5116,
>>> mainwindow.cpp:296 I want to connect my audiospectrum object to
>>> Render::audioSamplesSignal. But whatever I do, my method never
>>> receives the signal, although connecting works according to the return
>>> value, Q_ASSERT etc.
>>> 
>>> On line 298 I tried to find a reason for it and used the audio volume
>>> signal. It is defined as:
>>>  void showAudioSignal(const QByteArray);
>>> According to the Qt documentation and some people in #qt, Qt uses
>>> normalizedSignature[1] for signal/slot connections. Meaning that I
>>> should be able to just use
>>>  SIGNAL(showAudioSignal(QByteArray))
>>> to connect the signal. But then connecting fails, telling me that
>>> there is no such signal.
>>> 
>>> I do not get an error though when using
>>>  SIGNAL(showAudioSignal(const QByteArray)
>>> i.e. the connection is set up correctly. Nevertheless the connected
>>> slot is never called. Only if I use
>>>  SIGNAL(showAudioSignal(const QByteArray&)
>>> connecting works AND the slot gets called. Although the & is not in
>>> showAudioSignal's signature.
>>> 
>>> So I tried to use the & for my signal (audioSamplesSignal) as well:
>>>  audioSamplesSignal(const QVector<int16_t>&,int,int,int)
>>> with
>>>  void audioSamplesSignal(const QVector<int16_t>,int,int,int)
>>> but this fails with «no such signal». Why should I have to add a & for
>>> a QByteArray, but I'm forbidden to do so for the QVector?
>>> 
>>> I then tried to change everything (including the signal's signature)
>>> to const type& (whether making sense or not – what I noticed above
>>> does not make sense to me anyway). But still, no signal received.
>>> 
>>> Can anyone help me? Why is qt behaving that way? What is the problem?
>>> 
>>> thanks
>>> Simon
>>> 
>>> [1] http://doc.qt.nokia.com/4.7/qmetaobject.html#normalizedSignature
>>> 
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>> 
>> 
>> ------------------------------------------------------------------------------
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>> 
> 
> ------------------------------------------------------------------------------
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> Tap into the largest installed PC base & get more eyes on your game by
> optimizing for Intel(R) Graphics Technology. Get started today with the
> Intel(R) Software Partner Program. Five $500 cash prizes are up for grabs.
> http://p.sf.net/sfu/intelisp-dev2dev
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