[Interest] General QTimer question

[Harish Surana]

Yes, reuse them. I had similar problem when I was creating a digital
signage solution.


On Thu, Dec 12, 2013 at 2:53 PM, Jason Kretzer <Jason at gocodigo.com> wrote:

> So, reuse the QWebViews instead of destroying and creating new ones.
>
> Interesting.
>
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> *Jason R. **Kretzer*
>
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> *Jason at gocodigo.com <Jason at gocodigo.com>*
>
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>
>
>
> On Dec 12, 2013, at 8:44 AM, Harish Surana <surana4u at gmail.com> wrote:
>
> I would say change your approach little bit:
>
> 1. Create only 3 instance of QWebView
> 2. Whenever QTimer shots change content of QWebView and show them.
> 3. After they are finished displaying content hide them.
> 4. repeat step 2 and 3
>
>
> On Thu, Dec 12, 2013 at 1:57 PM, Jason Kretzer <Jason at gocodigo.com> wrote:
>
>> Good Morning!
>>
>>
>>
>> This is more a general question about the behavior of QTimer followed by
>> a more specific instance of the question.
>>
>>
>>
>> What can make a QTimer not timeout()?  In a general sense, what can make
>> it miss its firing?
>>
>>
>>
>> That was the general question.  My specific situation:
>>
>>
>>
>> I display 3 QWebViews.  They are to be displayed on different parts of a
>> screen for 20 seconds.  The 20 seconds is arbitrary, they could have
>> different durations.  I have a QTimer that fires every second.  During any
>> given second any of the three QWebViews can be triggered to start to
>> display.  During each timeout of the QTimer, a slot is called which does
>> the following
>>
>> {
>>
>> ALL content(html) that is supposed to start during this second are pulled
>> from a QMultiMap.  There can be several – up to 3.
>>
>> A for loop is used to iterate over them and show them as below.
>>
>> They are loaded into a QWebView, geometry is set on the QWebView.
>>
>> QWebView is shown
>>
>> A SingleShot timer is set up to deleteLater the QWebView after the
>> duration has expired.
>>
>> }
>>
>>
>>
>> In the case where durations for the content are all the same – lets say
>> 20seconds – the QWebViews are basically synched up where they all start and
>> stop on the same second.  Then the second right after they stop, they all
>> three start up again.
>>
>>
>>
>> Here is where the weirdness starts:  exactly every 1 minute, the QTimer
>> which is supposed to fire every 1 second stops firing for 20-22seconds.  At
>> the beginning of that time, the three QWebViews finish their previous time
>> and leave as expected.  Then, nothing for 20-22 seconds.  The screen where
>> they are supposed to be is blank.  I put qDebugs in the firing slot so I
>> could see when it was being called but nothing.  I don’t see qDebug
>> messages from anywhere else either during that time.  Like clockwork
>> though, after the 20-22seconds of nothing, the QTimer starts firing again
>> and repeats.
>>
>>
>>
>> So, generally, what can keep a QTimer from firing like that?  I don’t
>> have any processes that run every 1 minute like that.  Also, I am asking
>> the QTimer to fire every 1 second – it is not like I am trying to get 10ms
>> precision here.
>>
>>
>>
>> If it makes any difference, this is a win7 pro OS.
>>
>>
>>
>> Ideas?  I was intentionally a bit vague above as I am just asking for
>> things to look for so that I can discover the answer on my own instead of
>> just being given the answer.
>>
>>
>>
>> Thanks!
>>
>>
>>
>> -Jason
>>
>>
>>
>> *- - - - - - - - - - - - - - - - - - - - - - -*
>>
>> *Jason R. **Kretzer*
>>
>>
>>
>> *Application Developer*
>>
>> *Google # 606-887-9011*
>>
>> *Cell # 606-792-0079*
>>
>> *Jason at gocodigo.com* <Jason at gocodigo.com>
>>
>>
>>
>> *“quidquid latine dictum sit altum videtur”*
>>
>>
>>
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>>
>>
>>
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