[Lazarus] [lazarus-br] Re: Como passar uma procedure local como callback?

[waldo kitty]

On 2/21/2012 18:01, Hans-Peter Diettrich wrote:
> waldo kitty schrieb:
>
>> eg: http://www.freepascal.org/docs-html/rtl/sysutils/datetostr.html
>>
>> there should be sample output and definitely something for the
>> formatsettings...
>> http://www.freepascal.org/docs-html/rtl/sysutils/tformatsettings.html
>> definitely doesn't help and i spent hours digging in there (the site) trying
>> to find something... i finally got to
>> http://www.freepascal.org/docs-html/rtl/sysutils/formatdatetime.html and found
>> a little bit of help which i still had to guess at some stuff and i have *just
>> now* noticed the link to
>> http://www.freepascal.org/docs-html/rtl/sysutils/formatchars.html which
>> appears to offer more than what i had found before... but even that page needs
>> some concrete alpha-numerical examples of what the output would look like...
>
> Please suggest a pleasant solution. Perhaps a separate overview topic could be
> added, explaining the date and time formatting. "Using Dates and Times"...

that might be ok as long as it is prominent... i've been on several of those 
pages numerous times and the links just do not stand out in a very visible 
way... i was very surprised to find the link i did considering i had been back 
and forth to the previous page(s) containing ig a huge number of times :?

>>> While RTL and FCL topics can be demonstrated in simple console applications, LCL
>>> topics usually require big sample applications. See how e.g.
>>> examples/listview/listview.lpi demonstrates the capabilities of a TListView.
>>
>> i see it, yes but i'm lost in all the other controls' code in there...
>
> This example demonstrates the effects of various property settings, and how to
> access detailed information in code.

so it is more than just a listview demonstrator?

>> running the project doesn't help me to understand a listview, either :? yes, i
>> see the effect of some of the controls but, for example, it is not clear to me
>> why i can select "new 1" or "New 2" but not "Sub 1"...
>
> A ListView is not a Grid.

wotz a "grid"? remember, i do not have any delphi experience nor turbovision, 
really... i've always written straight forward, non-complicated apps and tools 
with no graphics or other things to slow processing or bloat unnecessarily... in 
other words, i've always written my code like a bikini... short and to the point ;)

>> neither is it clear to me what the items and columns tabs are for...
>
> It should be obvious, from the buttons in those pages, that they demonstrate
> adding and removing items and columns.

yeah, i guess but...

>> i can't even get anything to react when i choose the columns tab and click
>> about :(
>
> The About menu shows information about the application, not help.

nonononono... "click about" meaning "clicking on random stuff to try to figure 
it out"...

> Again feel free to supply whatever you think would be better :-)
> Topic "Using ListView"?

i don't have any idea what to supply... it is all alien to me but i'm trying to 
learn it with the materials, what few they are, at hand... i don't even know why 
i would want to use a "grid" or "listview", TBH... what is their basic purpose? 
is this documented anywhere or is it all just "here! we can do this with that. 
ya got the code if ya wanna know more."

>>> About things like callback functions, which are common to many components, there
>>> should exist references to examples that *also* demonstrate such features,
>>> amongst possibly many others.
>>
>> agreed... i think... but yes, everything should be documented that can be...
>> even basic things like what a "callback" is... i see/hear that and i think
>> telco stuff :(
> Topic "Using Callbacks"?

yes, i guess that would be ok as would one for listview and grid ;)