Il giorno 30/mar/2016, alle ore 09:46, Elvis Stansvik <elvst...@gmail.com> ha
scritto:
> Hi Gianluca,
>
> 2016-03-30 10:16 GMT+02:00 Gianluca <gmax...@gmail.com>:
>>
>> Il giorno 30/mar/2016, alle ore 07:43, Elvis Stansvik <elvst...@gmail.com>
>> ha scritto:
>>
>> Den 30 mar 2016 8:36 fm skrev "Elvis Stansvik" <elvst...@gmail.com>:
>>>
>>> Hi all,
>>>
>>> I can understand why I can do
>>>
>>> property Item foo: Foo {}
>>> property Item bar: Bar {}
>>> property variant items: {
>>> "foo": foo,
>>> "bar": bar
>>> }
>>>
>>> but not
>>>
>>> property variant items: {
>>> "foo": Foo{},
>>> "bar": Bar{}
>>> }
>>>
>>> The first opening { in the second example probably puts me in JS
>>> territory, where the Item {} syntax is not understood as a static definition
>>> of an item.
>>>
>>> However, is there some way of defining a map of static items like this,
>>> without having to bind the item instances to properties first? Such that I
>>> can later do e.g. items["foo"] to access an item?
>>
>> I should state my use case as well: I'm doing a small page based embedded
>> app (less than 20 pages), based on a StackView, where I'm thankfully not
>> hardware constrained (it's a fast PC). So I have no reason to use Loader to
>> load pages dynamically but was thinking of keeping them all statically in a
>> map, so that I can switch page based on the name of the page (e.g
>> "WelcomeScreen") by calling some function or perhaps emitting a signal with
>> the name as argument.
>>
>> For this use cases (and others), I usually use one of the ObjectModel,
>> DelegateModel or Package (or the older VisualDataModel). They are wonderful
>> for creating models containing QML object and they can created as you want.
>> Also DelegateModel can contains groups so you can filter them, and Package
>> let you to name the items so you can access using dot syntax: views.foo,
>> views.bar
>> In your case, I will use DelegateModel and access using numeric index, but
>> you can also explore Package and use the attached propertied Package.name to
>> give a name to all the views.
>
> Thanks a lot for the suggestions.
>
> I must ask though. Why would you use a DelegateModel in my case? Would
> you manage the name -> index mapping separately then? (to avoid
> hardcoded indices throughout the code).
>
> I think I will go the Package route, the dot syntax seems like a nice
> thing I can use.
>
> Elvis
I think that the Package may be the best route for you, but I suppose it can be
used only with a DelegateModel and not alone. And of course, I suggest you to
give a try.
The Package has been added recently, before the introducing of Package I used
to use the Component.onCompleted to construct the name -> index mapping. In
this way, it’s less hardcoded and inside the definition of the Items. So, if
you move an item or you insert a new one in the middle, the name -> index
mapping is automatically updated without need to touch anything.
Ciao,
Gianluca.
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