[Interest] Define map of static items in QML

[Gianluca]

Il giorno 30/mar/2016, alle ore 09:46, Elvis Stansvik <elvstone at gmail.com> ha scritto:

> Hi Gianluca,
> 
> 2016-03-30 10:16 GMT+02:00 Gianluca <gmaxera at gmail.com>:
>> 
>> Il giorno 30/mar/2016, alle ore 07:43, Elvis Stansvik <elvstone at gmail.com>
>> ha scritto:
>> 
>> Den 30 mar 2016 8:36 fm skrev "Elvis Stansvik" <elvstone at 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.