ListViewItemState.data casting

chatmurai74

Hi! I'd like to cast a ListViewItemState.data into a custom value object class of my own but it triggers a runtime error : conversion of Object@2464497057f1 into vo.RiderVO impossible

The update function of the recycler is like that:
recycler.update = (itemRenderer:ItemRenderer, state:ListViewItemState) -> {

		var rider:RiderVO = cast(state.data, RiderVO);
		itemRenderer.text = rider.firstName;
		itemRenderer.secondaryText = rider.name;

	};

If I use the item.data as this: var item = state.data; I can dynamically access all the properties of the item object because ListViewItemState.data. is of Dynamic type, but it feels like there is something wrong with it.

Thanks for your help !

joshtynjala

state.data references one of the items that you passed to the dataProvider property of the ListView. If you want to cast to a class named RiderVO, that's the type of object that you need to populate the dataProvider with.

listView.dataProvider = new ArrayCollection([
    new RiderVO(/* args */),
    new RiderVO(/* args */)
]);

Alternatively, you could define a Haxe typedef instead of a class, if you want to keep using anonymous structures to populate the dataProvider, for some reason.

typedef RiderVO = {
    var firstName:String;
    var name:String;
}

listView.dataProvider = new ArrayCollection<RiderVO>([
    {name: "John Smith", firstName: "John},
    { /* etc. */}
]);

chatmurai74

I am working on an equestrian riders management and I use Cairngorm. In the AppModeLocator, there is an array collection like...

public var ridersListDP(default, set):ArrayCollection<RiderVO>;

    private function set_ridersListDP(value:ArrayCollection<RiderVO>):ArrayCollection<RiderVO> {
		ridersListDP = value;
		dispatchEvent(new Event(RIDERS_LIST_DP_CHANGE));
		return ridersListDP;
	}

...that I populate with an external JSON, so I am pretty sure that each record in the DataProvider is in fact an instance of the RiderVO class.

I populate the DataProvider from LoadRiderCommand:

       var riders:Array<RiderVO> = cast(rpcEvent, ResultEvent).result;
       model.ridersListDP = new ArrayCollection(riders);

thanks, I'll have a look to Haxe typedef

joshtynjala

var riders:Array<RiderVO> = cast(rpcEvent, ResultEvent).result;

Unfortunately, this won't automatically convert anonymous structures to RiderVO. The result property is of type Dynamic, which can be assigned to anything without any compile-time type checking. It's probably an Array of some type, though (most likely Array<Dynamic>). To get an actual Array<RiderVO>, you'd need to loop through that array parsed from JSON and manually call new RiderVO() for each item and populate its fields. You could also use the map() function to do that, instead of a regular loop.

chatmurai74

Oh I see... so I did:

	var rac:ArrayCollection<RiderVO> = new ArrayCollection();
	for (v in riders) {
		var rider:RiderVO = cast v;
		rac.add(rider);
	}
	model.ridersListDP = rac;

It's not that great because I had to use an unsafe cast, but it works. However, I couldn't find the map() function... I looked into the Haxe documentation and only found a Map class.

chatmurai74

No — my code doesn't work after all. Sorry, I didn't understand that the map() method was a member of the ArrayCollection() class. I tried to use it but the callback thing is causing me trouble. I ended up doing something like this, which is pretty ugly given the number of properties the RiderVO class has:

	var riders:Array<RiderVO> = [];
	for (i in 0...data.length) {
		var r:Object = data[i];

		var id:Int = Std.parseInt(r.id);
		var name:String = r.name;
		var firstName:String = r.firstName;
		var age:Int = Std.parseInt(r.age);
		var lastLessonDate:Int = Std.parseInt(r.lastLessonDate);
		var level:Int = Std.parseInt(r.level);
		var credit:Int = Std.parseInt(r.credit);
		var address:String = r.address;
		var notes:String = r.notes;
		var ffeLicence:Bool = stringToBool(r.ffeLicence);
		var ffeLicenceValidityYear:Int = Std.parseInt(r.ffeLicenceValidityYear);
		var ffeLicenceNumber:String = r.ffeLicenceNumber;
		var legalGuardianName:String = r.legalGuardianName;
		var legalGuardianFirstName:String = r.legalGuardianFirstName;
		var legalGuardianRole:String = r.legalGuardianRole;
		var legalGuardianPhoneNumber:String = r.legalGuardianPhoneNumber;
		var legalGuardianEmail:String = r.legalGuardianEmail;

		var rider:RiderVO = new RiderVO(id, name, firstName, age, lastLessonDate, level, credit, address, notes, ffeLicence, ffeLicenceValidityYear,ffeLicenceNumber,legalGuardianName,legalGuardianFirstName,legalGuardianRole,legalGuardianPhoneNumber,legalGuardianEmail);
		riders.push(rider);
	}
	model.ridersListDP = new ArrayCollection(riders);

I am pretty sure there is a smarter way to do this (maybe using a for in loop or too nested loops) but my brain refuses to do that !

joshtynjala

Sorry for not being more clear. I meant the map() method of the Array class.

var riders:Array<RiderVO> = data.map((r:Dynamic) -> {
	var id:Int = Std.parseInt(r.id);
	var name:String = r.name;
	var firstName:String = r.firstName;
	var age:Int = Std.parseInt(r.age);
	var lastLessonDate:Int = Std.parseInt(r.lastLessonDate);
	var level:Int = Std.parseInt(r.level);
	var credit:Int = Std.parseInt(r.credit);
	var address:String = r.address;
	var notes:String = r.notes;
	var ffeLicence:Bool = stringToBool(r.ffeLicence);
	var ffeLicenceValidityYear:Int = Std.parseInt(r.ffeLicenceValidityYear);
	var ffeLicenceNumber:String = r.ffeLicenceNumber;
	var legalGuardianName:String = r.legalGuardianName;
	var legalGuardianFirstName:String = r.legalGuardianFirstName;
	var legalGuardianRole:String = r.legalGuardianRole;
	var legalGuardianPhoneNumber:String = r.legalGuardianPhoneNumber;
	var legalGuardianEmail:String = r.legalGuardianEmail;

	return new RiderVO(id, name, firstName, age, lastLessonDate, level, credit, address, notes, ffeLicence, ffeLicenceValidityYear,ffeLicenceNumber,legalGuardianName,legalGuardianFirstName,legalGuardianRole,legalGuardianPhoneNumber,legalGuardianEmail);
});