Cannot pass in struct to ChartDataEntry

[YileiHeOMT]

In the class ChartDataEntry:
The initialiser is

public init(value: Double, xIndex: Int, data: AnyObject?)
    {
        super.init()

        self.value = value
        self.xIndex = xIndex
        self.data = data
    }

For the third parameter, I can only pass in a class type object. That makes it impossible to pass in a struct or a tuple. So I recommend changing the type or data to Any?

[liuxuan30]

well why you want to use struct or tuple for data? you can convert it to Object and move on.
BTW, struct and class are different at low level of swift (value type and reference type). Changing to struct needs more considerations and changes and I just can't see what's the benefit

[YileiHeOMT]

@liuxuan30
My case is:
In my line chart, the value for each XIndex is a double type value(certainly it is). When I click on the chart, I want the pop-up overlay(aka. marker) to show more details like "date".

Let's see a example:

struct CarSalesHistoryItem {
 var profit:Double
 var date: NSDate
 var numberOfCarsSold:Int
//...
}

In the chart, I get a array of CarSalesHistoryItem. I use profit as yAxis value and date as xAxis value. When I tap on a point, I want it to display all the information of that history item.
Then in the method public override func refreshContent(entry entry: ChartDataEntry, highlight: ChartHighlight) of ChartMarker, I can get the data from entry.data for display.

You may say, changing CarSalesHistoryItem to class type will fix it. But in many projects, we use struct as data model. Because struct is "value type" while class is "reference type".

[liuxuan30]

yeah, then it's your duty to take care of them. It's very easy for you to sub class the entry class that can take a struct and send back to you, or write an extension to convert between struct and class, or at least you can add a new init method for ChartDataEntry

[YileiHeOMT]

Fair enough

[pmairoldi]

I'm not sure but I believe it might be anyobject for technical reasons. I don't think any translates to objc