CODEWITHSUNDEEP
objective-cswiftoption-type
theblindprophet
theblindprophet

Reputation: 7937

How can I cast NSDecimalNumber from Objective-C to Float in Swift without compiler warnings

I have this function in Swift 3:

if let rating = product.rating as? Float {
    itemRating.update(rating) //sets item rating. Number of stars
}

where product.rating is a NSDecimalNumber coming from an Objective C function.

I am in the midst of converting everything to Swift.

Every time I call itemRating.update(rating) it gives the notorious:

fatal error: unexpectedly found nil while unwrapping an Optional value

The only way I got it to work was by this ugly implementation:

if let rating = product.rating as Decimal?, let floatRating = rating as? Float {
    itemRating.update(floatRating) //sets item rating. Number of stars
}

which always gives a warning:

Cast from 'Decimal' to unrelated type 'Float' always fails.

Every other way I tried fails with the above error.

Here is the definition for update():

- (void)updateRating:(float)inRating;

What is going on with this?

Upvotes: 0

Views: 354

Answers (1)

vadian
vadian

Reputation: 285160

if product.rating is really a NSDecimalNumber (not (NS)Decimal) instance just use optional binding to unwrap the optional then get the floatValue since NSDecimalNumber inherits from NSNumber.

if let rating = product.rating {
    itemRating.update(rating.floatValue)
}

Upvotes: 3

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