CODEWITHSUNDEEP
swift
doubleforte
doubleforte

Reputation: 103

Can't figure out how to add two CGFloats?

I'm getting this error "Cannot invoke '+' wit an argument list of type '(CGFloat, CGFloat)' when using this Swift code.

var added = CGFloat(gestureRecognizer.view?.center.y) + CGFloat(translation.y)

What am I doing wrong. I have two floats and I want to add them together.

Upvotes: 0

Views: 804

Answers (1)

Alex Wayne
Alex Wayne

Reputation: 187134

This line here:

gestureRecognizer.view?.center.y

Can be thought of as an expression that returns a CGFloat? optional. If view is nil, it returns nil. If view has a value, it drills in. And CGFloat(nil) is a compile error.

var added = CGFloat(gestureRecognizer.view!.center.y) + CGFloat(translation.y)
//                                        ^ ! instead of ?

You really want to unwrap it here. Because if view is nil you pass nil to CGFloat() which isn't gonna be cool. But you do have to think about what might happen when view is nil.

Perhaps that will never happen in the flow of your program, I don't know. But if it is nil that will cause a runtime crash.

Upvotes: 3

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