CODEWITHSUNDEEP
swiftif-statement
M Swapnil
M Swapnil

Reputation: 2381

how to give nil parameter in if condition in swift?

In Objective-C:

if (!myImageView) {
    NSLog(@"hdhd");
}
else {
 //DO SOMETHING
}

But in Swift:

if (!myImageView) {  
   println("somethin")
}
else {
   println("somethin")
}

This code is giving me the error:

Could not find an overload for '!' that accepts the supplied arguments'

myImageView is class variable UIImageView.

What should I do?

Upvotes: 0

Views: 523

Answers (3)

Clafou
Clafou

Reputation: 15400

If your variable is of type UIImageView then it cannot ever be nil. However if you want your code to be equivalent to your Objective-C code, change the variable type to UIImageView? (an optional type) and replace: 

if (!myImageView) {

with:

if (myImageView == nil) {

Upvotes: 1

nhgrif
nhgrif

Reputation: 62052

Usually, the best way to deal with checking variables for nil in Swift is going to be with the if let or if var syntax.

if let imageView = self.imageView {
    // self.imageView is not nil
    // we can access it through imageView
} else {
    // self.imageView is nil
}

But for this to work (or for comparison against nil with either == nil or != nil), self.imageView must be an optional (implicitly unwrapped or otherwise).

Non-optionals can not be nil, and therefore the compiler will not let you compare them against nil. They'll never be nil.

So if if let imageView = self.imageView or self.imageView != nil or self.imageView == nil are giving you errors, it's almost certainly because self.imageView is not an optional.

Upvotes: 2

matthias
matthias

Reputation: 947

Test for myImageView != nil or myImageView.image != nil.

Upvotes: 0

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