Syntax of Block in Swift

Question

I am trying to rewrite from Objective-C to Swift, I cannot work out the syntax or understand the docs Here is a simplified example in Objective-C I wrote: ``` [UIView animateWithDuration:10.0 animations:^{self.navigationController.toolbar.frame = CGRectMake(0,10,0,10);}]; ``` How do I write this in Swift? This is the template autocomplete gives: ``` UIView.animateWithDuration(duration: NSTimeInterval, animations: (() -> Void)) ```

Accepted Answer

Since the expected argument types and return type to the animations argument are known the compiler can infer them without a problem. This should work (though I don't have the playground available right at the moment:

```
UIView.animateWithDuration(10.0, animations: {
  self.navigationController.toolbar.frame = CGRect(x:0.0, y:10.0, width:10.0, height:0.0)
})
```

for more info about closures see the chapter in the swift docs

note about `CGRect()` - the developer docs show `CGRect()` being used in swift code. Perhaps it requires an import?

update for comments: you can also use a trailing closure like so:

```
UIView.animateWithDuration(10.0) {
  self.navigationController.toolbar.frame = CGRect(x:0.0, y:10.0, width:10.0, height:0.0)
}
```

Syntax of Block in Swift

Solution

Problem