Swift中Block的语法 [英] Syntax of Block in Swift

问题描述

我正在尝试从Objective-C重写为Swift，我无法弄清楚语法或理解文档

I am trying to rewrite from Objective-C to Swift, I cannot work out the syntax or understand the docs

这是Objective-C中的简化示例写道：

Here is a simplified example in Objective-C I wrote:

[UIView animateWithDuration:10.0 animations:^{self.navigationController.toolbar.frame = CGRectMake(0,10,0,10);}];

如何在Swift中写这个？

How do I write this in Swift?

这是模板自动完成给出：

This is the template autocomplete gives:

UIView.animateWithDuration(duration: NSTimeInterval, animations: (() -> Void))

推荐答案

由于预期的参数类型和动画参数的返回类型是已知的，编译器可以毫无问题地推断它们。这应该有用（虽然我目前没有可用的游乐场：

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)
})

有关闭包的更多信息，请参阅 swift docs中的章节

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

关于 CGRect（）的注释 - 开发人员文档显示 CGRect（）在swift代码中使用。也许它需要导入？

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

更新注释：你也可以使用这样的尾随闭包：

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)
}

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