如何将多个枚举值作为函数参数传递 [英] How to pass multiple enum values as a function parameter

问题描述

我将如何执行以下操作 - 在 swift 中将两个 NSStringDrawing 选项作为函数参数传递:

How would I do the following - passing two NSStringDrawing options as a function parameter in swift:

CGRect boundingRect = [string boundingRectWithSize:CGSizeMake(280.0, NSIntegerMax)
                                                      options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
                                                   attributes:options context:nil];

推荐答案

在 Swift 3.0 中:

let options: NSStringDrawingOptions = [.usesLineFragmentOrigin, .usesFontLeading]

<小时>

这是在 Swift 2.0 中使用选项枚举的方式:

let options: NSStringDrawingOptions = [.UsesLineFragmentOrigin, .UsesFontLeading]

<小时>

问题有已在 iOS 8.3 SDK Beta 1 (12F5027d) 中解决:

修改后的NSStringDrawingOptions [struct]

Modified NSStringDrawingOptions [struct]

• 来自:enum NSStringDrawingOptions : Int
• 收件人:struct NSStringDrawingOptions : RawOptionSetType

你现在可以写:

let options : NSStringDrawingOptions = .UsesLineFragmentOrigin | .UsesFontLeading

<小时>

经过一些研究和@Anton Tcholakov 的评论":

---

After some research and and @Anton Tcholakov's "comment":

1. 如果您的目标是 OS X 10.10，这样做很简单:

1. If you're targeting OS X 10.10, this is as simple way to do it:

let size = CGSize(width: 280, height: Int.max)
let options : NSStringDrawingOptions = .UsesLineFragmentOrigin | .UsesFontLeading

let boundingRect = string.bridgeToObjectiveC().boundingRectWithSize(size, options: options, attributes: attributes, context: nil)

但是，在 iOS 8 SDK(在当前种子中)中，存在一个错误，其中 NSStringDrawingOptions 被移植到 Swift 作为 enum : Int，而不是struct : RawOptionSet.您应该向 Apple 发送错误报告，说明这个严重的问题.

However, in iOS 8 SDK (in the current seed), there's a bug, where NSStringDrawingOptions is ported to Swift as enum : Int, instead of struct : RawOptionSet. You should send a bug report to Apple describing this serious problem.

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