“Swift automatically bridges between the String type and the NSString class. This means that anywhere you use an NSString object,you can use a Swift String type instead and gain the benefits of both types—the String type’s interpolation and Swift-designed APIs and the NSString class’s broad functionality. For this reason,you should almost never need to use the NSString class directly in your own code. In fact,when Swift imports Objective-C APIs,it replaces all of the NSString types with String types. When your Objective-C code uses a Swift class,the importer replaces all of the String types with NSString in imported API.

要启用字符串桥接,只需导入基础“.

我做了这个…考虑：

import Foundation

var str = "Hello World"

var range = str.rangeOfString("e")

// returns error: String does not contain member named: rangeOfString()

然而：

var str = "Hello World" as NSString

var range = str.rangeOfString("e")

// returns correct (2,1)

我错过了什么吗？