IOS/Objective-C/Swift/Speech: 在声明 SFSpeech 识别器变量时指定语言环境

IOS/Objective-C/Swift/Speech: Specify Locale when declaring SFSpeech Recognizer variable

我正在尝试将我刚刚学习的一些 Swift 翻译成 Objective-C 用于语音项目。

Swift 显然允许您在声明变量时指定 speechRecognizer 的语言环境,如下所示:

private let speechRecognizer = SFSpeechRecognizer(locale: Locale.init(identifier: "en-US"))

是否可以在 Objective-C 中执行此操作?现在我在接口中声明了一个变量:

SFSpeechRecognizer *speechRecognizer;

稍后再设置语言环境:

speechRecognizer = [[SFSpeechRecognizer alloc] initWithLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en-US"]];

理想情况下,我想在声明的一开始就这样做,但我不清楚 Swift 和 Objective-C 之间的区别。

感谢您的任何建议或见解。

考虑按以下顺序构建的 Swift 调用:

// Create a Locale object for US English
let locale = Locale.init(identifier: "en-US")
// Create a speech recognizer object for US English
let speechRecognizer = SFSpeechRecognizer(locale: locale)

然后将 Swift 代码与 Objective-C 进行比较:

// Here you are create an uninitialized variable of type SFSpeechRecognizer
// this will then hold the SFSpeechRecognizer when you initialize it in the next line
SFSpeechRecognizer *speechRecognizer;
// This is accomplishing the same logic as the above Swift call
speechRecognizer = [[SFSpeechRecognizer alloc] initWithLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en-US"]];

如果您希望将 objective-c 调用写成一行,您可以将其重写为如下所示:

SFSpeechRecognizer *speechRecognizer = [[SFSpeechRecognizer alloc] initWithLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en-US"]];

这两种方法都没有错,只是Swift可以推断变量类型,所以在启动语音识别器之前不需要创建空变量。 Objective-C 可以 NOT 推断变量类型,因此命令可能被拆分只是为了让行更短一些。