[英]IOS/Objective-C/Swift: Handling UnsafePointer in Swift
In an Objective-C method I use for speech recognition, I have some code to measure the speakers volume.在我用于语音识别的 Objective-C 方法中,我有一些代码来测量扬声器的音量。 When I try to translate it to Swift, however, I'm having trouble with how Swift handles pointers relative to Objective-C.但是,当我尝试将其转换为 Swift 时,我遇到了 Swift 如何处理相对于 Objective-C 的指针的问题。
Here is the Objective-C doe:这是Objective-C doe:
AVAudioFormat *recordingFormat = [inputNode outputFormatForBus:0];
[inputNode installTapOnBus:0 bufferSize:1024 format:recordingFormat block:^(AVAudioPCMBuffer * _Nonnull buffer, AVAudioTime * _Nonnull when) {
if ([buffer floatChannelData] != nil) {//open 1 in block
float volume = fabsf(*buffer.floatChannelData[0]);
}
}];
Trying to do this in Swift does:尝试在 Swift 中执行此操作会:
let data = UnsafeMutablePointer<Float>(buffer.floatChannelData)
if let data = &buffer.floatChannelData?[0] {
let _ : Float = data[0]
}
give multiple errors.给出多个错误。
Thanks in advance for any suggestions.在此先感谢您的任何建议。
I do not understand why you need data
.我不明白你为什么需要data
。
You can write something like this:你可以这样写:
if buffer.floatChannelData != nil {
let volume = buffer.floatChannelData![0].pointee
//...
}
Or more swifty as follows:或者更快捷如下:
if let floatChannelPointers = buffer.floatChannelData {
let volume = floatChannelPointers[0].pointee
//...
}
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