Swift 上的 USB 连接委托

使用Swift编程语言，我们可以通过USB连接委托来实现与USB设备的通信。USB连接委托提供了一种简单而强大的方式，使我们能够与外部设备进行数据交换和控制。

swift
import Foundation
import ExternalAccessory
class USBConnectionDelegate: NSObject, EAAccessoryDelegate, EASessionDelegate {
    var accessory: EAAccessory?
    var session: EASession?
    
    func setupConnection() {
        let connectedAccessories = EAAccessoryManager.shared().connectedAccessories
        for accessory in connectedAccessories {
            if accessory.protocolStrings.contains("com.example.usbprotocol") {
                self.accessory = accessory
                break
            }
        }
        
        if let accessory = self.accessory {
            accessory.delegate = self
            self.session = EASession(accessory: accessory, forProtocol: "com.example.usbprotocol")
            self.session?.inputStream?.delegate = self
            self.session?.inputStream?.schedule(in: .current, forMode: .default)
            self.session?.inputStream?.open()
            self.session?.outputStream?.delegate = self
            self.session?.outputStream?.schedule(in: .current, forMode: .default)
            self.session?.outputStream?.open()
        }
    }
    
    // 实现委托方法和其他相关方法
    // ...
    
    func sendData(data: Data) {
        if let outputStream = self.session?.outputStream {
            outputStream.write(data: data, maxLength: data.count)
        }
    }
    
    func receiveData() -> Data? {
        guard let inputStream = self.session?.inputStream else {
            return nil
        }
        
        var buffer = [UInt8](repeating: 0, count: 1024)
        let bytesRead = inputStream.read(&buffer, maxLength: buffer.count)
        
        if bytesRead > 0 {
            return Data(bytes: buffer, count: bytesRead)
        }
        
        return nil
    }
}
// 在应用程序的主要功能模块中使用USB连接委托
let delegate = USBConnectionDelegate()
delegate.setupConnection()
// 发送数据
let dataToSend = "Hello, USB device!".data(using: .utf8)
delegate.sendData(data: dataToSend!)
// 接收数据
if let receivedData = delegate.receiveData() {
    let receivedString = String(data: receivedData, encoding: .utf8)
    print(receivedString)
}