为啥没有调用协议函数

Posted 2023-03-05

【中文标题】为啥没有调用协议函数

【英文标题】：Why is the protocol function not being called为什么没有调用协议函数

【发布时间】：2014-07-14 22:42:34

【问题描述】：

我有一个实现协议的文件和另一个调用该协议的文件

 //
//  DeviceBLE.swift
//

import Foundation
import CoreBlueTooth
import QuartzCore
import UIKit

class DeviceBLE: NSObject, CBCentralManagerDelegate, CBPeripheralDelegate 

    var centralManager : CBCentralManager!

    init() 
        super.init()
        centralManager = CBCentralManager(delegate: self, queue: nil)
    

    func centralManagerDidUpdateState(central: CBCentralManager!)
        // Determine the state of the peripheral
        if (central.state == .PoweredOff) 
            println("CoreBluetooth BLE hardware is powered off")
        
        else if (central.state == .PoweredOn) 
            println("CoreBluetooth BLE hardware is powered on and ready")
            //            connectPeripheral(_ peripheral: CBPeripheral!,
            //                options options: [NSObject : AnyObject]!)
        
        else if (central.state == .Unauthorized) 
            println("CoreBluetooth BLE state is unauthorized")
        
        else if (central.state == .Unknown) 
            println("CoreBluetooth BLE state is unknown")
        
        else if (central.state == .Unsupported) 
            println("CoreBluetooth BLE hardware is unsupported on this platform")
        
    

这是调用文件

//  ViewController.swift
//  BleTest
import Foundation
import CoreBlueTooth
import QuartzCore
import UIKit

class ViewController: UIViewController 

    override func viewDidLoad() 
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        var myBle = DeviceBLE()
     

    override func didReceiveMemoryWarning() 
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    

问题是当 DeviceBle 被实例化时，centralManagerDidUpdateState 永远不会被调用。我不明白我做错了什么。有人可以帮忙吗？

【参考方案1】：

可能是您将myBle 设置为局部变量，因此在viewDidLoad 方法执行结束时，DeviceBLE 被释放。尝试将 myBle 设为 ViewController 类的实例变量。

class ViewController: UIViewController 
    var myBle: CBCentralManager?

    override func viewDidLoad() 
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        self.myBle = DeviceBLE()
      

    override func didReceiveMemoryWarning() 
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    

另外，在您的委托方法中。最好使用switch 语句而不是多个if 语句。

【讨论】：

谢谢。这解决了这个问题。它不会让我投票给你。不过还是谢谢。

您能否通过单击我帖子左上角的对勾将答案标记为正确？