iOS WiFi - NEHotspotHelper

最近项目有个Heatmap的功能，大致就是需要扫描附近WiFi网络，并且获取他们的信号强度，BSSID， SSID、加密等级等的功能。

技术选型：

通过一顿搜索，得知WiFi可以通过NEHotspotHelper 去获取对应的信息。
支持的信息如下：

@available(iOS 9.0, *)
open class NEHotspotNetwork : NSObject {

    /**
     * @property SSID
     * @discussion The SSID of the Wi-Fi network.
     */
    @available(iOS 9.0, *)
    open var ssid: String { get }

    /**
     * @property BSSID
     * @discussion The BSSID of the Wi-Fi network.
     */
    @available(iOS 9.0, *)
    open var bssid: String { get }

    /**
     * @property securityType
     * @discussion The security type of the Wi-Fi network.
     */
    @available(iOS 15.0, *)
    open var securityType: NEHotspotNetworkSecurityType { get }

    
    @available(iOS 14.0, *)
    open class func fetchCurrent(completionHandler: @escaping (NEHotspotNetwork?) -> Void)

   
    @available(iOS 14.0, *)
    open class func fetchCurrent() async -> NEHotspotNetwork?
}
@available(iOS 9.0, *)
extension NEHotspotNetwork {

    /**
     * @property signalStrength
     * @discussion
     *   The signal strength for the Wi-Fi network. The value lies within
     *   the range 0.0 (weak/no signal) to 1.0 (strong signal).
     */
    @available(iOS 9.0, *)
    open var signalStrength: Double { get }

    /**
     * @property secure
     * @discussion Indicates whether the network is secure
     */
    @available(iOS 9.0, *)
    open var isSecure: Bool { get }

    /**
     * @property autoJoined
     * @discussion
     *   Indicates whether the network was joined automatically
     *   (YES) or joined by the user (NO).
     */
    @available(iOS 9.0, *)
    open var didAutoJoin: Bool { get }

    /**
     * @property justJoined
     * @discussion
     *   Indicates whether the network was just joined. Useful in the
     *   Maintaining state to differentiate whether the Maintain command
     *   is for the initial join, or the subsequent periodic callback.
     */
    @available(iOS 9.0, *)
    open var didJustJoin: Bool { get }

    /**
     * @property chosenHelper
     * @discussion
     *   Indicates whether the HotspotHelper is the chosen helper for
     *   the network. The NEHotspotNetwork must have been instantiated via a
     *   call to the +[NEHotspotHelper supportedNetworkInterfaces] method. This
     *   is useful to restore state after the HotspotHelper application is quit
     *   and restarted.
     */
    @available(iOS 9.0, *)
    open var isChosenHelper: Bool { get }


    @available(iOS 9.0, *)
    open func setConfidence(_ confidence: NEHotspotHelperConfidence)

    @available(iOS 9.0, *)
    open func setPassword(_ password: String)
}

基本符合我们的需求预期，于是开整：

 if #available(iOS 13.0, *) {
            Task {
                if #available(iOS 14.0, *) {
                    NEHotspotNetwork.fetchCurrent { info in
                        self.wifiName = info?.ssid ?? ""
                        let signalStrength = info?.signalStrength
                        let helper = info?.isChosenHelper
                        result(true, self.wifiName, signalStrength ?? 0)
                    }
                } else {
                    // Fallback on earlier versions
                    XCGLog.info("不支持当前系统版本")
                    result(false, "", 0)
                    
                }
            }
        } else {
            // Fallback on earlier versions
            XCGLog.info("不支持当前系统版本")
            result(false, "", 0)
        }

注意

1. NEHotspotNetwork.fetchCurrent的系统支持版本最低是iOS14.0，其中 securityType需要iOS15.0才能支持。
2. 如果你按照上面操作，依然无法获取signalStrength,返回一直为0. 这时你需要看下isChosenHelper返回是否为false。如果是，那么恭喜，我们需要去官方开发者平台申请对应权限，才能够获取。
3. 获取权限方式，参考NEHotspotHelper权限获取方式，挺麻烦的，后面如果我通过了，再来反馈申请时间多长。
   4.最后提醒，如果我们的目的是想表明当前网络好还是不好，苹果工程师不建议我们通过使用信号值这种方式去表现，建议通过文件测速的方式，去判断当前网络的有效可用性。相关论坛讨论发言稿地址参考 。 当然，如果只是简单的展现信号值，这种方式是可取的。