Swift CoreMotion在后台检测设备上的Tap或Knock

Question

我目前正在构建我的第一个iOS Swift应用程序,使用此应用程序我想在应用程序在后台运行时执行操作.

一旦用户在设备上点击两次,就需要执行该操作.

我启用了后台模式:应用功能中的位置更新

并在AppDelegate中设置AccelerometerUpdatesToQueue函数:

let manager = CMMotionManager()

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.

if manager.accelerometerAvailable {
    manager.accelerometerUpdateInterval = 0.01
    manager.startAccelerometerUpdatesToQueue(NSOperationQueue.mainQueue()) {
        [weak self] (data: CMAccelerometerData!, error: NSError!) in

        println(data.acceleration.z)
    }
}

     return true
}

控制台按预期打印出acceleration.z值,但是一旦按下主页按钮,控制台就会打印停止.

我在网上搜索了一个关于如何做到这一点的示例代码,我知道这是可能的...因为我们都知道应用程序"Knock Knock to unlock",但我似乎无法找到一段示例代码对斯威夫特来说.

Answer 1

我得到了它的工作!这是我的解决方案,随意提出改进:)

class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    let manager = CMMotionManager()
    var knocked : Bool = false
    let motionUpdateInterval : Double = 0.05
    var knockReset : Double = 2.0

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

        if manager.deviceMotionAvailable {
            manager.deviceMotionUpdateInterval = motionUpdateInterval // seconds

            manager.startDeviceMotionUpdatesToQueue(NSOperationQueue.mainQueue()) {
                [weak self] (data: CMDeviceMotion!, error: NSError!) in


                if (data.userAcceleration.z < -0.7) || (data.userAcceleration.z > 0.7) { // Check if device is knocked

                    // Check for double knock
                    if self!.knocked == false {
                        // First knock
                        println("First Knock")
                        self!.knocked = true

                    }else{
                        // Second knock
                        println("Double Knocked")
                        self!.knocked = false
                        self!.knockReset = 2.0

                        // Action:
                    }
                }

                // Countdown for reset action (second knock must be within the knockReset limit)
                if (self!.knocked) && (self!.knockReset >= 0.0) {

                    self!.knockReset = self!.knockReset - self!.motionUpdateInterval

                }else if self!.knocked == true {
                    self!.knocked = false
                    self!.knockReset = 2.0
                    println("Reset")
                }

            }
        }

        return true
    }