当需要判断屏幕方向时，我们通常使用UIDevice或者statusBar，但是还有一种方法就是使用陀螺仪来进行判断。上代码：

初始化motionManager和timer计时器

    let motionManager = CMMotionManager()
    var timer: Timer!
    
        motionManager.startAccelerometerUpdates()
        motionManager.startGyroUpdates()
        motionManager.startMagnetometerUpdates()
        motionManager.startDeviceMotionUpdates()
        
       //注册timer监听
        timer = Timer.scheduledTimer(timeInterval: 3.0, target: self, selector: #selector(ViewController.update), userInfo: nil, repeats: true)

update函数实现

  
    @objc func update() {
        if let accelerometerData = motionManager.accelerometerData {
            print(accelerometerData)
        }
        if let gyroData = motionManager.gyroData {
            print(gyroData)
        }
        if let magnetometerData = motionManager.magnetometerData {
            print(magnetometerData)
        }
        var result = "unknow"

        if let motion = motionManager.deviceMotion {
            //print(deviceMotion)
            let x = motion.gravity.x
            
            let y = motion.gravity.y
            
            if fabs(y) >= fabs(x) {
                
                if y >= 0 {
                    result =  "updown"
                    // UIDeviceOrientationPortraitUpsideDown;
                    
                } else {
                    result =  "updown"
                    // UIDeviceOrientationPortrait;
                    
                }
                
            } else {
                
                if x >= 0 {
                    result = "right"
                    // UIDeviceOrientationLandscapeRight;
                    
                } else {
                    result = "left"
                    // UIDeviceOrientationLandscapeLeft;
                    
                }
                
            }
            print(result)
        }
    }