UIDynamicAnimator - 基于设备运动滚动移动视图

Question

我正在尝试读取我的设备运动，特别是设备处于横向模式时的滚动，并将返回的角度转换为 UIView 的位置（基本上在屏幕上制作“级别”以向用户显示手机处于理想的角度）。

此代码给出了所需的滚动结果，但由于某种原因没有按预期更新 levelIndicator 视图。我没有收到任何错误，所以我一定是错误地使用了 UIPushBehavior，但我不清楚我需要修复什么。我不确定在 Motion Update 上将指示器设置为新的 Y 位置。

import UIKit
import AVFoundation
import CoreMotion
import GLKit

class CameraView: BaseViewController {

    var animator : UIDynamicAnimator? = nil;
    var currentRoll     : Float = 0.0;
    let manager = CMMotionManager()
    let motionQueue = NSOperationQueue()

    var countingDown:Bool = false;

    @IBOutlet weak var levelIndicator: UIView!
    @IBOutlet weak var level: UIView!

    override func viewDidLoad() {
        super.viewDidLoad()
        self.animator = UIDynamicAnimator(referenceView: self.level)
        let continuousPush: UIPushBehavior = UIPushBehavior(items: [levelIndicator], mode: UIPushBehaviorMode.Continuous)
        self.animator?.addBehavior(continuousPush)
    }

    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(true)
        self.startReadingMotion()
    }

    func startReadingMotion() {
        if manager.deviceMotionAvailable {
            manager.deviceMotionUpdateInterval = 0.1
            manager.startDeviceMotionUpdatesToQueue(motionQueue, withHandler: checkStability)
        }
    }

    func checkStability(motion: CMDeviceMotion!, error: NSError!) {

        var orientation = UIDevice.currentDevice().orientation

        if (error != nil) {
            NSLog("\(error)")
        }

        var quat = motion.attitude.quaternion

        //We Probably only need to check the Angle of the Roll (Phone Angle in Landscape mode)
        var roll = GLKMathRadiansToDegrees(Float(atan2(2*(quat.y*quat.w - quat.x*quat.z), 1 - 2*quat.y*quat.y - 2*quat.z*quat.z))) ;

        //Other Angles are available for more refinement to stabilty

        //var pitch = GLKMathRadiansToDegrees(Float(atan2(2*(quat.x*quat.w + quat.y*quat.z), 1 - 2*quat.x*quat.x - 2*quat.z*quat.z)));
        //var yaw = GLKMathRadiansToDegrees(Float(asin(2*quat.x*quat.y + 2*quat.w*quat.z)));

        if(orientation == .LandscapeLeft) {
            roll *= -1
        }

        if(roll > 100) {
            roll = 100
        } else if(roll < 0) {
            roll = 0
        }

        self.currentRoll = roll

        var pos = self.level.frame.height*CGFloat(roll/100)
        var rect = self.levelIndicator.frame
        rect.origin.y = pos
        self.levelIndicator.frame = rect

        if(roll > 85 && roll < 87) {
            if(!countingDown) {
                //This is the ideal roll position of the phone
                self.levelIndicator.backgroundColor = UIColor.redColor()
            }
        } else {
            countingDown = false;
            self.levelIndicator.backgroundColor = UIColor.blackColor()
        }
    }

    func stopReading() {
        manager.stopDeviceMotionUpdates();
    }
}

Answer 1

对于任何感兴趣的人，我最终没有为此使用 UIDynamicAnimator，但找到了一个更简单的解决方案，转换返回的姿态变化弧度并使用它来检查设备的滚动。还向主队列添加了调度以更新屏幕级别的 UI。

func checkStability(motion: CMDeviceMotion!, error: NSError!) {

    var orientation = UIDevice.currentDevice().orientation

    if (error != nil) {
        NSLog("\(error)")
    }

    var roll:Float = 0.0
    if let attitude = motion.attitude {
        roll = GLKMathRadiansToDegrees(Float(attitude.roll))
    }

    dispatch_async(dispatch_get_main_queue()) {
        var pos = self.level.frame.height*CGFloat(roll/100)
        var rect = self.levelIndicator.frame
        rect.origin.y = self.level.frame.height-pos
        self.levelIndicator.frame = rect

        if(roll > 85 && roll < 90) {
            //This is where I want the Roll to be
        } else {
            //The Roll is not correct yet
        }
    }
}