/
TiltingScrollView.swift
67 lines (55 loc) · 2.22 KB
/
TiltingScrollView.swift
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//
// TiltingScrollView.swift
// TiltingScrollView
//
// Created by Evan Dekhayser on 3/6/16.
// Copyright © 2016 Evan Dekhayser. All rights reserved.
//
import UIKit
import CoreMotion
public class TiltingScrollView: UIScrollView {
public var tiltingFactor: CGFloat = 20
private var motionManager = CMMotionManager()
private var initialAcceleration: Double!
public func calibrate(){
if UIInterfaceOrientationIsPortrait(UIApplication.sharedApplication().statusBarOrientation){
initialAcceleration = motionManager.accelerometerData!.acceleration.y
} else {
initialAcceleration = motionManager.accelerometerData!.acceleration.x
}
}
public func beginTiltToScroll(){
guard motionManager.accelerometerAvailable else {
print("TiltingScrollView: Accelerometer is not available on this device.")
return
}
scrollEnabled = false
motionManager.accelerometerUpdateInterval = 0.001
motionManager.startAccelerometerUpdatesToQueue(NSOperationQueue.mainQueue()) { (data, error) in
guard let data = data else { return }
if self.initialAcceleration == nil{
self.calibrate()
}
let yAcceleration: Double
if UIInterfaceOrientationIsPortrait(UIApplication.sharedApplication().statusBarOrientation){
yAcceleration = self.initialAcceleration - data.acceleration.y
} else {
yAcceleration = self.initialAcceleration - data.acceleration.x
}
let yOffset = self.tiltingFactor * CGFloat(yAcceleration)
self.contentOffset = CGPoint(x: self.frame.origin.x, y: max(min(self.contentOffset.y - yOffset, self.contentSize.height - self.frame.size.height), 0))
}
}
public func setTiltingEnabled(tiltingEnabled: Bool){
if tiltingEnabled{
if !motionManager.accelerometerActive{
calibrate()
beginTiltToScroll()
}
scrollEnabled = false
} else {
motionManager.stopAccelerometerUpdates()
scrollEnabled = true
}
}
}