How to implement range slider in Swift - ios

Question

I'm trying to implement Range Slider and I used custom control called NMRangeSlider.
But when I use it, the slider doesn't appear at all. Could it be also because it's all written in Objective-C?
This is how I've currently implemented it:
var rangeSlider = NMRangeSlider(frame: CGRectMake(16, 6, 275, 34))
rangeSlider.lowerValue = 0.54
rangeSlider.upperValue = 0.94
self.view.addSubview(rangeSlider)

Answer 1

To create a custom Range Slider I found a good solution here: range finder tutorial iOS 8 but I needed this in swift 3 for my project. I updated this for Swift 3 iOS 10 here:
in your main view controller add this to viewDidLayOut to show a range slider.
override func viewDidLayoutSubviews() {
let margin: CGFloat = 20.0
let width = view.bounds.width - 2.0 * margin
rangeSlider.frame = CGRect(x: margin, y: margin + topLayoutGuide.length + 170, width: width, height: 31.0)
}
create the helper function to print slider output below viewDidLayoutSubviews()
func rangeSliderValueChanged() { //rangeSlider: RangeSlider
print("Range slider value changed: \(rangeSlider.lowerValue) \(rangeSlider.upperValue) ")//(\(rangeSlider.lowerValue) \(rangeSlider.upperValue))
}
Create the file RangeSlider.swift and add this to it:
import UIKit
import QuartzCore
class RangeSlider: UIControl {
var minimumValue = 0.0
var maximumValue = 1.0
var lowerValue = 0.2
var upperValue = 0.8
let trackLayer = RangeSliderTrackLayer()//= CALayer() defined in RangeSliderTrackLayer.swift
let lowerThumbLayer = RangeSliderThumbLayer()//CALayer()
let upperThumbLayer = RangeSliderThumbLayer()//CALayer()
var previousLocation = CGPoint()
var trackTintColor = UIColor(white: 0.9, alpha: 1.0)
var trackHighlightTintColor = UIColor(red: 0.0, green: 0.45, blue: 0.94, alpha: 1.0)
var thumbTintColor = UIColor.white
var curvaceousness : CGFloat = 1.0
var thumbWidth: CGFloat {
return CGFloat(bounds.height)
}
override init(frame: CGRect) {
super.init(frame: frame)
trackLayer.rangeSlider = self
trackLayer.contentsScale = UIScreen.main.scale
layer.addSublayer(trackLayer)
lowerThumbLayer.rangeSlider = self
lowerThumbLayer.contentsScale = UIScreen.main.scale
layer.addSublayer(lowerThumbLayer)
upperThumbLayer.rangeSlider = self
upperThumbLayer.contentsScale = UIScreen.main.scale
layer.addSublayer(upperThumbLayer)
}
required init?(coder: NSCoder) {
super.init(coder: coder)
}
func updateLayerFrames() {
trackLayer.frame = bounds.insetBy(dx: 0.0, dy: bounds.height / 3)
trackLayer.setNeedsDisplay()
let lowerThumbCenter = CGFloat(positionForValue(value: lowerValue))
lowerThumbLayer.frame = CGRect(x: lowerThumbCenter - thumbWidth / 2.0, y: 0.0,
width: thumbWidth, height: thumbWidth)
lowerThumbLayer.setNeedsDisplay()
let upperThumbCenter = CGFloat(positionForValue(value: upperValue))
upperThumbLayer.frame = CGRect(x: upperThumbCenter - thumbWidth / 2.0, y: 0.0,
width: thumbWidth, height: thumbWidth)
upperThumbLayer.setNeedsDisplay()
}
func positionForValue(value: Double) -> Double {
return Double(bounds.width - thumbWidth) * (value - minimumValue) /
(maximumValue - minimumValue) + Double(thumbWidth / 2.0)
}
override var frame: CGRect {
didSet {
updateLayerFrames()
}
}
override func beginTracking(_ touch: UITouch, with event: UIEvent?) -> Bool {
previousLocation = touch.location(in: self)
// Hit test the thumb layers
if lowerThumbLayer.frame.contains(previousLocation) {
lowerThumbLayer.highlighted = true
} else if upperThumbLayer.frame.contains(previousLocation) {
upperThumbLayer.highlighted = true
}
return lowerThumbLayer.highlighted || upperThumbLayer.highlighted
}
func boundValue(value: Double, toLowerValue lowerValue: Double, upperValue: Double) -> Double {
return min(max(value, lowerValue), upperValue)
}
override func continueTracking(_ touch: UITouch, with event: UIEvent?) -> Bool {
let location = touch.location(in: self)
// 1. Determine by how much the user has dragged
let deltaLocation = Double(location.x - previousLocation.x)
let deltaValue = (maximumValue - minimumValue) * deltaLocation / Double(bounds.width - thumbWidth)
previousLocation = location
// 2. Update the values
if lowerThumbLayer.highlighted {
lowerValue += deltaValue
lowerValue = boundValue(value: lowerValue, toLowerValue: minimumValue, upperValue: upperValue)
} else if upperThumbLayer.highlighted {
upperValue += deltaValue
upperValue = boundValue(value: upperValue, toLowerValue: lowerValue, upperValue: maximumValue)
}
// 3. Update the UI
CATransaction.begin()
CATransaction.setDisableActions(true)
updateLayerFrames()
CATransaction.commit()
sendActions(for: .valueChanged)
return true
}
override func endTracking(_ touch: UITouch?, with event: UIEvent?) {
lowerThumbLayer.highlighted = false
upperThumbLayer.highlighted = false
}
}
Next add the thumb layer subclass file RangeSliderThumbLayer.swift and add this to it:
import UIKit
class RangeSliderThumbLayer: CALayer {
var highlighted = false
weak var rangeSlider: RangeSlider?
override func draw(in ctx: CGContext) {
if let slider = rangeSlider {
let thumbFrame = bounds.insetBy(dx: 2.0, dy: 2.0)
let cornerRadius = thumbFrame.height * slider.curvaceousness / 2.0
let thumbPath = UIBezierPath(roundedRect: thumbFrame, cornerRadius: cornerRadius)
// Fill - with a subtle shadow
let shadowColor = UIColor.gray
ctx.setShadow(offset: CGSize(width: 0.0, height: 1.0), blur: 1.0, color: shadowColor.cgColor)
ctx.setFillColor(slider.thumbTintColor.cgColor)
ctx.addPath(thumbPath.cgPath)
ctx.fillPath()
// Outline
ctx.setStrokeColor(shadowColor.cgColor)
ctx.setLineWidth(0.5)
ctx.addPath(thumbPath.cgPath)
ctx.strokePath()
if highlighted {
ctx.setFillColor(UIColor(white: 0.0, alpha: 0.1).cgColor)
ctx.addPath(thumbPath.cgPath)
ctx.fillPath()
}
}
}
}
Finally add the track layer subclass file RangeSliderTrackLayer.swift and add the following to it:
import Foundation
import UIKit
import QuartzCore
class RangeSliderTrackLayer: CALayer {
weak var rangeSlider: RangeSlider?
override func draw(in ctx: CGContext) {
if let slider = rangeSlider {
// Clip
let cornerRadius = bounds.height * slider.curvaceousness / 2.0
let path = UIBezierPath(roundedRect: bounds, cornerRadius: cornerRadius)
ctx.addPath(path.cgPath)
// Fill the track
ctx.setFillColor(slider.trackTintColor.cgColor)
ctx.addPath(path.cgPath)
ctx.fillPath()
// Fill the highlighted range
ctx.setFillColor(slider.trackHighlightTintColor.cgColor)
let lowerValuePosition = CGFloat(slider.positionForValue(value: slider.lowerValue))
let upperValuePosition = CGFloat(slider.positionForValue(value: slider.upperValue))
let rect = CGRect(x: lowerValuePosition, y: 0.0, width: upperValuePosition - lowerValuePosition, height: bounds.height)
ctx.fill(rect)
}
}
}
Build Run and Get:

Answer 2

UPDATE:
It did not show to me, because it was all white. So the solution, without using any other framework and sticking with this one - you need to set all the views for all the components and then it will display well:
I have tried to import it in Swift as I used it before in Objective-C code, but without any luck. If I set everything properly and add it either in viewDidLoad() or viewDidAppear(), nothing gets displayed. One thing is worth mentioning, though - when I enter View Debug Hierarchy, the slider actually is there on the canvas:
But it's simply not rendered with all the colors that I did set before adding in it to the view. For the record - this is the code I used:
override func viewDidAppear(animated: Bool) {
var rangeSlider = NMRangeSlider(frame: CGRectMake(50, 50, 275, 34))
rangeSlider.lowerValue = 0.54
rangeSlider.upperValue = 0.94
let range = 10.0
let oneStep = 1.0 / range
let minRange: Float = 0.05
rangeSlider.minimumRange = minRange
let bgImage = UIView(frame: rangeSlider.frame)
bgImage.backgroundColor = .greenColor()
rangeSlider.trackImage = bgImage.pb_takeSnapshot()
let trackView = UIView(frame: CGRectMake(0, 0, rangeSlider.frame.size.width, 29))
trackView.backgroundColor = .whiteColor()
trackView.opaque = false
trackView.alpha = 0.3
rangeSlider.trackImage = UIImage(named: "")
let lowerThumb = UIView(frame: CGRectMake(0, 0, 8, 29))
lowerThumb.backgroundColor = .whiteColor()
let lowerThumbHigh = UIView(frame: CGRectMake(0, 0, 8, 29))
lowerThumbHigh.backgroundColor = UIColor.blueColor()
rangeSlider.lowerHandleImageNormal = lowerThumb.pb_takeSnapshot()
rangeSlider.lowerHandleImageHighlighted = lowerThumbHigh.pb_takeSnapshot()
rangeSlider.upperHandleImageNormal = lowerThumb.pb_takeSnapshot()
rangeSlider.upperHandleImageHighlighted = lowerThumbHigh.pb_takeSnapshot()
self.view.addSubview(rangeSlider)
self.view.backgroundColor = .lightGrayColor()
}
Using the method for capturing the UIView as UIImage mentioned in this question:
extension UIView {
func pb_takeSnapshot() -> UIImage {
UIGraphicsBeginImageContextWithOptions(bounds.size, false, UIScreen.mainScreen().scale)
drawViewHierarchyInRect(self.bounds, afterScreenUpdates: true)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
}
}
Other solution:
You can also try sgwilly/RangeSlider instead, it's written in Swift and therefore you won't even need a Bridging Header.

Answer 3

try this code :
override func viewDidLayoutSubviews() {
let margin: CGFloat = 20.0
let width = view.bounds.width - 2.0 * margin
rangeSlider.frame = CGRect(x: margin, y: margin + topLayoutGuide.length,
width: width, height: 31.0)
}

Answer 4

I implemented the range slider using :
https://github.com/Zengzhihui/RangeSlider
In the GZRangeSlider class, there is a method called :
private func setLabelText()
In that method, just put :
leftTextLayer.frame = CGRectMake(leftHandleLayer.frame.minX - 0.5 * (kTextWidth - leftHandleLayer.frame.width), leftHandleLayer.frame.minY - kTextHeight, kTextWidth, kTextHeight)
rightTextLayer.frame = CGRectMake(rightHandleLayer.frame.minX - 0.5 * (kTextWidth - leftHandleLayer.frame.width), leftTextLayer.frame.minY, kTextWidth, kTextHeight)
to animate the lower and upper labels..
This one is working well for me and its in swift.. just try it..