PositionScrollView

Position Scroll View is pure Swift UI Scroll View which can get or move scroll position.

Features

• Get scroll position of scroll
• Vertical, Horizontal, Two Dimensional scroll
• Move scroll position by code
• Stick edge of scroll page or follow momentum after scroll ends.

Requirements

• Xcode 11.6+
• Swift 5.2+

Install

SwiftPackageManager

Add https://github.com/kazuooooo/PositionScrollView in the Swit Package Magener tab in Xcode

CocoaPods

pod ‘PositionScrollView’ 

Usage

PositionScrollView divides whole target view to pages and units to treat scroll position easily.

And you can get/set position in each ranges.

Minimal horizontal scroll view example below.

import Foundation
import SwiftUI
import PositionScrollView

/// Extended ScrollView which can controll position
public struct MinimalHorizontalExample: View, PositionScrollViewDelegate {
    /// Page size of Scroll
    var pageSize = CGSize(width: 200, height: 300)
    
    // Create PositionScrollViewModel
    // (Need to create in parent view to bind the state between this view and PositionScrollView)
    @ObservedObject var psViewModel = PositionScrollViewModel(
        pageSize: CGSize(width: 200, height: 300),
        horizontalScroll: Scroll(
            scrollSetting: ScrollSetting(pageCount: 5, afterMoveType: .fitToNearestUnit),
            pageLength: 200
        )
    )
    
    public var body: some View {
        return VStack {
            PositionScrollView(
                viewModel: self.psViewModel,
                delegate: self
            ) {
                HStack(spacing: 0) {
                    ForEach(0...4, id: \.self){ i in
                        ZStack {
                            Rectangle()
                                .fill(Color.gray)
                                .border(Color.white)
                                .frame(
                                    width: self.pageSize.width, height: self.pageSize.height
                            )
                            Text("Page\(i)")
                                .foregroundColor(Color.white)
                                .font(.system(size: 24, weight: .heavy, design: .default))
                        }
                    }
                    
                }
            }
            Text("page: \(self.psViewModel.horizontalScroll?.page ?? 0)")
            Text("position: \(self.psViewModel.horizontalScroll?.position ?? 0)")
        }
    }
    
    struct SampleView_Previews: PreviewProvider {
        static var previews: some View {
            return MinimalHorizontalExample()
        }
    }
    
    // Delegate methods of PositionScrollView
    public func onScrollStart() {
        print("onScrollStart")
    }
    public func onChangePage(page: Int) {
        print("onChangePage to page: \(page)")
    }
    
    public func onChangePosition(position: CGFloat) {
        print("position: \(position)")
    }
    
    public func onScrollEnd() {
        print("onScrollEnd")
    }
}

API Details

ScrollSetting

Setting variables

ValueName	Type	Default	Detail
pageCount*	Int	-	Count of page
initialPage	Int	0	Initial page of scroll
unitCountInPage	Int	1	Unit count of single page
afterMoveType	AfterScrollEndsBehavior	.stickToNearestUnitEdge	Behavior of scroll move after scroll ends stickToNearestUnitEdge: Stick nearest unit edge momentum: It move until momentum disappear.
scrollSpeedToDetect	Double	30	Scroll speed to detect

Scroll

Variables

ValueName	Type	Detail
position	CGFloat	Position based on the start of page 0
page	Int	Current page
positionInPage	CGFloat	Current position based on the start of the page
unit	Int	Current unit in page
positionInUnit	CGFloat	Current position based on the start of the unit

Functions

FunctionName	Args	Detail
moveBy	value: CGFloat	Move scroll by argment value
moveTo	position: CGFloat	Move scroll to argment position
moveToPage	page: Int unit: Int = 0 positionInUnit: CGFloat = 0	Move scroll to argument page

PositionScrollViewDelegate

FunctionName	Args	Detail
onScrollStart	-	Called when a scroll starts
onChangePosition	position: CGFloat	Called when position changed
onChangePage	page: Int	Called when scroll page changed
onChangeUnit	unit: Int	Called when unit changed
onChangePositionInPage	positionInPage: CGFloat	Called when position in page changed
onChangePositionInUnit	positionInUnit: CGFloat	Called when position in unit changed
onScrollEnd	-	Called when a scroll ends

Contact, Author

Please feel free to contact me. kazuooooo

Company