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ButtonBarView.swift
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ButtonBarView.swift
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// ButtonBarView.swift
// XLPagerTabStrip ( https://github.com/xmartlabs/XLPagerTabStrip )
//
// Copyright (c) 2017 Xmartlabs ( http://xmartlabs.com )
//
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
import UIKit
public enum PagerScroll {
case no
case yes
case scrollOnlyIfOutOfScreen
}
public enum SelectedBarAlignment {
case left
case center
case right
case progressive
}
public enum SelectedBarVerticalAlignment {
case top
case middle
case bottom
}
open class ButtonBarView: UICollectionView {
open lazy var selectedBar: UIView = { [unowned self] in
let bar = UIView(frame: CGRect(x: 0, y: self.frame.size.height - CGFloat(self.selectedBarHeight), width: 0, height: CGFloat(self.selectedBarHeight)))
bar.layer.zPosition = 9999
return bar
}()
internal var selectedBarHeight: CGFloat = 4 {
didSet {
updateSelectedBarYPosition()
}
}
var selectedBarVerticalAlignment: SelectedBarVerticalAlignment = .bottom
var selectedBarAlignment: SelectedBarAlignment = .center
var selectedIndex = 0
required public init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
addSubview(selectedBar)
}
public override init(frame: CGRect, collectionViewLayout layout: UICollectionViewLayout) {
super.init(frame: frame, collectionViewLayout: layout)
addSubview(selectedBar)
}
open func moveTo(index: Int, animated: Bool, swipeDirection: SwipeDirection, pagerScroll: PagerScroll) {
selectedIndex = index
updateSelectedBarPosition(animated, swipeDirection: swipeDirection, pagerScroll: pagerScroll)
}
open func move(fromIndex: Int, toIndex: Int, progressPercentage: CGFloat,pagerScroll: PagerScroll) {
selectedIndex = progressPercentage > 0.5 ? toIndex : fromIndex
let fromFrame = layoutAttributesForItem(at: IndexPath(item: fromIndex, section: 0))!.frame
let numberOfItems = dataSource!.collectionView(self, numberOfItemsInSection: 0)
var toFrame: CGRect
if toIndex < 0 || toIndex > numberOfItems - 1 {
if toIndex < 0 {
let cellAtts = layoutAttributesForItem(at: IndexPath(item: 0, section: 0))
toFrame = cellAtts!.frame.offsetBy(dx: -cellAtts!.frame.size.width, dy: 0)
}
else {
let cellAtts = layoutAttributesForItem(at: IndexPath(item: (numberOfItems - 1), section: 0))
toFrame = cellAtts!.frame.offsetBy(dx: cellAtts!.frame.size.width, dy: 0)
}
}
else {
toFrame = layoutAttributesForItem(at: IndexPath(item: toIndex, section: 0))!.frame
}
var targetFrame = fromFrame
targetFrame.size.height = selectedBar.frame.size.height
targetFrame.size.width += (toFrame.size.width - fromFrame.size.width) * progressPercentage
targetFrame.origin.x += (toFrame.origin.x - fromFrame.origin.x) * progressPercentage
selectedBar.frame = CGRect(x: targetFrame.origin.x, y: selectedBar.frame.origin.y, width: targetFrame.size.width, height: selectedBar.frame.size.height)
var targetContentOffset: CGFloat = 0.0
if contentSize.width > frame.size.width {
let toContentOffset = contentOffsetForCell(withFrame: toFrame, andIndex: toIndex)
let fromContentOffset = contentOffsetForCell(withFrame: fromFrame, andIndex: fromIndex)
targetContentOffset = fromContentOffset + ((toContentOffset - fromContentOffset) * progressPercentage)
}
let animated = abs(contentOffset.x - targetContentOffset) > 30 || (fromIndex == toIndex)
setContentOffset(CGPoint(x: targetContentOffset, y: 0), animated: animated)
}
open func updateSelectedBarPosition(_ animated: Bool, swipeDirection: SwipeDirection, pagerScroll: PagerScroll) -> Void {
var selectedBarFrame = selectedBar.frame
let selectedCellIndexPath = IndexPath(item: selectedIndex, section: 0)
let attributes = layoutAttributesForItem(at: selectedCellIndexPath)
let selectedCellFrame = attributes!.frame
updateContentOffset(animated: animated, pagerScroll: pagerScroll, toFrame: selectedCellFrame, toIndex: (selectedCellIndexPath as NSIndexPath).row)
selectedBarFrame.size.width = selectedCellFrame.size.width
selectedBarFrame.origin.x = selectedCellFrame.origin.x
if animated {
UIView.animate(withDuration: 0.3, animations: { [weak self] in
self?.selectedBar.frame = selectedBarFrame
})
}
else {
selectedBar.frame = selectedBarFrame
}
}
// MARK: - Helpers
private func updateContentOffset(animated: Bool, pagerScroll: PagerScroll, toFrame: CGRect, toIndex: Int) -> Void {
guard pagerScroll != .no || (pagerScroll != .scrollOnlyIfOutOfScreen && (toFrame.origin.x < contentOffset.x || toFrame.origin.x >= (contentOffset.x + frame.size.width - contentInset.left))) else { return }
let targetContentOffset = contentSize.width > frame.size.width ? contentOffsetForCell(withFrame: toFrame, andIndex: toIndex) : 0
setContentOffset(CGPoint(x: targetContentOffset, y: 0), animated: animated)
}
private func contentOffsetForCell(withFrame cellFrame: CGRect, andIndex index: Int) -> CGFloat {
let sectionInset = (collectionViewLayout as! UICollectionViewFlowLayout).sectionInset
var alignmentOffset: CGFloat = 0.0
switch selectedBarAlignment {
case .left:
alignmentOffset = sectionInset.left
case .right:
alignmentOffset = frame.size.width - sectionInset.right - cellFrame.size.width
case .center:
alignmentOffset = (frame.size.width - cellFrame.size.width) * 0.5
case .progressive:
let cellHalfWidth = cellFrame.size.width * 0.5
let leftAlignmentOffset = sectionInset.left + cellHalfWidth
let rightAlignmentOffset = frame.size.width - sectionInset.right - cellHalfWidth
let numberOfItems = dataSource!.collectionView(self, numberOfItemsInSection: 0)
let progress = index / (numberOfItems - 1)
alignmentOffset = leftAlignmentOffset + (rightAlignmentOffset - leftAlignmentOffset) * CGFloat(progress) - cellHalfWidth
}
var contentOffset = cellFrame.origin.x - alignmentOffset
contentOffset = max(0, contentOffset)
contentOffset = min(contentSize.width - frame.size.width, contentOffset)
return contentOffset
}
private func updateSelectedBarYPosition() {
var selectedBarFrame = selectedBar.frame
switch selectedBarVerticalAlignment {
case .top:
selectedBarFrame.origin.y = 0
case .middle:
selectedBarFrame.origin.y = (frame.size.height - selectedBarHeight) / 2
case .bottom:
selectedBarFrame.origin.y = frame.size.height - selectedBarHeight
}
selectedBarFrame.size.height = selectedBarHeight
selectedBar.frame = selectedBarFrame
}
override open func layoutSubviews() {
super.layoutSubviews()
updateSelectedBarYPosition()
}
}