仅在 UIView 布局后才发送数据源信息?
Sending datasource information only when UIView has been laid out?
我无法理解这一点。我之前已经能够完成这样的项目,但现在类似的方法对我不起作用。
这是问题所在:
我有一个 UIPageViewController 有 4 storyViewControllers
。
每个 storyViewControllers
都有一个自定义 containerView
。我想在 containerView
上添加 'n' 个 UIViews
。我从视图控制器发送 dataSource
或 'n'。但是,我无法在容器视图上正确布置子视图。
基本上我想知道什么时候从视图控制器发送数据源信息。显然我想在添加自定义容器视图后发送它。
我正在使用 viewDidLayoutSubviews
。这使它工作。但是,我认为这不是正确的方法。现在,每次视图控制器布置子视图时,我的委托都会被调用。
我在 viewDidLoad()
中尝试过这样做,但这也不起作用。
这行得通。但似乎不对。阿尔斯
我的storyViewController
代码
override func viewDidLoad() {
super.viewDidLoad()
segmentContainerView = ATCStorySegmentsView()
view.addSubview(segmentContainerView)
configureSegmentContainerView()
segmentContainerView.translatesAutoresizingMaskIntoConstraints = false
}
override func viewDidLayoutSubviews() {
segmentContainerView.delegate = self
DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
self.segmentContainerView.startAnimation() // I am also animating these views that are laid on the containerView. Doing them here starts the animation randomly whenever I scroll through the UIPageController
}
}
在containerView
:
var delegate: ATCSegmentDataSource? {
didSet {
addSegments()
}
}
private func addSegments() {
let numberOfSegment = delegate?.numberOfSegmentsToShow()
guard let segmentQuantity = numberOfSegment else { return }
layoutIfNeeded()
setNeedsLayout()
for i in 0..<segmentQuantity {
let segment = Segment()
addSubview(segment.bottomSegment)
addSubview(segment.topSegment)
configureSegmentFrame(index: i, segmentView: segment)
segmentsArray.append(segment)
}
}
private func configureSegmentFrame(index: Int, segmentView: Segment) {
let numberOfSegment = delegate?.numberOfSegmentsToShow()
guard let segmentQuantity = numberOfSegment else { return }
let widthOfSegment : CGFloat = (self.frame.width - (padding * CGFloat(segmentQuantity - 1))) / CGFloat(segmentQuantity)
let i = CGFloat(index)
let segmentFrame = CGRect(x: i * (widthOfSegment + padding), y: 0, width: widthOfSegment, height: self.frame.height)
segmentView.bottomSegment.frame = segmentFrame
segmentView.topSegment.frame = segmentFrame
segmentView.topSegment.frame.size.width = 0
}
这是它应有的方式。但是当我滚动 UIPageViewController 时,动画并不总是从头开始。因为它依赖于布局子视图。有时,如果我慢慢滚动浏览页面控制器,那么子视图会再次布局,动画会从头开始。其他时候,当视图已经加载时,动画会从我遗漏的地方开始。
问题我想知道将数据源从视图控制器发送到容器视图的最佳方式是什么?该数据源是生成要添加到 containerView 的视图数量所需要的。
如果我从 viewDidLayoutSubviews
发送数据源,这就是我得到的结果。我今天早些时候问了另一个问题,列出了我用来发送数据源的其他方法。也看看这个:Not able to lay out Subviews on a custom UIView in Swift
这是一个非常基本的例子...
它有:
- a
Segment: UIView
sub-class 包含一个 "bottomSegment" 和一个 "topSegment"
- a
ATCStorySegmentsView: UIView
sub-class 和 UIStackView
以布局所需数量的段
- a
StoryViewController: UIViewController
sub-class 在其视图的顶部添加 ATCStorySegmentsView
,然后告诉该视图为 viewDidAppear()
[=45= 上的第一段设置动画]
class Segment: UIView {
let topSegment: UIView = {
let v = UIView()
v.translatesAutoresizingMaskIntoConstraints = false
v.backgroundColor = .white
return v
}()
let bottomSegment: UIView = {
let v = UIView()
v.translatesAutoresizingMaskIntoConstraints = false
v.backgroundColor = .gray
return v
}()
var startConstraint: NSLayoutConstraint = NSLayoutConstraint()
var endConstraint: NSLayoutConstraint = NSLayoutConstraint()
override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func commonInit() -> Void {
addSubview(bottomSegment)
addSubview(topSegment)
// start constraint has width of Zero
startConstraint = topSegment.widthAnchor.constraint(equalTo: bottomSegment.widthAnchor, multiplier: 0.0)
// end constraint has width of bottomSegment
endConstraint = topSegment.widthAnchor.constraint(equalTo: bottomSegment.widthAnchor, multiplier: 1.0)
NSLayoutConstraint.activate([
// bottomSegment constrained to all 4 sides
bottomSegment.topAnchor.constraint(equalTo: topAnchor),
bottomSegment.bottomAnchor.constraint(equalTo: bottomAnchor),
bottomSegment.leadingAnchor.constraint(equalTo: leadingAnchor),
bottomSegment.trailingAnchor.constraint(equalTo: trailingAnchor),
// topSegment constrained top, bottom and leading
topSegment.topAnchor.constraint(equalTo: topAnchor),
topSegment.bottomAnchor.constraint(equalTo: bottomAnchor),
topSegment.leadingAnchor.constraint(equalTo: leadingAnchor),
// activate topSegemnt width constraint
startConstraint,
])
}
func showTopSegment() -> Void {
// deactivate startConstraint
startConstraint.isActive = false
// activate endConstraint
endConstraint.isActive = true
}
}
protocol ATCSegmentDataSource {
func numberOfSegmentsToShow() -> Int
}
class ATCStorySegmentsView: UIView {
let theStackView: UIStackView = {
let v = UIStackView()
v.translatesAutoresizingMaskIntoConstraints = false
v.axis = .horizontal
v.alignment = .fill
v.distribution = .fillEqually
v.spacing = 4
return v
}()
var segmentsArray: [Segment] = [Segment]()
var delegate: ATCSegmentDataSource? {
didSet {
addSegments()
}
}
override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func commonInit() -> Void {
addSubview(theStackView)
NSLayoutConstraint.activate([
// constrain stack view to all 4 sides
theStackView.topAnchor.constraint(equalTo: topAnchor),
theStackView.bottomAnchor.constraint(equalTo: bottomAnchor),
theStackView.leadingAnchor.constraint(equalTo: leadingAnchor),
theStackView.trailingAnchor.constraint(equalTo: trailingAnchor),
])
}
private func addSegments() {
let numberOfSegment = delegate?.numberOfSegmentsToShow()
guard let segmentQuantity = numberOfSegment else { return }
// add desired number of Segment subviews to teh stack view
for _ in 0..<segmentQuantity {
let seg = Segment()
seg.translatesAutoresizingMaskIntoConstraints = false
theStackView.addArrangedSubview(seg)
segmentsArray.append(seg)
}
}
func startAnimation() -> Void {
// this will animate changing the topSegment's width
self.segmentsArray.first?.showTopSegment()
UIView.animate(withDuration: 1.5, animations: {
self.layoutIfNeeded()
})
}
}
class StoryViewController: UIViewController, ATCSegmentDataSource {
let segmentContainerView: ATCStorySegmentsView = ATCStorySegmentsView()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .red
view.addSubview(segmentContainerView)
segmentContainerView.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
// constrain segmentContainerView to top (safe-area) + 20-pts "padding",
segmentContainerView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20.0),
// leading and trailing with "padding" of 20-pts
segmentContainerView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 20.0),
segmentContainerView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -20.0),
// constrain height to 10-pts
segmentContainerView.heightAnchor.constraint(equalToConstant: 10.0),
])
// set the delegate
segmentContainerView.delegate = self
}
override func viewDidAppear(_ animated: Bool) {
segmentContainerView.startAnimation()
}
func numberOfSegmentsToShow() -> Int {
return 3
}
}
结果(当视图出现时,白色条以动画方式穿过灰色条):
有 5 个片段:
请注意,正如 auto-layout 的设计目的,它也处理 size-changes,例如当设备旋转时:
我无法理解这一点。我之前已经能够完成这样的项目,但现在类似的方法对我不起作用。
这是问题所在:
我有一个 UIPageViewController 有 4 storyViewControllers
。
每个 storyViewControllers
都有一个自定义 containerView
。我想在 containerView
上添加 'n' 个 UIViews
。我从视图控制器发送 dataSource
或 'n'。但是,我无法在容器视图上正确布置子视图。
基本上我想知道什么时候从视图控制器发送数据源信息。显然我想在添加自定义容器视图后发送它。
我正在使用 viewDidLayoutSubviews
。这使它工作。但是,我认为这不是正确的方法。现在,每次视图控制器布置子视图时,我的委托都会被调用。
我在 viewDidLoad()
中尝试过这样做,但这也不起作用。
这行得通。但似乎不对。阿尔斯
我的storyViewController
代码
override func viewDidLoad() {
super.viewDidLoad()
segmentContainerView = ATCStorySegmentsView()
view.addSubview(segmentContainerView)
configureSegmentContainerView()
segmentContainerView.translatesAutoresizingMaskIntoConstraints = false
}
override func viewDidLayoutSubviews() {
segmentContainerView.delegate = self
DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
self.segmentContainerView.startAnimation() // I am also animating these views that are laid on the containerView. Doing them here starts the animation randomly whenever I scroll through the UIPageController
}
}
在containerView
:
var delegate: ATCSegmentDataSource? {
didSet {
addSegments()
}
}
private func addSegments() {
let numberOfSegment = delegate?.numberOfSegmentsToShow()
guard let segmentQuantity = numberOfSegment else { return }
layoutIfNeeded()
setNeedsLayout()
for i in 0..<segmentQuantity {
let segment = Segment()
addSubview(segment.bottomSegment)
addSubview(segment.topSegment)
configureSegmentFrame(index: i, segmentView: segment)
segmentsArray.append(segment)
}
}
private func configureSegmentFrame(index: Int, segmentView: Segment) {
let numberOfSegment = delegate?.numberOfSegmentsToShow()
guard let segmentQuantity = numberOfSegment else { return }
let widthOfSegment : CGFloat = (self.frame.width - (padding * CGFloat(segmentQuantity - 1))) / CGFloat(segmentQuantity)
let i = CGFloat(index)
let segmentFrame = CGRect(x: i * (widthOfSegment + padding), y: 0, width: widthOfSegment, height: self.frame.height)
segmentView.bottomSegment.frame = segmentFrame
segmentView.topSegment.frame = segmentFrame
segmentView.topSegment.frame.size.width = 0
}
这是它应有的方式。但是当我滚动 UIPageViewController 时,动画并不总是从头开始。因为它依赖于布局子视图。有时,如果我慢慢滚动浏览页面控制器,那么子视图会再次布局,动画会从头开始。其他时候,当视图已经加载时,动画会从我遗漏的地方开始。
问题我想知道将数据源从视图控制器发送到容器视图的最佳方式是什么?该数据源是生成要添加到 containerView 的视图数量所需要的。
如果我从 viewDidLayoutSubviews
发送数据源,这就是我得到的结果。我今天早些时候问了另一个问题,列出了我用来发送数据源的其他方法。也看看这个:Not able to lay out Subviews on a custom UIView in Swift
这是一个非常基本的例子...
它有:
- a
Segment: UIView
sub-class 包含一个 "bottomSegment" 和一个 "topSegment" - a
ATCStorySegmentsView: UIView
sub-class 和UIStackView
以布局所需数量的段 - a
StoryViewController: UIViewController
sub-class 在其视图的顶部添加ATCStorySegmentsView
,然后告诉该视图为viewDidAppear()
[=45= 上的第一段设置动画]
class Segment: UIView {
let topSegment: UIView = {
let v = UIView()
v.translatesAutoresizingMaskIntoConstraints = false
v.backgroundColor = .white
return v
}()
let bottomSegment: UIView = {
let v = UIView()
v.translatesAutoresizingMaskIntoConstraints = false
v.backgroundColor = .gray
return v
}()
var startConstraint: NSLayoutConstraint = NSLayoutConstraint()
var endConstraint: NSLayoutConstraint = NSLayoutConstraint()
override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func commonInit() -> Void {
addSubview(bottomSegment)
addSubview(topSegment)
// start constraint has width of Zero
startConstraint = topSegment.widthAnchor.constraint(equalTo: bottomSegment.widthAnchor, multiplier: 0.0)
// end constraint has width of bottomSegment
endConstraint = topSegment.widthAnchor.constraint(equalTo: bottomSegment.widthAnchor, multiplier: 1.0)
NSLayoutConstraint.activate([
// bottomSegment constrained to all 4 sides
bottomSegment.topAnchor.constraint(equalTo: topAnchor),
bottomSegment.bottomAnchor.constraint(equalTo: bottomAnchor),
bottomSegment.leadingAnchor.constraint(equalTo: leadingAnchor),
bottomSegment.trailingAnchor.constraint(equalTo: trailingAnchor),
// topSegment constrained top, bottom and leading
topSegment.topAnchor.constraint(equalTo: topAnchor),
topSegment.bottomAnchor.constraint(equalTo: bottomAnchor),
topSegment.leadingAnchor.constraint(equalTo: leadingAnchor),
// activate topSegemnt width constraint
startConstraint,
])
}
func showTopSegment() -> Void {
// deactivate startConstraint
startConstraint.isActive = false
// activate endConstraint
endConstraint.isActive = true
}
}
protocol ATCSegmentDataSource {
func numberOfSegmentsToShow() -> Int
}
class ATCStorySegmentsView: UIView {
let theStackView: UIStackView = {
let v = UIStackView()
v.translatesAutoresizingMaskIntoConstraints = false
v.axis = .horizontal
v.alignment = .fill
v.distribution = .fillEqually
v.spacing = 4
return v
}()
var segmentsArray: [Segment] = [Segment]()
var delegate: ATCSegmentDataSource? {
didSet {
addSegments()
}
}
override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func commonInit() -> Void {
addSubview(theStackView)
NSLayoutConstraint.activate([
// constrain stack view to all 4 sides
theStackView.topAnchor.constraint(equalTo: topAnchor),
theStackView.bottomAnchor.constraint(equalTo: bottomAnchor),
theStackView.leadingAnchor.constraint(equalTo: leadingAnchor),
theStackView.trailingAnchor.constraint(equalTo: trailingAnchor),
])
}
private func addSegments() {
let numberOfSegment = delegate?.numberOfSegmentsToShow()
guard let segmentQuantity = numberOfSegment else { return }
// add desired number of Segment subviews to teh stack view
for _ in 0..<segmentQuantity {
let seg = Segment()
seg.translatesAutoresizingMaskIntoConstraints = false
theStackView.addArrangedSubview(seg)
segmentsArray.append(seg)
}
}
func startAnimation() -> Void {
// this will animate changing the topSegment's width
self.segmentsArray.first?.showTopSegment()
UIView.animate(withDuration: 1.5, animations: {
self.layoutIfNeeded()
})
}
}
class StoryViewController: UIViewController, ATCSegmentDataSource {
let segmentContainerView: ATCStorySegmentsView = ATCStorySegmentsView()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .red
view.addSubview(segmentContainerView)
segmentContainerView.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
// constrain segmentContainerView to top (safe-area) + 20-pts "padding",
segmentContainerView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20.0),
// leading and trailing with "padding" of 20-pts
segmentContainerView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 20.0),
segmentContainerView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -20.0),
// constrain height to 10-pts
segmentContainerView.heightAnchor.constraint(equalToConstant: 10.0),
])
// set the delegate
segmentContainerView.delegate = self
}
override func viewDidAppear(_ animated: Bool) {
segmentContainerView.startAnimation()
}
func numberOfSegmentsToShow() -> Int {
return 3
}
}
结果(当视图出现时,白色条以动画方式穿过灰色条):
有 5 个片段:
请注意,正如 auto-layout 的设计目的,它也处理 size-changes,例如当设备旋转时: