我可以用这个简单的例子来演示我的问题。
我在我的 iOS 应用程序中使用 AsyncDisplayKit/Texture。
我有一个
ASTableNodeNSTextAttachmentBundleNSTextAttachment我面临的问题是，尽管我在获取图像后更新图像和 NSTextAttachment 的边界后调用
setNeedsLayout()layoutIfNeeded()ASTextNode代码：
import UIKit
import AsyncDisplayKit
class ViewController: ASDKViewController<ASDisplayNode>, ASTableDataSource {
let tableNode = ASTableNode()
override init() {
super.init(node: tableNode)
tableNode.dataSource = self
}
required init?(coder aDecoder: NSCoder) {
fatalError()
}
func tableNode(_ tableNode: ASTableNode, numberOfRowsInSection section: Int) -> Int {
return 1
}
func tableNode(_ tableNode: ASTableNode, nodeBlockForRowAt indexPath: IndexPath) -> ASCellNodeBlock {
let row = indexPath.row
return {
let node = MyCellNode(index: row, before: """
Item \(row).
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.
""",
after: """
Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old.
""")
return node
}
}
}
class MyCellNode: ASCellNode {
fileprivate var myTextNode = ASTextNode()
init(index : Int, before: String, after: String) {
super.init()
debugName = "Row \(index)"
automaticallyManagesSubnodes = true
automaticallyRelayoutOnSafeAreaChanges = true
automaticallyRelayoutOnLayoutMarginsChanges = true
let attributedText = NSMutableAttributedString(attributedString: (before+"\n").formattedText())
let attachment = CustomAttachment(url: Bundle.main.url(forResource: "test", withExtension: "png")!)
attachment.bounds = CGRect(x: 0, y: 0, width: CGFLOAT_MIN, height: CGFLOAT_MIN)
attachment.image = UIImage()
let attachmentAttributedString = NSMutableAttributedString(attachment: attachment)
let style = NSMutableParagraphStyle()
style.alignment = .center
attachmentAttributedString.addAttribute(.paragraphStyle, value: style)
attributedText.append(attachmentAttributedString)
attributedText.append(("\n"+after).formattedText())
myTextNode.attributedText = attributedText
}
override func layoutSpecThatFits(_ constrainedSize: ASSizeRange) -> ASLayoutSpec {
if let attributedText = myTextNode.attributedText {
attributedText.enumerateAttribute(NSAttributedString.Key.attachment, in: NSRange(location: 0, length: attributedText.length)) { a, range, _ in
if let attachment = a as? CustomAttachment {
print("attachment: \(attachment.bounds)")
}
}
}
let paddingToUse = 10.0
return ASInsetLayoutSpec(insets: UIEdgeInsets(top: paddingToUse, left: paddingToUse, bottom: paddingToUse, right: paddingToUse), child: myTextNode)
}
override func layout() {
super.layout()
}
override func didEnterPreloadState() {
super.didEnterPreloadState()
print("----- didEnterPreloadState: \(String(describing: debugName))")
if let attributedText = myTextNode.attributedText {
attributedText.enumerateAttribute(NSAttributedString.Key.attachment, in: NSRange(location: 0, length: attributedText.length)) { a, range, _ in
if let attachment = a as? CustomAttachment {
// print("attachment: \(attachment.url)")
if let imageData = NSData(contentsOf: attachment.url), let img = UIImage(data: imageData as Data) {
print("Size: \(img.size)")
attachment.image = img
attachment.bounds = CGRect(x: 0, y: 0, width: 200, height: 200)
setNeedsLayout()
layoutIfNeeded()
}
}
}
}
}
override func didExitPreloadState() {
super.didExitPreloadState()
print("----- didExitPreloadState: \(String(describing: debugName))")
}
}
extension String {
func formattedText() -> NSAttributedString {
return NSAttributedString(string: self, attributes: [NSAttributedString.Key.foregroundColor : UIColor.white,NSAttributedString.Key.font: UIFont.systemFont(ofSize: 20, weight: .regular)])
}
}
extension NSMutableAttributedString {
func addAttribute(_ name: NSAttributedString.Key, value: Any) {
addAttribute(name, value: value, range: NSRange(location: 0, length: length))
}
func addAttributes(_ attrs: [NSAttributedString.Key : Any]) {
addAttributes(attrs, range: NSRange(location: 0, length: length))
}
}
class CustomAttachment: NSTextAttachment {
var url : URL
public init(url: URL) {
self.url = url
super.init(data: nil, ofType: nil)
}
required init?(coder: NSCoder) {
fatalError()
}
}
我自己找到了解决方案。
基本上，首先我将
attributedTextASTextNodeNSAttributedStringNSTextAttachmentURLattachmentBoundsdidEnterPreloadStateattachmentSDWebImageManagerreplaceCharactersNSAttributedStringNSTextAttachmentimageattributedTextASTextNodeattributedTextinvalidateCalculatedLayoutsetNeedsLayout这是完整的演示代码：
import UIKit
import AsyncDisplayKit
import SDWebImage
struct Item {
var index : Int
var before : String
var after : String
var image : String
}
class ViewController: ASDKViewController<ASDisplayNode>, ASTableDataSource {
let tableNode = ASTableNode()
let imagesToEmbed = ["https://images.unsplash.com/photo-1682686581264-c47e25e61d95?q=80&w=2574&auto=format&fit=crop&ixlib=rb-4.0.3&ixid=M3wxMjA3fDF8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D",
"https://plus.unsplash.com/premium_photo-1700391547517-9d63b8a8b351?q=80&w=2670&auto=format&fit=crop&ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D",
"https://images.unsplash.com/photo-1682686580849-3e7f67df4015?q=80&w=2670&auto=format&fit=crop&ixlib=rb-4.0.3&ixid=M3wxMjA3fDF8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D",
"https://i.ytimg.com/vi/dBymYOAvgdA/maxresdefault.jpg",
"https://i.ytimg.com/vi/q2DBeby7ni8/maxresdefault.jpg",
"https://i.ytimg.com/vi/-28apOHT9Rk/maxresdefault.jpg",
"https://i.ytimg.com/vi/O4t8hAEEKI4/maxresdefault.jpg"
]
override init() {
super.init(node: tableNode)
tableNode.dataSource = self
tableNode.setTuningParameters(ASRangeTuningParameters(leadingBufferScreenfuls: 3, trailingBufferScreenfuls: 3), for: .preload)
tableNode.setTuningParameters(ASRangeTuningParameters(leadingBufferScreenfuls: 3, trailingBufferScreenfuls: 3), for: .display)
}
required init?(coder aDecoder: NSCoder) {
fatalError()
}
func tableNode(_ tableNode: ASTableNode, numberOfRowsInSection section: Int) -> Int {
return imagesToEmbed.count
}
func tableNode(_ tableNode: ASTableNode, nodeBlockForRowAt indexPath: IndexPath) -> ASCellNodeBlock {
let row = indexPath.row
let img = imagesToEmbed[row]
return {
let node = MyCellNode(item: Item(index: row, before: "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum is simply dummy text of the printing and typesetting industry.", after: "Contrary to popular belief, Lorem Ipsum is not simply random text. Lorem Ipsum is simply dummy text of the printing and typesetting industry.",image: img))
return node
}
}
}
class MyCellNode: ASCellNode {
fileprivate var myTextNode = ASTextNode()
var item : Item
init(item : Item) {
self.item = item
super.init()
debugName = "Row \(item.index)"
automaticallyManagesSubnodes = true
automaticallyRelayoutOnSafeAreaChanges = true
automaticallyRelayoutOnLayoutMarginsChanges = true
let attributedText = NSMutableAttributedString(attributedString: ("\(item.index). "+item.before+"==\n\n").formattedText())
attributedText.append(NSMutableAttributedString(attachment: CustomAttachment(url: URL(string: item.image)!)))
attributedText.append(("\n\n=="+item.after).formattedText())
myTextNode.attributedText = attributedText
}
override func layoutSpecThatFits(_ constrainedSize: ASSizeRange) -> ASLayoutSpec {
let paddingToUse = 10.0
return ASInsetLayoutSpec(insets: UIEdgeInsets(top: paddingToUse, left: paddingToUse, bottom: paddingToUse, right: paddingToUse), child: myTextNode)
}
override func layout() {
super.layout()
}
override func didEnterPreloadState() {
super.didEnterPreloadState()
print("----- didEnterPreloadState: \(String(describing: debugName))")
if let attributedText = myTextNode.attributedText {
attributedText.enumerateAttribute(NSAttributedString.Key.attachment, in: NSRange(location: 0, length: attributedText.length)) { a, range, _ in
if let attachment = a as? CustomAttachment {
print("attachment: \(attachment.url)")
SDWebImageManager.shared.loadImage(with: attachment.url) { a, b, c in
print("Progress: \(a), \(b), \(c)")
} completed: { img, data, err, cacheType, finished, url in
if let img = img {
attachment.image = img
let attachmentAttributedString = NSMutableAttributedString(attachment: attachment)
let style = NSMutableParagraphStyle()
style.alignment = .center
attachmentAttributedString.addAttribute(.paragraphStyle, value: style)
let toEdit = NSMutableAttributedString(attributedString: attributedText)
toEdit.replaceCharacters(in: range, with: attachmentAttributedString)
self.myTextNode.attributedText = toEdit
self.invalidateCalculatedLayout()
self.setNeedsLayout()
}
}
}
}
}
}
override func didExitPreloadState() {
super.didExitPreloadState()
print("----- didExitPreloadState: \(String(describing: debugName))")
}
}
extension String {
func formattedText() -> NSAttributedString {
return NSAttributedString(string: self, attributes: [NSAttributedString.Key.foregroundColor : UIColor.white,NSAttributedString.Key.font: UIFont.systemFont(ofSize: 16, weight: .regular)])
}
}
extension NSMutableAttributedString {
func addAttribute(_ name: NSAttributedString.Key, value: Any) {
addAttribute(name, value: value, range: NSRange(location: 0, length: length))
}
func addAttributes(_ attrs: [NSAttributedString.Key : Any]) {
addAttributes(attrs, range: NSRange(location: 0, length: length))
}
}
class CustomAttachment: NSTextAttachment {
var url : URL
public init(url: URL) {
self.url = url
super.init(data: nil, ofType: nil)
}
required init?(coder: NSCoder) {
fatalError()
}
override func attachmentBounds(for textContainer: NSTextContainer?, proposedLineFragment lineFrag: CGRect, glyphPosition position: CGPoint, characterIndex charIndex: Int) -> CGRect {
guard let image = image else {
return .zero
}
var boundsToReturn = bounds
boundsToReturn.size.width = min(image.size.width, lineFrag.size.width)
boundsToReturn.size.height = image.size.height/image.size.width * boundsToReturn.size.width
// print("attachment: \(lineFrag.size.width), \(bounds), \(image.size), \(boundsToReturn)")
return boundsToReturn
}
}