我正在尝试实现项目的多行序列（如 Final Cut Pro 或 Adobe Premiere pro 中的视频编辑序列，如下所示）。
虽然我总是可以使用 UIScrollView 实现它并手动放置自定义视图，但它会很乏味，特别是在重新排序项目和动画更改以及使用捏合手势在时间轴上缩放时。是否可以使用 UICollectionViewCompositionalLayout 和 UICollectionViewDiffableDataSource 使用 UICollectionView 来实现它？从 WWDC 视频来看，使用组合布局似乎几乎一切皆有可能，但尚不清楚是否可以使用它来实现时间线。也许 UICollectionView 不是这个用例的正确范例，应该使用 UIScrollView？即使我使用 UIScrollView，管理诸如拖动和重新排序项目、动画数据源更改、修剪项目、缩放内容之类的事情也会成为问题。任何指向实现这些功能的现有代码库的指针？
这是我的游乐场代码，作为一个简单的空 iOS Playground 文件的部分答案。它应该让您了解如何使用 SpriteKit 实现它。我没有添加任何动画，到目前为止，场景的宽度是固定的，“相机”也是固定的，还不允许缩放。但我想给你一些东西，这样你就可以决定这是否是适合你的解决方案。
import UIKit
import SpriteKit
import PlaygroundSupport
class MyViewController: UIViewController {
override func loadView() {
// Setting up a basic UIView as parent
let parentView = UIView()
parentView.frame = CGRect(x: 0, y: 0, width: 600, height: 600)
parentView.backgroundColor = .black
// Defining the SKView
let tracksSKView = SKView(frame: parentView.frame)
tracksSKView.ignoresSiblingOrder = false
// Options to debug visually
// tracksSKView.showsNodeCount = true
// tracksSKView.showsPhysics = true
// tracksSKView.showsFields = true
// tracksSKView.showsLargeContentViewer = true
// Defining our subclassed SKScene
let scene = GameScene(size: tracksSKView.bounds.size)
// Presenting and adding views and sceens
tracksSKView.presentScene(scene)
parentView.addSubview(tracksSKView)
self.view = parentView
}
}
//MARK: - Custom SKScene
class GameScene: SKScene {
let trackSize = CGSize(width: 2048, height: 120)
let tracksCount = 4
// Hardcoded clips, use your data source and update when a clip has been moved in any way.
let clips: [Clip] = [
Clip(name: "SongA", track: 1, xPosition: 0, lengh: 245),
Clip(name: "SongB", track: 2, xPosition: 200, lengh: 166, color: .blue),
Clip(name: "SongC", track: 3, xPosition: 200, lengh: 256, color: .red)
]
var touchingClip = false
var touchedClip = SKNode()
// Bacically like loadView or viewDidLoad
override func didMove(to view: SKView) {
physicsWorld.contactDelegate = self
self.size = CGSize(width: 1024, height: 768)
self.name = "scene"
addTracks(amount: tracksCount)
addClips(clips: clips)
}
// Adding x amount of tracks.
func addTracks(amount: Int) {
for n in 0..<amount {
let trackNode = SKSpriteNode(color: n%2 == 0 ? .systemGray : .systemGray2, size: trackSize)
// Setting up physical propeties of the border of the track
trackNode.physicsBody = SKPhysicsBody(edgeLoopFrom: trackNode.frame)
trackNode.physicsBody?.restitution = 0.2
trackNode.physicsBody?.allowsRotation = false
trackNode.physicsBody?.affectedByGravity = false
trackNode.physicsBody?.isDynamic = false
// Positioning the track
trackNode.zPosition = -1
trackNode.position.y = frame.minY + trackSize.height / 2 + CGFloat(n) * trackSize.height
addChild(trackNode)
}
}
// Adding the Clip objects stored in an array.
func addClips(clips: [Clip]) {
for clip in clips {
let clipNode = SKSpriteNode(color: clip.color, size: CGSize(width: clip.lengh, height: Int(trackSize.height) - 20))
clipNode.position.x = clip.xPosition + CGFloat(clip.lengh / 2)
clipNode.position.y = frame.minY + (trackSize.height * CGFloat(clip.track)) + 1
clipNode.zPosition = 1
clipNode.physicsBody = SKPhysicsBody(rectangleOf: clipNode.frame.size)
clipNode.physicsBody?.affectedByGravity = true
clipNode.physicsBody?.allowsRotation = false
clipNode.physicsBody?.restitution = 0.2
addChild(clipNode)
}
}
//MARK: - User interaction
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in touches {
let location = touch.location(in: self)
// getting all nodes the user touched (visible and hidden below others.
let tappedNodes = nodes(at: location)
//getting the top node
if let node = tappedNodes.first {
touchedClip = node
touchingClip = true
}
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
guard touchingClip else { return }
// Moving the clip (node) based on the movement of the touch. It's very basic and can look jittery. Using the animate methods would create better results.
for touch in touches {
let location = touch.location(in: self)
touchedClip.position = location
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
touchingClip = false
}
}
//MARK: - Interaction in between object like collisions etc.
extension GameScene: SKPhysicsContactDelegate {
// handle different contact cases here
}
//MARK: - Clip object
struct Clip {
var name: String
var track: Int
var xPosition: CGFloat
var lengh: Int
var color: UIColor = .green
}
PlaygroundPage.current.liveView = MyViewController()
我添加了一个手势识别器，用于长按移动剪辑，而触摸和平移不会调整剪辑的大小。这是新代码：
import UIKit
import SpriteKit
import PlaygroundSupport
PlaygroundPage.current.liveView = MyViewController()
class MyViewController: UIViewController {
override func loadView() {
// Setting up a basic UIView as parent
let parentView = UIView()
parentView.frame = CGRect(x: 0, y: 0, width: 600, height: 600)
parentView.backgroundColor = .black
// Defining the SKView
let tracksSKView = SKView(frame: parentView.frame)
tracksSKView.ignoresSiblingOrder = false
// Options to debug visually
tracksSKView.showsNodeCount = true
tracksSKView.showsPhysics = true
tracksSKView.showsFields = true
tracksSKView.showsLargeContentViewer = true
// Defining our subclassed SKScene
let scene = GameScene(size: tracksSKView.bounds.size)
// Presenting and adding views and sceens
tracksSKView.presentScene(scene)
parentView.addSubview(tracksSKView)
self.view = parentView
}
}
//MARK: - Custom SKScene
class GameScene: SKScene {
let trackSize = CGSize(width: 2048, height: 120)
let tracksCount = 4
// Hardcoded clips, use your data source and update when a clip has been moved in any way.
let clips: [Clip] = [
Clip(name: "SongA", track: 1, xPosition: 0, lengh: 245),
Clip(name: "SongB", track: 2, xPosition: 200, lengh: 166, color: .blue),
Clip(name: "SongC", track: 3, xPosition: 200, lengh: 256, color: .red)
]
// Different interactions, I used a sepperate variable for each interaction instead of one to be able to add more later.
var touchingClip = false
var movingClip = false
var resizingClip = true
var touchedClip = SKNode()
var location = CGPoint()
// Bacically like loadView or viewDidLoad
override func didMove(to view: SKView) {
physicsWorld.contactDelegate = self
// Using the UI gesture recognizer in the case of a long press seemed easier than trying to figure out the gestures in the touches methods.
let longPressRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(GameScene.longPress))
self.view!.addGestureRecognizer(longPressRecognizer)
// Adding tracks and clips
addTracks(amount: tracksCount)
addClips(clips: clips)
}
// Method that handles the long press
@objc func longPress(sender: UILongPressGestureRecognizer) {
if sender.state == .began || sender.state == .changed {
movingClip = true
resizingClip = false
} else {
movingClip = false
resizingClip = true
}
location = sender.location(in: self.view)
}
//MARK: - Setting up the tracks and clips
// Adding x amount of tracks.
func addTracks(amount: Int) {
for n in 0..<amount {
let trackNode = SKSpriteNode(color: n%2 == 0 ? .systemGray : .systemGray2, size: trackSize)
// Setting up physical propeties of the border of the track
trackNode.physicsBody = SKPhysicsBody(edgeLoopFrom: trackNode.frame)
trackNode.physicsBody?.restitution = 0.2
trackNode.physicsBody?.allowsRotation = false
trackNode.physicsBody?.affectedByGravity = false
trackNode.physicsBody?.isDynamic = false
// Positioning the track
trackNode.zPosition = -1
trackNode.position.y = frame.minY + trackSize.height / 2 + CGFloat(n) * trackSize.height
addChild(trackNode)
}
}
// Adding the Clip objects stored in an array.
func addClips(clips: [Clip]) {
for clip in clips {
let clipNode = SKSpriteNode(color: clip.color, size: CGSize(width: clip.lengh, height: Int(trackSize.height) - 20))
clipNode.name = clip.name
clipNode.position.x = clip.xPosition + CGFloat(clip.lengh / 2)
clipNode.position.y = frame.minY + (trackSize.height * CGFloat(clip.track)) + 1
clipNode.zPosition = 1
clipNode.physicsBody = SKPhysicsBody(rectangleOf: clipNode.frame.size)
clipNode.physicsBody?.affectedByGravity = true
clipNode.physicsBody?.allowsRotation = false
clipNode.physicsBody?.restitution = 0.2
clipNode.physicsBody?.isDynamic = true
addChild(clipNode)
}
}
//MARK: - User interaction
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
guard touches.first != nil else { return }
for touch in touches {
let location = touch.location(in: self)
touchedClip = atPoint(location) as! SKSpriteNode
if clips.contains(where: { $0.name == touchedClip.name }) {
touchingClip = true
}
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
guard touchingClip else { return }
for touch in touches {
if resizingClip {
let resizeValue = touch.location(in: touchedClip).x - touch.previousLocation(in: touchedClip).x
// Checking that we're only adding width to the clip or trimming no more then the remaining width.
if resizeValue > 0 || (resizeValue < 0 && abs(resizeValue) < touchedClip.frame.size.width) {
let action = SKAction.resize(byWidth: resizeValue, height: 0, duration: 0.0)
action.timingMode = .linear
touchedClip.run(action)
}
}
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
touchingClip = false
resizingClip = true
movingClip = false
}
//MARK: - Scene update
// Runs as long as scene is active once per frame (target of 60 frames per second)
override func update(_ currentTime: TimeInterval) {
// The moving needs to be done in the update method, the touches methods are unresponsive while the gesture recognizer is active.
if movingClip && touchingClip {
let newLocation = convertPoint(fromView: location)
let action = SKAction.move(to: newLocation, duration: 0.1)
action.timingMode = .easeInEaseOut
touchedClip.run(action)
}
// The physics body does not change when the clip node is resized. I'm updating it here.
if resizingClip && touchingClip {
touchedClip.physicsBody = SKPhysicsBody(rectangleOf: touchedClip.frame.size)
touchedClip.physicsBody?.affectedByGravity = true
touchedClip.physicsBody?.allowsRotation = false
touchedClip.physicsBody?.restitution = 0.2
touchedClip.physicsBody?.isDynamic = true
}
}
}
//MARK: - Interaction in between object like collisions etc.
extension GameScene: SKPhysicsContactDelegate {
// handle different contact cases here
}
//MARK: - Clip object
struct Clip {
var name: String
var track: Int
var xPosition: CGFloat
var lengh: Int
var color: UIColor = .green
}
资料来源：
www.udemy.com/course/dive-into-spritekit（很好，但不是很好）
designcode.io（不推荐）
stackoverflow.com/questions/30337608/detect-long-touch-in-sprite-kit
以及更多 SO 和Apple Dev :)