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Delegateͷڞ௨ॲཧΛ
Message ForwardingΛར༻ͯ͠
ҙͷNamespaceͰӅṭ͢Δ
AKIBA.swift×SwiftѪձ vol2
2017/03/06
marty-suzuki
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NoticeObserveKit
https://github.com/marty-suzuki/NoticeObserveKit
class ViewController: UIViewController {
let pool = NoticeObserverPool()
override func viewDidLoad() {
super.viewDidLoad()
//NoticeType͕࠾༻͞ΕͨstructͷInfoTypeΛͱʹɺ௨͞ΕΔΦϒδΣΫτͷܕਪΛߦ͍ͬͯΔ
UIKeyboardWillShow.observe { [unowned self] in
self.keyboardAnimation(with: $0)
}.addObserverTo(pool)
}
func keyboardAnimation(with keyboard: UIKeyboardInfo) {
//ΩʔϘʔυͷΞχϝʔγϣϯॲཧ
}
}
struct UIKeyboardWillShow: NoticeType {
typealias InfoType = UIKeyboardInfo
static let name: Notification.Name = .UIKeyboardWillShow
}
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ͦΕͰຊʹ
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͜ͷΑ͏ͳ࣮Λߦ͏ͱ͖
Ͳ͏͠·͔͢ʁ
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Paging
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Paging + UITableViewDelegate
class ViewController: UIViewController, UITableViewDelegate {
@IBOutlet weak var tableView: UITableView!
private var reachedBottom: Bool = false {
didSet {
if reachedBottom == oldValue { return }
guard reachedBottom else { return }
didReachBottom()
}
}
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
}
private func didReachBottom() {
//UITableViewͷఈʹ౸ୡͨ͠ࡍͷॲཧ
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let maxDistance = max(0, scrollView.contentSize.height - scrollView.bounds.size.height)
reachedBottom = maxDistance < scrollView.contentOffset.y
}
}
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Paging
Solution
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͜ͷΑ͏ͳܗͰॻ͚ͨΒϕλʔͰͳ͍Ͱ͠ΐ͏͔ʁ
class ViewController: UIViewController {
@IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
//.reΛՃ͢Δ͚ͩ
tableView.re.delegate = self
tableView.re.scrollViewDidReachBottom = { scrollView in
print("scrollViewDidReachBottom!")
}
}
}
extension ViewController: UITableViewDelegate {
//ViewControllerͰDelegateͷϋϯυϦϯά͕Մೳ
func scrollViewDidScroll(_ scrollView: UIScrollView) {
print("scrollViewDidScroll = \(scrollView.contentOffset.y)")
}
}
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Implementation
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DelegateTransporter.h
@interface DelegateTransporter : NSObject
- (nonnull instancetype)initWithDelegates:(NSArray * __nonnull)delegates NS_REFINED_FOR_SWIFT;
@end
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DelegateTransporter.h
@interface DelegateTransporter : NSObject
- (nonnull instancetype)initWithDelegates:(NSArray * __nonnull)delegates NS_REFINED_FOR_SWIFT;
@end
SwiftͰUITableViewDelegate༻ͷDelegateTransporterΛॻ͘ͷ
ͰɺNS_REFINED_FOR_SWIFTʹͯ͠.init(__deleate:)Ͱݺͼ
ग़͢Α͏ʹ͢Δɻ
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DelegateTransporter.m
@interface DelegateTransporter ()
@property (nonnull, nonatomic, strong) NSHashTable *delegates;
@end
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DelegateTransporter.m
@interface DelegateTransporter ()
@property (nonnull, nonatomic, strong) NSHashTable *delegates;
@end
ྻͰड͚औͬͨdelegateΛऑࢀরͰอ͍࣋ͨ͠ͷͰɺ
NSHashTableΛར༻͢Δɻself.delegates[NSHashTable
weakObjectsHashTable]ͰॳظԽ͢Δɻ
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DelegateTransporter.m
@interface DelegateTransporter ()
@property (nonnull, nonatomic, strong) NSHashTable *delegates;
@end
@implementation DelegateTransporter
- (instancetype)initWithDelegates:(NSArray *)delegates {
self = [super init];
if (self != nil) {
self.delegates = [NSHashTable weakObjectsHashTable];
for (id delegate in delegates) {
if (![delegates isKindOfClass:[NSObject class]]) {
continue;
}
[self.delegates addObject:delegate];
}
}
return self;
}
//...etc
@end
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Message Forwarding
https://developer.apple.com/library/content/documentation/
Cocoa/Conceptual/ObjCRuntimeGuide/Articles/
ocrtForwarding.html
Apple Sample Code
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DelegateTransporter.m
- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector {
for (NSObject *delegate in self.delegates) {
if ([delegate isKindOfClass:[NSNull class]]) { continue; }
if ([delegate respondsToSelector:aSelector]) { return [delegate methodSignatureForSelector:aSelector]; }
}
return nil;
}
- (void)forwardInvocation:(NSInvocation *)anInvocation {
for (NSObject *delegate in self.delegates) {
if ([delegate isKindOfClass:[NSNull class]]) { continue; }
if ([delegate respondsToSelector:anInvocation.selector]) { [anInvocation invokeWithTarget:delegate]; }
}
}
- (BOOL)respondsToSelector:(SEL)aSelector {
for (NSObject *delegate in self.delegates) {
if ([delegate isKindOfClass:[NSNull class]]) { continue; }
if ([delegate respondsToSelector:aSelector]) { return YES; }
}
return NO;
}
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UITableViewDelegateTransporter
class UITableViewDelegateTransporter: DelegateTransporter, UITableViewDelegate {
@nonobjc convenience init(delegates: [UITableViewDelegate]) {
self.init(__delegates: delegates)
}
}
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UITableView.ReachExtension
extension UITableView {
final class ReachExtension: NSObject {
private var delegateTransporter: UITableViewDelegateTransporter? {
didSet { base?.delegate = delegateTransporter }
}
weak var delegate: UITableViewDelegate? {
didSet {
guard let delegate = delegate else {
delegateTransporter = nil
return
}
delegateTransporter = UITableViewDelegateTransporter(delegates: [delegate, self])
}
}
fileprivate var reachedBottom: Bool = false {
didSet {
if reachedBottom == oldValue { return }
guard let base = base, reachedBottom else { return }
scrollViewDidReachBottom?(base)
}
}
var scrollViewDidReachBottom: ((UIScrollView) -> ())?
private weak var base: UITableView?
init(_ base: UITableView) {
self.base = base
super.init()
}
}
}
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UITableView.ReachExtension
extension UITableView.ReachExtension: UITableViewDelegate {
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let maxDistance = max(0, scrollView.contentSize.height - scrollView.bounds.size.height)
reachedBottom = maxDistance < scrollView.contentOffset.y
}
}
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UITableView
extension UITableView {
private struct AssociatedKey {
static var re: UInt8 = 0
}
var re: ReachExtension {
guard let re = objc_getAssociatedObject(self, &AssociatedKey.re) as? ReachExtension else {
let re = ReachExtension(self)
objc_setAssociatedObject(self, &AssociatedKey.re, re, .OBJC_ASSOCIATION_RETAIN)
return re
}
return re
}
}
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reΛফ͚ͩ͢Ͱ௨ৗͷڍಈʹ
tableView.re.delegate = self
↓
tableView.delegate = self
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Advanced Usage
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• UIViewControllerͳͲͰɺtableView.transform = .init(rotationAngle: .pi)Λهड़
͠ͳ͚ΕͳΒͳ͍
• UIViewControllerͳͲͰɺUITableViewͷcontentInsetscrollIndicatorInsetsͳ
ͲΛసͤ͞Δهड़Λ͠ͳ͚ΕͳΒͳ͍
• UITableViewCellͷawakeFromNibʹtransform = .init(rotationAngle: .pi)ΛCell
͝ͱʹهड़͠ͳ͚ΕͳΒͳ͍
స͕ෆཁʹͳͬͨ߹ʹɺ্هͷ࣮Λͯ͢আ͠ͳ͚Ε
ͳΒͳ͘ͳΔ
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ReverseExtension
https://github.com/marty-suzuki/ReverseExtension
extension UITableView {
final class ReverseExtension: NSObject {
//some implementation
//...
private var lastScrollIndicatorInsets: UIEdgeInsets?
private var lastContentInset: UIEdgeInsets?
private var mutex = pthread_mutex_t()
init(_ base: UITableView) {
self.base = base
super.init()
configureTableView(base)
}
//some implementation
//...
}
}
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UITableView.ReverseExtension
private func configureTableView(_ tableView: UITableView) {
guard let base = self.base else { return }
if base.transform == CGAffineTransform.identity {
UIView.setAnimationsEnabled(false)
base.transform = CGAffineTransform.identity.rotated(by: .pi)
UIView.setAnimationsEnabled(true)
}
tableView.addObserver(self,
forKeyPath: #keyPath(UITableView.contentInset),
options: [.new, .old],
context: nil)
}
public override func observeValue(forKeyPath keyPath: String?,
of object: Any?,
change: [NSKeyValueChangeKey : Any]?,
context: UnsafeMutableRawPointer?) {
switch keyPath {
case (#keyPath(UITableView.contentInset))?:
DispatchQueue.global().async { [weak self] in
DispatchQueue.main.async {
self?.configureTableViewInsets()
}
}
default:
break
}
}
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UITableView.ReverseExtension
private func configureTableViewInsets() {
defer { pthread_mutex_unlock(&mutex) }
pthread_mutex_lock(&mutex)
guard let base = base else { return }
if let _ = self.lastContentInset, let _ = self.lastScrollIndicatorInsets { return }
let contentInset = base.contentInset
base.contentInset.bottom = contentInset.top
base.contentInset.top = contentInset.bottom
self.lastContentInset = base.contentInset
let scrollIndicatorInsets = base.scrollIndicatorInsets
base.scrollIndicatorInsets.bottom = scrollIndicatorInsets.top
base.scrollIndicatorInsets.top = scrollIndicatorInsets.bottom
base.scrollIndicatorInsets.right = base.bounds.size.width - 8
self.lastScrollIndicatorInsets = base.scrollIndicatorInsets
}
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UITableView.ReverseExtension
extension UITableView.ReverseExtension: UITableViewDelegate {
func tableView(_ tableView: UITableView,
willDisplay cell: UITableViewCell,
forRowAt indexPath: IndexPath) {
if cell.transform == CGAffineTransform.identity {
UIView.setAnimationsEnabled(false)
cell.transform = CGAffineTransform.identity.rotated(by: .pi)
UIView.setAnimationsEnabled(true)
}
}
}
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tableView(_:willDisplay:forRowAt:)
ʹUITableViewCellͷసॲཧΛهड़͢Δ͜ͱͰ
֤UITableViewCellͷawakeFromNibʹ
هड़͢Δ͜ͱ͕ෆཁʹ
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͏Ұݴ͍·͕͢ɺreΛফ͚ͩ͢Ͱ௨ৗͷڍಈʹ
tableView.re.delegate = self
↓
tableView.delegate = self
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ϞόΠϧΞϓϦ։ൃΤΩεύʔτཆಡຊʢ4/11ൃചʣ
https://www.amazon.co.jp/dp/4774188638
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͝੩ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠ʂ
marty-suzuki