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finish retry load more customization, add UIApplication states handling and cover public methods with documentation

This commit is contained in:
Ivan Smolin 2017-04-11 13:12:19 +03:00
parent 7355ebc858
commit b3dface0c8
5 changed files with 219 additions and 62 deletions
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213
LeadKit/LeadKit/Classes/Pagination/PaginationTableViewWrapper.swift
View File

@ -24,57 +24,81 @@ import UIKit
import RxSwift
import UIScrollView_InfiniteScroll
/// PaginationTableViewWrapper delegate used for pagination results handling and
/// customization of bound states (loading, empty, error, etc.).
public protocol PaginationTableViewWrapperDelegate: class {
associatedtype Cursor: ResettableCursorType
/// Delegate method that handles loading new chunk of data.
///
/// - Parameters:
/// - wrapper: Wrapper object that loaded new items.
/// - newItems: New items.
func paginationWrapper(wrapper: PaginationTableViewWrapper<Cursor, Self>,
didLoad newItems: [Cursor.Element])
/// Delegate method that handles reloading or initial loading of data.
///
/// - Parameters:
/// - wrapper: Wrapper object that reload items.
/// - allItems: New items.
func paginationWrapper(wrapper: PaginationTableViewWrapper<Cursor, Self>,
didReload allItems: [Cursor.Element])
/// Delegate method that returns placeholder view for empty state.
///
/// - Parameter wrapper: Wrapper object that requests empty placeholder view.
/// - Returns: Configured instace of UIView.
func emptyPlaceholder(forPaginationWrapper wrapper: PaginationTableViewWrapper<Cursor, Self>) -> UIView
/// Delegate method that returns placeholder view for error state.
///
/// - Parameters:
/// - wrapper: Wrapper object that requests error placeholder view.
/// - error: Error that occured due data loading.
/// - Returns: Configured instace of UIView.
func errorPlaceholder(forPaginationWrapper wrapper: PaginationTableViewWrapper<Cursor, Self>,
forError error: Error) -> UIView
/// Delegate method that returns loading idicator for initial loading state.
/// This indicator will appear at center of the placeholders container.
///
/// - Parameter wrapper: Wrapper object that requests loading indicator
/// - Returns: Configured instace of AnyLoadingIndicator.
func initialLoadingIndicator(forPaginationWrapper wrapper: PaginationTableViewWrapper<Cursor, Self>) -> AnyLoadingIndicator
/// Delegate method that returns loading idicator for initial loading state.
///
/// - Parameter wrapper: Wrapper object that requests loading indicator.
/// - Returns: Configured instace of AnyLoadingIndicator.
func loadingMoreIndicator(forPaginationWrapper wrapper: PaginationTableViewWrapper<Cursor, Self>) -> AnyLoadingIndicator
/// Delegate method that returns instance of UIButton for "retry load more" action.
///
/// - Parameter wrapper: Wrapper object that requests button for "retry load more" action.
/// - Returns: Configured instace of AnyLoadingIndicator.
func retryLoadMoreButton(forPaginationWrapper wrapper: PaginationTableViewWrapper<Cursor, Self>) -> UIButton
/// Delegate method that returns preferred height for "retry load more" button.
///
/// - Parameter wrapper: Wrapper object that requests height "retry load more" button.
/// - Returns: Preferred height of "retry load more" button.
func retryLoadMoreButtonHeight(forPaginationWrapper wrapper: PaginationTableViewWrapper<Cursor, Self>) -> CGFloat
}
public class PaginationTableViewWrapper<C: ResettableCursorType, D: PaginationTableViewWrapperDelegate>
/// Class that connects PaginationViewModel with UITableView. It handles all non-visual and visual states.
final public class PaginationTableViewWrapper<C: ResettableCursorType, D: PaginationTableViewWrapperDelegate>
where D.Cursor == C {
public typealias PlaceholderTransform = (UIView, CGPoint) -> Void
private let tableView: UITableView
private let placeholdersContainerView: UIView
private let paginationViewModel: PaginationViewModel<C>
private weak var delegate: D?
public var placeholderTransformOnScroll: PlaceholderTransform = { view, offset in
var newFrame = view.frame
newFrame.origin.y = -offset.y
view.frame = newFrame
}
public var scrollObservable: Observable<CGPoint>? {
didSet {
scrollObservable?.subscribe(onNext: { [weak self] offset in
guard let placeholder = self?.currentPlaceholderView else {
return
}
self?.placeholderTransformOnScroll(placeholder, offset)
})
.addDisposableTo(disposeBag)
}
}
/// Sets the offset between the real end of the scroll view content and the scroll position,
/// so the handler can be triggered before reaching end. Defaults to 0.0;
public var infiniteScrollTriggerOffset: CGFloat {
get {
return tableView.infiniteScrollTriggerOffset
@ -89,47 +113,52 @@ where D.Cursor == C {
private var currentPlaceholderView: UIView?
private let applicationCurrentyActive = Variable<Bool>(false)
private var waitingOperations: [() -> Void] = []
/// Initializer with table view, placeholders container view, cusor and delegate parameters.
///
/// - Parameters:
/// - tableView: UITableView instance to work with.
/// - placeholdersContainer: UIView container to be used for placeholders.
/// - cursor: Cursor object that acts as data source.
/// - delegate: Delegate object for data loading events handling and UI customization.
public init(tableView: UITableView, placeholdersContainer: UIView, cursor: C, delegate: D) {
self.tableView = tableView
self.placeholdersContainerView = placeholdersContainer
self.paginationViewModel = PaginationViewModel(cursor: cursor)
self.delegate = delegate
paginationViewModel.state.drive(onNext: { [weak self] state in
print(state)
switch state {
case .initial:
self?.onInitialState()
case .loading(let after):
self?.onLoadingState(afterState: after)
case .loadingMore(let after):
self?.onLoadingMoreState(afterState: after)
case .results(let newItems, let after):
self?.onResultsState(newItems: newItems, afterState: after)
case .error(let error, let after):
self?.onErrorState(error: error, afterState: after)
case .empty:
self?.onEmptyState()
case .exhausted:
self?.onExhaustedState()
}
})
.addDisposableTo(disposeBag)
bindViewModelStates()
let refreshControl = UIRefreshControl()
refreshControl.rx.controlEvent(.valueChanged)
.bindNext { [weak self] in
self?.reload()
}
.addDisposableTo(disposeBag)
createRefreshControl()
tableView.support.setRefreshControl(refreshControl)
bindAppStateNotifications()
}
/// Method that reload all data in internal view model.
public func reload() {
paginationViewModel.load(.reload)
}
/// Method that enables placeholders animation due pull-to-refresh interaction.
///
/// - Parameter scrollObservable: Observable that emits content offset as CGPoint.
public func setScrollObservable(_ scrollObservable: Observable<CGPoint>) {
scrollObservable.subscribe(onNext: { [weak self] offset in
guard let placeholder = self?.currentPlaceholderView else {
return
}
var newFrame = placeholder.frame
newFrame.origin.y = -offset.y
placeholder.frame = newFrame
})
.addDisposableTo(disposeBag)
}
// MARK: States handling
private func onInitialState() {
@ -165,7 +194,7 @@ where D.Cursor == C {
}
private func onLoadingMoreState(afterState: PaginationViewModel<C>.State) {
if case .error = afterState {
if case .error = afterState { // user tap retry button in table footer
tableView.tableFooterView = nil
addInfiniteScroll()
tableView.beginInfiniteScroll(true)
@ -206,10 +235,13 @@ where D.Cursor == C {
tableView.removeInfiniteScroll()
let retryButton = UIButton(type: .custom)
retryButton.backgroundColor = .lightGray
retryButton.frame = CGRect(x: 0, y: 0, width: tableView.bounds.width, height: 44)
retryButton.setTitle("Retry load more", for: .normal)
guard let retryButton = delegate?.retryLoadMoreButton(forPaginationWrapper: self),
let retryButtonHeigth = delegate?.retryLoadMoreButtonHeight(forPaginationWrapper: self) else {
return
}
retryButton.frame = CGRect(x: 0, y: 0, width: tableView.bounds.width, height: retryButtonHeigth)
retryButton.rx.controlEvent(.touchUpInside)
.bindNext { [weak self] in
self?.paginationViewModel.load(.next)
@ -246,6 +278,51 @@ where D.Cursor == C {
tableView.infiniteScrollIndicatorView = delegate?.loadingMoreIndicator(forPaginationWrapper: self).view
}
private func createRefreshControl() {
let refreshControl = UIRefreshControl()
refreshControl.rx.controlEvent(.valueChanged)
.bindNext { [weak self] in
self?.reload()
}
.addDisposableTo(disposeBag)
tableView.support.setRefreshControl(refreshControl)
}
private func bindViewModelStates() {
paginationViewModel.state.drive(onNext: { [weak self] state in
let stateHandling = { [weak self] in
switch state {
case .initial:
self?.onInitialState()
case .loading(let after):
self?.onLoadingState(afterState: after)
case .loadingMore(let after):
self?.onLoadingMoreState(afterState: after)
case .results(let newItems, let after):
self?.onResultsState(newItems: newItems, afterState: after)
case .error(let error, let after):
self?.onErrorState(error: error, afterState: after)
case .empty:
self?.onEmptyState()
case .exhausted:
self?.onExhaustedState()
}
}
guard let strongSelf = self else {
return
}
if strongSelf.applicationCurrentyActive.value {
stateHandling()
} else {
strongSelf.waitingOperations.append(stateHandling)
}
})
.addDisposableTo(disposeBag)
}
private func enterPlaceholderState() {
tableView.support.refreshControl?.endRefreshing()
tableView.isUserInteractionEnabled = true
@ -260,6 +337,32 @@ where D.Cursor == C {
placeholderView.anchorConstrainst(to: placeholdersContainerView).forEach { $0.isActive = true }
}
private func bindAppStateNotifications() {
let notificationCenter = NotificationCenter.default.rx
notificationCenter.notification(.UIApplicationWillResignActive)
.subscribe(onNext: { [weak self] _ in
self?.applicationCurrentyActive.value = false
})
.addDisposableTo(disposeBag)
notificationCenter.notification(.UIApplicationDidBecomeActive)
.subscribe(onNext: { [weak self] _ in
self?.applicationCurrentyActive.value = true
})
.addDisposableTo(disposeBag)
applicationCurrentyActive.asDriver()
.drive(onNext: { [weak self] appActive in
if appActive {
self?.waitingOperations.forEach { $0() }
self?.waitingOperations = []
}
})
.addDisposableTo(disposeBag)
}
}
private extension UIView {

43
LeadKit/LeadKit/Classes/Pagination/PaginationViewModel.swift
View File

@ -23,22 +23,44 @@
import RxSwift
import RxCocoa
/// Cursor type which can be resetted
public typealias ResettableCursorType = CursorType & ResettableType
/// Class that encapsulate all pagination logic
public final class PaginationViewModel<C: ResettableCursorType> {
/// Enum contains all possible states for PaginationViewModel class.
///
/// - initial: initial state of view model.
/// Can occur only once after initial binding.
/// - loading: loading state of view model. Contains previous state of view model.
/// Can occur after any state.
/// - loadingMore: loading more items state of view model. Contains previous state of view model.
/// Can occur after error or results state.
/// - results: results state of view model. Contains loaded items and previous state of view model.
/// Can occur after loading or loadingMore state.
/// - error: error state of view model. Contains received error and previous state of view model.
/// Can occur after loading or loadingMore state.
/// - empty: empty state of view model.
/// Can occur after loading or loadingMore state when we got empty result (zero items).
/// - exhausted: exhausted state of view model.
/// Can occur after results state or after initial->loading state when cursor reports that it's exhausted.
public indirect enum State {
case initial
case loading(after: State) // can be after any state
case loadingMore(after: State) // can be after error or results
case results(newItems: [C.Element], after: State) // can be after loading or loadingMore
case error(error: Error, after: State) // can be after loading or loadingMore
case empty // can be after loading or loadingMore
case exhausted // can be after results
case loading(after: State)
case loadingMore(after: State)
case results(newItems: [C.Element], after: State)
case error(error: Error, after: State)
case empty
case exhausted
}
/// Enum represents possible load types for PaginationViewModel class
///
/// - reload: reload all items and reset cursor to initial state.
/// - next: load next batch of items.
public enum LoadType {
case reload
@ -54,14 +76,21 @@ public final class PaginationViewModel<C: ResettableCursorType> {
private let internalScheduler = SerialDispatchQueueScheduler(qos: .default)
/// Current PaginationViewModel state Driver
public var state: Driver<State> {
return internalState.asDriver()
}
/// Initializer with enclosed cursor
///
/// - Parameter cursor: cursor to use for pagination
public init(cursor: C) {
self.cursor = cursor
}
/// Mathod which triggers loading of items.
///
/// - Parameter loadType: type of loading. See LoadType enum.
public func load(_ loadType: LoadType) {
switch loadType {
case .reload:
@ -71,7 +100,7 @@ public final class PaginationViewModel<C: ResettableCursorType> {
internalState.value = .loading(after: internalState.value)
case .next:
if case .exhausted(_) = internalState.value {
preconditionFailure("You shouldn't call load(.next) after got .exhausted state!")
fatalError("You shouldn't call load(.next) after got .exhausted state!")
}
internalState.value = .loadingMore(after: internalState.value)

12
LeadKit/LeadKit/Extensions/PaginationTableViewWrapperDelegate/PaginationTableViewWrapperDelegate+DefaultImplementation.swift
View File

@ -71,4 +71,16 @@ public extension PaginationTableViewWrapperDelegate {
return AnyLoadingIndicator(indicator)
}
func retryLoadMoreButton(forPaginationWrapper wrapper: PaginationTableViewWrapper<Cursor, Self>) -> UIButton {
let retryButton = UIButton(type: .custom)
retryButton.backgroundColor = .lightGray
retryButton.setTitle("Retry load more", for: .normal)
return retryButton
}
func retryLoadMoreButtonHeight(forPaginationWrapper wrapper: PaginationTableViewWrapper<Cursor, Self>) -> CGFloat {
return 44
}
}

6
LeadKit/LeadKit/Protocols/LoadingIndicatorProtocol.swift
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@ -22,17 +22,23 @@
import UIKit
/// Protocol that ensures that specific type support basic animation actions.
public protocol Animatable {
/// Method that starts animation.
func startAnimating()
/// Method that stops animation.
func stopAnimating()
}
/// Protocol that describes badic loading indicator.
public protocol LoadingIndicator {
/// Type of view. Should be instance of UIView with basic animation actions.
associatedtype View: UIView, Animatable
/// The underlying view.
var view: View { get }
}

7
LeadKit/LeadKit/Protocols/ResettableType.swift
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@ -22,14 +22,21 @@
import Foundation
/// Protocol that ensures that specific type can init new resetted instance from another instance.
public protocol ResettableType {
/// Initializer with other instance parameter.
///
/// - Parameter other: Other instance of specific type.
init(initialFrom other: Self)
}
public extension ResettableType {
/// Method that creates new resseted instance of self
///
/// - Returns: resseted instance of self
func reset() -> Self {
return Self(initialFrom: self)
}