Olivier Halligon
72 lines
2.3 KiB
Swift
72 lines
2.3 KiB
Swift
//
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// FetchableTrait.swift
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// Dip
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//
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// Created by Olivier Halligon on 09/10/2015.
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// Copyright © 2015 AliSoftware. All rights reserved.
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//
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import UIKit
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protocol FetchableTrait: class {
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typealias ObjectType
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var objects: [ObjectType]? { get set }
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var batchRequestID: Int { get set }
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var tableView: UITableView! { get }
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func fetchIDs(completion: [Int] -> Void)
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func fetchOne(id: Int, completion: ObjectType? -> Void)
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var fetchProgress: (current: Int, total: Int?) { get set }
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}
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extension FetchableTrait {
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func loadObjects(objectIDs: [Int]) {
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self.batchRequestID += 1
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let batch = self.batchRequestID
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objects?.removeAll()
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fetchProgress = (0,objectIDs.count)
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for objectID in objectIDs {
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fetchOne(objectID) { (object: ObjectType?) in
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// Exit if we failed to retrive an object for this ID, or if the request
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// should be ignored because a new batch request has been started since
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guard let object = object where batch == self.batchRequestID else { return }
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if self.objects == nil { self.objects = [] }
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self.objects?.append(object)
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self.fetchProgress.current = self.objects?.count ?? 0
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self.tableView?.reloadData()
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}
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}
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}
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func loadFirstPage() {
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self.batchRequestID += 1
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let batch = self.batchRequestID
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fetchProgress = (0, nil)
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fetchIDs() { objectIDs in
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guard batch == self.batchRequestID else { return }
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self.loadObjects(objectIDs)
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}
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}
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func displayProgressInNavBar(navigationItem: UINavigationItem) {
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let text: String
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if let total = fetchProgress.total {
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if fetchProgress.current == fetchProgress.total {
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text = "Done."
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} else {
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text = "Loading \(fetchProgress.current) / \(total)…"
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}
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} else {
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text = "Loading IDs…"
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}
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let label = UILabel(frame: CGRect(x: 0, y: 0, width: 0, height: 0))
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label.text = text
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label.textColor = .grayColor()
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label.font = .systemFontOfSize(12)
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label.sizeToFit()
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navigationItem.rightBarButtonItem = UIBarButtonItem(customView: label)
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}
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}
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