Refactors save state thumbnail loading to prevent placeholder image flickering

This commit is contained in:
Riley Testut 2016-03-14 19:23:58 -05:00
parent 129cef9cb8
commit ba6805b0f1
6 changed files with 148 additions and 79 deletions

View File

@ -9,12 +9,30 @@
import Foundation
import ImageIO
public class LoadImageOperation: NSOperation
import Roxas
public class LoadImageOperation: RSTOperation
{
public let URL: NSURL
public var completionHandler: (UIImage? -> Void)?
public var imageCache: NSCache?
public var completionHandler: (UIImage? -> Void)? {
didSet {
self.completionBlock = {
rst_dispatch_sync_on_main_thread() {
self.completionHandler?(self.image)
}
}
}
}
public var imageCache: NSCache? {
didSet {
// Ensures if an image is cached, it will be returned immediately, to prevent temporary flash of placeholder image
self.immediate = self.imageCache?.objectForKey(self.URL) != nil
}
}
private var image: UIImage?
public init(URL: NSURL)
{
@ -28,23 +46,11 @@ public extension LoadImageOperation
{
override func main()
{
var image: UIImage?
defer
{
if !self.cancelled
{
dispatch_async(dispatch_get_main_queue()) {
self.completionHandler?(image)
}
}
}
guard !self.cancelled else { return }
if let cachedImage = self.imageCache?.objectForKey(self.URL) as? UIImage
{
image = cachedImage
self.image = cachedImage
return
}
@ -61,7 +67,7 @@ public extension LoadImageOperation
self.imageCache?.setObject(loadedImage, forKey: self.URL)
image = loadedImage
self.image = loadedImage
}
}
}

View File

@ -1,41 +0,0 @@
//
// NSOperationQueue+KeyValue.swift
// Delta
//
// Created by Riley Testut on 2/26/16.
// Copyright © 2016 Riley Testut. All rights reserved.
//
import Foundation
import ObjectiveC.runtime
extension NSOperationQueue
{
private struct AssociatedKeys
{
static var OperationsDictionary = "delta_operationsDictionary"
}
private var operationsDictionary: NSMapTable {
get {
return objc_getAssociatedObject(self, &AssociatedKeys.OperationsDictionary) as? NSMapTable ?? NSMapTable.strongToWeakObjectsMapTable()
}
set {
objc_setAssociatedObject(self, &AssociatedKeys.OperationsDictionary, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
}
func addOperation(operation: NSOperation, forKey key: AnyObject)
{
self.operationsDictionary.objectForKey(key)
self.addOperation(operation)
}
func operationForKey(key: AnyObject) -> NSOperation?
{
let operation = self.operationsDictionary.objectForKey(key) as? NSOperation
return operation
}
}

View File

@ -10,7 +10,6 @@
AF0535CD7331785FA15E0864 /* Pods.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 22506DA00971C4300AF90A35 /* Pods.framework */; };
BF090CF41B490D8300DCAB45 /* UIDevice+Vibration.m in Sources */ = {isa = PBXBuildFile; fileRef = BF090CF31B490D8300DCAB45 /* UIDevice+Vibration.m */; };
BF0CDDAD1C8155D200640168 /* LoadImageOperation.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF0CDDAC1C8155D200640168 /* LoadImageOperation.swift */; };
BF0CDDAF1C81604100640168 /* NSOperationQueue+KeyValue.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF0CDDAE1C81604100640168 /* NSOperationQueue+KeyValue.swift */; };
BF107EC41BF413F000E0C32C /* GamesViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF107EC31BF413F000E0C32C /* GamesViewController.swift */; };
BF172AEB1C68986300C26774 /* NSManagedObjectContext+Conveniences.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF172AEA1C68986300C26774 /* NSManagedObjectContext+Conveniences.swift */; };
BF172AEC1C68986300C26774 /* NSManagedObjectContext+Conveniences.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF172AEA1C68986300C26774 /* NSManagedObjectContext+Conveniences.swift */; };
@ -135,7 +134,6 @@
BF090CF21B490D8300DCAB45 /* UIDevice+Vibration.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "UIDevice+Vibration.h"; sourceTree = "<group>"; };
BF090CF31B490D8300DCAB45 /* UIDevice+Vibration.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "UIDevice+Vibration.m"; sourceTree = "<group>"; };
BF0CDDAC1C8155D200640168 /* LoadImageOperation.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = LoadImageOperation.swift; path = Components/LoadImageOperation.swift; sourceTree = "<group>"; };
BF0CDDAE1C81604100640168 /* NSOperationQueue+KeyValue.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "NSOperationQueue+KeyValue.swift"; sourceTree = "<group>"; };
BF107EC31BF413F000E0C32C /* GamesViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = GamesViewController.swift; sourceTree = "<group>"; };
BF172AEA1C68986300C26774 /* NSManagedObjectContext+Conveniences.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "NSManagedObjectContext+Conveniences.swift"; sourceTree = "<group>"; };
BF1FB1821C5EE643007E2494 /* SaveState+CoreDataProperties.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "SaveState+CoreDataProperties.swift"; sourceTree = "<group>"; };
@ -318,7 +316,6 @@
children = (
BF762EAA1BC1B076002C8866 /* NSManagedObject+Conveniences.swift */,
BF172AEA1C68986300C26774 /* NSManagedObjectContext+Conveniences.swift */,
BF0CDDAE1C81604100640168 /* NSOperationQueue+KeyValue.swift */,
);
path = Extensions;
sourceTree = "<group>";
@ -723,7 +720,6 @@
BF1FB1861C5EE643007E2494 /* SaveState.swift in Sources */,
BFB141181BE46934004FBF46 /* GameCollectionViewDataSource.swift in Sources */,
BF1FB1841C5EE643007E2494 /* SaveState+CoreDataProperties.swift in Sources */,
BF0CDDAF1C81604100640168 /* NSOperationQueue+KeyValue.swift in Sources */,
BFFB709F1AF99B1700DE56FE /* EmulationViewController.swift in Sources */,
BFAA1FF41B8AD7F900495943 /* ControllersSettingsViewController.swift in Sources */,
BF353FF91C5D870B00C1184C /* PauseItem.swift in Sources */,

View File

@ -0,0 +1,97 @@
<?xml version="1.0" encoding="UTF-8"?>
<Scheme
LastUpgradeVersion = "0710"
version = "1.3">
<BuildAction
parallelizeBuildables = "YES"
buildImplicitDependencies = "YES">
<BuildActionEntries>
<BuildActionEntry
buildForTesting = "YES"
buildForRunning = "YES"
buildForProfiling = "YES"
buildForArchiving = "YES"
buildForAnalyzing = "YES">
<BuildableReference
BuildableIdentifier = "primary"
BlueprintIdentifier = "BFFA71D61AAC406100EE9DD1"
BuildableName = "Delta.app"
BlueprintName = "Delta"
ReferencedContainer = "container:Delta.xcodeproj">
</BuildableReference>
</BuildActionEntry>
</BuildActionEntries>
</BuildAction>
<TestAction
buildConfiguration = "Debug"
selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
shouldUseLaunchSchemeArgsEnv = "YES">
<Testables>
</Testables>
<MacroExpansion>
<BuildableReference
BuildableIdentifier = "primary"
BlueprintIdentifier = "BFFA71D61AAC406100EE9DD1"
BuildableName = "Delta.app"
BlueprintName = "Delta"
ReferencedContainer = "container:Delta.xcodeproj">
</BuildableReference>
</MacroExpansion>
<AdditionalOptions>
</AdditionalOptions>
</TestAction>
<LaunchAction
buildConfiguration = "Debug"
selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
launchStyle = "0"
useCustomWorkingDirectory = "NO"
ignoresPersistentStateOnLaunch = "NO"
debugDocumentVersioning = "YES"
debugServiceExtension = "internal"
allowLocationSimulation = "YES">
<BuildableProductRunnable
runnableDebuggingMode = "0">
<BuildableReference
BuildableIdentifier = "primary"
BlueprintIdentifier = "BFFA71D61AAC406100EE9DD1"
BuildableName = "Delta.app"
BlueprintName = "Delta"
ReferencedContainer = "container:Delta.xcodeproj">
</BuildableReference>
</BuildableProductRunnable>
<CommandLineArguments>
<CommandLineArgument
argument = "-com.apple.CoreData.ConcurrencyDebug 1"
isEnabled = "YES">
</CommandLineArgument>
</CommandLineArguments>
<AdditionalOptions>
</AdditionalOptions>
</LaunchAction>
<ProfileAction
buildConfiguration = "Release"
shouldUseLaunchSchemeArgsEnv = "YES"
savedToolIdentifier = ""
useCustomWorkingDirectory = "NO"
debugDocumentVersioning = "YES">
<BuildableProductRunnable
runnableDebuggingMode = "0">
<BuildableReference
BuildableIdentifier = "primary"
BlueprintIdentifier = "BFFA71D61AAC406100EE9DD1"
BuildableName = "Delta.app"
BlueprintName = "Delta"
ReferencedContainer = "container:Delta.xcodeproj">
</BuildableReference>
</BuildableProductRunnable>
</ProfileAction>
<AnalyzeAction
buildConfiguration = "Debug">
</AnalyzeAction>
<ArchiveAction
buildConfiguration = "Release"
revealArchiveInOrganizer = "YES">
</ArchiveAction>
</Scheme>

View File

@ -45,7 +45,7 @@ class SaveStatesViewController: UICollectionViewController
private var fetchedResultsController: NSFetchedResultsController!
private let imageOperationQueue = NSOperationQueue()
private let imageOperationQueue = RSTOperationQueue()
private let imageCache = NSCache()
private let dateFormatter: NSDateFormatter
@ -122,7 +122,7 @@ extension SaveStatesViewController
super.viewWillAppear(animated)
}
override func didReceiveMemoryWarning()
{
super.didReceiveMemoryWarning()
@ -157,26 +157,36 @@ private extension SaveStatesViewController
self.backgroundView.hidden = false
}
}
}
private extension SaveStatesViewController
{
func configureCollectionViewCell(cell: GridCollectionViewCell, forIndexPath indexPath: NSIndexPath)
//MARK: - Configure Cell -
func configureCollectionViewCell(cell: GridCollectionViewCell, forIndexPath indexPath: NSIndexPath, ignoreExpensiveOperations ignoreOperations: Bool = false)
{
let saveState = self.fetchedResultsController.objectAtIndexPath(indexPath) as! SaveState
cell.imageView.backgroundColor = UIColor.whiteColor()
cell.imageView.image = UIImage(named: "DeltaPlaceholder")
let imageOperation = LoadImageOperation(URL: saveState.imageFileURL)
imageOperation.completionHandler = { image in
if let image = image
{
cell.imageView.image = image
if !ignoreOperations
{
let imageOperation = LoadImageOperation(URL: saveState.imageFileURL)
imageOperation.imageCache = self.imageCache
imageOperation.completionHandler = { image in
if let image = image
{
cell.imageView.image = image
}
}
}
self.imageOperationQueue.addOperation(imageOperation, forKey: indexPath)
// Ensure initially visible cells have loaded their image before they appear to prevent potential flickering from placeholder to thumbnail
if self.appearing
{
imageOperation.immediate = true
}
self.imageOperationQueue.addOperation(imageOperation, forKey: indexPath)
}
cell.maximumImageSize = CGSizeMake(self.prototypeCellWidthConstraint.constant, (self.prototypeCellWidthConstraint.constant / 8.0) * 7.0)
@ -293,7 +303,8 @@ extension SaveStatesViewController: UICollectionViewDelegateFlowLayout
{
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
{
self.configureCollectionViewCell(self.prototypeCell, forIndexPath: indexPath)
// No need to load images from disk just to determine size, so we pass true for ignoreExpensiveOperations
self.configureCollectionViewCell(self.prototypeCell, forIndexPath: indexPath, ignoreExpensiveOperations: true)
let size = self.prototypeCell.contentView.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize)
return size

2
External/Roxas vendored

@ -1 +1 @@
Subproject commit 6dc906703bb5870d268d341cefd1fdcc40001eb9
Subproject commit c795d0ace22cfe57c3b73613630e14b58d2f8f09