iKy1e | iOS Developer

It's a fairly simple request you'd imagine. Simply put a slider inside some content which scrolls.

As this is on iOS that content is obviously inside a UIScrollView.

  The Problem

The main problem with the above is that they don't like each other. If you place a standard UISlider inside a normal UIScrollView the scroll view delays the touches for a fraction of a second to see if you are scrolling. Here is the big problem, you swipe sideways to scroll and you, want to, swipe sideways on the sliders thumb to quickly change it's value.

As a result you have to tap, pause and then drag the slider in order to use it. Manageable but hardly smooth or ideal to use.

Of course there is a very simple way to avoid this.

scrollView.delaysContentTouches = NO;

Simple? Well, at least for me on iOS 5, a little too simple. This caused almost all objects to prevent my scrollView from scrolling, buttons, sliders, even an image view seemed to block it. So we filter for the slider?

If we look at the UIScrollView documentation we see a few little things that allow us to control the delays and cancelling touches. Creating a custom subclass gives us a little more power, but still not enough.

What do we do with our new subclass then? Well, we need to control when to allow touches to behave normally and when we should scroll.

@interface KHCustomScrollView : UIScrollView @property (nonatomic, assign) BOOL ignoreSliders; @end @implementation KHCustomScrollView @synthesize ignoreSliders = _ignoreSliders; -(BOOL)touchesShouldCancelInContentView:(UIView *)view{ if (self.ignoreSliders) { if ([view isKindOfClass:[UISlider class]]) { return NO; } else { return YES; } } return [super touchesShouldCancelInContentView:view]; } @end // Somewhere else... scrollView.canCancelContentTouches = YES; scrollView.delaysContentTouches = NO; scrollView.ignoreSliders = YES;

What we do here is tell it we want the scrollView to let all touches to start normally, but we want it to be able to cancel them if it wants to scroll. Instead of the normal behavour of delaying them until its decided whether or not to scroll it now cancels touches when it wants to. Then we have our scrollView say it can cancel touches and start scrolling for everything, other than sliders.

Now can you guess the problem here?

If we touch anywhere on the slider it will not scroll, however the slider only responds over the thumb image that indicates the value selected. But we can fix this too, however we have to work with the sliders themselves :(, although luckily we don't need to subclass them.

// Somewhere... -(void)monitorSlider:(UISlider*)slider{ [slider addTarget:self action:@selector(willSlide:) forControlEvents:UIControlEventTouchDown]; [slider addTarget:self action:@selector(didSlide:) forControlEvents:UIControlEventTouchUpInside]; [slider addTarget:self action:@selector(didSlide:) forControlEvents:UIControlEventTouchUpOutside]; [slider addTarget:self action:@selector(didSlide:) forControlEvents:UIControlEventTouchCancel]; } -(void)willSlide:(id)sender{ scrollView.scrollEnabled = NO; } -(void)didSlide:(id)sender{ scrollView.scrollEnabled = YES; } // Someone else... [self monitorSlider:slider]; // In our scrollView subclass we made earilier if ([view isKindOfClass:[UISlider class]] && !self.scrollEnabled) { return NO; }

By the way that `scrollView.scrollEnabled` is only state storage. It could have been written scrollView.tag = 42, if (scrollView.tag == 42) ...

So now we allow touches to reach things inside the scrollView, we know when the slider was touched on its thumb image, and we can control which touches are canceled and which are allowed to prevent us from scrolling.

Toggling things like wifi or bluetooth on and off quickly and conveniently is a feature that has been added to lots of apps and tweaks since very early on since iOS was first jailbroken.

In the past

This trend started off with things like Bossprefs which managed various settings on the device but was a stand alone app and didn't have much flexibility:

Then you have SBSettings. SBSettings got lots of attention and quickly became one of the default things people installed on their jailbroken devices once they finished jailbreaking. And of cause it has it's own API so other developers could have it control their things, such as SSH or UserAgentFaker.

The problem with SBSettings API is it was designed quite early in iOS's history and so isn't designed very natively and could be much better (more on that later). It has it's advantages though, isn't quite simple. Each toggle has a dylib with a few simple C functions. SBSettings opens them and calls the functions to make things happen or check it's state. It also includes some more advanced options like presenting extra windows to show things like a list of processes running or a slider for the brightness. As a sign of it's age it must respring to reload it's settings. When it was designed that was the norm and having a tweak which could adapt to settings on the fly without resrpinging would be a killer feature.

Now

iOS and ObjectiveC has moved on quite a bit now and is much more advanced and more refined then it was. SBSettings was good but after iOS 4 I stopped using it. This was mostly down to notification centre taking over as the "above" window on my device. Having 2 windows that drop down form the top of the screen as a control centre for my device each activated under different circumstances just feels wrong, so I don't us it anymore (and it although quite a few people still use it, it isn't as popular as it once was).

NCSettings has mostly replaced it for me. SBSettings has a mode to run inside notification centre but it just doesn't fit well. It has been adapted quite well, but it and it's toggles weren't designed for that purpose. NCSettings by comparison was designed from the start to run in the notification centre and fits in very well with a minimal stripped back design.

And now everything offers some basic controls and toggles. Deck is an example of something like NCSettings designed to do just that. However, lots of tweaks now offer some sort of toggles, Auxo for example extends the simple mute/orientation lock toggle in the switcher to a more general control of the devices basic features. The problem with all these things is they are limited to what you can convince the developer to add support for and anything like SSH or your own add-on which is a separate package and my not be installed on everyones devices is going to be a hard sale to get added. In short none of them have an API and there's defiantly not a unified API among them. The closest I've seen is a tweak using SBSettings API for itself.

If you haven't already read @olebegemann's blog post about _UIRemoteView's and remote view controllers new in iOS 6 then please do so now and come back to this after you have finished it.

http://oleb.net/blog/2012/10/remote-view-controllers-in-ios-6/

  When I first read this post about iOS 6 and _UIRemoteView's which allowed apple to move things like email into different processes and still display them as if they where in the app there was one point I that caught my attention more then it would most peoples.

<_UIRemoteView: 0x1e05c300; frame = (0 0; 320 480); transform = [0.5, -0, 0, 0.5, -0, 0]; userInteractionEnabled = NO; layer = <CALayerHost: 0x1e05c460>>

CALayerHost, the instant I sure that I thought, "wow, Apple finally put it to good use'. From my experiments with CardSwitcher I have come across CALayerHost's before. They are actually how CardSwitcher's live views work. More then displaying part of an app, however, they also allow interaction through to that app (although that is buggy iOS 5, haven't tested 6 yet). For CardSwitcher to use them as live views into apps it actually has to block interaction, if you remove that you get this http://www.youtube.com/watch?v=1D1NyXITjI0.

If you are a heavy email user you will likely have noticed in iOS's default mail app you have to select each and every email separately, so if you want to select lots, say 30 emails, you have to scroll through the list selecting each and every one. Check allows you to just tap and hold on an email and then scroll as far as you like before tapping another. Everything between those 2 emails will be selected (or deselected) automatically.

The idea was originally Joshua Tucker's and he planned out the details, like the flashing animation to show which is the start point, and then I worked out how to implement them. 

http://www.idownloadblog.com/2012/07/09/check/

I recently released a joint project with Jonas Gessner called MountainCenter, it was inspired by MountainLion's implementation of NotificationCenter which has the notification center appear from under the right hand side of the screen.

It also has a smooth dragging gesture from the edge of the screen to drag it over and reveal the notification center underneath.

http://www.idownloadblog.com/2012/06/23/mountain-center-cydia/

For the last 2 months almost all my work has been on reversing how iOS displays apps on screen. There are a few ways to get the display information and pass touch events down to the application. Currently I'd like to think I understand about 80-90% of how SpringBoard manages and displays apps.

For instance, when the App Switcher launches it doesn't move the applications window 'up' as it looks like visually but rather displays a view that is rendering the applications SBContext's instead of it. That is then moved up so the application itself is not involved (why if you check the window's frame of an application it doesn't change with the app switcher's opening and closing.

Once the iPad is jailbroken I'll start writing this up into an actual tweak, mostly for iPhone apps on iPad (but it's big enough for multiple iPad apps on screen too). Also once I'm confident I understand iOS's app rendering fully I plan to release my notes on it all.

CardSwitcher

I've also been rewriting CardSwitcher and to put more thought into the API's design, the first one wasn't designed to do more then the WebOS style interface mode and the UI & data stuff where horrible interlinked.

My work on understanding how iOS displays things also means I have a new faster, better & just generally much improved way to get screenshots of the apps (unlike multifl0w which uses UIGetScreenImage() this method won't capture the app switcher if it's open, for example). And I can also now have a live view of any currently running apps (open or backgrounded with backgrounder) rather then a static image. Another small improvement is pausing the application when entering CardSwitcher, like the app switcher does. By pausing I don't mean suspending but informing the app that the appswitcher is open and so games should open the pause menu, ext.

I've been working with the SBDisplayStack's lately and trying to control how apps launch and finally got it working, much more simply then a was trying originally.

The finished code has been put together into an opensource library on GitHub called LibDisplay.

One odd thing that caught me out, for ages, is you have to start launching the next app before getting rid of the current one.

/* References: * http://iky1e.tumblr.com/post/13985531616/raw-log-sbdisplay-settings * http://iphonedevwiki.net/index.php/SBDisplay * http://iphonedevwiki.net/index.php/SBDisplayStack * http://code.google.com/p/iphone-tweaks/wiki/DevelopmentNotes */ -(void)activateApplication:(SBApplication *)toApp animated:(BOOL)animated{ // Get the currently open application. SBApplication *fromApp = [self topApplication]; // Check if it's the same as the currently open application, if it is there's nothing todo. if ([[toApp displayIdentifier] isEqualToString:[fromApp displayIdentifier]]) return; // If animated they want the system default (app to app transition, or zoom on homescreen). if (animated && toApp) { [(SBUIController*)[objc_getClass("SBUIController") sharedInstance] activateApplicationFromSwitcher:toApp]; return; // Done, wasn't that easy. } // Now, if we were asked to, open the other app. if (toApp) { [toApp clearDisplaySettings]; [toApp clearActivationSettings]; [toApp clearDeactivationSettings]; // 20 = appToApp [toApp setActivationSetting:20 flag:YES]; // Note if it's a large application the user might see a brief flash of the homescreen. [[self SBWPreActivateDisplayStack] pushDisplay:toApp]; } // If another app is open then close it if (fromApp) { // Clear any animation settings the app may have [fromApp clearDisplaySettings]; [fromApp clearActivationSettings]; [fromApp clearDeactivationSettings]; // Now pop is from the Active displayStack [[self SBWActiveDisplayStack] popDisplay:fromApp]; // And push it onto the Suspending displayStack [[self SBWSuspendingDisplayStack] pushDisplay:fromApp]; } if (!toApp) { // The user should now be on the homescreen. // There's a bug above 4.? (4.1 or 4.2 I think) where the status bar won't be there. SBUIController *uiController = (SBUIController*)[objc_getClass("SBUIController") sharedInstance]; if ([uiController respondsToSelector:@selector(createFakeSpringBoardStatusBar)]) { [uiController createFakeSpringBoardStatusBar]; } } }

A few notes about this:

This info is "as of" iOS 5.0.1 and I can only confirm that it works on iOS 5.x.

although, Multifl0w pushes the displaystacks around itself and worked without modification (to the best of my knowledge) when iOS 5 was released (so it might not break very often).

This is how SpringBoard describes it's activation settings (there might be more but I stopped when it stopped telling me things).

Activation Setting

cy# [app descriptionForActivationSetting:1] "asPanel " cy# [app descriptionForActivationSetting:2] "suspended " cy# [app descriptionForActivationSetting:3] "URL " cy# [app descriptionForActivationSetting:4] "remoteNotification " cy# [app descriptionForActivationSetting:5] "localNotification " cy# [app descriptionForActivationSetting:6] "eventOnly " cy# [app descriptionForActivationSetting:7] "safe " cy# [app descriptionForActivationSetting:8] "animateOthersSuspension " cy# [app descriptionForActivationSetting:9] "didAnimateOthersSuspension " cy# [app descriptionForActivationSetting:10] "slideOthersSuspension " cy# [app descriptionForActivationSetting:11] "flipOthersSuspension " cy# [app descriptionForActivationSetting:12] "contextInfoForOthersSuspension " cy# [app descriptionForActivationSetting:13] "animateScaleForOthersSuspension " cy# [app descriptionForActivationSetting:14] "animationStartForOthersSuspension " cy# [app descriptionForActivationSetting:15] "animationStart " cy# [app descriptionForActivationSetting:16] "flip " cy# [app descriptionForActivationSetting:17] "animationDuration " cy# [app descriptionForActivationSetting:18] "animationDurationForOthersSuspension " cy# [app descriptionForActivationSetting:19] "firstLaunchAfterBoot " cy# [app descriptionForActivationSetting:20] "appToApp " cy# [app descriptionForActivationSetting:21] "activateFromLocked " cy# [app descriptionForActivationSetting:22] "originatingURLDisplayIdentifier " cy# [app descriptionForActivationSetting:23] "annotation " cy# [app descriptionForActivationSetting:24] "noAnimate " cy# [app descriptionForActivationSetting:25] "launchOptions " cy# [app descriptionForActivationSetting:26] "withNoZoomLayerSetting " cy# [app descriptionForActivationSetting:27] "launchImageName " cy# [app descriptionForActivationSetting:28] "fromSwitcher " cy# [app descriptionForActivationSetting:29] "shouldUnlockOrientationForSwitcherSetting " cy# [app descriptionForActivationSetting:30] "viaSlideTopAppToReveal " cy# [app descriptionForActivationSetting:31] "fromBanner " cy# [app descriptionForActivationSetting:32] "fromBulletinList " cy# [app descriptionForActivationSetting:33] "fromAssistant "

Deactivation Setting

cy# [app descriptionForDeactivationSetting:1] "eventOnly " cy# [app descriptionForDeactivationSetting:2] "animate " cy# [app descriptionForDeactivationSetting:3] "slide " cy# [app descriptionForDeactivationSetting:4] "animationStart " cy# [app descriptionForDeactivationSetting:5] "forceExit " cy# [app descriptionForDeactivationSetting:6] "afterNextLaunch " cy# [app descriptionForDeactivationSetting:7] "flip " cy# [app descriptionForDeactivationSetting:8] "contextInfo " cy# [app descriptionForDeactivationSetting:9] "animationScale " cy# [app descriptionForDeactivationSetting:10] "returnToLastApp " cy# [app descriptionForDeactivationSetting:11] "startForOthersActivation " cy# [app descriptionForDeactivationSetting:12] "killed " cy# [app descriptionForDeactivationSetting:13] "underLock " cy# [app descriptionForDeactivationSetting:14] "animationDuration " cy# [app descriptionForDeactivationSetting:15] "durationForOthersSuspension " cy# [app descriptionForDeactivationSetting:16] "deactivateAnimateOthersResumption " cy# [app descriptionForDeactivationSetting:17] "suspensionAnimationDelay " cy# [app descriptionForDeactivationSetting:18] "disableIconUnscatterAnimation " cy# [app descriptionForDeactivationSetting:19] "slideStatusBarStyleSetting " cy# [app descriptionForDeactivationSetting:20] "deactivateFromSwitcherSetting " cy# [app descriptionForDeactivationSetting:21] "zoomAnimateOtherOnResume " cy# [app descriptionForDeactivationSetting:22] "displayFenceTeardown " cy# [app descriptionForDeactivationSetting:23] "orderOutOnlyIfOnTop " cy# [app descriptionForDeactivationSetting:24] "viaSystemGesture " cy# [app descriptionForDeactivationSetting:25] "crossfade "

Display Setting

I had written a little method to open and close apps for me so I could do quicker then just 0.5 second animations (the app switchers speed). I wrote it from a mixture of logging the description of different SBDisplay methods (the "-(NSString*)descriptionFor*****Setting:(unsigned)number" one's) and this (though it doesn't work on iOS 4+5). 

I wanted to know how iOS closes an app without an animation as that's the only thing I had left not working and this is what I got when I logified the interesting methods in SBDisplay and "-(void)kill"ed and app.

I was looking for a way to get a list of all applications, that aren't hidden (so excluding things like Web.app). And although I found it ((NSArray*)[[SBIconModel sharedInstance] visibleIconIdentifiers]). I also found a dictionary SpringBoard keeps of the Icon layout.

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>buttonBar</key> <array> <string>com.apple.MobileSMS</string> <string>com.apple.mobilemail</string> <string>com.apple.mobilesafari</string> </array> <key>iconLists</key> <array> <array> <string>com.apple.mobilephone</string> <string>com.apple.mobilecal</string> <string>com.apple.mobileslideshow</string> <string>com.apple.camera</string> <string>com.apple.videos</string> <string>com.apple.youtube</string> <string>com.apple.Maps</string> <string>com.apple.weather</string> <string>com.apple.mobilenotes</string> <string>com.apple.reminders</string> <string>com.apple.mobiletimer</string> <string>com.apple.gamecenter</string> <dict> <key>displayName</key> <string>Apple</string> <key>iconLists</key> <array> <array> <string>com.apple.mobileme.fmf1</string> <string>com.apple.Cards</string> <string>com.apple.iBooks</string> </array> </array> <key>listType</key> <string>folder</string> </dict> <string>com.apple.MobileStore</string> <string>com.apple.AppStore</string> <string>com.apple.Preferences</string> </array> <array> <dict> <key>displayName</key> <string>Utilities</string> <key>iconLists</key> <array> <array> <string>com.apple.MobileAddressBook</string> <string>com.apple.calculator</string> <string>com.apple.VoiceMemos</string> </array> </array> <key>listType</key> <string>folder</string> </dict> <dict> <key>displayName</key> <string>Jailbreak</string> <key>iconLists</key> <array> <array> <string>com.saurik.Cydia</string> <string>libactivator</string> <string>eu.heinelt.ifile</string> <string>crash-reporter</string> <string>com.googlecode.mobileterminal.Terminal</string> </array> </array> <key>listType</key> <string>folder</string> </dict> <dict> <key>displayName</key> <string>Social</string> <key>iconLists</key> <array> <array> <string>com.atebits.Tweetie2</string> <string>info.colloquy.mobile</string> <string>com.tapbots.Tweetbot</string> </array> </array> <key>listType</key> <string>folder</string> </dict> <dict> <key>displayName</key> <string>Other</string> <key>iconLists</key> <array> <array> <string>com.apple.stocks</string> <dict> <key>displayName</key> <string>Newsstand</string> <key>iconLists</key> <array/> <key>listType</key> <string>newsstand</string> </dict> </array> </array> <key>listType</key> <string>folder</string> </dict> <string>com.clickgamer.AngryBirds</string> <string>com.apple.mobileipod</string> </array> </array> </dict> </plist>

Lets take a closer look at this:

the dock icons are in a separate array for key 'buttonBar';

the pages are in the array for key 'iconLists';

each page is a separate array in the iconLists array;

in the array for each page the icons are string;

the icons string is the apps displayId;

a folder is an NSDictionary;

each folder has these keys;

a displayName key which is a string, it's name;

iconLists which is an array of icons like each pages (displayId strings);

To make a change to the icon-state do:

[[SBIconModel sharedInstance] _writeIconState:modifiedIconState toPath:[[SBIconModel sharedInstance] iconStatePath]]; // And then to actually have it update the icons [[SBIconModel sharedInstance] noteIconStateChangedExternally];

While I was working on the "Cardflow" interface mode for CardSwitcher I had to work out get custom page widths and custom effects as you scroll through the cards, this is actually quite simple but I haven't seen many posts on customising a UIScrollView. Most of the tips are spread across lots of different stackoverflow questions.

Problems with custom scrollview's

To start with (actually while I was working on the first version of CardSwitcher) I looked into iCarousel, which has quite a lot of cool effects and a tableView style data source and delegate protocols. However as the first version of CardSwitcher was actually just a standard WebOS, or Safari tab's style, linear layout that highlighted a problem with iCarousel (which joehewitt also noticed with iScroll), caused by the fact it doesn't customize a UIScrollView but instead uses UIGestureRecognizers to do the scrolling itself (like UIScrollView itself).

However because of this the scrolling just feel wrong, the physics are off by a little bit. The bounce as you scroll of the edge, flicking and then how many pages it scrolls past before stopping and the paging effect all just feels off slightly.

When using iCarousel for the purpose it was designed for, the coverflow or other custom modes, and you might not notice. However as CardSwitcher would have used the linear mode only, at least for the initial release, that would annoy me. For instance Multifl0w's 'cards' style has a custom scrolling too, it feels very smooth but isn't quite right still.

So after explaining why I didn't like using a custom methods I'll now point out why people feel a need to develop these custom methods rather then using a UIScrollView.

The most obvious problem is "paging". To activate paging on a UIScrollView you just set it's pagingEnabled property to YES. However it defaults to each page being the same width as the scrollview itself, meaning if you want to achieve a preview effect like in Safari (screenshot below) you can't do it by simply specifing a custom page width.

Also the custom scrollview's all have built in ways to create custom effects whereas UIScrollView provides no built in way to achieve cool effects, so you'll have to work it out yourself.

Despite the need to subclass and customize the UIScrollView yourself it's is a very refined and very well built UIKit class and over all I think it's best to just deal with the one or 2 limitations then throw it all away and start again from scratch or use a custom scrollview library. The difficulty of matching the refinement of a UIScrollView is highlighted well by the numerous JavaScript libraries which try to mimic it for web apps and the native attempts at making custom scrollviews (none of which get the physics quite right).

Customizing UIScrollView & Adding Effects

So now to the fun bit (the code). Customizing the page width of a UIScrollView is actually quite simple, set the width to whatever you want and then set the 'clipsToBounds' property to NO, very simple. Except it's not quite that simple as there's a little problem with that (how big a problem depends on how small you want to the page widths to be). The problem is that touches will only be received inside the view's bounds. So if your use for this is a scrolling menu (like a UITableView) that's page width is the width of one cell only the center one will receive touches. To fix that you need to subclass UIScrollView and override the -(BOOL)pointInside: withEvent: method.

@interface CustomScrollView : UIScrollView @property (nonatomic, assign) UIEdgeInsets responseInsets; @end @implementation CustomScrollView - (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event { CGPoint parentLocation = [self convertPoint:point toView:self.superview]; CGRect responseRect = self.frame; responseRect.origin.x -= self.responseInsets.left; responseRect.origin.y -= self.responseInsets.top; responseRect.size.width += (self.responseInsets.left + self.responseInsets.right); responseRect.size.height += (self.responseInsets.top + self.responseInsets.bottom); return CGRectContainsPoint(responseRect, parentLocation); } @end

Though for CardSwitcher I use a less flexible implementation because it does what I want.

@implementation CustomScrollView - (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event { CGPoint parentLocation = [self convertPoint:point toView:self.superview]; return [self.superview pointInside:parentLocation withEvent:event]; } @end

This now means that no matter how small the scrollview (in Cardflow mode it's only 30px wide) you'll still be able to scroll by dragging anywhere on it's parent view.

Cool Effects

Now we're going to go through and create a few cool scrolling effects.

Now I actually have each card keep track of it's offset and set it's own transform but you can easily do this in a for loop in the scrollViewDidScroll delegate method if you want. Note though that you'll need a way to track the index of each card (hopefully besides just using it's position in the UIView's subviews).

// Method that get's called every time the scrollView scrolls. -(void)setTransform{ /// setting up zoom effect!!!!!! UIScrollView *scrollView = //get the scrollView (most likely either self.scrollView or self.superView); // Set the layers transform back to normal so it's frame wouldn't be effected while we do the calculations self.layer.transform = CATransform3DIdentity; // Easier reference to these CGFloat scrollViewWidth = scrollView.bounds.size.width; CGFloat offset = scrollView.contentOffset.x; // Do some initial calculations to see how far off it is from being the center card CGFloat pageIndex = ([/* an array (hopefully not self.superviews.subviews)*/ indexOfObject:self]); CGFloat currentPage = (offset/scrollViewWidth); CGFloat pageDifference = (pageIndex-currentPage); // And the default values CGFloat scale = 1.0f; CGFloat alpha = 1.0f; /*** NOW FOR THE EFFECTS ***/ // Scale it based on how far it is from being centered scale += (pageDifference*0.2); // If it's meant to have faded into the screen fade it out if (pageDifference > 0.0f) { alpha = 1 - pageDifference; } // Don't let it get below nothing (like reversed is -1) if (scale < 0.0f) { scale = 0.0f; } // If you can't see it disable userInteraction so as to stop it preventing touches on the one bellow. if (alpha <= 0.0f) { alpha = 0.0f; self.userInteractionEnabled = NO; } else{ self.userInteractionEnabled = YES; } /*** Set our effects ***/ self.alpha = alpha; // We could do just self.transform = but it comes by default with an animation. [CATransaction begin]; [CATransaction setValue:(id)kCFBooleanTrue forKey:kCATransactionDisableActions]; self.layer.transform = CATransform3DMakeScale(scale, scale, 1.0f); [CATransaction commit]; }

This will create the same effect as the 'Cardflow' mode in CardSwitcher. However the important bit's are those initial variables and then the end bit where you set it's transform. In between you can fiddle with those values to create the cool effects.

If you want some examples of cool scrollView effects have a look at the iCarousel Demo project, which includes these effects: Linear, Rotary, Inverted Rotary, Cylinder, Inverted Cylinder, CoverFlow, CoverFlow2 and a Custom one similar to this one.