iOS7 Custom Transitions

iOS7 Custom Transitions
iOS7 Custom Transitions

iOS7 Series –Custom Transitions

There is a hierarchy of actors you need to visualize here.  It goes a little something like:

  1. A TransitioningDelegate
  2. An AnimatedTransitioning
  3. A ContextTransitioning

The VC you start out with and that will call the transition will adopt the first protocol, the TransitioningDelegate Protocol.  The purpose of doing so is to obtain the authority to manage the entire transition process.

You will then create a Transitioning class which we can call the Transition Manager.  This class will adopt the AnimatedTransitioning protocol.  The purpose of this protocol is to animate the transition.

The Transition Manager class receives all the necessary information from the Transitioning Context (a protocol adopted by a class you wont really see) and it sends that info to the TransitioningDelegate in order for it to call the shots.

The process itself is quite simple.  We create a Transition Manager class, which adopts the AnimatedTransitioning protocol as stated above.  Then we instantiate this class and call its methods from our initial view controller, who has adopted the TransitioningDelegate protocol in order to call the shots.  Voila, our VC calls the transition for us.

So create a subclass of NSObject and call it what you wish, I called it PinRotatingTransitionManager.  Of course make it adopt the AnimatedTransitioning protocol like so:

<UIViewControllerAnimatedTransitioning>

There are 2 methods you must implement in order to adopt this protocol.  The first one is:

//Define the transition duration

-(NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{

return 1.0;

}

As you can see this simply states how long the transition will last.  It returns a value of type NSTimeInterval and takes in the transition context.

The second method is for describing the animation and it’s a bit long so let’s go one step at a time:

//1. Get current state

UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];

UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];

CGRect sourceRect = [transitionContext initialFrameForViewController:fromVC];

First we get some values for the current state; who is our fromVC, who is our toVC and what is the relevant frame of our current, fromVC.  Remember we are transitioning between two vcs.  The one we are in is called the fromVC or initialVC or if you prefer to keep the original iOS lingo, our sourceVC.  The second one is called our toVC or finalVC or destinationVC.

We need to get a reference to both of them (basically to say THIS vc will do this and THAT vc will do that!).  And of course we need to know the frame we are starting from.

//2.Settings for the fromVC ……………………….

CGAffineTransform rotation;

rotation = CGAffineTransformMakeRotation(M_PI);

fromVC.view.frame = sourceRect;

fromVC.view.layer.anchorPoint = CGPointMake(0.5, 0.0);

fromVC.view.layer.position = CGPointMake(160.0, 0);

We create a rotation transform which will rotate anything by M_PI.  Then we set our fromVC frame to the sourceRect, we define an anchor point for it and a position for it.

//3.Insert the toVC view………………………

UIView *container = [transitionContext containerView];

[container insertSubview:toVC.view belowSubview:fromVC.view];

CGPoint final_toVC_Center = toVC.view.center;

Now we need to do something quite important…get a container view to put everything into in order to run the transition.  To that container view we must add the toVC, because the fromVC is already added for us.

//4.Insert the toVC view………………………

toVC.view.center = CGPointMake(-sourceRect.size.width, sourceRect.size.height);

toVC.view.transform = CGAffineTransformMakeRotation(M_PI/2);

Now we set the toVC’s center point and apply the transform created.

And finally we perform the animation:

//5. Animate..

[UIView animateWithDuration:1.0

delay:0.0

usingSpringWithDamping:.8

initialSpringVelocity:6.0

options:UIViewAnimationOptionCurveEaseIn

animations:^{

//Setup final params of the views

fromVC.view.transform = rotation;

toVC.view.center = final_toVC_Center;

toVC.view.transform = CGAffineTransformMakeRotation(0);

} completion:^(BOOL finished) {

//When done call completeTransition

[transitionContext completeTransition:YES];

}];

This is quite simple.  We define some parameters for the animation and call a block which applies the rotation and center etc.  Once complete we call completeTransition which is mandatory.

Now run your app and you should have a very nice transition where the fromVC slides left and the toVC rotates down into place.

 

Neat huh!

Creating a Menu in SpriteKit

SpriteKit Menu by Santiapps.com Marcio Valenzuela
SpriteKit Menu

Cocos2d has a easy to use CCMenu object to which you add CCMenuItems.  In SpriteKit however, you are back to UIKit objects.  This doesn’t not mean its more complicated, its just different :-).  You will need to create a UIControl such as a button or you can use SpriteKit’s SKNode to create the visual object onscreen:

SKLabelNode*  someNode = [SKLabelNode labelNodeWithFontNamed:@”Chalkduster”];
[someNode setText:@”Play Game”];
[someNode setPosition:CGPointMake(CGRectGetMidX(self.frame)+5,CGRectGetMidY(self.frame)-40)];
[self addChild: someNode];

Now you simply connect the object action to some event like so:

for (UITouch *touch in touches) {
CGPoint location = [touch locationInNode:self];

if ([someNode containsPoint:location]) {
SKTransition* present = [SKTransition revealWithDirection:SKTransitionDirectionDown duration:1];
GameScene* gameScene = [[GameScene alloc] initWithSize:CGSizeMake(1024, 768)];
[self.scene.view presentScene: someNode transition:present];

}
}

Voila!  You are DONE!

Creating a simple UICollectionView in iOS

Steps

1) Create Master-Detail Application & Replace the MasterViewController

First we want to create a Master-Detail Application just because it sets up a Master-Detail relationship even though thats the first thing we are going to break :).  So go ahead and create a new project in XCode4 based on a Master-Detail Application type.  Use ARC, Storyboards and CoreData because we will use CoreData to store information.  Your storyboard should look like this:

Master-Detail Storyboard
Master-Detail Storyboard

Now select the Master scene until its highlighted in blue and delete it with the Delete key.  We simply replace it by dragging in a UICollectionViewController onto the storyboard in its place.  This places a UICollectionViewController scene with a small empty collectionview cell in the top left corner.  I made a few adjustments to mine and here is what it looks like but Ill go over those later:

UICollectionViewController Storyboard
UICollectionViewController Storyboard

The changes I made to it are the following:

a – Select the entire scene (again until its highlighted blue) and change its Class type from UICollectionViewController to MasterViewController.

b – Enlarged the UICollectionViewCell from 50×50 to 145×145 in the Dimension’s Inspector

Here are some clips of the Identity Inspector of the MasterViewController and Dimension’s Inspector of the UICollectionViewCell:

UICollectionViewController Identity Inspector
UICollectionViewController Identity Inspector
UICollectionViewCell Dimensions Inspector
UICollectionViewCell Dimensions Inspector

We did set the new UICollectionViewController to a new class, the MasterViewController class.  We must do the same with the UICollectionViewCell but we must create its class first.

2)  Modify the MasterViewController class with the following in the .m file:

#import “MasterViewController.h”

#import “DetailViewController.h”

#import “MyCustomCell.h”

#import “AppDelegate.h”

static NSString *CellIdentifier = @”MyCustomCell”;

@interface MasterViewController ()

{

NSMutableArray *_objectChanges;

NSMutableArray *_sectionChanges;

}

@end

Now let’s go through the methods.  First the UICollectionView methods, which are quite similar to the UITableViewController methods:

#pragma mark – UICollectionView

– (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section

{

id <NSFetchedResultsSectionInfo> sectionInfo = [self.fetchedResultsController sections][section];

return [sectionInfo numberOfObjects];

}

// The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:

– (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath

{

MyCustomCell *cell = (MyCustomCell *)[collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];

NSManagedObject *object = [self.fetchedResultsController objectAtIndexPath:indexPath];

[cell setImage:[UIImage imageWithData:[object valueForKey:@”photoImageData”]]];

return cell;

}

– (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender

{

if ([[segue identifier] isEqualToString:@”showDetail”]) {

NSIndexPath *indexPath = [[self.collectionView indexPathsForSelectedItems] lastObject];

NSManagedObject *object = [[self fetchedResultsController] objectAtIndexPath:indexPath];

[[segue destinationViewController] setDetailItem:object];

}

}

The MyCustomCell Class is the one we will create in the next section.  For now we are simply filling in the cell’s image data with some fetched managed object which we will also create later.  A couple of more interesting tidbits for example; we gave our UICollectionViewCell a reuse identifier and we gave our segue an identifier as well.  We must make sure these identifiers also exist in the storyboard inspectors for the cell and segue respectively.

3) Create UICollectionViewCell Class & Connect it

Let’s go ahead and Create a New File in our project, base it off of Objective C Class.  Type in UICollectionViewCell as the subclass and name it MyCustomCell.  We are simply going to define a class for our UICollectionViewCell and once we are finished, we must go to Storyboard and set our cell to use this new class type.

Add a UIImageView property to the class so that your .h file looks like this:

#import <UIKit/UIKit.h>

@interface MyCustomCell : UICollectionViewCell{

IBOutlet UIImageView *imageView;

}

-(void)setImage:(UIImage *)image;

@end

and now implement the setter in your .m so that it looks like this:

#import “MyCustomCell.h”

@implementation MyCustomCell

-(void)setImage:(UIImage *)image{

[imageView setImage:image];

}

@end

4) Create the data model.  First let’s do the easiest part, which is creating the data model.  Select your project’s xcdatamodel file and create a new Entity, call it Snapshots if you’d like.  Now add 3 attributes to it and make them of this type:

Core Data Entity Data Model
Core Data Entity Data Model

Once that is done, we have a storage container for our data.  Let’s look at the code used by our app to access this store and manipulate it.

#pragma mark – Fetched results controller

– (NSFetchedResultsController *)fetchedResultsController

{

if (_fetchedResultsController != nil) {

return _fetchedResultsController;

}

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];

// Edit the entity name as appropriate.

NSEntityDescription *entity = [NSEntityDescription entityForName:@”Snapshots” inManagedObjectContext:self.managedObjectContext];

[fetchRequest setEntity:entity];

// Set the batch size to a suitable number.

[fetchRequest setFetchBatchSize:20];

// Edit the sort key as appropriate.

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@”photoName” ascending:NO];

NSArray *sortDescriptors = @[sortDescriptor];

[fetchRequest setSortDescriptors:sortDescriptors];

// Edit the section name key path and cache name if appropriate.

// nil for section name key path means “no sections”.

NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:@”Master”];

aFetchedResultsController.delegate = self;

self.fetchedResultsController = aFetchedResultsController;

NSError *error = nil;

if (![self.fetchedResultsController performFetch:&error]) {

// Replace this implementation with code to handle the error appropriately.

// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.

NSLog(@”Unresolved error %@, %@”, error, [error userInfo]);

abort();

}

return _fetchedResultsController;

}

– (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo

atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type

{

NSMutableDictionary *change = [NSMutableDictionary new];

switch(type) {

case NSFetchedResultsChangeInsert:

change[@(type)] = @(sectionIndex);

break;

case NSFetchedResultsChangeDelete:

change[@(type)] = @(sectionIndex);

break;

}

[_sectionChanges addObject:change];

}

– (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject

atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type

newIndexPath:(NSIndexPath *)newIndexPath

{

NSMutableDictionary *change = [NSMutableDictionary new];

switch(type)

{

case NSFetchedResultsChangeInsert:

change[@(type)] = newIndexPath;

break;

case NSFetchedResultsChangeDelete:

change[@(type)] = indexPath;

break;

case NSFetchedResultsChangeUpdate:

change[@(type)] = indexPath;

break;

case NSFetchedResultsChangeMove:

change[@(type)] = @[indexPath, newIndexPath];

break;

}

[_objectChanges addObject:change];

}

– (void)controllerDidChangeContent:(NSFetchedResultsController *)controller

{

if ([_sectionChanges count] > 0)

{

[self.collectionView performBatchUpdates:^{

for (NSDictionary *change in _sectionChanges)

{

[change enumerateKeysAndObjectsUsingBlock:^(NSNumber *key, id obj, BOOL *stop) {

NSFetchedResultsChangeType type = [key unsignedIntegerValue];

switch (type)

{

case NSFetchedResultsChangeInsert:

[self.collectionView insertSections:[NSIndexSet indexSetWithIndex:[obj unsignedIntegerValue]]];

break;

case NSFetchedResultsChangeDelete:

[self.collectionView deleteSections:[NSIndexSet indexSetWithIndex:[obj unsignedIntegerValue]]];

break;

case NSFetchedResultsChangeUpdate:

[self.collectionView reloadSections:[NSIndexSet indexSetWithIndex:[obj unsignedIntegerValue]]];

break;

}

}];

}

} completion:nil];

}

if ([_objectChanges count] > 0 && [_sectionChanges count] == 0)

{

[self.collectionView performBatchUpdates:^{

for (NSDictionary *change in _objectChanges)

{

[change enumerateKeysAndObjectsUsingBlock:^(NSNumber *key, id obj, BOOL *stop) {

NSFetchedResultsChangeType type = [key unsignedIntegerValue];

switch (type)

{

case NSFetchedResultsChangeInsert:

[self.collectionView insertItemsAtIndexPaths:@[obj]];

break;

case NSFetchedResultsChangeDelete:

[self.collectionView deleteItemsAtIndexPaths:@[obj]];

break;

case NSFetchedResultsChangeUpdate:

[self.collectionView reloadItemsAtIndexPaths:@[obj]];

break;

case NSFetchedResultsChangeMove:

[self.collectionView moveItemAtIndexPath:obj[0] toIndexPath:obj[1]];

break;

}

}];

}

} completion:nil];

}

[_sectionChanges removeAllObjects];

[_objectChanges removeAllObjects];

}

I know its long, but its pretty simple.  The first method, – (NSFetchedResultsController *)fetchedResultsController, basically opens up the store, fetches all entities by the name “Snapshots” and places them into a special object called NSFetchedResultsController.

The didChangeSection method is called when there is a change within a section.  We only have 1 section in our UICollectionView.

The didChangeObject method is called when a particular object is changed within our UICollectionView.

The controllerDidChangeContent actually manages the changes made.  Basically we update our two arrays, _sectionChanges and _objectChanges with each change in the data in order to keep our UICollectionView current.

5) Connect to Flickr API.  So what constitutes a change in those sections and objects?  There is an acronym that datastore managers use, CRUD, which basically says that everytime you create, read, update or delete you create a transaction.  Thats basically what we want to track (except for the read part :)).  So whenever we download a new photo to our datastore, update a photo or delete one, we trigger changes in objects and thus in sections.

We want to use the Flickr API to get images from the web and populate our collection view.  We are basically going to perform a fetch to Flickr API using our own key or identifier.  You must register for one at flickr.com/.

a – Get FlickrAPIKey and add it here to this string constant atop your .m file like so:

NSString *const FlickrAPIKey = @"YOURAPIKEYVALUE";

b – Add the loadFlickrPhotos method to fetch pics from the web.  So add this method:

– (void)loadFlickrPhotos{

// 1. Build your Flickr API request w/Flickr API key in FlickrAPIKey.h

NSString *urlString = [NSString stringWithFormat:@”http://api.flickr.com/services/rest/?method=flickr.photos.search&api_key=%@&tags=%@&per_page=10&format=json&nojsoncallback=1″, FlickrAPIKey, @”bayern”];

NSURL *url = [NSURL URLWithString:urlString];

// 2. Get URLResponse string & parse JSON to Foundation objects.

NSString *jsonString = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];

NSError *e = nil;

NSDictionary *results = [NSJSONSerialization JSONObjectWithData:[jsonString dataUsingEncoding:NSUTF8StringEncoding]options:NSJSONReadingMutableContainers error:&e];

photos = [[results objectForKey:@”photos”] objectForKey:@”photo”];

for (NSDictionary *photo in photos) {

// 3.a Get title for e/ photo

NSString *title = [photo objectForKey:@”title”];

[photoNames addObject:(title.length > 0 ? title : @”Untitled”)];

// 3.b Construct URL for e/ photo.

NSString *photoURLString = [NSString stringWithFormat:@”http://farm%@.static.flickr.com/%@/%@_%@_s.jpg”, [photo objectForKey:@”farm”], [photo objectForKey:@”server”], [photo objectForKey:@”id”], [photo objectForKey:@”secret”]];

[photoURLs addObject:[NSURL URLWithString:photoURLString]];

}

// Process into CoreData

[self processCoreData];

}

It basically looks for Flickr photos of Bayern and stores the results in the photos ivar.  Now we must populate our CoreData db with these data.

c – Populate our CoreData model.  Add the processCoreData method to your MasterViewController.m like so:

-(void)processCoreData{

AppDelegate *myDelegate = [[UIApplication sharedApplication] delegate];

for (NSDictionary *photoDictionary in photos){

NSManagedObject *photoModel = [NSEntityDescription insertNewObjectForEntityForName:@”AFPhotoModel” inManagedObjectContext:myDelegate.managedObjectContext];

//[photoModel setValue:[photoDictionary valueForKey:@”rating”] forKey:@”photoRating”];

[photoModel setValue:[photoDictionary valueForKey:@”title”] forKey:@”photoName”];

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{

//Build URL

NSString *photoURLString = [NSString stringWithFormat:@”http://farm%@.static.flickr.com/%@/%@_%@_s.jpg”, [photoDictionary objectForKey:@”farm”], [photoDictionary objectForKey:@”server”], [photoDictionary objectForKey:@”id”], [photoDictionary objectForKey:@”secret”]];

NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:photoURLString]];

dispatch_async(dispatch_get_main_queue(), ^{

[photoModel setValue:imageData forKey:@”photoImageData”];

});

});

}

}

Voila!  Run your app!