DynamicBehaviorsViewController.m

//
//  DynamicBehaviorsViewController.m
//  iOS7Sampler
//
//  Created by shuichi on 9/21/13.
//  Copyright (c) 2013 Shuichi Tsutsumi. All rights reserved.
//

#import "DynamicBehaviorsViewController.h"

@interface DynamicBehaviorsViewController ()
@property (nonatomic, strong) UIDynamicAnimator *animator;
@property (nonatomic, strong) UIGravityBehavior *gravityBeahvior;
@property (nonatomic, strong) UICollisionBehavior *collisionBehavior;
@property (nonatomic, strong) UIDynamicItemBehavior *itemBehavior;
@end


@implementation DynamicBehaviorsViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIGestureRecognizer *gesture = [[UITapGestureRecognizer alloc] initWithTarget:self
                                                                           action:@selector(tapped:)];
    [self.view addGestureRecognizer:gesture];


    // Set up
    self.animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];
    
    self.gravityBeahvior = [[UIGravityBehavior alloc] initWithItems:nil];
    
    self.collisionBehavior = [[UICollisionBehavior alloc] initWithItems:nil];
    self.collisionBehavior.translatesReferenceBoundsIntoBoundary = YES;
    
    self.itemBehavior = [[UIDynamicItemBehavior alloc] initWithItems:nil];
    self.itemBehavior.elasticity = 0.6;
    self.itemBehavior.friction = 0.5;
    self.itemBehavior.resistance = 0.5;

    
    [self.animator addBehavior:self.gravityBeahvior];
    [self.animator addBehavior:self.collisionBehavior];
    [self.animator addBehavior:self.itemBehavior];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}


// =============================================================================
#pragma mark - Gesture Handler

- (void)tapped:(UITapGestureRecognizer *)gesture {

  //  NSUInteger num = arc4random() % 40 + 1;
  //  NSString *filename = [NSString stringWithFormat:@"m%lu", (unsigned long)num];
        NSString *filename = @"apposta@2x.png";
    UIImage *image = [UIImage imageNamed:filename];
    UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
    [self.view addSubview:imageView];
    
    CGPoint tappedPos = [gesture locationInView:gesture.view];
    imageView.center = tappedPos;
    
    [self.gravityBeahvior addItem:imageView];
    [self.collisionBehavior addItem:imageView];
    [self.itemBehavior addItem:imageView];
}

@end