物理仿真

//UIDynamicAnimator :动态仿真

#import "ViewController.h"

 

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UIView *rectGreen;

@property (weak, nonatomic) IBOutlet UIView *rectBlue;

//创建仿真类

@property(nonatomic,strong)UIDynamicAnimator *animator;

 

@end

 

@implementation ViewController

//懒加载创建物理仿真类

-(UIDynamicAnimator*)animator

{

    //1.创建仿真器指定仿真范围

    if (!_animator) {

        _animator=[[UIDynamicAnimator alloc]initWithReferenceView:self.view];

    }

    return _animator;

}

 

 

 

- (void)viewDidLoad {

    [super viewDidLoad];

    

    //2创建仿真行为(重力),指定仿真元素

    UIGravityBehavior *gravity=[[UIGravityBehavior alloc]initWithItems:@[self.rectGreen]];

    //量级

    gravity.magnitude=2;

    //3添加仿真行为到仿真器

    [self.animator addBehavior:gravity];

    //4创建碰撞行为

    UICollisionBehavior *collision=[[UICollisionBehavior alloc]initWithItems:@[self.rectGreen,self.rectBlue] ];

    //设置碰撞边界

    collision.translatesReferenceBoundsIntoBoundary=YES;

    //开始仿真

    [self.animator addBehavior:collision];

    

//    UIGravityBehavior *blue=[[UIGravityBehavior alloc]initWithItems:@[self.rectBlue]];

//    //量级

//    blue.magnitude=0.1;

//    //3添加仿真行为到仿真器

//    [self.animator addBehavior:blue];

 

    

}

//扑捉行为

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

    //可以移除之前的所有行为

    //[self.animator removeAllBehaviors];

    //获得点击的坐标

    UITouch *touch=[touches anyObject];

    CGPoint point=[touch locationInView:touch.view];

    //创建捕捉行为

    UISnapBehavior *snap=[[UISnapBehavior alloc]initWithItem:self.rectBlue snapToPoint:point];

    //设置减震属性

    snap.damping=arc4random_uniform(100)/100.0;

    

    //添加开始仿真

    [self.animator addBehavior:snap];

    

}

 

 

@end