//

//

//  捕捉行为:可以让物体迅速冲到某个位置（捕捉位置），捕捉到位置之后会带有一定的震动

//

#import "YFSnapBehaviorViewController.h"

@interface YFSnapBehaviorViewController()

@property(nonatomic,strong)UIDynamicAnimator *animator;

@property (nonatomic, strong) UIButton *blueView;

@end

@implementation YFSnapBehaviorViewController

-(void)viewDidLoad {

    [super viewDidLoad];

    self.view.backgroundColor = [UIColor whiteColor];

    UIButton *blueView = [[UIButton alloc] init];

    blueView.frame = CGRectMake(, , , );

    blueView.backgroundColor = [UIColor blueColor];

    [self.view addSubview:blueView];

    self.blueView = blueView;

}

-(UIDynamicAnimator *)animator

{

    if (_animator==nil) {

        //创建物理仿真器，设置仿真范围，ReferenceView为参照视图

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

    }

    return _animator;

}

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

{

    //获取一个触摸点

    UITouch *touch=[touches anyObject];

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

    //1.创建捕捉行为

    //需要传入两个参数：一个物理仿真元素，一个捕捉点

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

    //设置防震系数（0~1，数值越大，震动的幅度越小）

    snap.damping=arc4random_uniform()/10.0;

    //2.执行捕捉行为

    //注意：这个控件只能用在一个仿真行为上，如果要拥有持续的仿真行为，那么需要把之前的所有仿真行为删除

    //删除之前的所有仿真行为

    [self.animator removeAllBehaviors];

    [self.animator addBehavior:snap];

}

@end