UIDynamic--动力元素行为:UIDynamicItemBehavior

1 @property (nonatomic, readonly, copy) NSArray* items;  
2   
3 @property (readwrite, nonatomic) CGFloat elasticity; // Usually between 0 (inelastic) and 1 (collide elastically) 弹性系数 在0~1之间  
4 @property (readwrite, nonatomic) CGFloat friction; // 0 being no friction between objects slide along each other 摩擦力系数  
5 @property (readwrite, nonatomic) CGFloat density; // 1 by default 跟size大小相关，计算物体块的质量。  
6 @property (readwrite, nonatomic) CGFloat resistance; // 0: no velocity damping 阻力系数  
7 @property (readwrite, nonatomic) CGFloat angularResistance; // 0: no angular velocity damping 旋转阻力  
8 @property (readwrite, nonatomic) BOOL allowsRotation; // force an item to never rotate  是否能旋转

 1 //
 2 //  YFDynamicItemViewController.m
 3 //  BigShow1949
 4 //
 5 //  Created by apple on 16/8/25.
 6 //  Copyright © 2016年 BigShowCompany. All rights reserved.
 7 //
 8 
 9 #import "YFDynamicItemViewController.h"
10 
11 @interface YFDynamicItemViewController ()
12 @property(nonatomic,strong)UIDynamicAnimator *animator;
13 @property (nonatomic, strong) UIView *redView;
14 
15 
16 @end
17 
18 @implementation YFDynamicItemViewController
19 
20 - (void)viewDidLoad {
21 
22     [super viewDidLoad];
23     self.view.backgroundColor = [UIColor whiteColor];
24     
25     
26     UIView *redView = [[UIView alloc] init];
27     redView.frame = CGRectMake(100, 100, 100, 100);
28     redView.backgroundColor = [UIColor redColor];
29     self.redView = redView;
30     [self.view addSubview:redView];
31 }
32 
33 
34 
35 - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
36 
37     [self testGravityAndCollsion];
38 }
39 /**
40  *  重力行为+碰撞检测
41  */
42 -(void)testGravityAndCollsion
43 {
44     //1.重力行为
45     UIGravityBehavior *gravity=[[UIGravityBehavior alloc]init];
46     [gravity addItem:self.redView];
47     
48     //2碰撞检测行为
49     UICollisionBehavior *collision=[[UICollisionBehavior alloc]init];
50     [collision addItem:self.redView];
51     //让参照视图的边框成为碰撞检测的边界
52     collision.translatesReferenceBoundsIntoBoundary=YES;
53     
54     // 动力元素行为
55     UIDynamicItemBehavior * itemBehavior = [[UIDynamicItemBehavior alloc] initWithItems:@[self.redView]];
56     itemBehavior.elasticity = 1.2;
57     itemBehavior.friction = 1.;
58     itemBehavior.density = 1;
59     itemBehavior.resistance = 3; // 阻力系数
60     itemBehavior.allowsRotation = NO;
61     itemBehavior.angularResistance = 1;
62     
63     //3.执行仿真
64     [self.animator addBehavior:gravity];
65     [self.animator addBehavior:collision];
66     [self.animator addBehavior:itemBehavior];
67 }
68 
69 
70 -(UIDynamicAnimator *)animator
71 {
72     if (_animator==nil) {
73         //创建物理仿真器（ReferenceView:参照视图，设置仿真范围）
74         self.animator=[[UIDynamicAnimator alloc]initWithReferenceView:self.view];
75     }
76     return _animator;
77 }
78 
79 
80 @end