重力碰撞

#import "ViewController.h"@interface ViewController ()<UIDynamicAnimatorDelegate,UICollisionBehaviorDelegate>{ UIDynamicAnimator *animator; UIView *view; UIView *view2;}@end@implementation ViewController- (void)viewDidLoad { [super viewDidLoad];// UIDynamicAnimator /* UIDynamic是从ios7开始引入的一种新技术 属于UIKit框架 可以模拟现实生活中的物理现象 如碰撞 抖动 摆动 等 动力效果：如动吉他，电吉他有效果器 可以添加各种电子效果 动力效果也有一个效果器，叫做动力效果器，里面可以添加动力效果 电吉他可以叠加多个效果 动力效果也是一样 动力效果的使用步骤： 1、创建动力效果器（UIDynamicAnimator） 2、创建动力效果（Behavior）添加到对应的视图上 3、将动力效果添加到动力效果器中开始动力效果 再是用动力效果的时候必须遵守UIDynamicItem这个协议才可以使用动力效果 UIView默认遵守了UIDynamicItem协议 UIDynamic提供的动力效果 UIGravityBehavior：重力效果 UICollisionBehavior：碰撞效果 UIDynamicItemBehavior：动力元素效果 UIPushBehavior：推动效果 UISnapBehavior：迅速移动效果 UIAttachmentBehavior：附着效果 都继承自UIDynamicBehavior 动力效果器：UIDynamicAnimator 可以把UIDynamicAnimator看做动力效果的容器 它制定了动力效果的有效范围 在初始化的时候可以指定他的有效范围 - (instancetype)initWithReferenceView:(UIView*)view; 作用在哪一个view上 哪一个view就是他产生动力效果的有效范围 既然是容器 他还可以添加移除 动力效果 - (void)addBehavior:(UIDynamicBehavior *)behavior; 添加动力效果 - (void)removeBehavior:(UIDynamicBehavior *)behavior; 移除动力效果 - (void)removeAllBehaviors; 移除之前添加过的所有动力效果 动力效果器常用的属性 @property (nonatomic, readonly) UIView* referenceView;作用的区域 @property (nonatomic, readonly, copy) NSArray* behaviors;添加到效果器中的所有效果 @property (nonatomic, readonly, getter = isRunning) BOOL running;是否正在进行 @property (nonatomic, assign) id <UIDynamicAnimatorDelegate> delegate;可以检测开始暂停 - (void)dynamicAnimatorWillResume:(UIDynamicAnimator*)animator; - (void)dynamicAnimatorDidPause:(UIDynamicAnimator*)animator; */ animator = [[UIDynamicAnimator alloc]initWithReferenceView:self.view];// self.view是产生动力效果的区域 animator.delegate = self; view = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)]; view.layer.cornerRadius = 50; view.backgroundColor = [UIColor colorWithRed:0.345 green:1.000 blue:0.391 alpha:1.000]; [self.view addSubview:view]; view2 = [[UIView alloc]initWithFrame:CGRectMake(50, 200, 100, 100)]; view2.layer.cornerRadius = 50; view2.backgroundColor = [UIColor colorWithRed:1.000 green:0.282 blue:0.298 alpha:1.000]; [self.view addSubview:view2];/* 碰撞效果 UICollisionBehavior 可以让物体之间实现碰撞效果 也可以通过添加边界（boundary）在边界实现碰撞效果 边界相关的方法 - (void)addBoundaryWithIdentifier:(id <NSCopying>)identifier forPath:(UIBezierPath*)bezierPath; 添加一个贝塞尔曲线路径的边界 - (void)addBoundaryWithIdentifier:(id <NSCopying>)identifier fromPoint:(CGPoint)p1 toPoint:(CGPoint)p2; 通过添加两个点连成的线 作为边界 - (UIBezierPath*)boundaryWithIdentifier:(id <NSCopying>)identifier; 通过ID找到边界路径 - (void)removeBoundaryWithIdentifier:(id <NSCopying>)identifier; 移除ID对应的边界 @property (nonatomic, readonly, copy) NSArray* boundaryIdentifiers; 边界数组 - (void)removeAllBoundaries;移除所有边界 碰撞的方式 typedef NS_OPTIONS(NSUInteger, UICollisionBehaviorMode) { UICollisionBehaviorModeItems = 1 << 0,元素碰撞 UICollisionBehaviorModeBoundaries = 1 << 1,边界碰撞 UICollisionBehaviorModeEverything = NSUIntegerMax 全体碰撞 } NS_ENUM_AVAILABLE_IOS(7_0); // 视图碰撞边界的时候 触发 - (void)collisionBehavior:(UICollisionBehavior*)behavior beganContactForItem:(id <UIDynamicItem>)item withBoundaryIdentifier:(id <NSCopying>)identifier atPoint:(CGPoint)p; - (void)collisionBehavior:(UICollisionBehavior*)behavior endedContactForItem:(id <UIDynamicItem>)item withBoundaryIdentifier:(id <NSCopying>)identifier; //两个元素相互碰撞 - (void)collisionBehavior:(UICollisionBehavior*)behavior beganContactForItem:(id <UIDynamicItem>)item1 withItem:(id <UIDynamicItem>)item2 atPoint:(CGPoint)p; - (void)collisionBehavior:(UICollisionBehavior*)behavior endedContactForItem:(id <UIDynamicItem>)item1 withItem:(id <UIDynamicItem>)item2; */}#pragma mark 动力效果器的代理方法//启动- (void)dynamicAnimatorWillResume:(UIDynamicAnimator*)animator{}//暂停- (void)dynamicAnimatorDidPause:(UIDynamicAnimator*)animator{}#pragma mark 手指触摸屏幕添加动力效果- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{ UITouch *touch = [touches anyObject]; CGPoint touchPoint = [touch locationInView:self.view]; view.center = touchPoint;}- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{#pragma mark 重力效果// 把之前添加过的重力效果移除 [animator removeAllBehaviors];// 初始化重力效果 UIGravityBehavior *gravityBehavior = [[UIGravityBehavior alloc]initWithItems:@[view]];// 设置掉落方向 gravityBehavior.gravityDirection = CGVectorMake(0, 1);// 设置加速度 数值越大 碰撞效果越大 gravityBehavior.magnitude = 1;// 添加到效果器里面 [animator addBehavior:gravityBehavior];#pragma mark 碰撞效果 /*// 初始化碰撞效果的对象 ，并给View添加碰撞的效果 UICollisionBehavior *collisionBehavior = [[UICollisionBehavior alloc]initWithItems:@[view]];// 把动力效果器的范围当做边界 collisionBehavior.translatesReferenceBoundsIntoBoundary = YES; collisionBehavior.collisionDelegate = self;#pragma mark 通过两个点画一条线当做边界// [collisionBehavior addBoundaryWithIdentifier:@"line" fromPoint:CGPointMake(0, 300) toPoint:CGPointMake(100, 600)];// [collisionBehavior addBoundaryWithIdentifier:@"line1" fromPoint:CGPointMake(375, 300) toPoint:CGPointMake(275, 600)];#pragma mark 通过一个圈来当做边界 UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 200, 375, 375)]; [collisionBehavior addBoundaryWithIdentifier:@"圆形" forPath:path]; [animator addBehavior:collisionBehavior]; */#pragma mark 两个视图之间的碰撞 UICollisionBehavior *coll = [[UICollisionBehavior alloc]initWithItems:@[view,view2]]; coll.translatesReferenceBoundsIntoBoundary = YES;// 如果是两个元素之间相互碰撞 设置边界 也不起作用 coll.collisionMode = UICollisionBehaviorModeEverything; coll.collisionDelegate = self; [animator addBehavior:coll];}- (void)collisionBehavior:(UICollisionBehavior*)behavior beganContactForItem:(id <UIDynamicItem>)item1 withItem:(id <UIDynamicItem>)item2 atPoint:(CGPoint)p{}- (void)collisionBehavior:(UICollisionBehavior*)behavior endedContactForItem:(id <UIDynamicItem>)item1 withItem:(id <UIDynamicItem>)item2{}#pragma mark 碰撞动力效果的代理方法- (void)collisionBehavior:(UICollisionBehavior*)behavior beganContactForItem:(id <UIDynamicItem>)item withBoundaryIdentifier:(id <NSCopying>)identifier atPoint:(CGPoint)p{ NSLog(@"%f\n%f",p.x,p.y);}- (void)collisionBehavior:(UICollisionBehavior*)behavior endedContactForItem:(id <UIDynamicItem>)item withBoundaryIdentifier:(id <NSCopying>)identifier{}