各种碰撞、吸附、点击展开等物理视觉效果大都是通过UIDynamic来实现的
直接上代码看各种效果：
#import "ViewController.h"
@interface ViewController ()
@property (strong, nonatomic) UIView *squareView;
@property (strong, nonatomic) UIDynamicAnimator *animator;
@property (nonatomic, strong) UIAttachmentBehavior *attachmentB;//附着行为
@property (nonatomic, strong) NSMutableArray *itemsA;
@property (nonatomic, strong) UIGravityBehavior *gravityB;//重力行为
@property (assign, nonatomic) CGPoint curTickleStart;
@property (nonatomic, assign) CGPoint oldCenter;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.squareView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 200, 200)];
_squareView.backgroundColor = [UIColor orangeColor];
[self.view addSubview:self.squareView];
self.oldCenter = _squareView.center;
self.itemsA = [NSMutableArray arrayWithCapacity:0];
for (int i = 0; i<5; i++) {
UIView *view1 = [[UIView alloc] initWithFrame:CGRectMake(10 + i * 30, 100, 20, 20)];
view1.backgroundColor = [UIColor colorWithRed:arc4random()% 255 / 255.0 green:arc4random()% 255 / 255.0 blue:arc4random()% 255 / 255.0 alpha:1.0];
[self.view addSubview:view1];
[_itemsA addObject:view1];
}
self.animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];
// NSArray *itemsArr = [self.animator itemsInRect:CGRectMake(0, 100, self.view.bounds.size.width, 50)];
// - (NSArray*)itemsInRect:(CGRect)rect; //只有在添加行为后，才有值
//- (void)removeBehavior:(UIDynamicBehavior *)behavior;
//- (void)removeAllBehaviors;
//- (void)addBehavior:(UIDynamicBehavior *)behavior;
self.gravityB = [[UIGravityBehavior alloc] initWithItems:_itemsA]; // 创建一个重力行为
// 在进行动画时的 block 回调 @property(nonatomic, copy) void (^action)(void)
// _gravityB.action = ^{
// NSLog(@"ing animation");
// };
_gravityB.gravityDirection = CGVectorMake(0.5, 0.8); // 在垂直向下方向 1000 点/平方秒 的速度 , 第一个参数是方向，第二个是速度
[self.animator addBehavior:_gravityB];
// 添加到该动态行为中的子动态行为 @property(nonatomic, readonly, copy) NSArray *childBehaviors
// gravity.childBehaviors;
// 该动态行为相关联的dynamicAnimator
// @property(nonatomic, readonly) UIDynamicAnimator *dynamicAnimator
//添加一个子动态行为
// - (void)addChildBehavior:(UIDynamicBehavior *)behavior
// 移除一个子动态行为
// - (void)removeChildBehavior:(UIDynamicBehavior *)behavior
// 当该动态行为将要被添加到一个UIDynamicAnimator中时，这个方法会被调用。
// - (void)willMoveToAnimator:(UIDynamicAnimator *)dynamicAnimator
// 创建碰撞行为
UICollisionBehavior *collision = [[UICollisionBehavior alloc] initWithItems:_itemsA];
// 指定 Reference view 的边界为可碰撞边界
collision.translatesReferenceBoundsIntoBoundary = YES;
collision.collisionDelegate = self;
// UICollisionBehaviorModeItems:item 只会和别的 item 发生碰撞；UICollisionBehaviorModeBoundaries：item 只和碰撞边界进行碰撞；UICollisionBehaviorModeEverything:item 和 item 之间会发生碰撞，也会和指定的边界发生碰撞。
collision.collisionMode = UICollisionBehaviorModeEverything;
[self.animator addBehavior:collision];
//UICollisionBehavior通过下面两个方法来添加碰撞边界，可以根据贝塞尔曲线或者一条直线生成碰撞边界。
// - (void)addBoundaryWithIdentifier:(id )identifier forPath:(UIBezierPath*)bezierPath;
// - (void)addBoundaryWithIdentifier:(id )identifier fromPoint:(CGPoint)p1 toPoint:(CGPoint)p2;
//UICollisionBehavior 里的 item 每次发生碰撞都可以通过 delegate 来监听事件。
// item 与 item 之间开始碰撞。
// - (void)collisionBehavior:(UICollisionBehavior*)behavior beganContactForItem:(id )item1 withItem:(id )item2 atPoint:(CGPoint)p;
//
// // item 与 item 之间结束碰撞。
// - (void)collisionBehavior:(UICollisionBehavior*)behavior endedContactForItem:(id )item1 withItem:(id )item2;
//
//
// // item 和边界开始碰撞
// - (void)collisionBehavior:(UICollisionBehavior*)behavior beganContactForItem:(id )item withBoundaryIdentifier:(id )identifier atPoint:(CGPoint)p;
//
// // item 和边界结束碰撞
// - (void)collisionBehavior:(UICollisionBehavior*)behavior endedContactForItem:(id )item withBoundaryIdentifier:(id )identifier;
//UIAttachmentBehavior 附着行为，让物体附着在某个点或另外一个物体上。可以设置附着点的到物体的距离，阻尼系数和振动频率等。
/**
/ UIAttachmentBehaviorTypeAnchor类型的依赖行为的锚点，锚点与行为相关的动力动画的坐标系统有关。
@property(readwrite, nonatomic) CGPoint anchorPoint
// 吸附行为的类型
@property(readonly, nonatomic) UIAttachmentBehaviorType attachedBehaviorType
// 描述吸附行为减弱的阻力大小
@property(readwrite, nonatomic) CGFloat damping
// 吸附行为震荡的频率
@property(readwrite, nonatomic) CGFloat frequency
// 与吸附行为相连的动态项目，当吸附行为类型是UIAttachmentBehaviorTypeItems时有2个元素，当吸附行为类型是UIAttachmentBehaviorTypeAnchor时只有一个元素。
@property(nonatomic, readonly, copy) NSArray *items
// 吸附行为中的两个吸附点之间的距离，通常用这个属性来调整吸附的长度，可以创建吸附行为之后调用。系统基于你创建吸附行为的方法来自动初始化这个长度
@property(readwrite, nonatomic) CGFloat length
*/
// UIAttachmentBehavior *attachment = [[UIAttachmentBehavior alloc] initWithItem:self.squareView attachedToAnchor:self.squareView.center];
// attachment.length = 200;
// attachment.damping = 0.5;
// attachment.frequency = 1;
// [self.animator addBehavior:attachment];
//UIDynamicItemBehavior 物体属性，如密度、弹性系数、摩擦系数、阻力、转动阻力等。 接下来我们修改物体的物理属性，为了能看到这个效果，我们先删除 UIAttachmentBehavior 相关的代码，并在 - (void)viewDidAppear:(BOOL)animated 末尾添加如下代码：
/**
// 弹力，通常设置 0~1 之间
@property (readwrite, nonatomic) CGFloat elasticity;
// 摩擦力，0表示完全光滑无摩擦
@property (readwrite, nonatomic) CGFloat friction;
// 密度，一个 100x100 points（1 point 在 retina 屏幕上等于2像素，在普通屏幕上为1像素。）大小的物体，密度1.0，在上面施加 1.0 的力，会产生 100 point/平方秒 的加速度。
@property (readwrite, nonatomic) CGFloat density;
// 线性阻力，物体在移动过程中受到的阻力大小
@property (readwrite, nonatomic) CGFloat resistance;
// 旋转阻力，物体旋转过程中的阻力大小
@property (readwrite, nonatomic) CGFloat angularResistance;
// 是否允许旋转
@property (readwrite, nonatomic) BOOL allowsRotation;
*/
UIDynamicItemBehavior *itemBehavior = [[UIDynamicItemBehavior alloc] initWithItems:_itemsA];
itemBehavior.elasticity = 1; // 改变弹性
itemBehavior.allowsRotation = YES; // 允许旋转
[itemBehavior addAngularVelocity:1 forItem:self.squareView]; // 让物体旋转
[self.animator addBehavior:itemBehavior];
//UIPushBehavior 对物体施加力，可以是持续性的力也可以是一次性的力。用一个向量(CGVector)来表示力的方向和大小。
//这次我们通过手势来动态的为物体添加推力，首先注释重力行为的相关代码，然后在 - (void)viewDidAppear:(BOOL)animated 末尾添加如下代码
/**
// 推力模式，UIPushBehaviorModeContinuous：持续型。UIPushBehaviorModeInstantaneous：一次性推力。
@property (nonatomic, readonly) UIPushBehaviorMode mode;
// 推力是否被激活，在激活状态下，物体才会受到推力效果
@property(nonatomic, readwrite) BOOL active
// 推力的大小和方向
@property (readwrite, nonatomic) CGVector pushDirection;
*/
// UITapGestureRecognizer *viewTapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapViewHandler:)];
// [self.view addGestureRecognizer:viewTapGesture];
//UISnapBehavior 将一个物体钉在某一点。它只有一个初始化方法和一个属性。
// 根据 item 和 point 来确定一个 item 要被定到哪个点上。
// - (instancetype)initWithItem:(id )item snapToPoint:(CGPoint)point;
//
// // 减震系数，范围在0.0~1.0
// @property (nonatomic, assign) CGFloat damping;
//添加拖拽手势
UIPanGestureRecognizer *panGes = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];
panGes.delegate = self;
[self.squareView addGestureRecognizer:panGes];
}
- (void)tapViewHandler:(UITapGestureRecognizer *)gestureRecognizer
{
UIPushBehavior *push = [[UIPushBehavior alloc] initWithItems:@[self.squareView] mode:UIPushBehaviorModeInstantaneous];
CGPoint location = [gestureRecognizer locationInView:self.view];
CGPoint itemCenter = self.squareView.center;
push.pushDirection = CGVectorMake((location.x - itemCenter.x) / 100, (location.y - itemCenter.y) / 100);
[self.animator addBehavior:push];
}
//拖拽手势
- (void) handlePan:(UIPanGestureRecognizer*) recognizer
{
CGPoint translation = [recognizer translationInView:self.view];
NSLog(@"wgj：%lf,%lf",translation.x,translation.y);
NSLog(@"wgj001：%lf,%lf",recognizer.view.center.x,recognizer.view.center.y);
recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,
recognizer.view.center.y + translation.y);
[recognizer setTranslation:CGPointZero inView:self.view];//防止移动量累计增加
CGPoint location = recognizer.view.center;
CGFloat itemW = recognizer.view.bounds.size.width;
CGFloat itemH = recognizer.view.bounds.size.height;
CGFloat viewW = self.view.bounds.size.width;
CGFloat viewH = self.view.bounds.size.height;
if (recognizer.view.center.x < itemW * 0.5) {
recognizer.view.center = CGPointMake(itemW * 0.5, location.y);
}
if (recognizer.view.center.y < itemH * 0.5) {
recognizer.view.center = CGPointMake(location.x, itemH * 0.5);
}
if (recognizer.view.center.x > viewW - itemW * 0.5) {
recognizer.view.center = CGPointMake(viewW - itemW * 0.5, location.y);
}
if (recognizer.view.center.y > viewH - itemH * 0.5) {
recognizer.view.center = CGPointMake(location.x, viewH - itemH * 0.5);
}
if (recognizer.state == UIGestureRecognizerStateBegan) {
[self.animator removeBehavior:self.attachmentB];
// [self.animator removeAllBehaviors];
}
if (recognizer.state == UIGestureRecognizerStateEnded) {
[self.animator addBehavior:self.attachmentB];//添加吸附行为
}
//让小物体改变角度
_gravityB.angle = 3;
//
// if (recognizer.state == UIGestureRecognizerStateEnded) {
//
// CGPoint velocity = [recognizer velocityInView:self.view];
// CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y));
// CGFloat slideMult = magnitude / 200;
// NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult);
//
// float slideFactor = 0.1 * slideMult; // Increase for more of a slide
// CGPoint finalPoint = CGPointMake(recognizer.view.center.x + (velocity.x * slideFactor),
// recognizer.view.center.y + (velocity.y * slideFactor));
// finalPoint.x = MIN(MAX(finalPoint.x, 0), self.view.bounds.size.width);
// finalPoint.y = MIN(MAX(finalPoint.y, 0), self.view.bounds.size.height);
//
// [UIView animateWithDuration:slideFactor*2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{
// recognizer.view.center = finalPoint;
// } completion:nil];
// }
}
- (UIAttachmentBehavior *)attachmentB
{
if (_attachmentB == nil) {
self.attachmentB = [[UIAttachmentBehavior alloc] initWithItem:self.squareView attachedToAnchor:CGPointMake(150, 200)];
_attachmentB.length = 0;
_attachmentB.damping = 0.6;//阻尼
_attachmentB.frequency = 1.2; //震频
}
return _attachmentB;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end