UIDynamic-附着行为:UIAttachmentBehavior

直接上代码:

 //
 //  YFAttachmentBehaviorViewController.m
 //  BigShow1949
 //
 //  Created by apple on 16/8/25.
 //  Copyright © 2016年 BigShowCompany. All rights reserved.
 //

 #import "YFAttachmentBehaviorViewController.h"

 @interface YFAttachmentBehaviorViewController ()

 @property (nonatomic, strong) UIView *square1;
 @property(nonatomic,strong)UIDynamicAnimator *animator;
 @property (nonatomic, strong) UIAttachmentBehavior *attachmentBehavior;

 @end

 @implementation YFAttachmentBehaviorViewController

 - (void)viewDidLoad
 {
     [super viewDidLoad];

     self.view.backgroundColor = [UIColor whiteColor];

     // 创建一个正方形
     self.square1 =[[UIView alloc] initWithFrame: CGRectMake(0.0f, -, 80.0f, 80.0f)];
     self.square1.backgroundColor = [UIColor greenColor];
     self.square1.center = self.view.center;
     [self.view addSubview:self.square1];

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

     UICollisionBehavior* collision = [[UICollisionBehavior alloc] initWithItems:@[self.square1]];
     collision.translatesReferenceBoundsIntoBoundary = YES;

     UIGravityBehavior *gravity = [[UIGravityBehavior alloc] initWithItems:@[self.square1]];

     [self.animator addBehavior:collision];
     [self.animator addBehavior:gravity];

     // 视图手势
     [self createGestureRecognizer];
 }

 - (void)createGestureRecognizer{
     UIPanGestureRecognizer *tapGestureRecognizer =
     [[UIPanGestureRecognizer alloc] initWithTarget:self  action:@selector(handleTap:)];
     [self.view addGestureRecognizer:tapGestureRecognizer];
 }

 - (void)handleTap:(UIPanGestureRecognizer *)gesture{

     if (gesture.state == UIGestureRecognizerStateBegan){
         NSLog(@"----Began");

         CGPoint squareCenterPoint = CGPointMake(self.square1.center.x, self.square1.center.y - 100.0);

         UIAttachmentBehavior* attachmentBehavior = [[UIAttachmentBehavior alloc] initWithItem:self.square1 attachedToAnchor:squareCenterPoint];

         self.attachmentBehavior = attachmentBehavior;
         [self.animator addBehavior:attachmentBehavior];

     } else if ( gesture.state == UIGestureRecognizerStateChanged) {
         NSLog(@"----Changed");
         [self.attachmentBehavior setAnchorPoint:[gesture locationInView:self.view]];

     } else if (gesture.state == UIGestureRecognizerStateEnded) {
         NSLog(@"----Ended");
         [self.animator removeBehavior:self.attachmentBehavior];
     }
 }

 @end