UIDynamic - 推动行为: UIPushBehavior

用途:

从一个点移动到另外一个点;

相关属性:

mode : UIPushBehaviorModeContinuous  //推移模式

angle : setAngle  //推移角度

magnitude : setMagnitude  //速度   每1个magnigude将会引起100/平方秒的加速度

图片说明:

p1 : squareView的中心点  p2 : 单击的点

促使squareView朝着p2移动，因为加了UICollisionBehavior，所以移动时又不会超过边界

代码:

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

 #import "YFPushBehaviorViewController.h"

 @interface YFPushBehaviorViewController ()
 @property(nonatomic,strong)UIDynamicAnimator *animator;
 @property (nonatomic, strong) UIView *squareView;
 @property (nonatomic, strong) UIPushBehavior *pushBehavior;

 @end

 @implementation YFPushBehaviorViewController
 - (void)viewDidLoad {

     [super viewDidLoad];
     self.view.backgroundColor = [UIColor whiteColor];

 }

 - (void)viewDidAppear:(BOOL)animated{
     [super viewDidAppear:animated];

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

     // 视图单机手势
     [self createGestureRecognizer];

     [self createAnimatorAndBehaviors];
 }

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

 - (void) handleTap:(UITapGestureRecognizer *)paramTap{

     CGPoint tapPoint = [paramTap locationInView:self.view];  //p2
     CGPoint squareViewCenterPoint = self.squareView.center;  //p1

     CGFloat deltaX = tapPoint.x - squareViewCenterPoint.x;
     CGFloat deltaY = tapPoint.y - squareViewCenterPoint.y;
     CGFloat angle = atan2(deltaY, deltaX);
     [self.pushBehavior setAngle:angle];  //推移的角度

     //勾股
     CGFloat distanceBetweenPoints =
     sqrt(pow(tapPoint.x - squareViewCenterPoint.x, 2.0) +
          pow(tapPoint.y - squareViewCenterPoint.y, 2.0));
     //double pow(double x, double y）;计算以x为底数的y次幂
     //double sqrt (double);开平方

     //推力的大小（移动速度）
     [self.pushBehavior setMagnitude:distanceBetweenPoints / 50.0f];
     //每1个magnigude将会引起100/平方秒的加速度，这里分母越大，速度越小

 }
 - (void) createSmallSquareView{
     self.squareView =[[UIView alloc] initWithFrame: CGRectMake(0.0f, 0.0f, 80.0f, 80.0f)];

     self.squareView.backgroundColor = [UIColor greenColor];
     self.squareView.center = self.view.center;

     [self.view addSubview:self.squareView];
 }
 - (void) createAnimatorAndBehaviors{
     self.animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];

     /* Create collision detection */
     UICollisionBehavior *collision = [[UICollisionBehavior alloc]
                                       initWithItems:@[self.squareView]];
     collision.translatesReferenceBoundsIntoBoundary = YES;

     self.pushBehavior = [[UIPushBehavior alloc]
                          initWithItems:@[self.squareView]
                          mode:UIPushBehaviorModeContinuous];

     [self.animator addBehavior:collision];
     [self.animator addBehavior:self.pushBehavior];
 }

 @end