UIDynamics -- 力学部分

#import "ViewController.h"
#import "AZball.h"

@interface ViewController ()
{
AZball *_ball;
UIDynamicAnimator *dynamicAnimator;
}
@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.

/**
UIDynamics -- 力学部分
*/

_ball=[[AZball alloc] initWithFrame:CGRectMake(30, 40, 30, 30)];
[self.view addSubview:_ball];

//创建行为
/*
可以自定义行为，也可以使用默认的已经封装的一些无力行为：

重力行为：UIGravityBehavior
碰撞行为：UICollisionBehavior
施加一个力:UIPushBehavior

*/

// 力学容器,不能提前释放，成员变量
dynamicAnimator=[[UIDynamicAnimator alloc] initWithReferenceView:self.view];

// 重力行为
UIGravityBehavior *gravityBehiver=[[UIGravityBehavior alloc] init];

// 添加受力对象
[gravityBehiver addItem:_ball];

// 碰撞行为
UICollisionBehavior *collisionBehavior=[[UICollisionBehavior alloc] initWithItems:@[_ball]];
//墙壁反弹
collisionBehavior .translatesReferenceBoundsIntoBoundary=YES;

// 施加力
UIPushBehavior *pushBehiver=[[UIPushBehavior alloc] initWithItems:@[_ball] mode:UIPushBehaviorModeContinuous];
// 施加力的方向
pushBehiver.pushDirection=CGVectorMake(0.8, 0);

//将行为放置到 力学容器 ，开始力学效应。

[dynamicAnimator addBehavior:gravityBehiver];
[dynamicAnimator addBehavior:collisionBehavior];
[dynamicAnimator addBehavior:pushBehiver];

}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}