彈簧效果

#import "ViewController.h"

@interface ViewController ()
{
    UIImageView *_imageView;
    
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    _imageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"ball"]];
    _imageView.center = CGPointMake(375/2, 667/2);
    [self.view addSubview:_imageView];
    
    
}
//立即點擊觸發彈性動畫
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    UITouch *touch = [touches anyObject];
    CGPoint location = [touch locationInView:self.view];
    //建立彈性動畫
    //阻尼：返回0-1 ，越接近0，彈性效果越明顯
    //velocity：彈性復原速度
    [UIView animateWithDuration:5.0 delay:0 usingSpringWithDamping:0.1 initialSpringVelocity:1.0 options:UIViewAnimationOptionCurveLinear animations:^{
        _imageView.center = location;//最終小球位置
        NSLog(@"%.2f----%.2f",location.x,location.y);
    }completion:nil];
}
//點擊後鬆開手瞬間觸發彈性動畫
//-(void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
//    UITouch *touch = [touches anyObject];
//    CGPoint location = [touch locationInView:self.view];
//    [UIView animateWithDuration:5 delay:0 usingSpringWithDamping:0.1 initialSpringVelocity:1.0 options:UIViewAnimationOptionCurveLinear animations:^{
//        _imageView.center = location;
//    } completion:nil];
//}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end