iOS 手势识别——拖拽

#import "MJViewController.h"

@interface MJViewController ()
@property (weak, nonatomic) IBOutlet UIView *purpleView;

@end

@implementation MJViewController

- (void)viewDidLoad
{
[super viewDidLoad];

UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panView:)];
[self.purpleView addGestureRecognizer:pan];
}

- (void)panView:(UIPanGestureRecognizer *)pan
{

switch (pan.state) {
case UIGestureRecognizerStateBegan: // 开始触发手势

break;

case UIGestureRecognizerStateEnded: // 手势结束

break;

default:
break;
}

// 1.在view上面挪动的距离
CGPoint translation = [pan translationInView:pan.view];
CGPoint center = pan.view.center;
center.x += translation.x;
center.y += translation.y;
pan.view.center = center;

// 2.清空移动的距离
[pan setTranslation:CGPointZero inView:pan.view];
}

@end