touchesBegan:withEvent:          //触摸屏幕的最开始被调用 touchesMoved:withEvent:         //移动过程中被调用 touchesEnded:withEvent:         //动作结束时被调用 touchesCancelled:WithEvent:

UIPanGestureRecognizer * panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self                                                                                             action:@selector(doHandlePanAction:)];     [self.vLight addGestureRecognizer:panGestureRecognizer];

- (void) doHandlePanAction:(UIPanGestureRecognizer *)paramSender{         CGPoint point = [paramSender translationInView:self.view];     NSLog(@"X:%f;Y:%f",point.x,point.y);         paramSender.view.center = CGPointMake(paramSender.view.center.x + point.x, paramSender.view.center.y + point.y);     [paramSender setTranslation:CGPointMake(0, 0) inView:self.view];     }

#import <UIKit/UIKit.h>    @interface GragView : UIImageView  {      CGPoint startPoint;  }  @end  #import "GragView.h"    @implementation GragView    - (id)initWithFrame:(CGRect)frame  {      self = [super initWithFrame:frame];      if (self) {          // Initialization code          //允许用户交互          self.userInteractionEnabled = YES;      }      return self;  }    - (id)initWithImage:(UIImage *)image  {      self = [super initWithImage:image];      if (self) {          //允许用户交互          self.userInteractionEnabled = YES;      }      return self;  }    - (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event  {      //保存触摸起始点位置      CGPoint point = [[touches anyObject] locationInView:self];      startPoint = point;            //该view置于最前      [[self superview] bringSubviewToFront:self];  }    -(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event  {      //计算位移=当前位置-起始位置      CGPoint point = [[touches anyObject] locationInView:self];      float dx = point.x - startPoint.x;      float dy = point.y - startPoint.y;            //计算移动后的view中心点      CGPoint newcenter = CGPointMake(self.center.x + dx, self.center.y + dy);                  /* 限制用户不可将视图托出屏幕 */      float halfx = CGRectGetMidX(self.bounds);      //x坐标左边界      newcenter.x = MAX(halfx, newcenter.x);      //x坐标右边界      newcenter.x = MIN(self.superview.bounds.size.width - halfx, newcenter.x);            //y坐标同理      float halfy = CGRectGetMidY(self.bounds);      newcenter.y = MAX(halfy, newcenter.y);      newcenter.y = MIN(self.superview.bounds.size.height - halfy, newcenter.y);            //移动view      self.center = newcenter;  }    /*  // Only override drawRect: if you perform custom drawing.  // An empty implementation adversely affects performance during animation.  - (void)drawRect:(CGRect)rect  {      // Drawing code  }  */    @end