1.在UITableView上添加长按手势：

UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressed:)];
[self.myTableView addGestureRecognizer:longPress];

2.长按手势的方法：

//cell长按拖动排序
- (void)longPressRecognizer:(UILongPressGestureRecognizer *)longPress{
    //获取长按的点及cell
    CGPoint location = [longPress locationInView:self.myTableView];
    NSIndexPath *indexPath = [self.myTableView indexPathForRowAtPoint:location];
    UIGestureRecognizerState state = longPress.state;
    
    static UIView *snapView = nil;
    static NSIndexPath *sourceIndex = nil;
    switch (state) {
        case UIGestureRecognizerStateBegan:{
            if (indexPath) {
                sourceIndex = indexPath;
                UITableViewCell *cell = [self.myTableView cellForRowAtIndexPath:indexPath];
                cell.selectionStyle = UITableViewCellSelectionStyleNone;
                snapView = [self customViewWithTargetView:cell];
                
                __block CGPoint center = cell.center;
                snapView.center = center;
                snapView.alpha = 0.0;
                [self.myTableView addSubview:snapView];
                
                [UIView animateWithDuration:0.1 animations:^{
                    center.y = location.y;
                    snapView.center = center;
                    snapView.transform = CGAffineTransformMakeScale(1.05, 1.05);
                    snapView.alpha = 0.5;
                    
                    cell.alpha = 0.0;
                }];
            }
        }
            break;
            
        case UIGestureRecognizerStateChanged:{
            CGPoint center = snapView.center;
            center.y = location.y;
            snapView.center = center;
            
            UITableViewCell *cell = [self.myTableView cellForRowAtIndexPath:sourceIndex];
            cell.alpha = 0.0;
            
            if (indexPath && ![indexPath isEqual:sourceIndex]) {
                
                [self.dataArrayM exchangeObjectAtIndex:indexPath.row withObjectAtIndex:sourceIndex.row];
                
                [self.myTableView moveRowAtIndexPath:sourceIndex toIndexPath:indexPath];
                
                sourceIndex = indexPath;
            }
            
        }
            break;
            
        default:{
            UITableViewCell *cell = [self.myTableView cellForRowAtIndexPath:sourceIndex];
            [UIView animateWithDuration:0.25 animations:^{
                snapView.center = cell.center;
                snapView.transform = CGAffineTransformIdentity;
                snapView.alpha = 0.0;
                
                cell.alpha = 1.0;
            } completion:^(BOOL finished) {
                [snapView removeFromSuperview];
                snapView = nil;
            }];
            sourceIndex = nil;
        }
            break;
    }
}

//截取选中cell
- (UIView *)customViewWithTargetView:(UIView *)target{
    UIGraphicsBeginImageContextWithOptions(target.bounds.size, NO, 0);
    [target.layer renderInContext:UIGraphicsGetCurrentContext()];
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    UIView *snapshot = [[UIImageView alloc] initWithImage:image];
    snapshot.layer.masksToBounds = NO;
    snapshot.layer.cornerRadius = 0.0;
    snapshot.layer.shadowOffset = CGSizeMake(-5.0, 0.0);
    snapshot.layer.shadowRadius = 5.0;
    snapshot.layer.shadowOpacity = 0.4;
    
    return snapshot;
}