设置cell的margin

#import"LYTopicCell.h"
#import "LYTopic.h"

@implementation LYTopicCell

- (void)awakeFromNib {
    self.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@""]];
}

- (void)setTopic:(LYTopic *)topic {
    _topic = topic;
}

- (void)setFrame:(CGRect)frame {
    static CGFloat margin = 10;
    frame.origin.x = margin;
    frame.origin.y -= margin;
    frame.size.width -= 2 * margin;
    frame.size.height -= margin;
    [super setFrame:frame];
}

- (void)setSelected:(BOOL)selected animated:(BOOL)animated {
    [super setSelected:selected animated:animated];
    // Configure the view for the selected state
}

@end