调整cell的间距

-(instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier{
    if (self == [super initWithStyle:style reuseIdentifier:reuseIdentifier]) {
        self = [[NSBundle mainBundle] loadNibNamed:@"MessageNotificationTableViewCell" owner:nil options:nil][0];
        // self.contentView.backgroundColor=[UIColor clearColor];
        //self.backgroundColor=[UIColor clearColor];
        self.selectionStyle=UITableViewCellSelectionStyleNone;
        UIView *view = [[UIView alloc ]initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, 10)];
        
        view.backgroundColor =MAIN_COLOR_GRAY;
        
        [self.contentView addSubview:view];
        
       
    }
    return self;
}