根据文字计算cell的高度

FinanceNewsModel *fin = [FinanceNewsListModelsharedInstance].list4[indexPath.row];

NSDictionary *attrbute = @{NSFontAttributeName:[UIFontsystemFontOfSize:12]};//字号

float ff =[fin.news_contentboundingRectWithSize:CGSizeMake(WIDTH-6,2000)options:NSStringDrawingUsesLineFragmentOrigin |NSStringDrawingUsesFontLeadingattributes:attrbute context:nil].size.height;//字占得宽度 字的个数最多

NSLog(@"%f",ff);

return ff+40;