ios - how to have Multiple lines of NSAttributedString - ios

Question

There are 3 UIlabel in my TableViewCell.xib.One of them need to set attributedText with NSMutableAttributedString,the code like this:
NSString * htmlString = [NSString stringWithFormat:#"将订单状态从 %# 改变为 %# ，原因：%#",lb.order_status,lb.changed_status,lb.remark];
NSMutableAttributedString * attrStr = [[NSMutableAttributedString alloc] initWithData:[htmlString dataUsingEncoding:NSUnicodeStringEncoding] options:#{ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType } documentAttributes:nil error:nil];
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
style.lineBreakMode = NSLineBreakByTruncatingTail;
style.lineHeightMultiple = 0;
[attrStr addAttribute:NSParagraphStyleAttributeName
value:style
range:NSMakeRange(0, attrStr.length)];
[attrStr addAttribute:NSFontAttributeName value:[UIFont fontWithName:#"Palatino-Roman" size:13.0] range:NSMakeRange(0, attrStr.length)];
lbRemark.attributedText=attrStr;
Question 1:
lbRemark cannot display with multiple-lines, but if I do not use NSAttributedString to set lbRemark then it can display with multiple-lines.Is there something wrong with NSAttributedString?
Question 2: I need my Cell to calculate it's height with lbRemark' height.

Answer 1

Since iOS8, you don't need to calculate the height of the label. Auto-layout will do that for you.
Attach top and bottom constraints between the UILabel and the cell - do not set a height constraint for the UILabel.
In the viewDidLoad: method of your UIViewController, just do the following (replace the 50.0f with the default height of your rows):
self.tableView.estimatedRowHeight = 50.0f;
self.tableView.rowHeight = UITableViewAutomaticDimension;

Answer 2

1: Set this for multiple lines:
lbRemark.numberOfLines = 0;
2: This is how to calculate height of label according to text:
NSString * htmlString = [NSString stringWithFormat:#"将订单状态从 %# 改变为 %# ，原因：%#",#"test",#"test1",#"test2"];
NSMutableAttributedString * attrStr = [[NSMutableAttributedString alloc] initWithData:[htmlString dataUsingEncoding:NSUnicodeStringEncoding] options:#{ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType } documentAttributes:nil error:nil];
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
style.lineBreakMode = NSLineBreakByTruncatingTail;
style.lineHeightMultiple = 0;
[attrStr addAttribute:NSParagraphStyleAttributeName
value:style
range:NSMakeRange(0, attrStr.length)];
[attrStr addAttribute:NSFontAttributeName value:[UIFont fontWithName:#"Palatino-Roman" size:13.0] range:NSMakeRange(0, attrStr.length)];
lbRemark.numberOfLines = 0;
CGRect paragraphRect = [attrStr boundingRectWithSize:CGSizeMake(625, CGFLOAT_MAX)
options:(NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading)
context:nil]; //here 625 is width of label, use whatever your width
NSLog(#"height = %f", paragraphRect.size.height); //it should be height for label
lbRemark.attributedText=attrStr;

Answer 3

Hum...finally I got a solution for it.It's not anything wrong with NSAttributedString.I implement a function(my workmate who often helped me offer it )：
static UITableViewCell *sizingLogCell = nil;
static dispatch_once_t onceToken;
if ([indentifier isEqualToString:#"logCell"]) {
dispatch_once(&onceToken, ^{
sizingLogCell = [tableView dequeueReusableCellWithIdentifier:indentifier];
});
sizingLogCell.bounds = CGRectMake(0.0f, 0.0f, CGRectGetWidth(tableView.bounds), CGRectGetHeight(tableView.bounds));
[sizingLogCell setNeedsLayout];
[sizingLogCell layoutSubviews];
[self configureLogCell:sizingLogCell forIndexPath:indexPath];
CGSize size = [sizingLogCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
return size.height + 1;
}
The function's name is :
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath indentifierForCell:(NSString *)indentifier
The most important thing is 'size.height + 1',if without '+1' label still can not display with multi-lines.