ios中根据文本设置label高度

UILabel * label = [[UILabel alloc] init];      

    NSString * text = @"hellohellohellohellohellohellohellohellohellohellohellohello ";      

    label.text = text;  

    [label setNumberOfLines:0];  

    UIFont *font = [UIFont fontWithName:@"Arial" size:14];      

    //设置字体      

    label.font = font;      

    CGSize size = CGSizeMake(300, 20000.0f);  

    size = [text sizeWithFont:font constrainedToSize:size lineBreakMode:NSLineBreakByCharWrapping];  

    [label setFrame:CGRectMake(10, 0, size.width, size.height)];  

   [self.view addSubview:label];  

lineBreakMode：设置标签文字过长时的显示方式。 

label.lineBreakMode = NSLineBreakByCharWrapping;以字符为显示单位显示，后面部分省略不显示。 

label.lineBreakMode = NSLineBreakByClipping;剪切与文本宽度相同的内容长度，后半部分被删除。 

label.lineBreakMode = NSLineBreakByTruncatingHead;前面部分文字以……方式省略，显示尾部文字内容。 

label.lineBreakMode = NSLineBreakByTruncatingMiddle;中间的内容以……方式省略，显示头尾的文字内容。 

label.lineBreakMode = NSLineBreakByTruncatingTail;结尾部分的内容以……方式省略，显示头的文字内容。 

label.lineBreakMode = NSLineBreakByWordWrapping;以单词为显示单位显示，后面部分省略不显示。

UIFont *fontText = [UIFont fontWithName:[AppHandlers zHandler].fontName size:16];

NSDictionary *attributes = @{NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue" size:14.0f]};
CGRect rect = [textToMeasure boundingRectWithSize:CGSizeMake(width, MAXFLOAT)
                                          options:NSStringDrawingUsesLineFragmentOrigin
                                       attributes:attributes
                                          context:nil];

expectedLabelSize = CGSizeMake(textRect.size.width, textRect.size.height);