如何取得所选字体中指定字符串的高度和宽度 并 使用

    UIFont *font = [UIFont systemFontOfSize:18];      CGSize size = [text sizeWithFont:font constrainedToSize:CGSizeMake(210.0f, 1000.0f) lineBreakMode:UILineBreakModeCharacterWrap];  

获取字符串在指定的size内(宽度超过210,则换行)所需的的实际高度和宽度.

将获取的宽度和高度用于UILabel

    UILabel *bubbleText = [[UILabel alloc] initWithFrame:CGRectMake(0.0f, 0.0f, size.width+10, size.height+10)];      bubbleText.backgroundColor = [UIColor clearColor];      bubbleText.font = font;      bubbleText.numberOfLines = 0;      bubbleText.lineBreakMode = UILineBreakModeCharacterWrap;            bubbleText.text = text;