ios動的設定lbl文字ラベルの高さ

 txtlbl.font = [UIFont boldSystemFontOfSize:14.0f];  

   txtlbl.numberOfLines = 0;  

NSString *str = @"                         w              i                                          w              i                           ";

   CGSize size = [str sizeWithFont:txtlbl.font constrainedToSize:CGSizeMake(txtlbl.frame.size.width, MAXFLOAT) lineBreakMode:NSLineBreakByWordWrapping];

   //          txtlbl   

   [txtlbl setFrame:CGRectMake(7, 0, 310, size.height)];

   txtlbl.text = str;

方法二：

  // iOS7_API_           Label  

    //   Label    HelveticaNeue  Courier

    UIFont *fnt = [UIFont fontWithName:@"HelveticaNeue" size:24.0f];

    _nameLabel.font = fnt;

    //       NSString   

    CGSize size = [_nameLabel.text sizeWithAttributes:[NSDictionary dictionaryWithObjectsAndKeys:fnt,NSFontAttributeName, nil]];

    //    H

    CGFloat nameH = size.height;

    //    W

    CGFloat nameW = size.width;

    _nameLabel.frame = CGRectMake(0, 0, nameW,nameH);

方法三：

    //   W

    CGFloat contentW = self.bounds.size.width - _content.frame.origin.x - kMargin;

    // label    HelveticaNeue  Courier

    UIFont *fnt = [UIFont fontWithName:@"HelveticaNeue" size:18.0f];

    _content.font = fnt;

    _content.numberOfLines = 0;

    _content.lineBreakMode = NSLineBreakByWordWrapping;

    // iOS7           iOS6  sizeWithFont:constrainedToSize:lineBreakMode:  

    CGRect tmpRect = [_content.text boundingRectWithSize:CGSizeMake(contentW, 1000) options:NSStringDrawingUsesLineFragmentOrigin attributes:[NSDictionary dictionaryWithObjectsAndKeys:fnt,NSFontAttributeName, nil] context:nil];

    

    //   H

    CGFloat contentH = tmpRect.size.height;

    NSLog(@"        :%f,    :%f"contentW,contentH);

    _content.frame = CGRectMake(0, 0, contentW,contentH);