IOS15UIButton根据文字长度计算宽高

自定义一个UIButton，如何不设置它的宽高，让其根据自身文字的多少，自动设置自身大小呢，
主要使用ios7推出的boundingRectWithSize方法.最后把文字的宽度加上图片的宽度，加上文字的偏移值。

- (void)layoutSubviews{
    [super layoutSubviews];
    NSDictionary *attrs = @{
        NSFontAttributeName: self.titleLabel.font
    };
    CGFloat titleW = [self.title boundingRectWithSize:CGSizeMake(MAXFLOAT,MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:attrs context:nil].size.width;
    self.hm_width = titleW + self.titleEdgeInsets.left + self.currentImage.size.width;
}
@end

Xnip2021-11-29_14-36-35.jpg

swift5写法

//
//  TitleButton.swift
//  testLabelSwift
//
//  Created by lujun on 2021/11/29.
//

import UIKit

class TitleButton: UIButton {
   var titleStr: String? {
        didSet {
            guard let titleStr = titleStr else {
                return
            }
            self.setTitle(titleStr, for: .normal)
        }
    }
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.isUserInteractionEnabled = false
        self.setImage(UIImage(named:"navbar_netease"), for: .normal)
        self.titleLabel?.font = UIFont.systemFont(ofSize: 22)
        self.titleEdgeInsets = UIEdgeInsets(top: 0, left: 8, bottom: 0, right: 0)

        self.frame.size.height =  CGFloat(self.currentImage!.size.height)
        self.setTitleColor(.white, for: .normal)
    }
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    override func layoutSubviews() {
        super.layoutSubviews()
        let dict = [NSAttributedString.Key.font : self.titleLabel?.font]
        let titleW = (titleStr! as NSString).boundingRect(with: CGSize(width: LONG_MAX, height: LONG_MAX), options: .usesLineFragmentOrigin, attributes: dict as [NSAttributedString.Key : Any], context: nil).size.width
        let imageW = self.currentImage?.size.width
        self.frame = CGRect(x: 0, y: 0, width: titleW + self.titleEdgeInsets.left + (imageW ?? 0), height: 30)
        }
}