let btn_fontSizeMinus = UIButton(type: .roundedRect)
btn_fontSizeMinus.frame = CGRect(x: 0, y: 10, width: 70, height: 30)
btn_fontSizeMinus.setTitle("Aa-", for: .normal)
btn_fontSizeMinus.setTitleColor(.white, for: .normal)
btn_fontSizeMinus.layer.cornerRadius = 5
btn_fontSizeMinus.layer.borderWidth = 1
btn_fontSizeMinus.layer.borderColor = UIColor.white.cgColor
btn_fontSizeMinus.addTarget(self, action: #selector(btn_fontSizeMinusClick), for: .touchUpInside)
self.viewReadSet.addSubview(btn_fontSizeMinus)
以上为动态生成按钮 btn_fontSizeMinus 的过程。