無法以編程方式更改視圖的大小

Question

我有一個UIButton ，我嘗試以編程方式更改它的大小，但是它沒有作用。 這是我寫的：

import UIKit

class HomeVC: UIViewController {

let addGroupBtn = UIButton(frame: CGRect(x: 0, y: 0, width: 50, height: 50))
let addGroupLabel = UILabel()

override func viewDidLoad() {
    super.viewDidLoad()
    view.backgroundColor = UIColor(red: 110/255, green: 178/255, blue: 87/255, alpha: 1.0)
    setAddGroupBtn()
}

func setAddGroupBtn(){
    addGroupBtn.setImage(UIImage(named: "addIcon"), for: .normal)
    addGroupBtn.addTarget(self, action: #selector(moveToAddGroup), for: .touchUpInside)
    addGroupBtn.translatesAutoresizingMaskIntoConstraints = false

    self.view.addSubview(addGroupBtn)

    addGroupBtn.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor, constant: 50).isActive = true
    addGroupBtn.leadingAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.leadingAnchor, constant: 14).isActive = true
}

func setAddGroupLabel(){
    addGroupLabel.translatesAutoresizingMaskIntoConstraints = false
    addGroupLabel.text = "Add Group"
}

@objc func moveToAddGroup(){
    print("ADD GROUP")
    //Move to another VC
}
}

我在Stackoverflow和其他地方嘗試了幾種不同的解決方案，但是沒有任何效果。 它總是這樣：

Answer 1

您需要Plus widthAnchor和heightAnchor

NSLayoutConstraint.activate([
    addGroupBtn.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor, constant: 50),
    addGroupBtn.leadingAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.leadingAnchor, constant: 14),
    addGroupBtn.widthAnchor.constraint(equalToConstant:50),
    addGroupBtn.heightAnchor.constraint(equalToConstant:50)
]) 

由於按鈕具有固有的內容大小，因此可以根據其內容進行拉伸