在uitextfield中添加图标-iOS Swift

Question

我正在尝试在文本字段中添加图标。 这是我的UI现在的样子 ，下面的代码

我希望我的UI看起来与此图像相似

//创建视图（holderView）以保存图标image（image）并将视图添加到textField（txtEmail）

    let holderView = UIView(frame: CGRect(x:0, y:0, width: 40, height: 40))

    let imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: 20, height: 20))

    let image = UIImage(named: "ic_lock_48pt")

    imageView.image = image

    holderView.backgroundColor = UIColor.lightGray

    holderView.addSubview(imageView)

    imageView.center = CGPoint(x: holderView.frame.size.width / 2, y: holderView.frame.size.height / 2)

    txtEmail.leftView = holderView

（ 如果我正在花很长时间解决此问题，请告诉我 ）

所以我想以编程方式添加约束以进行修复，下面是代码

    holderView.translatesAutoresizingMaskIntoConstraints = false

    let leadingConstraint = NSLayoutConstraint(item: holderView, attribute: .leading, relatedBy: .equal, toItem: emailView, attribute: .leading, multiplier: 1, constant: 0)

    let trailingConstraint = NSLayoutConstraint(item: holderView, attribute: .trailing, relatedBy: .equal, toItem: emailView, attribute: .trailing, multiplier: 0.12, constant: 0)

    let topConstraint = NSLayoutConstraint(item: holderView, attribute: .top, relatedBy: .equal, toItem: emailView, attribute: .top, multiplier: 1, constant: 0)

    let bottomConstraint = NSLayoutConstraint(item: holderView, attribute: .bottom, relatedBy: .equal, toItem: emailView, attribute: .bottom, multiplier: 1, constant: 0)

//我在另一个视图中有txtEmail（emailView）//运行下面两行代码中的任何一条时出错

    emailView.addConstraints([leadingConstraint, trailingConstraint, topConstraint, bottomConstraint]) //or
   txtEmail.addConstraints([leadingConstraint, trailingConstraint, topConstraint, bottomConstraint])

请给我建议如何解决这个问题

Answer 1

试试他的代码：

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    textfield.leftViewMode = UITextFieldViewMode.always
    let imageView = UIImageView(frame: CGRect(x: -1, y: 0, width: 30, height: 40))
    let image = UIImage(named: "q.png")
    imageView.backgroundColor = UIColor(white: 0.7, alpha: 0.6)
    imageView.image = image
    textfield.leftView = imageView

    textfield.layer.borderColor = UIColor(white: 0.7, alpha: 0.6).cgColor
    textfield.layer.borderWidth = 2

    imageView.layer.borderColor = UIColor(white: 0.7, alpha: 0.6).cgColor
    imageView.layer.borderWidth = 2

    textfield.layer.cornerRadius = 5
    textfield.layer.masksToBounds = true

 }

注意：您必须创建一个类似于下图的图标图像才能达到效果，这全部与创建图标并将其放置在正确的位置有关。希望这会有所帮助。

输出：