将两个（并排）按钮作为 UITextField 的右侧叠加层

Question

(Swift3/iOS10)

我正在尝试使用rightView 属性在UITextField 中放置两个按钮（保存/取消）。我的基本设置代码（来自viewDidLoad）如下：

private func accesorizeRenameField() {
    let saveButton = UIButton(type: .system)
    saveButton.setImage(#imageLiteral(resourceName: "buttonCheckmark"), for: .normal)
    saveButton.addTarget(self, action: #selector(renameSave), for: .touchUpInside)
    saveButton.tintColor = UIColor(white: 0.15, alpha: 1)

    let cancelButton = UIButton(type: .system)
    cancelButton.setImage(#imageLiteral(resourceName: "buttonX"), for: .normal)
    cancelButton.addTarget(self, action: #selector(renameCancel), for: .touchUpInside)
    cancelButton.tintColor = UIColor(227, 34, 60, 1)

    let container = UIView()
    container.addSubview(saveButton)
    container.addSubview(cancelButton)
    container.translatesAutoresizingMaskIntoConstraints = false
    container.backgroundColor = UIColor.cyan

    saveButton.centerYAnchor.constraint(equalTo: container.centerYAnchor).isActive = true
    cancelButton.centerYAnchor.constraint(equalTo: container.centerYAnchor).isActive = true
    saveButton.heightAnchor.constraint(equalTo: container.heightAnchor).isActive = true
    cancelButton.heightAnchor.constraint(equalTo: container.heightAnchor).isActive = true
    saveButton.leadingAnchor.constraint(equalTo: container.leadingAnchor).isActive = true
    saveButton.trailingAnchor.constraint(equalTo: container.centerXAnchor).isActive = true
    cancelButton.leadingAnchor.constraint(equalTo: container.centerXAnchor).isActive = true
    cancelButton.trailingAnchor.constraint(equalTo: container.trailingAnchor).isActive = true

    self.renameField.rightView = container
    self.renameField.rightViewMode = .always
}

稍后，当我通过一些动画暴露重命名字段时，我调用

self.renameField.rightView?.bounds = CGRect(x: 0, y: 0, width: self.renameField.bounds.height * 2, height: self.renameField.bounds.height)
self.renameField.rightView?.setNeedsLayout()
"rightView.frame \(self.renameField.rightView?.frame)".print()
self.renameField.rightView?.subviews.enumerated().forEach() {index,child in
    "child \(index) frame \(child.frame)".print()
}

但是，我无法显示按钮。青色背景（用于调试）出现，但实际上是正方形（应该是 2:1 矩形）。 print 显示子视图的帧大小为 0。正确的/惯用方法是什么？我觉得我只是在这里扔锤子......

Answer 1

将 UIButton 创建为 .custom 而不是 .system 的类型。

而且您已经知道 viewDidLoad 中 renameField 的高度，因此您无需担心约束。

下面的代码就足够了。

override func
viewDidLoad() {
    super.viewDidLoad()

    let wSize = renameField.frame.size.height - 2

    let saveButton = UIButton( type: .custom )
    saveButton.setImage( #imageLiteral(resourceName: "buttonCheckmark"), for: .normal )
    saveButton.addTarget( self, action: #selector(renameSave), for: .touchUpInside )
    saveButton.frame = CGRect( x: 0, y: 0, width: wSize, height: wSize )

    let cancelButton = UIButton( type: .custom )
    cancelButton.setImage( #imageLiteral(resourceName: "buttonX"), for: .normal )
    cancelButton.addTarget( self, action: #selector(renameCancel), for: .touchUpInside )
    cancelButton.frame = CGRect( x: wSize, y: 0, width: wSize, height: wSize )

    let wV = UIView()
    wV.frame = CGRect( x:0, y:0, width: wSize * 2, height: wSize )
    wV.addSubview( saveButton )
    wV.addSubview( cancelButton )

    renameField.rightView = wV;
    renameField.rightViewMode = .always;
}