这是我通常构建子类(UIView)的示例。我将内容作为变量存储,以便稍后可以在其他类中访问和调整。我还展示了如何使用自动布局和添加内容。
例如,在ViewController中,我初始化了这个视图In ViewDidLoad(),因为只有当视图可见时才会调用它。然后我使用这些函数addContentToView()
和activateConstraints()
来构建内容并设置约束。如果我稍后在ViewController中想要让某个按钮的颜色变成红色,我只需要在那个特定的函数中进行设置。
像这样:func tweaksome(){ self.customView.someButton.color = UIColor.red}
class SomeView: UIView {
var leading: NSLayoutConstraint!
var trailing: NSLayoutConstraint!
var bottom: NSLayoutConstraint!
var height: NSLayoutConstraint!
var someButton: UIButton = {
var btn: UIButton = UIButton(type: UIButtonType.system)
btn.setImage(UIImage(named: "someImage"), for: .normal)
btn.translatesAutoresizingMaskIntoConstraints = false
return btn
}()
var btnLeading: NSLayoutConstraint!
var btnBottom: NSLayoutConstraint!
var btnTop: NSLayoutConstraint!
var btnWidth: NSLayoutConstraint!
var textfield: UITextField = {
var tf: UITextField = UITextField()
tf.adjustsFontSizeToFitWidth = true
tf.placeholder = "Cool placeholder"
tf.translatesAutoresizingMaskIntoConstraints = false
tf.backgroundColor = UIColor.white
tf.textColor = UIColor.black
return tf
}()
var txtfieldLeading: NSLayoutConstraint!
var txtfieldTrailing: NSLayoutConstraint!
var txtfieldCenterY: NSLayoutConstraint!
override init(frame: CGRect){
super.init(frame: frame)
self.translatesAutoresizingMaskIntoConstraints = false
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
func activateConstraints(){
NSLayoutConstraint.activate([self.btnLeading, self.btnBottom, self.btnTop, self.btnWidth])
NSLayoutConstraint.activate([self.txtfieldCenterY, self.txtfieldLeading, self.txtfieldTrailing])
}
func addContentToView(){
self.addSubview(self.userLocationBtn)
self.btnLeading = NSLayoutConstraint(
item: someButton,
attribute: .leading,
relatedBy: .equal,
toItem: self,
attribute: .leading,
multiplier: 1.0,
constant: 5.0)
self.btnBottom = NSLayoutConstraint(
item: someButton,
attribute: .bottom,
relatedBy: .equal,
toItem: self,
attribute: .bottom,
multiplier: 1.0,
constant: 0.0)
self.btnTop = NSLayoutConstraint(
item: someButton,
attribute: .top,
relatedBy: .equal,
toItem: self,
attribute: .top,
multiplier: 1.0,
constant: 0.0)
self.btnWidth = NSLayoutConstraint(
item: someButton,
attribute: .width,
relatedBy: .equal,
toItem: self,
attribute: .height,
multiplier: 1.0,
constant: 0.0)
self.addSubview(self.textfield)
self.txtfieldLeading = NSLayoutConstraint(
item: self.textfield,
attribute: .leading,
relatedBy: .equal,
toItem: someButton,
attribute: .trailing,
multiplier: 1.0,
constant: 5)
self.txtfieldTrailing = NSLayoutConstraint(
item: self.textfield,
attribute: .trailing,
relatedBy: .equal,
toItem: self.doneButton,
attribute: .leading,
multiplier: 1.0,
constant: -5)
self.txtfieldCenterY = NSLayoutConstraint(
item: self.textfield,
attribute: .centerY,
relatedBy: .equal,
toItem: self,
attribute: .centerY,
multiplier: 1.0,
constant: 0.0)
}
}
CGRect.zeroRect
而不是CGRectZero
。 - Mr Rogers