详细代码： dropDownMenu
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87class dropDownBtn: UIButton, dropDownProtocol {
func dropDownPressed(string: String) {
self.setTitle(string, for: .normal)
self.dismissDropDown()
}
var dropView = dropDownView()
var height = NSLayoutConstraint()
override init(frame: CGRect) {
super.init(frame: frame)
self.backgroundColor = UIColor.darkGray
dropView = dropDownView.init(frame: CGRect.init(x: 0, y: 0, width: 0, height: 0))
dropView.translatesAutoresizingMaskIntoConstraints = false
dropView.delegate = self
}
// 本视图被添加到父视图上时调用
override func didMoveToSuperview() {
self.superview?.addSubview(dropView)
self.superview?.bringSubview(toFront: dropView)
dropView.topAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
dropView.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
dropView.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
height = dropView.heightAnchor.constraint(equalToConstant: 0)
}
var isOpen = false
// 刚触摸时调用
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if isOpen == false {
isOpen = true
NSLayoutConstraint.deactivate([self.height])
if self.dropView.tableView.contentSize.height > 150 {
self.height.constant = 150
} else {
self.height.constant = self.dropView.tableView.contentSize.height
}
NSLayoutConstraint.activate([self.height])
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
self.dropView.layoutIfNeeded()
print(self.center, self.dropView.center, self.dropView.frame.height, self.dropView.frame.width)
self.dropView.center.y += self.dropView.frame.height / 2
}, completion: nil)
} else {
isOpen = false
NSLayoutConstraint.deactivate([self.height])
self.height.constant = 0
NSLayoutConstraint.activate([self.height])
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
self.dropView.center.y -= self.dropView.frame.height / 2
self.dropView.layoutIfNeeded()
}, completion: nil)
}
}
func dismissDropDown() {
isOpen = false
NSLayoutConstraint.deactivate([self.height])
self.height.constant = 0
NSLayoutConstraint.activate([self.height])
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
self.dropView.center.y -= self.dropView.frame.height / 2
self.dropView.layoutIfNeeded()
}, completion: nil)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}下拉视图
dropDownView1
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54class dropDownView: UIView, UITableViewDelegate, UITableViewDataSource {
var dropDownOptions = [String]()
var tableView = UITableView()
var delegate: dropDownProtocol!
override init(frame: CGRect) {
super.init(frame: frame)
tableView.backgroundColor = UIColor.darkGray
self.backgroundColor = UIColor.darkGray
tableView.delegate = self
tableView.dataSource = self
tableView.translatesAutoresizingMaskIntoConstraints = false
self.addSubview(tableView)
tableView.leftAnchor.constraint(equalTo: self.leftAnchor).isActive = true
tableView.rightAnchor.constraint(equalTo: self.rightAnchor).isActive = true
tableView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
tableView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return dropDownOptions.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell()
cell.textLabel?.text = dropDownOptions[indexPath.row]
cell.backgroundColor = UIColor.darkGray
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
self.delegate.dropDownPressed(string: dropDownOptions[indexPath.row])
self.tableView.deselectRow(at: indexPath, animated: true)
}
}
