swift - Swift 委托协议未调用
问题描述
我是 Swift 的初学者。我正在尝试使用委托和协议将数据从子视图向后发送到根视图(在导航控制器中)
这是我的代码:
//FilterViewController.swift:
protocol FilterDelegate: class {
func finishFilter(query: String);
}
class FilterViewController:BaseViewController,....{
....
weak var delegate : FilterDelegate?
@IBAction func acceptTapped(_ sender: UIButton) {
var querystring = ""
var conditions: [String] = []
//some logic works with conditions
querystring = conditions.joined(separator: "&")
self.delegate?.finishFilter(query: querystring)
self.navigationController?.popViewController(animated: true)
}
}
这是我从过滤器调用委托的地方
//HouseListController.swift
class HouseListController: BaseViewController,..{
var filterController = FilterViewController()
//Here is where I push the FilterViewController
@IBAction func filterTapped(_ sender: UIButton) {
self.currentMode = .filter
self.tracking.previousMode = .filter
self.filterController = storyboard?.instantiateViewController(withIdentifier: "FilterView") as! FilterViewController
self.navigationController?.pushViewController(self.filterController, animated: true)
}
override func viewDidLoad() {
self.filterController.delegate = self
}
}
extension HouseListController : FilterDelegate {
func finishFilter(query: String) {
switch self.currentMode{
case .normal:
_ = self.filterHouse(querystring: query , offset: 0, limit: self.tracking.limit).done{ dataHouses in
self.houses.filter = dataHouses
self.houses.defaultHouses = dataHouses
}.done{ _ in
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
case .search:
_ = self.filterHouse(searchKey: self.tracking.search.searchKey, querystring: query, offset: 0, limit: self.tracking.limit).done{ dataHouses in
self.houses.filter = dataHouses
self.houses.defaultHouses = dataHouses
}.done{ _ in
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
default:
_ = self.filterHouse(querystring: query , offset: 0, limit: self.tracking.limit).done{ dataHouses in
self.houses.filter = dataHouses
self.houses.defaultHouses = dataHouses
}.done{ _ in
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
}
self.currentMode = .filter
}
}
委托没有调用我的 finishFilter 函数。相反,当我在 FilterController 中弹出视图时,它会直接转到 HouseListController 中的 viewWillAppear 并停留在那里而没有调用委托。
我错过了什么吗?
解决方案
您显示的代码filterTapped
是问题所在。您从情节提要创建了一个新实例,FilterViewController
但从未设置该实例的delegate
属性。
我会摆脱你的filterController
财产。摆脱viewDidLoad
设置其delegate
. 您从未使用过该代码,因此您不需要它。
然后更新filterTapped
:
@IBAction func filterTapped(_ sender: UIButton) {
self.currentMode = .filter
self.tracking.previousMode = .filter
let filterController = storyboard?.instantiateViewController(withIdentifier: "FilterView") as! FilterViewController // Update this line
filterController.delegate = self // Add this line
self.navigationController?.pushViewController(self.filterController, animated: true)
}
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