我将下面的UITableViewController作为searchResultsController附加：
import UIKit
import MapKit
class LocationSearchTable : UITableViewController {
var matchingItems:[MKMapItem] = []
var mapView: MKMapView? = nil
override func viewDidLoad() {
super.viewDidLoad()
tableView.dataSource = self
tableView.delegate = self
}
}
extension LocationSearchTable : UISearchResultsUpdating {
func updateSearchResults(for searchController: UISearchController){
guard let mapView = mapView,let searchBarText = searchController.searchBar.text else { return }
let request = MKLocalSearchRequest()
request.naturalLanguageQuery = searchBarText
request.region = mapView.region
let search = MKLocalSearch(request: request)
search.start { response,_ in
guard let response = response else {
return
}
self.matchingItems = response.mapItems
self.tableView.reloadData()
}
}
}
extension LocationSearchTable {
override func tableView(_ tableView: UITableView,numberOfRowsInSection section: Int) -> Int {
print(matchingItems.count)
return matchingItems.count
}
func tableView(tableView: UITableView,cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell")!
let selectedItem = matchingItems[indexPath.row].placemark
cell.textLabel?.text = selectedItem.name
cell.detailTextLabel?.text = ""
return cell
}
}
一旦matchItems.count不等于0,它就崩溃了,例如：
0 0 10 2016-10-20 15:43:53.914 ios-App[9137:977735] * Assertion
failure in -[UITableView _configureCellForDisplay:forIndexPath:],
/BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit_Sim/UIKit-3599.6/UITableView.m:8035
2016-10-20 15:43:53.927 ios-App[9137:977735] * Terminating app due
to uncaught exception ‘NSInternalInconsistencyException’,reason:
‘UITableView (; layer = ; contentOffset: {0,
-64}; contentSize: {768,440}>) Failed to obtain a cell from its dataSource
当我在cellForRowAtIndexPath中添加调试点时,它们永远不会到达,应用程序似乎在此之前崩溃了？
解决方法
错误
Failed to obtain a cell from its dataSource
因为cellForRowAtIndexPath的签名错误而发生.在Swift 3中它是
(override) func tableView(_ tableView: UITableView,cellForRowAt indexPath: IndexPath) -> UITableViewCell
并使用方便的方法
let cell = tableView.dequeueReusableCell(withIdentifier: "cell",for:indexPath)
它总是返回一个有效的非可选单元格.
PS：您不需要设置datasource和委托给self,因为UITableViewController隐式执行此操作
