搜索和过滤数组firebase数据swift3
问题描述:
我的应用程序崩溃时,在搜索栏中的文本与错误:thread1:信号SIGABRT可能是问题updateSearchResults()方法? 或数组的类型?我的初学者很快就有任何想法?搜索和过滤数组firebase数据swift3
@IBOutlet weak var tableView: UITableView!
var data = [Any]()
var ref:FIRDatabaseReference!
// Filter Data from Firebase
var filteredData = [Any]()
// Declare searchBar
let searchController = UISearchController(searchResultsController: nil)
//is the device landscape or portrait
var isPortraid = true
@IBOutlet weak var bannerView: GADBannerView!
func fetchDataFromFirebase(){
EZLoadingActivity.show("caricamento...", disableUI: true)
ref = FIRDatabase.database().reference()
ref.observe(.value, with: { (snapshot) in
let dataDict = snapshot.value as! NSDictionary
self.data = dataDict["data"] as! [Any]
self.filteredData = self.data
print ("Sacco di merda:\(self.filteredData)")
self.tableView.reloadData()
EZLoadingActivity.hide()
})
}
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
fetchDataFromFirebase()
// Implement searchBar
searchController.searchResultsUpdater = self
searchController.dimsBackgroundDuringPresentation = false
definesPresentationContext = true
tableView.tableHeaderView = searchController.searchBar
NotificationCenter.default.addObserver(self, selector: #selector(MainViewController.orientationChanged), name: NSNotification.Name.UIDeviceOrientationDidChange, object: nil)
}
//TableView Data Source and Delegate
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return filteredData.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "MainCell", for:indexPath) as! MainScreenTableViewCell
let rowData = self.filteredData[indexPath.row] as! NSDictionary
let imageName = rowData["imageName"] as! String
cell.backgroundImageView.image = UIImage(named: imageName)
let label = rowData["categoryName"] as! String
cell.mealCategoryLabel.text = label
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)
let categoryViewController = storyboard.instantiateViewController(withIdentifier: "CategoryViewController") as! CategoryViewController
let rowData = self.data[indexPath.row] as! NSDictionary
categoryViewController.categoryTitle = rowData["categoryName"] as! String
let categoryData = rowData["category"] as! [Any]
categoryViewController.data = categoryData
self.navigationController?.pushViewController(categoryViewController, animated: true)
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if isPortraid {
return UIScreen.main.bounds.height/3
} else {
return UIScreen.main.bounds.height/1.2
}
}
//方法更新搜索
func updateSearchResults(for searchController: UISearchController) {
if searchController.searchBar.text! == ""{
filteredData = data
} else {
filteredData = data.filter{($0 as AnyObject).contains(searchController.searchBar.text!)}
}
self.tableView.reloadData()
}
答
if searchController.searchBar.text! == ""
这几乎可以肯定是罪犯。 UI对象上的text
属性通常为零,因此当您强制解包时,应用会崩溃。你应该从来没有强行解开东西,除非你是绝对确定它永远不会在这一点零。
有几种不同的方法可以处理这个问题,基本上相当于确保text
在你做任何事情之前不是零。
个人而言,我会重写if语句解开可选的非空的情况下:
if let text = searchController.searchBar.text, text != "" {
filteredData = data.filter{($0 as AnyObject).contains(text)}
} else {
filteredData = data
}
您还可以使用nil-coalescing:
if (searchController.searchBar.text ?? "") == ""
,但我个人更喜欢将它写入即使你确定它不是零,也不要强行展开,所以我会推荐第一个。