Core Data with Table Views Part II

#swift #mobile #beginners

In this blog, I will try to extend the app we built in Part I by adding a search bar in the Main View Controller so that you type in the search bar and it will filter the employees based on the name, age or phone. I will also add other entities and add relationships between these entities.

In MainVC, add setupSearchBar() to add the searchBar in UI.

import UIKit

class MainVC: UIViewController {
    ...
    private let searchBar = UISearchBar()
    override func viewDidLoad() {
        ...
        setupSearchBar()
    }...
}

In extension MainVC, searchBar related functions are implemented as below.

extension MainVC: UITableViewDataSource, UITableViewDelegate, UISearchBarDelegate {
    private func setupSearchBar() {
        searchBar.placeholder = "Search Employees"
        navigationItem.titleView = searchBar
        searchBar.delegate = self
    }

    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        if searchText.isEmpty {
            empArray = CoreDataHandler.shared.fetchData()
        } else {
            empArray = CoreDataHandler.shared.searchData(with: searchText)
        }
    }

    func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
        searchBar.text = ""
        searchBar.resignFirstResponder()
        empArray = CoreDataHandler.shared.fetchData()
    }
...

Lastly, add searchData() in CoreDataHandler to retrieve data matching the user's input

class CoreDataHandler {
    ...
    func searchData(with searchText: String) -> [Emp] {
        let fetchRequest: NSFetchRequest<Emp> = Emp.fetchRequest()
        fetchRequest.predicate = NSPredicate(format: "name CONTAINS[c] %@ OR age == %@ OR phone CONTAINS[c] %@", searchText, searchText, searchText)
        do {
            let result = try context!.fetch(fetchRequest)
            return result
        } catch {
            print("Failed to search employees")
            return []
        }
    }
}