Ios swift – I want to add a search bar to the top of my TableView

Your question is quite broad so first things first. You should probably first start with a model definition for your data.

// This is a model for our table
struct University {
    let name: String
    let address: String

    static let allUniversities = [
        University(name: "The University of Texas at Austin", address: "110 Inner Campus Drive Austin, TX 78705"),
        University(name: "Rice University", address: "6100 Main St., Houston, TX 77005-1892"),
        University(name: "Texas A&M University", address: "Administration Building, 400 Bizzell St, College Station, TX 77843")
        // Add more universities here
    ]
}

This will clearly separate the model from the controller logic.

The best way to customize tables is to not use UITablewViewController but rather use UITableView with UISearchBar inside UIViewController. If using a storyboard it would look like this:

It’s important to add the search bar into the UITableView on top position. Now here’s what the view controller could look like.

class ViewController: UIViewController {

    // Make sure you connect those IBOutlets to your Storyboard
    @IBOutlet var tableView: UITableView!
    @IBOutlet var searchBar: UISearchBar!

    // This is our main data source
    let data: [University] = University.allUniversities

    // This is where we save filtered results from search and display it
    var searchedResults: [University] = []

    // This is a flag that determines if to show all the results or only the searched results
    var isSearching = false {
        didSet {
            tableView.reloadData() // Reload the data if the flag changes
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        tableView.dataSource = self
        searchBar.delegate = self
    }

    // MARK: - Helper methods

    /// Retuns active dataset based on the search state
    func activeDataset() -> [University] {
        if isSearching {
            return searchedResults
        } else {
            return data
        }
    }

    /// Returns a list of univerties matching given query
    func filteredUniversities(query: String) -> [University] {
        return data.filter { $0.name.contains(query) }
    }
}

As you can see in the viewDidLoad method, we added the ViewController as dataSource for the table and delegate for the search bar so we need to make sure to conform to those protocols

extension ViewController: UITableViewDataSource {

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
        let universities = activeDataset()
        let university = universities[indexPath.row] // Get data for the row

        cell.textLabel!.text = university.name // Update the cell with the data

        return cell
    }

    func numberOfSections(in tableView: UITableView) -> Int {
        return 1 // Our data are all in 1 section
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return activeDataset().count
    }
}

Here we created a logic to show either search results or all the data depending on if the search is active.

extension ViewController: UISearchBarDelegate {
    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        // Check if the searched text has at least 1 character otherwise show all results
        guard searchText != "" else {
            isSearching = false
            searchedResults.removeAll()
            return
        }

        searchedResults = filteredUniversities(query: searchText)
        isSearching = true
    }
}

And we use the UISearchBarDelegate to determine when the user types something into the search bar.

See full code here.