Creating a Picker View in iOS Swift with Multiple Selection

Introduction

When it comes to selecting multiple items from a list, the UITableView and its related classes can be a bit cumbersome. However, Apple provides an alternative solution through the UIPickerView. In this article, we’ll explore how to create a UIPickerView with multiple selection in iOS using Swift.

Prerequisites

Before diving into the implementation, make sure you have:

Xcode 11 or later installed on your machine.
A basic understanding of Swift programming language and iOS development.

Understanding UIPickerView

A UIPickerView is a view that allows users to select items from a list. Unlike UITableView, which uses rows to display data, UIPickerView displays data as separate components called “components”. Each component represents an item in the list.

Creating a Picker View with Multiple Selection

To create a picker view with multiple selection, we’ll need to follow these steps:

Step 1: Import Objective-C

We can import Objective-C code into our Swift project using Bridging the Code feature in Xcode. To do this:

Open your project in Xcode.
Go to File > New > File…
In the new file dialog, select Objective-C Header File (.h) and click Next
Name your file (e.g., bridgingHeader.h) and click Create

This step creates a new Objective-C header file that will be used to import our Swift code.

Step 2: Add Bridging Header

After creating the bridging header, Xcode will prompt you to create a bridging header file. To do this:

Open your project in Xcode.
Go to File > Project Settings
In the Build Settings, find the Framework Search Paths setting and add the path to your bridgingHeader.h file

This step tells Xcode where to look for our Swift code when importing Objective-C.

Step 3: Import Objective-C Code

We’ll now import our Objective-C code into our Swift project. To do this:

Open your bridging header file (bridgingHeader.h) and add the following line:

#import <UIKit/UIKit.h>

*   This imports the UIKit framework, which includes all the classes and protocols used in iOS development.

### Step 4: Create a Picker View

We'll now create our picker view using the `UIPickerView` class. To do this:

*   Open your main storyboard file (e.g., `Main.storyboard`) and drag a new object onto the scene.
*   Select **UIPickerView** from the object library
*   Set the **Picker Style** to **Picker Style** and the **Component Count** to 10

This step creates our picker view with two components.

### Step 5: Implement Picker View Delegate

To handle the selection of items in our picker view, we'll implement the `UIPickerViewDelegate` protocol. To do this:

*   Open your main storyboard file (e.g., `Main.storyboard`) and select the **UIPickerView** object
*   Go to **Identity Inspector**
*   In the **Delegate** field, click on the **Connect** button
*   Select the **ViewController** class

This step sets our view controller as the delegate for our picker view.

### Step 6: Implement Picker View Data Source

To handle the selection of items in our picker view, we'll implement the `UIPickerViewDataSource` protocol. To do this:

*   Open your main storyboard file (e.g., `Main.storyboard`) and select the **UIPickerView** object
*   Go to **Connection Inspector**
*   In the **Data Source** field, click on the **Connect** button
*   Select the **ViewController** class

This step sets our view controller as the data source for our picker view.

### Step 7: Implement Picker View Selection Handler

To handle the selection of items in our picker view, we'll implement the `pickerView(_:selectedRow ForComponent:)` method. To do this:

*   Open your **ViewController.swift** file and add the following code:
    ```swift
import UIKit

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {

    @IBOutlet weak var pickerView: UIPickerView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Set up picker view data source and delegate
        pickerView.dataSource = self
        pickerView.delegate = self

        // Set up picker view component count
        pickerView.componentsCount = 10
    }

    // MARK: - Picker View Data Source Methods

    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return 10
    }

    // MARK: - Picker View Delegate Methods

    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return "Item \(row)"
    }
}

This code sets up our picker view data source and delegate, as well as its component count.

Step 8: Run the App

To run the app and see our picker view in action:

Build and run your project
Select an item from the picker view to see it highlighted

Conclusion

In this article, we explored how to create a UIPickerView with multiple selection in iOS using Swift. We covered the basics of UIPickerView, implemented the delegate and data source protocols, and set up our picker view components.

I hope this helps you understand how to use UIPickerView in your own iOS apps!

Last modified on 2024-09-24