UIKit provides a powerful framework for building custom user interfaces in iOS applications. Custom UI components can enhance the user experience by making your app unique and interactive. In this tutorial, we will create two custom components:

  1. MoodButton – A custom button that changes its appearance based on mood (Happy, Sad, Neutral).
  2. MoodSlider – A custom slider that changes its color based on mood level.

Step 1: Setting up the Project

First, make sure you have a project set up in Xcode or use Visual Studio Code (VSCode) with Swift and UIKit support. Then, create a new file where you’ll write your custom UI components.

Step 2: Defining a Mood Enum

We start by creating an enum to represent different moods. This helps categorize the button and slider’s behavior.

import UIKit

enum Mood {
    case happy
    case sad
    case neutral
}

Step 3: Creating the Custom MoodButton

Next, we’ll define a MoodButton class. This button will change its background color depending on the current mood (happy, sad, neutral). We also provide functionality to cycle through moods when tapped.

class MoodButton: UIButton {
    var mood: Mood = .neutral {
        didSet {
            updateBackgroundColor(for: mood)
        }
    }

    private func updateBackgroundColor(for mood: Mood) {
        switch mood {
        case .happy:
            self.backgroundColor = .yellow
        case .sad:
            self.backgroundColor = .blue
        case .neutral:
            self.backgroundColor = .gray
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        setUpButton()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setUpButton()
    }

    private func setUpButton() {
        self.layer.cornerRadius = 10
        self.clipsToBounds = true
        self.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
    }

    @objc private func buttonTapped() {
        // Simulate mood change on tap
        switch mood {
        case .happy:
            mood = .sad
        case .sad:
            mood = .neutral
        case .neutral:
            mood = .happy
        }
    }
}

Step 4: Creating the Custom MoodSlider

The MoodSlider is another custom component that changes its appearance based on the slider’s value. It will display different colors for sad (blue), neutral (gray), and happy (yellow) moods.

class MoodSlider: UISlider {
    var moodLevel: Float = 0.5 {
        didSet {
            updateSliderAppearance()
        }
    }

    private func updateSliderAppearance() {
        if moodLevel < 0.3 {
            self.minimumTrackTintColor = .blue // Sad
        } else if moodLevel > 0.7 {
            self.minimumTrackTintColor = .yellow // Happy
        } else {
            self.minimumTrackTintColor = .gray // Neutral
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        setUpSlider()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setUpSlider()
    }

    private func setUpSlider() {
        self.minimumValue = 0
        self.maximumValue = 1
        self.value = moodLevel
        self.addTarget(self, action: #selector(sliderValueChanged), for: .valueChanged)
    }

    @objc private func sliderValueChanged() {
        moodLevel = self.value
    }
}

Step 5: Setting Up the ViewController

Finally, we need a ViewController to bring everything together. This is where we will add our MoodButton and MoodSlider to the view, giving them specific positions on the screen.

class ViewController: UIViewController {

    var moodButton: MoodButton!
    var moodSlider: MoodSlider!

    override func viewDidLoad() {
        super.viewDidLoad()

        self.view.backgroundColor = .white

        // Set up MoodButton
        moodButton = MoodButton(frame: CGRect(x: 100, y: 150, width: 200, height: 50))
        moodButton.setTitle("Change Mood", for: .normal)
        self.view.addSubview(moodButton)

        // Set up MoodSlider
        moodSlider = MoodSlider(frame: CGRect(x: 50, y: 250, width: 300, height: 50))
        self.view.addSubview(moodSlider)
    }
}

Step 6: Running the App

Now that we have set up the custom components, run the app in the simulator or on a real device. You’ll see the following:
• A MoodButton with a title of “Change Mood”. When tapped, it cycles through happy (yellow), sad (blue), and neutral (gray) moods.
• A MoodSlider that changes its color based on the value, with blue for sad, yellow for happy, and gray for neutral.

Conclusion

By creating custom UI components like MoodButton and MoodSlider, you can provide users with interactive and engaging elements in your iOS app. These custom components can be reused across your project to ensure consistency and a better user experience.

⸻

Now, you can try adding more features to these components, like custom animations, to make them even more engaging!