Activity Indicators (UIActivityIndicatorView)

What is UIActivityIndicatorView?

UIActivityIndicatorView is a built-in loading spinner in iOS that provides visual feedback when a task is in progress (e.g., loading data, making network requests). It is commonly used to indicate ongoing processes and improve the user experience.

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1. How to Add UIActivityIndicatorView in Swift

A. Adding UIActivityIndicatorView Programmatically

import UIKit

class ViewController: UIViewController {

    let activityIndicator = UIActivityIndicatorView(style: .large)

    override func viewDidLoad() {
        super.viewDidLoad()

        // Set position
        activityIndicator.center = view.center
        
        // Set color
        activityIndicator.color = .blue
        
        // Hide when stopped
        activityIndicator.hidesWhenStopped = true

        // Add to view
        view.addSubview(activityIndicator)

        // Start loading
        activityIndicator.startAnimating()

        // Simulate a delay (e.g., network call)
        DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
            self.activityIndicator.stopAnimating()
        }
    }
}

✅ Explanation:

• Creates a UIActivityIndicatorView.
• Sets its color and hides it when stopped.
• Starts animating and stops after 3 seconds.

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B. Adding UIActivityIndicatorView via Storyboard

1. Open Main.storyboard in Xcode.
2. Drag and drop a UIActivityIndicatorView onto your ViewController.
3. Set the Style, Color, and Behavior in the Attributes Inspector.
4. Create an IBOutlet in ViewController.swift: @IBOutlet weak var activityIndicator: UIActivityIndicatorView!
5. Start and stop animation when needed: activityIndicator.startAnimating() // Show loading activityIndicator.stopAnimating() // Hide loading

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2. Customizing UIActivityIndicatorView

A. Changing the Size

activityIndicator.style = .large  // Use .medium for smaller size

B. Changing the Color

activityIndicator.color = .red

C. Hiding When Stopped

activityIndicator.hidesWhenStopped = true

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3. Using UIActivityIndicatorView with Network Requests

import UIKit

class ViewController: UIViewController {

    let activityIndicator = UIActivityIndicatorView(style: .large)

    override func viewDidLoad() {
        super.viewDidLoad()

        // Configure and add activity indicator
        activityIndicator.center = view.center
        activityIndicator.color = .gray
        activityIndicator.hidesWhenStopped = true
        view.addSubview(activityIndicator)

        // Simulate API call
        loadData()
    }

    func loadData() {
        activityIndicator.startAnimating()  // Show loading

        DispatchQueue.global(qos: .background).async {
            // Simulating a network delay
            sleep(3)

            DispatchQueue.main.async {
                self.activityIndicator.stopAnimating()  // Hide loading
            }
        }
    }
}

✅ Explanation:

• Starts animating before a network call.
• Runs the task on a background thread to avoid UI freezing.
• Stops animating after the task completes.

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4. UIActivityIndicatorView in a Button Action

@IBAction func loadData(_ sender: UIButton) {
    sender.isEnabled = false  // Disable button
    activityIndicator.startAnimating()
    
    DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
        self.activityIndicator.stopAnimating()
        sender.isEnabled = true  // Re-enable button
    }
}

✅ Explanation:

• Disables the button while loading.
• Re-enables the button after 3 seconds.

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5. Using UIActivityIndicatorView in UITableView

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return data.isEmpty ? 1 : data.count
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
    
    if data.isEmpty {
        let activityIndicator = UIActivityIndicatorView(style: .medium)
        activityIndicator.startAnimating()
        cell.contentView.addSubview(activityIndicator)
        activityIndicator.center = cell.contentView.center
    } else {
        cell.textLabel?.text = data[indexPath.row]
    }
    
    return cell
}

✅ Explanation:

• Shows a loading spinner in a table cell if data is empty.
• Displays regular table rows when data is available.

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6. Summary of UIActivityIndicatorView Features

Feature	Code Example
Set size	activityIndicator.style = .large
Change color	activityIndicator.color = .blue
Hide when stopped	activityIndicator.hidesWhenStopped = true
Start animation	activityIndicator.startAnimating()
Stop animation	activityIndicator.stopAnimating()
Use with API calls	DispatchQueue.global(qos: .background).async { sleep(3) }

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Conclusion

UIActivityIndicatorView is an easy-to-use loading spinner that enhances user experience during waiting times. It can be used in buttons, table views, and network calls to indicate background processes.

Would you like a customized version with a progress bar or animation? 🚀