A small extension for UISearchBar which shows an UIActivityIndicator while searching

UISearchBar+Ext.swift

//
//  UISearchBar+Ext.swift
//  frazeit
//
//  Created by Maysam Shahsavari on 7/30/18.
//  Updated on 9/26/19.
//  Copyright © 2018 Maysam Shahsavari. All rights reserved.
//  Updated: 10/02/2020.

import Foundation
import UIKit

extension UIImage {
    func imageWithPixelSize(size: CGSize, filledWithColor color: UIColor = UIColor.clear, opaque: Bool = false) -> UIImage? {
        return imageWithSize(size: size, filledWithColor: color, scale: 1.0, opaque: opaque)
    }
    
    func imageWithSize(size: CGSize, filledWithColor color: UIColor = UIColor.clear, scale: CGFloat = 0.0, opaque: Bool = false) -> UIImage? {
        let rect = CGRect.init(x: 0, y: 0, width: size.width, height: size.height)
        UIGraphicsBeginImageContextWithOptions(size, opaque, scale)
        color.set()
        UIRectFill(rect)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
    
}

extension UISearchBar {
    private var textField: UITextField? {
            let subViews = self.subviews.flatMap { $0.subviews }
            if #available(iOS 13, *) {
                if let _subViews = subViews.last?.subviews {
                    return (_subViews.first { $0 is UITextField }) as? UITextField
                } else {
                    return nil
                }
            } else {
                return (subViews.first { $0 is UITextField }) as? UITextField
            }
        }

        private var searchIcon: UIImage? {
            let subViews = subviews.flatMap { $0.subviews }
            return  ((subViews.first { $0 is UIImageView }) as? UIImageView)?.image
        }

        private func getViewElement<T>(type: T.Type) -> T? {
            let svs = subviews.flatMap { $0.subviews }
            guard let element = (svs.first { $0 is T }) as? T else { return nil }
            return element
        }
    
    func getSearchBarTextField() -> UITextField? {
        return getViewElement(type: UITextField.self)
    }
    
    func setTextColor(color: UIColor) {
        if let textField = getSearchBarTextField() {
            textField.textColor = color
        }
    }
    
    func setTextFieldColor(color: UIColor) {
        if let textField = getViewElement(type: UITextField.self) {
            switch searchBarStyle {
            case .minimal:
                textField.layer.backgroundColor = color.cgColor
                textField.layer.cornerRadius = 6
                
            case .prominent, .default:
                textField.backgroundColor = color
            @unknown default:
                break
            }
        }
    }
    
    func setPlaceholderTextColor(color: UIColor) {
        
        if let textField = getSearchBarTextField() {
            textField.attributedPlaceholder = NSAttributedString(string: self.placeholder != nil ? self.placeholder! : "", attributes: [NSAttributedString.Key.foregroundColor: color])
        }
    }
        
    ///////
    private var activityIndicator: UIActivityIndicatorView? {
        return textField?.leftView?.subviews.compactMap{ $0 as? UIActivityIndicatorView }.first
    }
    
    // Public API
    var isLoading: Bool {
        get {
            return activityIndicator != nil
        } set {
            let _searchIcon = searchIcon
            if newValue {
                if activityIndicator == nil {
                    let _activityIndicator: UIActivityIndicatorView
                    if #available(iOS 13.0, *) {
                        _activityIndicator = UIActivityIndicatorView(style: .medium)
                    } else {
                        _activityIndicator = UIActivityIndicatorView(style: .gray)
                    }
                    _activityIndicator.startAnimating()
                    _activityIndicator.backgroundColor = UIColor.clear
                    let clearImage = UIImage().imageWithPixelSize(size: CGSize.init(width: 14, height: 14)) ?? UIImage()
                    self.setImage(clearImage, for: .search, state: .normal)
                    textField?.leftViewMode = .always
                    textField?.leftView?.addSubview(_activityIndicator)
                    let leftViewSize = CGSize.init(width: 14.0, height: 14.0)
                    _activityIndicator.center = CGPoint(x: leftViewSize.width/2, y: leftViewSize.height/2)
                }
            } else {
                self.setImage(_searchIcon, for: .search, state: .normal)
                activityIndicator?.removeFromSuperview()
            }
        }
    }
}

/*
 Usage:
 
 To show the acttivity indicator
 searchController.searchBar.isLoading = true
 
 To stop the activity indicator (assuming it will be called when a network or extensive block is finished)
 DispatchQueue.main.async {
    searchController.searchBar.isLoading = false
 }
*/

@onursahindur Have you tried the new code?

@maysamsh yes, I tried on Swift 5 with Xcode 11.2.1, on Simulator running iOS 13.2. However after the search icon replaced with the indicator, the search icon disappears from the left side of search field's text field.

First all, thanks for the gist and the great solution. I will like to suggest some improvements:

To remove the warning on iOS 13 and use the correct style:

if activityIndicator == nil {
                    let _activityIndicator: UIActivityIndicatorView
                    if #available(iOS 13.0, *) {
                        _activityIndicator = UIActivityIndicatorView(style: .medium)
                    } else {
                        _activityIndicator = UIActivityIndicatorView(style: .gray)
                    }

use first instead of filter

private var textField: UITextField? {
        let subViews = self.subviews.flatMap { $0.subviews }
        if #available(iOS 13, *) {
            if let _subViews = subViews.last?.subviews {
                return (_subViews.first { $0 is UITextField }) as? UITextField
            } else {
                return nil
            }
        } else {
            return (subViews.first { $0 is UITextField }) as? UITextField
        }
    }

    private var searchIcon: UIImage? {
        let subViews = subviews.flatMap { $0.subviews }
        return  ((subViews.first { $0 is UIImageView }) as? UIImageView)?.image
    }

    private func getViewElement<T>(type: T.Type) -> T? {
        let svs = subviews.flatMap { $0.subviews }
        guard let element = (svs.first { $0 is T }) as? T else { return nil }
        return element
    }

remove force

private func setPlaceholderTextColor(color: UIColor) {
        if let textField = getSearchBarTextField() {
            textField.attributedPlaceholder = NSAttributedString(string: self.placeholder ?? "", attributes: [NSAttributedString.Key.foregroundColor: color])
        }
    }