A simple subclass of UITextField for getting auto complete place search from Google Places.

AGAutocompletePlaceTextfield.swift

//
//  AGAutocompletePlaceTextfield.swift
//  AGAutocompletePlaceTextfield
//
//  Created by Arpit Jain on 28/07/17.
//  Copyright © 2017 Arpit Jain. All rights reserved.
//

import UIKit
import GooglePlaces

class AGAutocompletePlaceTextfield: UITextField , UITextFieldDelegate {
    
    //MARK: - PROPERTIES
    struct AGFilterPlace {
        let id: String
        let name: String
    }

    let placesClient = GMSPlacesClient()
    
    /// Instance of autoCompleteTableView
    fileprivate var tableView: UITableView?
    
    /// Gives the array of autoCompletePlacesData
    open var autoCompletePlacesData = [AGFilterPlace]()
    
    /// Gives the selected place and indexPath
    open var selectedPlace: ((GMSPlace) -> ())?

    /// Font for the places data
    open var autoCompleteTextFont = UIFont.systemFont(ofSize: 12)
    
    /// Color of the places data
    open var autoCompleteTextColor = UIColor.black
    
    /// Used to set the height of cell for each suggestions
    open var autoCompleteCellHeight: CGFloat = 44.0
    
    /// The maximum visible suggestion
    open var maxAutoCompleteDataCount = 5
    
    /// Used to set your own preferred separator inset
    open var autoCompleteSeparatorInset = UIEdgeInsets.zero
    
    /// Hides autoCompleteTableView after selecting a place
    open var hidesWhenSelected = true
    
    /// Shows autoCompletePlacesData with formatting
    open var highLightTypeTextedEnabled: Bool?
    
    /// Define attributes for highlighted text
    open var highLightTypeTextedAttributes: [NSAttributedStringKey: Any]?
    
    /// The autoCompleteTableView height
    open var autoCompleteTableHeight: CGFloat?{
        didSet{
            redrawTable()
        }
    }
   
    /// this is the x margin for table view from textfield
    open var autoCompleteTableMargin = CGFloat()

    //MARK: - INIT FUNCTIONS
    public required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
    
    open override func awakeFromNib() {
        super.awakeFromNib()
        commonInit()
        setupAutocompleteTable(superview!)
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        commonInit()
        setupAutocompleteTable(superview!)
        
    }
    
    open override func willMove(toSuperview newSuperview: UIView?) {
        super.willMove(toSuperview: newSuperview)
        commonInit()
        setupAutocompleteTable(newSuperview!)
    }
    
    fileprivate func commonInit(){
        
        tableView?.isHidden = true
        highLightTypeTextedEnabled = false
        highLightTypeTextedAttributes = [NSAttributedStringKey.foregroundColor: UIColor.black]
        highLightTypeTextedAttributes![NSAttributedStringKey.font] = UIFont.boldSystemFont(ofSize: 12)
        self.clearButtonMode = .always
        self.addTarget(self, action: #selector(AGAutocompletePlaceTextfield.textFieldDidChange), for: .editingChanged)
        self.addTarget(self, action: #selector(AGAutocompletePlaceTextfield.textFieldDidEndEditing), for: .editingDidEnd)
    }
    
    fileprivate func setupAutocompleteTable(_ view:UIView){
        
        autoCompleteTableMargin = 10.0
        tableView = UITableView(frame: CGRect(x: self.frame.origin.x + autoCompleteTableMargin/2, y: self.frame.origin.y + self.frame.height, width: (self.frame.width - autoCompleteTableMargin), height: 30.0))
        tableView?.dataSource = self
        tableView?.delegate = self
        tableView?.rowHeight = autoCompleteCellHeight
        tableView?.isHidden = true
        tableView?.layer.borderColor = UIColor.lightGray.cgColor
        tableView?.layer.borderWidth = 0.5
        tableView?.layer.zPosition = CGFloat(Float.greatestFiniteMagnitude)
        view.addSubview(tableView!)
        autoCompleteTableHeight = 200.0
    }
    
    fileprivate func redrawTable(){
        
        if let tableView = tableView, let autoCompleteTableHeight = autoCompleteTableHeight {
            var newFrame = tableView.frame
            newFrame.size.height = autoCompleteTableHeight
            tableView.frame = newFrame
        }
    }
    
    //MARK: - Private Methodss
    
    fileprivate func showHighlightedTypedText(aStr : NSString) -> NSAttributedString {
        
        let attrs = [NSAttributedStringKey.foregroundColor: autoCompleteTextColor, NSAttributedStringKey.font: autoCompleteTextFont]
        let range = aStr.range(of: text!, options: .caseInsensitive)
        let attString = NSMutableAttributedString(string: aStr as String, attributes: attrs)
        attString.addAttributes(highLightTypeTextedAttributes!, range: range)
        autoCompleteTextColor = UIColor.gray
        return attString
    }

    //MARK: - AJAutoCompleteTextfieldDelegate

    @objc func textFieldDidChange(){
        placesClient.autocompleteQuery(text ?? "", bounds: nil, filter: nil, callback: { (results, error) in
            DispatchQueue.main.async
            {
                self.autoCompletePlacesData.removeAll()
                if results != nil {
                    for result in results!{
                        if let placeId = result.placeID {
                            self.autoCompletePlacesData.append(AGFilterPlace(id: placeId , name: result.attributedFullText.string))
                        }
                    }
                }
                if self.autoCompletePlacesData.count != 0{
                    self.tableView?.isHidden = false
                    if self.autoCompletePlacesData.count < self.maxAutoCompleteDataCount{
                        self.autoCompleteTableHeight = self.tableView?.contentSize.height
                    }else{
                        self.autoCompleteTableHeight = 200
                    }
                    self.tableView?.reloadData()
                }else{
                    self.tableView?.isHidden = true
                }
            }
        })
    }
    
    func GetPlaceDataByPlaceID(pPlaceID: String) {
        
        //pPlaceID = "ChIJXbmAjccVrjsRlf31U1ZGpDM"
        
        self.placesClient.lookUpPlaceID(pPlaceID, callback: { (place, error) -> Void in
            
            if let error = error {
                print("lookup place id query error: \(error.localizedDescription)")
                return
            }
            
            if let place = place {
                DispatchQueue.main.async {
                    self.tableView?.isHidden = self.hidesWhenSelected
                    self.selectedPlace?(place)
                }

            }
            else {
                print("No place details for \(pPlaceID)")
            }
        })
    }
}

//MARK: - UITableViewDataSource & UITableViewDelegate

extension AGAutocompletePlaceTextfield: UITableViewDataSource, UITableViewDelegate {
    
    public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return autoCompletePlacesData.count
    }
    
    public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        let cellIdentifier = "autocompleteCellIdentifier"
        var cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier)
        
        if cell == nil{
            cell = UITableViewCell(style: .default, reuseIdentifier: cellIdentifier)
        }
        if highLightTypeTextedEnabled!{
            cell?.textLabel?.attributedText = showHighlightedTypedText(aStr: autoCompletePlacesData[indexPath.row].name as NSString)
        }else{
            cell?.textLabel?.font = autoCompleteTextFont
            cell?.textLabel?.textColor = autoCompleteTextColor
            cell?.textLabel?.text = autoCompletePlacesData[indexPath.row].name
        }
        cell?.textLabel?.numberOfLines = 0
        cell?.contentView.gestureRecognizers = nil
        return cell!
    }
    
    public func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        
        let cell = tableView.cellForRow(at: indexPath)
        
        if let selectedText = cell?.textLabel?.text {
            self.GetPlaceDataByPlaceID(pPlaceID: autoCompletePlacesData[indexPath.row].id)
            self.text = selectedText
            self.resignFirstResponder()
        }
    }
    
    public func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        
        if cell.responds(to: #selector(setter: UITableViewCell.separatorInset)){
            cell.separatorInset = autoCompleteSeparatorInset
        }
        if cell.responds(to: #selector(setter: UIView.preservesSuperviewLayoutMargins)){
            cell.preservesSuperviewLayoutMargins = false
        }
        if cell.responds(to: #selector(setter: UIView.layoutMargins)){
            cell.layoutMargins = autoCompleteSeparatorInset
        }
    }
    
    public func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return autoCompleteCellHeight
    }
}