Swift — настраиваемый вид ввода текста

Взгляните на MessageInputBar

https://github.com/MessageKit/MessageInputBar

Это облегчит вам задачу и не позволит вам заново изобретать колесо, плюс его широкие возможности настройки, вы можете запустить пример, чтобы увидеть, как он работает.

Редактировать

Просто чтобы дать вам представление

import UIKit
import MessageInputBar

class CustomInputBar: MessageInputBar {

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

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func configure() {
        backgroundView.backgroundColor = UIColor(red: 245/255, green: 245/255, blue: 245/255, alpha: 1)
        let button = InputBarButtonItem()
        button.setSize(CGSize(width: 36, height: 36), animated: false)
        button.setImage(#imageLiteral(resourceName: "ic_up").withRenderingMode(.alwaysTemplate), for: .normal)
        button.imageView?.contentMode = .scaleAspectFit
        button.tintColor = UIColor(red: 0, green: 122/255, blue: 1, alpha: 1)
        inputTextView.backgroundColor = .white
        inputTextView.placeholderTextColor = UIColor(red: 0.6, green: 0.6, blue: 0.6, alpha: 1)
        inputTextView.textContainerInset = UIEdgeInsets(top: 8, left: 16, bottom: 8, right: 16)
        inputTextView.placeholderLabelInsets = UIEdgeInsets(top: 8, left: 20, bottom: 8, right: 20)
        inputTextView.layer.borderColor = UIColor(red: 200/255, green: 200/255, blue: 200/255, alpha: 1).cgColor
        inputTextView.layer.borderWidth = 1.0
        inputTextView.layer.cornerRadius = 4.0
        inputTextView.layer.masksToBounds = true
        inputTextView.scrollIndicatorInsets = UIEdgeInsets(top: 8, left: 0, bottom: 8, right: 0)
        setLeftStackViewWidthConstant(to: 36, animated: false)
        setStackViewItems([button], forStack: .left, animated: false)
        sendButton.setSize(CGSize(width: 52, height: 36), animated: false)
    }

}

который будет выглядеть так:

Со всеми функциями, которые вы хотели, и даже больше.

Я немного отредактировал код из примера проекта, чтобы он выглядел именно так, как вы добавили в вопросе.

А ты ViewController будешь просто

import UIKit
import MessageInputBar

final class ExampleViewController: UITableViewController {

    // MARK: - Properties

    override var inputAccessoryView: UIView? {
        return messageInputBar
    }

    override var canBecomeFirstResponder: Bool {
        return true
    }

    // MARK: - MessageInputBar

    private let messageInputBar = CustomInputBar()

    // MARK: - View Life Cycle

    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = .white
        tableView.keyboardDismissMode = .interactive

        messageInputBar.delegate = self
    }
}

А чтобы послушать MessageInputBarDelegate просто добавьте

extension ExampleViewController: MessageInputBarDelegate {

    func messageInputBar(_ inputBar: MessageInputBar, didPressSendButtonWith text: String) {
        // Use to send the message
        messageInputBar.inputTextView.text = String()
        messageInputBar.invalidatePlugins()
    }

    func messageInputBar(_ inputBar: MessageInputBar, textViewTextDidChangeTo text: String) {
        // Use to send a typing indicator
    }

    func messageInputBar(_ inputBar: MessageInputBar, didChangeIntrinsicContentTo size: CGSize) {
        // Use to change any other subview insets
    }

}

Просто как тот :)

Если вы хотите сделать это программно самостоятельно, вы можете попробовать это.

Пользовательский вид ввода текста, который будет содержать ввод текста и кнопку отправки

import UIKit

class TextEntryView: UIView {

let tvMessage: UITextView = {
    let textView = UITextView()
    textView.translatesAutoresizingMaskIntoConstraints = false
    textView.textColor = Constants.charlie
    textView.font = UIFont.systemFont(ofSize: 17)
    textView.isScrollEnabled = false
    return textView
}()

let btnSend: UIButton = {
    let image: UIImage = UIImage(named: "send_icon")!
    let button = UIButton(type: .custom)
    button.translatesAutoresizingMaskIntoConstraints = false
    button.setImage(image, for: .normal)
    button.setContentHuggingPriority(UILayoutPriority(rawValue: 250), for: .horizontal)

    return button
}()

override init(frame: CGRect) {
    super.init(frame: frame)
    self.backgroundColor = .white
    self.addBorders(edges: .top, color: UIColor(red: 220/250, green: 220/250, blue: 220/250, alpha: 1))

    setupLayout()
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

override class var requiresConstraintBasedLayout: Bool {
    return true
}

private func setupLayout() {
    self.addSubview(tvMessage)
    self.addSubview(btnSend)

    tvMessage.topAnchor.constraint(equalTo: self.topAnchor, constant: 6).isActive = true
    tvMessage.leadingAnchor.constraint(equalTo: self.leadingAnchor, constant: 12).isActive = true
    tvMessage.trailingAnchor.constraint(equalTo: btnSend.leadingAnchor, constant: -12).isActive = true
    tvMessage.bottomAnchor.constraint(equalTo: self.bottomAnchor, constant: -6).isActive = true

    btnSend.topAnchor.constraint(equalTo: self.topAnchor,  constant: 6).isActive = true
    btnSend.trailingAnchor.constraint(equalTo: self.trailingAnchor, constant: -12).isActive = true
    btnSend.bottomAnchor.constraint(equalTo: self.bottomAnchor, constant: -6).isActive = true
    btnSend.widthAnchor.constraint(equalToConstant: 40).isActive = true
}
}

Добавить пользовательский вид в контроллере

import UIKit

class ChatController: UIViewController, UITextViewDelegate {

let textEntry = TextEntryView()


var bottomConstraint: NSLayoutConstraint?
var textEntryHeightConstraint: NSLayoutConstraint?

override func viewWillAppear(_ animated: Bool) {
    initViews()
    setupLayout()

    NotificationCenter.default.addObserver(self,
                                           selector: #selector(self.keyboardNotification(notification:)),
                                           name: NSNotification.Name.UIKeyboardWillChangeFrame,
                                           object: nil)

    let tapGesture = UITapGestureRecognizer(target: self, action: #selector(hideKeyboard))
    tapGesture.cancelsTouchesInView = true
    tableView.addGestureRecognizer(tapGesture)
}

@objc func hideKeyboard() {
    self.endEditing(true)
}

deinit {
    NotificationCenter.default.removeObserver(self)
}

@objc func keyboardNotification(notification: NSNotification) {
    if let userInfo = notification.userInfo {

        let keyboardFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
        let endFrameY = keyboardFrame?.origin.y ?? 0
        let duration:TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
        let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
        let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIViewAnimationOptions.curveEaseInOut.rawValue
        let animationCurve:UIViewAnimationOptions = UIViewAnimationOptions(rawValue: animationCurveRaw)
        if endFrameY >= UIScreen.main.bounds.size.height {
            bottomConstraint?.constant = 0
        } else {
            bottomConstraint?.constant = -(keyboardFrame?.size.height)!
        }
        UIView.animate(withDuration: duration,
                       delay: TimeInterval(0),
                       options: animationCurve,
                       animations: { self.layoutIfNeeded() },
                       completion: nil)
    }
}

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
    if (textEntry.tvMessage.contentSize.height + 12 < (textEntryHeightConstraint?.constant)!) {
        self.textEntry.tvMessage.isScrollEnabled = false
    } else {
        self.textEntry.tvMessage.isScrollEnabled = true
    }

    return true
}

func textViewDidBeginEditing(_ textView: UITextView) {
    if textEntry.tvMessage.textColor == .lightGray {
        textEntry.tvMessage.text = nil
        textEntry.tvMessage.textColor = Constants.tertiaryColor
    }
}

func textViewDidEndEditing(_ textView: UITextView) {
    if (textEntry.tvMessage.text?.isEmpty)! {
        textEntry.tvMessage.text = "Write a message"
        textEntry.tvMessage.textColor = .lightGray
    }
}

}

extension MessageView {
func initViews() {
    if #available(iOS 11.0, *) {
        bottomConstraint = NSLayoutConstraint(item: textEntry, attribute: .bottom, relatedBy: .equal, toItem: self.safeAreaLayoutGuide, attribute: .bottom, multiplier: 1, constant: 0)
    } else {
        // Fallback on earlier versions
        bottomConstraint = NSLayoutConstraint(item: textEntry, attribute: .bottom, relatedBy: .equal, toItem: self, attribute: .bottom, multiplier: 1, constant: 0)
    }

    textEntry.translatesAutoresizingMaskIntoConstraints = false
    textEntry.tvMessage.text = "Write a message"
    textEntry.tvMessage.textColor = .lightGray
    textEntry.tvMessage.delegate = self
}

func setupLayout() {
    self.addSubview(textEntry)

    textEntry.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
    textEntry.trailingAnchor.constraint(equalTo: self.trailingAnchor).isActive = true
    self.addConstraint(bottomConstraint!)

    textEntryHeightConstraint = textEntry.heightAnchor.constraint(lessThanOrEqualToConstant: 150)
    textEntryHeightConstraint?.isActive = true
}
}