利用 AVSpeechSynthesizer 講話

前期提要：

讓開不了口的 App 開口說話 !

利用 AVSpeechSynthesizer 講話

首先要import 才能使用AVSpeechSynthesizer這個函示庫

import AVFoundation

再來把元件連結Storyboard

@IBOutlet weak var speakTextfield: UITextField!
@IBOutlet weak var speakSpeed: UISlider!
@IBOutlet weak var speakRate: UISlider!
@IBOutlet weak var speakHistoryTableView: UITableView!
@IBOutlet weak var speakPlayButton: UIButton!

因為有加入歷史資料功能，所以有UITableView。

宣告變數（兩個內建語音合聲器與發聲器以及預設歷史資料）

var speakUtterance = AVSpeechUtterance()
var speakSynthesizer = AVSpeechSynthesizer()
var speakHistory : [SpeakHistory] = [SpeakHistory(speakText: "I Love Swift", speakRate: 1.0, speakSpeed: 1.0)]

我們在viewDidLoad畫面跑完的時候修改預設值，並委託TableView的delegate以及dataSource和AVSpeechSynthesizer的delegate給ViewController

speakRate.minimumValue = 0.5
speakRate.maximumValue = 2.0
speakRate.value = 1.0
// [0.5 - 2] Default = 1
speakSpeed.minimumValue = 0.0
speakSpeed.maximumValue = 1.0
speakSpeed.value = 1.0
// [0-1] Default = 1
self.speakHistoryTableView.delegate = self
self.speakHistoryTableView.dataSource = self
self.speakSynthesizer.delegate = self

建立語音的類別

class SpeakHistory{
var speakText: String
var speakRate: Float
var speakSpeed: Float
init(speakText: String, speakRate: Float, speakSpeed: Float) {
self.speakText = speakText
self.speakRate = speakRate
self.speakSpeed = speakSpeed
}
}

Xcode 14的新功能不用打init直接幫我們建立好，真的很棒！！

播放程式碼：

if(speakSynthesizer.isPaused){
speakSynthesizer.continueSpeaking()
}else if(speakSynthesizer.isSpeaking){
speakSynthesizer.pauseSpeaking(at: AVSpeechBoundary.immediate)
}else{
if let speakText = speakTextfield.text, !speakText.isEmpty{
speakUtterance = AVSpeechUtterance(string: speakText)
speakUtterance.pitchMultiplier = speakRate.value
speakUtterance.rate = speakRate.value
speakUtterance.voice = AVSpeechSynthesisVoice(language: "zh-TW")
speakSynthesizer.speak(speakUtterance)
speakHistory.insert(SpeakHistory(speakText: speakText, speakRate: speakRate.value, speakSpeed: speakSpeed.value),at: 0)
speakHistoryTableView.reloadData()
}
}

這裡有判斷speakSynthesizer是否為暫停、播放中，沒有的話就播放新內容，並且抓Slider的Value（包含語速及語調），當speakSynthesizer播放就新增一筆資料在TableView的頂端使用

陣列.insert(你的資料,at: 陣列的第幾個位置)

speakHistory.insert(SpeakHistory(speakText: speakText, speakRate: speakRate.value, speakSpeed: speakSpeed.value),at: 0)

TableView 回傳有幾個Cell，我們回傳陣列的數量

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return  speakHistory.count
}

TableView的資料處理，把speakHistory[第幾筆資料]帶進去cell

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = speakHistoryTableView.dequeueReusableCell(withIdentifier: "speakHistoryCell", for: indexPath) as? SpeakTableViewCell else {
return UITableViewCell()
}
cell.speakText.text = speakHistory[indexPath.row].speakText
cell.speakRate.text = "\(speakHistory[indexPath.row].speakRate)"
cell.speakSpeed.text = "\(speakHistory[indexPath.row].speakSpeed)"
print("init cell")
return cell
}

如果點擊Cell，資料會帶入Slider以及Textfield

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let speak = speakHistory[indexPath.row]
speakTextfield.text = speak.speakText
speakRate.value = speak.speakRate
speakSpeed.value = speak.speakSpeed
}

如果向左滑，並點擊刪除

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if(editingStyle == .delete){
speakHistory.remove(at: indexPath.row)
speakHistoryTableView.reloadData()
}
}

輸入AVSpeechSynthesizerDelegate並點選Jump to Definition

或者在 官網文件找到 AVSpeechSynthesizerDelegate

Apple Developer Documentation

在這裡我們可以看到AVSpeechSynthesizer 開放的Protocol，我們就可以委託ViewController 幫我們監聽 speechSynthesizer的delegate

self.speakSynthesizer.delegate = self

透過委託的方式幫我們更改播放按鈕的Title

delegate程式碼

func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didFinish utterance: AVSpeechUtterance) {
self.speakPlayButton.setTitle("播放", for: .normal)
}
func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didStart utterance: AVSpeechUtterance) {
self.speakPlayButton.setTitle("暫停", for: .normal)
}
func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didPause utterance: AVSpeechUtterance) {
self.speakPlayButton.setTitle("繼續播放", for: .normal)
}
func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didContinue utterance: AVSpeechUtterance) {
self.speakPlayButton.setTitle("暫停", for: .normal)
}

Github:

GitHub - WeiFangChou/Homework6-8