speech
AVSpeechUtterance 语音话语
包括： 语种（eg：zh-CN）、内容（文字）
@property(nonatomic) NSTimeInterval preUtteranceDelay; // Default is 0.0 读一段话之前的停顿
@property(nonatomic) NSTimeInterval postUtteranceDelay; // Default is 0.0 读完一段后的停顿时间
@property(nonatomic) float rate;// Values are pinned between AVSpeechUtteranceMinimumSpeechRate and AVSpeechUtteranceMaximumSpeechRate.
@property(nonatomic) float pitchMultiplier; // [0.5 - 2] Default = 1 音高
@property(nonatomic) float volume; // [0-1] Default = 1
初始化
+ (instancetype)speechUtteranceWithString:(NSString *)string;
+ (instancetype)speechUtteranceWithAttributedString:(NSAttributedString *)string API_AVAILABLE(ios(10.0), watchos(3.0), tvos(10.0));
- (instancetype)initWithString:(NSString *)string;
- (instancetype)initWithAttributedString:(NSAttributedString *)string API_AVAILABLE(ios(10.0), watchos(3.0), tvos(10.0));
创建发言对象通过内容
@property(nonatomic, readonly) NSString *speechString;
@property(nonatomic, readonly) NSAttributedString *attributedSpeechString API_AVAILABLE(ios(10.0), watchos(3.0), tvos(10.0));
应该是10 之后-支持了一些东西；
@property(nonatomic, retain, nullable) AVSpeechSynthesisVoice *voice;
声明为retain ，其实应该对应的就是一个位置的结构体类似；
语种的设置
@interface AVSpeechSynthesisVoice : NSObject<NSSecureCoding>
+ (NSArray<AVSpeechSynthesisVoice *> *)speechVoices; // 所有的饿支持的语种
+ (NSString *)currentLanguageCode; // 语种的代码
初始化 （通过语种代码）
+ (nullable AVSpeechSynthesisVoice *)voiceWithLanguage:(nullable NSString *)languageCode;
这个方式也是通过identifier来进行初始化； （应该是可以进行自定义一些内容）
+ (nullable AVSpeechSynthesisVoice *)voiceWithIdentifier:(NSString *)identifier NS_AVAILABLE_IOS(9_0);
读取的属性
@property(nonatomic, readonly) NSString *language;
@property(nonatomic, readonly) NSString *identifier NS_AVAILABLE_IOS(9_0);
@property(nonatomic, readonly) NSString *name NS_AVAILABLE_IOS(9_0);
@property(nonatomic, readonly) AVSpeechSynthesisVoiceQuality quality NS_AVAILABLE_IOS(9_0);
@end
AVSpeechSynthesizer 语音合成器
@property(nonatomic, weak, nullable) id<AVSpeechSynthesizerDelegate> delegate; 代理
@property(nonatomic, readonly, getter=isSpeaking) BOOL speaking; // 进行
@property(nonatomic, readonly, getter=isPaused) BOOL paused; // 暂停
- (void)speakUtterance:(AVSpeechUtterance *)utterance;
播放语音
停止播放语音的边界，打断当前的语音和清除队列；
/* Call stopSpeakingAtBoundary: to interrupt current speech and clear the queue. */
- (BOOL)stopSpeakingAtBoundary:(AVSpeechBoundary)boundary;
- (BOOL)pauseSpeakingAtBoundary:(AVSpeechBoundary)boundary;
- (BOOL)continueSpeaking;
typedef NS_ENUM(NSInteger, AVSpeechBoundary) {
AVSpeechBoundaryImmediate, //立刻停止
AVSpeechBoundaryWord // 读完最后一个字停止
} NS_ENUM_AVAILABLE_IOS(7_0);
@property(nonatomic, retain, nullable) NSArray<AVAudioSessionChannelDescription *> *outputChannels API_AVAILABLE(ios(10.0), watchos(3.0), tvos(10.0));
指定输出的渠道，这里是audiochannel 在当前的audio 的rote上；复制到指定的渠道里面
常量
个人测试的值是: 最小是0 ，最大是1.0 ，默认是0.5
觉得这里不够清楚，可以看官方文档，这里是对官方文档的一些理解
