• How to use AVSpeechSynthesizer To speak a sentence?
    • First, new an AVSpeechUtterance with text
    • Adjust voice, rate, pre pro latency of utterance
    • New a new AVSpeechSynthesizer or reuse one
    • Use synthesizer.speak(utterance)
  • How to use Objective-C Framework in Swift?
    • Drag framework to project
    • If there is no bridge file
      • New an Objective-C file and add a new bridging file(Xcode will ask you to create a bridging file)
      • Import <Module/MoudleName.h>
    • Now the framework can be used
  • How to use TTS Cloud service of Google?
    • Enable Google Cloud
    • New a project
    • Enable TTS API
    • Create a service account key
      • No role is needed for the service account
    • Download a json version of the key
    • Set environment variable to use the JSON file(which is your credential)
    • Install and init Cloud SDK
    • Use curl to use TTS api to transform text to mp3 and save to local
      • This is a json file
    • Save value for key “audioContent”, and save to a text file
    • Base64 decode this file to mp3
    • Play the mp3
    • So if you want to use this service, you must have a server do the previous steps, and then you can download the mp3 file to local and play it