You can use you tube "CommentThreads: insert" to post your comment via app

https://developers.google.com/***/v3/docs/commentThreads/insert

接下来是api调用

Post url : https://www.googleapis.com/***/v3/commentThreads?part=snippet&key={YOUR_API_KEY}

API 调用的主体是:

And body for the API call is:

Body

    { "snippet":{
      "topLevelComment":{
       "snippet":{
        "textOriginal": "YOUR_COMMENT_HERE",
        "videoId": "VIDEO_ID"
       }
      }
     }
    }

另外添加不要忘记添加以下范围https://www.googleapis.com/auth/***.force-ssl

Also add don't forget to add following scope https://www.googleapis.com/auth/***.force-ssl