As to the Android app with Youtube API to make a choice of the current account?
Our Android application interacts with the Youtube API v3 and users complained that it is impossible to choose a current account because the authorization is made by mail (using account Android) using OAuth 2 and grant access only to the main (not branded) account, and many users have several such accounts (to the main uchetku created multiple accounts brands). This functionality was implemented because at the time of developing this feature of Youtube on the choice of active account was lost. As I understand it, the accounts of brands to additional accounts, which are tied to the main account through which they and managed. Each account brand can have its own channel on Youtube and in General, such an account in the Google environment is represented as a single user, but with certain restrictions.
On the site Youtube in their Android app you can select the current active account. In Andorid Yotube API for authorization of such a choice is not present. In a network found the information that the authorization by means of Web has the choice of account and so Android was the way to authorize via WebView, but this method for Android is already off. There is therefore the question how Android to account list brands user and subsequently provide authorization in the Youtube API for that account? In General, you need the same window for selecting the account in the Youtube app with the subsequent possibility of obtaining data for a selected account, etc.