检测到一个 android 账号被删除

Question

i'm developing an android application with accounts, sync and content provider. adding an account works, syncing also and some data is saved in the content provider.

now, when the user deletes the account using the settings, syncing stops, but the data stays in the content provider.

i'd like to delete it, but i don't know how to catch the event of account deletion.

There is AccountManager.addOnAccountsUpdatedListener() , i've tried to add it to the sync service, but the sync service is started only for the sync and then stopped. so whenever the account gets deleted while there is no sync, it can't get caught.

is there a best practice on how to handle private data when an account gets deleted?

Answer 1

First You should add OnAccountsUpdateListener to you AccountManager using this command:

AccountManager mAccountMgr = AccountManager.get(getContext());
mAccountMgr.addOnAccountsUpdatedListener(new AccountsUpdateListener(), null, false);

AccountsUpdateListener is implemented class of OnAccountsUpdateListener like this:

private class AccountsUpdateListener implements OnAccountsUpdateListener {
    @Override
    public void onAccountsUpdated(Account[] accounts) {
        Account newAccount = null;
        for (final Account account : accounts) {
            if (account.type.equals(mAccountType)) {
                newAccount = account;
            }
        }

        if (newAccount == null) {
          // account removed, now you can handle your private data and remove anything you want here
        }
    }
}

onAccountsUpdated fired when you add an account or an account removed. so you can check your account type to find specified account in accounts array. if it doesn't exist it removed. mAccountType is your account type. eg mAccountType = "your application name"

Answer 2

You should use method getAccountRemovalAllowed from your AbstactAccountAuthenticator :

    class AccountAuthenticatorImpl(context: Context) : AbstractAccountAuthenticator(context) {
    
        override fun getAccountRemovalAllowed(
            response: AccountAuthenticatorResponse?,
            account: Account?
        ): Bundle {
            val result = super.getAccountRemovalAllowed(response, account)
            val canDelete = result.getBoolean(android.accounts.AccountManager.KEY_BOOLEAN_RESULT, false)
    
            if (canDelete) {
                // TODO: account was deleted, so react on it
                accountRepository.onAccountDeletedInSystem()
            }
    
            return result
        }
    
    
    }