Ответ 1
В примере с примером Google в отличие от файла helpl, включенного в дополнительный SDK "Google Play Billing". Я понятия не имею, почему они думали, что это хорошая идея. Просто замените helpl в своем проекте тем, который включен в примерный проект. Это содержит недостающие ссылки метода. Вы также можете скопировать и вставить приведенный ниже код в свой файл helpl внизу:
/**
* This API is currently under development.
*/
int stub(int apiVersion, String packageName, String type);
/**
* Returns a pending intent to launch the purchase flow for upgrading or downgrading a
* subscription. The existing owned SKU(s) should be provided along with the new SKU that
* the user is upgrading or downgrading to.
* @param apiVersion billing API version that the app is using, must be 5 or later
* @param packageName package name of the calling app
* @param oldSkus the SKU(s) that the user is upgrading or downgrading from,
* if null or empty this method will behave like {@link #getBuyIntent}
* @param newSku the SKU that the user is upgrading or downgrading to
* @param type of the item being purchased, currently must be "subs"
* @param developerPayload optional argument to be sent back with the purchase information
* @return Bundle containing the following key-value pairs
* "RESPONSE_CODE" with int value, RESULT_OK(0) if success, appropriate response codes
* on failures.
* "BUY_INTENT" - PendingIntent to start the purchase flow
*
* The Pending intent should be launched with startIntentSenderForResult. When purchase flow
* has completed, the onActivityResult() will give a resultCode of OK or CANCELED.
* If the purchase is successful, the result data will contain the following key-value pairs
* "RESPONSE_CODE" with int value, RESULT_OK(0) if success, appropriate response
* codes on failures.
* "INAPP_PURCHASE_DATA" - String in JSON format similar to
* '{"orderId":"12999763169054705758.1371079406387615",
* "packageName":"com.example.app",
* "productId":"exampleSku",
* "purchaseTime":1345678900000,
* "purchaseToken" : "122333444455555",
* "developerPayload":"example developer payload" }'
* "INAPP_DATA_SIGNATURE" - String containing the signature of the purchase data that
* was signed with the private key of the developer
* TODO: change this to app-specific keys.
*/
Bundle getBuyIntentToReplaceSkus(int apiVersion, String packageName,
in List<String> oldSkus, String newSku, String type, String developerPayload);