android 内购,有人了解android 内购吗？

import com.android.billingclient.api.BillingClient;

import com.android.billingclient.api.BillingClientStateListener;

import com.android.billingclient.api.BillingFlowParams;

import com.android.billingclient.api.ConsumeResponseListener;

import com.android.billingclient.api.Purchase;

import com.android.billingclient.api.PurchaseHistoryResponseListener;

import com.android.billingclient.api.PurchasesUpdatedListener;

import com.android.billingclient.api.SkuDetails;

import com.android.billingclient.api.SkuDetailsParams;

import com.android.billingclient.api.SkuDetailsResponseListener;