import com.android.billingclient.api.BillingClientStateListener; //导入依赖的package包/类
private void showDonateGooglePlay() {
    mBillingClient = BillingClient.newBuilder(this).setListener(this).build();

    mBillingClient.startConnection(new BillingClientStateListener() {
        @Override
        public void onBillingSetupFinished(@BillingResponse int billingResponseCode) {
            if (billingResponseCode == BillingResponse.OK) {
                // The billing client is ready. You can query purchases here.
                BillingFlowParams flowParams = BillingFlowParams.newBuilder()
                        .setSku("donate_2")
                        .setType(SkuType.INAPP)
                        .build();
                int responseCode = mBillingClient.launchBillingFlow(MainActivity.this, flowParams);
            }
        }
        @Override
        public void onBillingServiceDisconnected() {
            // Try to restart the connection on the next request to
            // Google Play by calling the startConnection() method.
        }
    });
}
 

import com.android.billingclient.api.BillingClientStateListener; //导入依赖的package包/类
public BillingManager(Activity activity) {
    mActivity = activity;
    mBillingClient = BillingClient.newBuilder(mActivity).setListener(this).build();
    mBillingClient.startConnection(new BillingClientStateListener() {
        @Override
        public void onBillingSetupFinished(@BillingClient.BillingResponse int billingResponse) {
            if (billingResponse == BillingClient.BillingResponse.OK) {
                Log.i(TAG, "onBillingSetupFinished() response: " + billingResponse);
            } else {
                Log.w(TAG, "onBillingSetupFinished() error code: " + billingResponse);
            }
        }
        @Override
        public void onBillingServiceDisconnected() {
            Log.w(TAG, "onBillingServiceDisconnected()");
        }
    });
}
 

import com.android.billingclient.api.BillingClientStateListener; //导入依赖的package包/类
private void startServiceConnection(final Runnable executeOnSuccess) {
    billingClient.startConnection(new BillingClientStateListener() {
        @Override
        public void onBillingSetupFinished(int responseCode) {
            Log.i(TAG, "Billing setup finished. Response code: " + responseCode);

            if (responseCode == BillingClient.BillingResponse.OK) {
                serviceConnected = true;
                if (executeOnSuccess != null) {
                    executeOnSuccess.run();
                }
            }
        }

        @Override
        public void onBillingServiceDisconnected() {
            Log.i(TAG, "Billing service disconnected");
            serviceConnected = false;
        }
    });
}
 

import com.android.billingclient.api.BillingClientStateListener; //导入依赖的package包/类
public void startServiceConnection(final Runnable executeOnSuccess) {
    mBillingClient.startConnection(new BillingClientStateListener() {
        @Override
        public void onBillingSetupFinished(@BillingResponse int billingResponseCode) {
            Log.d(TAG, "Setup finished. Response code: " + billingResponseCode);

            if (billingResponseCode == BillingResponse.OK) {
                mIsServiceConnected = true;
                if (executeOnSuccess != null) {
                    executeOnSuccess.run();
                }
            }
            mBillingClientResponseCode = billingResponseCode;
        }

        @Override
        public void onBillingServiceDisconnected() {
            mIsServiceConnected = false;
        }
    });
}
 

import com.android.billingclient.api.BillingClientStateListener; //导入依赖的package包/类
public void startServiceConnection(final Runnable executeOnSuccess) {
    billingClient.startConnection(new BillingClientStateListener() {
        @Override
        public void onBillingSetupFinished(@BillingResponse int billingResponseCode) {
            Log.d(TAG, "Setup finished. Response code: " + billingResponseCode);

            if (billingResponseCode == BillingResponse.OK) {
                isServiceConnected = true;
                if (executeOnSuccess != null) {
                    executeOnSuccess.run();
                }
            }
            billingClientResponseCode = billingResponseCode;
        }

        @Override
        public void onBillingServiceDisconnected() {
            isServiceConnected = false;
        }
    });
}
 

import com.android.billingclient.api.BillingClientStateListener; //导入依赖的package包/类
@Override
protected void onResume() {
  super.onResume();
  billingClient = new BillingClient.Builder(this).setListener(this).build();
  billingClient.startConnection(
      new BillingClientStateListener() {
        @Override
        public void onBillingSetupFinished(@BillingResponse int billingResponseCode) {
          if (billingResponseCode == BillingResponse.OK) {
            Purchase.PurchasesResult purchasesResult =
                billingClient.queryPurchases(BillingClient.SkuType.INAPP);
            onPurchasesUpdated(
                purchasesResult.getResponseCode(), purchasesResult.getPurchasesList());
          }
        }

        @Override
        public void onBillingServiceDisconnected() {}
      });
}
 

import com.android.billingclient.api.BillingClientStateListener; //导入依赖的package包/类
/**
 * Trying to restart service connection if it's needed or just execute a request.
 * <p>Note: It's just a primitive example - it's up to you to implement a real retry-policy.</p>
 * @param executeOnSuccess This runnable will be executed once the connection to the Billing
 *                         service is restored.
 */
private void startServiceConnectionIfNeeded(final Runnable executeOnSuccess) {
    if (mBillingClient.isReady()) {
        if (executeOnSuccess != null) {
            executeOnSuccess.run();
        }
    } else {
        mBillingClient.startConnection(new BillingClientStateListener() {
            @Override
            public void onBillingSetupFinished(@BillingResponse int billingResponse) {
                if (billingResponse == BillingResponse.OK) {
                    Log.i(TAG, "onBillingSetupFinished() response: " + billingResponse);
                    if (executeOnSuccess != null) {
                        executeOnSuccess.run();
                    }
                } else {
                    Log.w(TAG, "onBillingSetupFinished() error code: " + billingResponse);
                }
            }

            @Override
            public void onBillingServiceDisconnected() {
                Log.w(TAG, "onBillingServiceDisconnected()");
            }
        });
    }
}
 

import com.android.billingclient.api.BillingClientStateListener; //导入依赖的package包/类
public BillingManager(Activity activity) {
    mActivity = activity;
    mBillingClient = BillingClient.newBuilder(mActivity).setListener(this).build();
    mBillingClient.startConnection(new BillingClientStateListener() {
        @Override
        public void onBillingSetupFinished(@BillingResponse int billingResponse) {
            Log.i(TAG, "onBillingSetupFinished() response: " + billingResponse);
        }
        @Override
        public void onBillingServiceDisconnected() {
            Log.w(TAG, "onBillingServiceDisconnected()");
        }
    });
}
 

import com.android.billingclient.api.BillingClientStateListener; //导入依赖的package包/类
/**
 * Trying to restart service connection.
 * <p>Note: It's just a primitive example - it's up to you to develop a real retry-policy.</p>
 * @param executeOnSuccess This runnable will be executed once the connection to the Billing
 *                         service is restored.
 */
private void startServiceConnection(final Runnable executeOnSuccess) {
    mBillingClient.startConnection(new BillingClientStateListener() {
        @Override
        public void onBillingSetupFinished(@BillingResponse int billingResponse) {
            Log.i(TAG, "onBillingSetupFinished() response: " + billingResponse);
        }
        @Override
        public void onBillingServiceDisconnected() {
            Log.w(TAG, "onBillingServiceDisconnected()");
        }
    });
}
 

import com.android.billingclient.api.BillingClientStateListener; //导入依赖的package包/类
public void startBuyProcess(){
    final BillingClient mBillingClient;

    mBillingClient = BillingClient.newBuilder(getActivity().getApplicationContext()).setListener(this).build();
    mBillingClient.startConnection(new BillingClientStateListener() {
        @Override
        public void onBillingSetupFinished(@BillingClient.BillingResponse int billingResponseCode) {
            if (billingResponseCode == BillingClient.BillingResponse.OK) {
                // The billing client is ready
                final SharedPreferences settings = getActivity().getSharedPreferences(PREFS_NAME, 0);
                boolean donationPurchased = settings.getBoolean("donationPurchased", false);
                if(!donationPurchased){
                    // Start buy process
                    BillingFlowParams flowParams = BillingFlowParams.newBuilder()
                            .setSku("donation_upgrade")
                            .setType(BillingClient.SkuType.INAPP)
                            .build();
                    // Launch purchase
                    mBillingClient.launchBillingFlow(getActivity(), flowParams);
                }
            }
        }

        @Override
        public void onBillingServiceDisconnected() {
            // Try to restart the connection on the next request to
            // Google Play by calling the startConnection() method.
            if(getView() != null) {
                Snackbar.make(getView(), R.string.donation_cancelled, Snackbar.LENGTH_SHORT).show();
            }
        }
    });
}