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Wallet Module for Native Android

This section explains the steps to import now.gg Wallet libraries to your development environment and integrate the now.gg Gaming Wallet with your Android app/game.

To get started, download the nowSDK package that contains the now.gg Wallet module and add them to your development environment.

Note: The now.gg SDK download package contains the Wallet module, demo app, and code.

1. Add SDK Libraries

1. Extract the compressed now.gg Wallet module and locate the .aar file in the package:

   
 Wallet.aar

2. Add the following dependency to the build.gradle file of your game:

implementation fileTree(dir: 'libs', include: ['*.aar', '*.jar'], exclude: [])

 implementation "com.walletconnect:sign:2.7.0"
 implementation "com.walletconnect:android-core:1.9.0"
 implementation "com.squareup.moshi:moshi:1.14.0"
 implementation 'com.squareup.retrofit2:retrofit:2.9.0'
 implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
 implementation 'com.squareup.retrofit2:converter-scalars:2.9.0'

2. Initialize the Wallet Module

Once the now.gg Wallet Module has been imported, you can now initialize it.

To initialize now.gg Wallet module, you should call the initialize function of the NowGGWalletSdkManager class along with the required params, as illustrated below:

object Constants {
    const val CHAIN_NAMESPACE: String = "eip155"
    const val CHAIN_ID: String = "80001" // Replace this with your chain Id
    const val CAIP_CHAIN_ID: String = "$CHAIN_NAMESPACE:$CHAIN_ID"
    const val COIN_CONTRACT_ADDRESS: String = "0x1921fd1833efb4c7b9fbd635fb6710648f497e9a" // Replace this with your own ERC20 contract address
    const val API_KEY: String = "<YOUR_API_KEY>"
    const val APP_ID: String = "<YOUR_APP_ID>"

 }


 fun initializeWalletSdk(activity: MainActivity) {
    NowGGWalletSdkManager.getInstance()
        .initialize(activity, Constants.API_KEY, Constants.APP_ID, WalletDelegateHandler(), {
            //on success - Call other methods only after you receive this callback.
        }, {
            // on failed
        })
 }

public class ConstantsJava {

    public static final String CHAIN_NAMESPACE = "eip155";
    public static final String CHAIN_ID = "80001"; //your chain id
    public static final String CAIP_CHAIN_ID = "$CHAIN_NAMESPACE:$CHAIN_ID";
    public static final String COIN_CONTRACT_ADDRESS = "0x1921fd1833efb4c7b9fbd635fb6710648f497e9a"; // Replace this with your own ERC20 contract address
    public static final String API_KEY = "<YOUR_API_KEY>";
    public static final String APP_ID = "<YOUR_APP_ID>";
    
 }


 public void initializeWalletSdk(Activity activity) {
    NowGGWalletSdkManager.Companion.getInstance().initialize(activity, Constants.API_KEY, Constants.APP_ID, new WalletDelegateHandler(), () -> {
        //init success - Call other methods only after you receive this callback.
        return Unit.INSTANCE;
    }, (error) -> {
        //init failed
        return Unit.INSTANCE;
    });
 }

Important Information

You can generate the API_KEY and APP_ID by emailing us at dev-support@now.gg.
You can find the reference to the chain namespace as per CAIP here.
For a list of supported blockchains, please click here.
References associated with NowGGWalletSdkManager class are listed here.

3. Declaring Wallet Delegate

Once you have initialized the Wallet module, you must declare a wallet delegate to receive the responses using callbacks.

Create an implementation of the NowGGWalletDelegate as illustrated below:

class WalletDelegateHandler: NowGGWalletDelegate {

     // Triggered when the connection state changes.
     override fun onConnectionStateChange(isAvailable: Boolean) {

     }

     // Triggered when there is an error.
     override fun onError(error: String) {
         if (error == ErrorCodes.SESSION_EXPIRED){
           //Indicates that the earlier established session has failed. This may be because i.) the wallet is not responding or ii.) the wallet is in the killed state.
           //Call Connect again to reestablish the connection with the wallet.
         }
     }

     // Triggered when the session request is approved by the wallet.
     override fun onSessionApproved(approvedSession: ApprovedSession, user: User) {

         val approvedSessionTopic = approvedSession.topic
         val username = user.name
         val avatarUrl = user.avatar
         val walletAddress = approvedSession.accounts[0].split(":")[2]
     }

     // Triggered when the session is deleted
     override fun onSessionDelete(deletedSession: DeletedSession) {

     }

     // Triggered when the session request is rejected by the wallet.
     override fun onSessionRejected(rejectedSession: RejectedSession) {

     }

     // Triggered when session information is updated.
     override fun onSessionUpdate(updatedSession: UpdatedSession) {

     }

     // Triggered when there is an error while purchasing token
     override fun onTokenPurchaseError(error: String, extra: String? ) {

         // handle error while purchasing token

     }

     // Triggered when token purchase is successful.
     override fun onTokenPurchaseSuccess(result: SessionRequestResponse, extra: String? ) {
         Log.d("Your Tag", "onTokenPurchaseSuccess: " + result.result + "
             extra: $extra")

     }

     // Triggered when a transaction is completed with an error post wallet approval request.
     override fun onTransactionCompletedError(transactionInfo: TransactionInfo, extra: String? ) {

     }

     // Triggered when transaction was completed successful.
     override fun onTransactionCompletedSuccess(transaction: TransactionInfo, extra: String? ) {

         // handle successful transaction

     }

     // Triggered when there is an error while sending transaction to blockchain.
     override fun onTransactionSendError(error: String, extra: String? ) {

         //handle error while sending transaction to blockchain

     }

     // Triggered once a transaction is submitted to the blockchain by Wallet.
     override fun onTransactionSendSuccess(
         txnHash: String,
         caipChainId: String,
         extra: String?
     ) {

     }
 }

class WalletDelegateHandler implements NowGGWalletDelegate{

    // Triggered when the connection state changes.
    @Override
    public void onConnectionStateChange(boolean isAvailable) {

    }

    // Triggered when there is an error.
    @Override
    public void onError(@NonNull String error) {
       if (error == ErrorCodes.SESSION_EXPIRED){
           //Indicates that the earlier established session has failed. This may be because i.) the wallet is not responding or ii.) the wallet is in the killed state.
           //Call Connect again to reestablish the connection with the wallet.
        }
    }

    // Triggered when the session request is approved by the wallet.
    @Override
    public void onSessionApproved(@NonNull ApprovedSession approvedSession, @NonNull User user) {
        String approvedSessionTopic = approvedSession.getTopic();
        String username = user.getName();
        String avatarUrl = user.getAvatar();
        String walletAddress = approvedSession.getAccounts().get(0).split(":")[2];

    }

    // Triggered when the session is deleted
    @Override
    public void onSessionDelete(@NonNull DeletedSession deletedSession) {

    }

    // Triggered when the session request is rejected by the wallet
    @Override
    public void onSessionRejected(@NonNull RejectedSession rejectedSession) {

    }

    // Triggered when session information is updated.

    @Override
    public void onSessionUpdate(@NonNull UpdatedSession updatedSession) {

    }

    // Triggered when there is an error while purchasing token
    @Override
    public void onTokenPurchaseError(@NonNull String error, @Nullable String extra) {
        // handle error while purchasing token

    }
    // Triggered when token purchase is successful.
    @Override
    public void onTokenPurchaseSuccess(@NonNull SessionRequestResponse sessionRequestResponse, @Nullable String extra) {
       Log.d("Your Tag", "onTokenPurchaseSuccess: " + sessionRequestResponse.getResult() + " extra:" +extra );
    }

    // Triggered when a transaction is completed with an error post wallet approval request.
    @Override
    public void onTransactionCompletedError(@NonNull TransactionInfo transactionInfo, @Nullable String extra) {

    }

    // Triggered when transaction was completed successful.
    @Override
    public void onTransactionCompletedSuccess(@NonNull TransactionInfo transactionInfo, @Nullable String extra) {
        // handle successful transaction

    }

    // Triggered when there is an error while sending transaction to blockchain.
    @Override
    public void onTransactionSendError(@NonNull String error, @Nullable String extra) {
        //handle error while sending transaction to blockchain

    }
  
    // Triggered once a transaction is submitted to the blockchain by Wallet.
    @Override
    public void onTransactionSendSuccess(@NonNull String txnHash, @NonNull String caipChainId, @Nullable String extra) {

    }
 }

Important Information

Please make sure that isAvailable in onConnectionStateChange callback is true, before calling any now.gg wallet functions.

Reference

Detailed references related to NowGGWalletDelegate and the associated methods are listed here.

4. Connect to now.gg Wallet

The next step is to connect your game to the now.gg Wallet.

Connecting to the now.gg Wallet is required to carry out various operations, such as:

Buy Token
View Token balance
Send Transactions
Get the list of NFTs purchased by the user

To connect to now.gg Wallet, call the connect function as illustrated below:

fun connectWithWallet(activity: Activity) {
   try {
     NowGGWalletSdkManager.getInstance().connect(
       Constants.CAIP_CHAIN_ID,
       activity, {
         // on pairing invoked
       }, {
         error ->
         // on error
       }
     )
  
   } catch (ex: SocketNotConnectedException) {
      //This will occur if the connection state is not available.
      //Please wait for the connection state to be available before calling this function.
      //Add your handling here.

   } catch (ex: WalletSdkNotInitialisedException) {
       //This will occur if you call this function before initialization is successful.
       //Add your handling here.

   }
 }

public void connectWithWallet(Activity activity) {
   try {
     NowGGWalletSdkManager.Companion.getInstance().connect(Constants.CAIP_CHAIN_ID, activity, () -> {
       // on pairing invoked
       return Unit.INSTANCE;
     }, (error) -> {
       // on error
       return Unit.INSTANCE;
     });
  
   } catch (SocketNotConnectedException ex) {
     //This will occur if the connection state is not available.
     //Please wait for the connection state to be available before calling this function.
     //Add your handling here.

   } catch (WalletSdkNotInitialisedException ex) {
     //This will occur if you call this function before initialization is successful.
     //Add your handling here.
   }
 }

Flow Diagram

Click here to find the sequence diagram for Connect Wallet flow.

Reference

Detailed references related to NowGGWalletSdkManager and the associated methods are listed here.

Using Wallet Functions

Once you have connected to the now.gg Wallet, you can use the following functions:

Important Information

Please make sure that isAvailable in onConnectionStateChange callback is true, before calling any now.gg wallet functions.

1. Buy Token (Coming Soon)

You can use the now.gg Wallet module to enable the purchase of supported tokens by using the buyToken function, as illustrated below:

fun buyToken(amount: Int) {
   val extra = "BuyToken"
   try {
     NowGGWalletSdkManager.getInstance().buyToken(Constants.COIN_CONTRACT_ADDRESS, amount.toString(), Constants.CAIP_CHAIN_ID, extra)
   
   } catch (ex: SocketNotConnectedException) {
     //This will occur if the connection state is not available.
     //Please wait for the connection state to be available before calling this function.
     //Add your handling here.

   } catch (ex: WalletSdkNotInitialisedException) {
     //This will occur if you call this function before initialization is successful.
     //Add your handling here.

   }
 }

public void buyToken(int amount) {
   String extra = "BuyToken";
   try {
     NowGGWalletSdkManager.Companion.getInstance().buyToken(Constants.COIN_CONTRACT_ADDRESS, String.valueOf(amount), Constants.CAIP_CHAIN_ID, extra);
  
   } catch (SocketNotConnectedException ex) {
      //This will occur if the connection state is not available.
      //Please wait for the connection state to be available before calling this function.
      //Add your handling here.
  
   } catch (WalletSdkNotInitialisedException ex) {
     //This will occur if you call this function before initialization is successful.
     //Add your handling here.

   }
 }

Flow Diagram

Click here to find the sequence diagram for the Buy Token flow.

Reference

A detailed reference for the buyToken function is listed here.

2. Get Token Balance

You can request the user’s Token balance using the getTokenBalance function and receive the Token balance as a response, as illustrated below:

fun getTokenBalance() {
   try {
     NowGGWalletSdkManager.getInstance().getTokenBalance(Constants.COIN_CONTRACT_ADDRESS,
       Constants.CAIP_CHAIN_ID,
       walletAddress, {
         balance ->

         //You can update user about the balance here
       }, {
         error ->

         //handle error
       }
     )

   } catch (ex: WalletSdkNotInitialisedException) {
     //This will occur if you call this function before initialization is successful.
     //Add your handling here.

   }
 }

public void getTokenBalance() {
   try {
     NowGGWalletSdkManager.Companion.getInstance().getTokenBalance(Constants.COIN_CONTRACT_ADDRESS, Constants.CAIP_CHAIN_ID, walletAddress, (balance -> {

      //you can update user about the balance here
      return Unit.INSTANCE;
     }), (error -> {

      //handle error
      return Unit.INSTANCE;
     }));

   } catch (WalletSdkNotInitialisedException ex) {
     //This will occur if you call this function before initialization is successful.
     //Add your handling here.

   }
 }

Reference

A detailed reference for the getTokenBalance function is listed here.

3. Send Transaction

You can use the sendTransaction function to execute a transaction on the blockchain.

For instance, you can get approval to deduct a certain amount from the user’s wallet to purchase an NFT.

The following illustrates executing a contract on the blockchain using the sendTransaction function:

Use the sendTransaction function to get the NFT purchase approval.

fun sendTransaction() {
   val toAddress: String = Constants.COIN_CONTRACT_ADDRESS
   val nativeTokenValue = "0x0"
   //nftData is encoded method name with parameters of the NFT contract
   val nftData = "0x095ea7b3000000000000000000001111ff9f4c235d1508176cbe99891585e86b8fd3f09100000000000000000000000000000000000000000000001043561a8829300000"
   val extra = nftName
   try {
     NowGGWalletSdkManager.getInstance().sendTransaction(
       toAddress,
       nativeTokenValue,
       nftData,
       Constants.CAIP_CHAIN_ID,
       extra
     )
  
   } catch (ex: SocketNotConnectedException) {
     //This will occur if the connection state is not available.
     //Please wait for the connection state to be available before calling this function.
     //Add your handling here.

   } catch (ex: WalletSdkNotInitialisedException) {
     //This will occur if you call this function before initialization is successful.
     //Add your handling here.

   }
 }

public void sendTransaction() {
   String toAddress = Constants.COIN_CONTRACT_ADDRESS;
   String nativeTokenValue = "0x0"; //hex value in wei
   String nftData = "0x095ea7b3000000000000000000001111ff9f4c235d1508176cbe99891585e86b8fd3f09100000000000000000000000000000000000000000000001043561a8829300000";
   String extra = nftName;
   try {
     NowGGWalletSdkManager.Companion.getInstance().sendTransaction(
       toAddress,
       nativeTokenValue,
       nftData,
       Constants.CAIP_CHAIN_ID,
       extra
     );
  
   } catch (SocketNotConnectedException ex) {
     //This will occur if the connection state is not available.
     //Please wait for the connection state to be available before calling this function.
     //Add your handling here.

   } catch (WalletSdkNotInitialisedException ex) {
     //This will occur if you call this function before initialization is successful.
     //Add your handling here.

   }
 }

Important Information

nftData is an encoded method name with parameters of the NFT contract.
We have passed nftName within the extra parameter, you may pass any additional information here based on your requirement.
Depending on your requirement, you may use our implementation or write your logic.

Flow Diagram

Click here to find the sequence diagram for Send Transaction flow.

Reference

A detailed reference for the sendTransaction function is listed here.

4. Get NFts

You can request the list of NFTs purchased by the user with getNfts function, as illustrated below:

fun getNfts() {
   try {
     NowGGWalletSdkManager.getInstance()
       .getNfts(Constants.CAIP_CHAIN_ID, "Users_walletAddress_here", {
         nfts: List < Nft > ->
          //todo: handle the list of nfts.
       }, {
          //todo: handle error

       })
  
   } catch (ex: WalletSdkNotInitialisedException) {
     //This will occur if you call this function before initialization is successful.
     //Add your handling here.

   }
 }

public void getNfts() {
   try {
     NowGGWalletSdkManager.Companion.getInstance().getNfts(Constants.CAIP_CHAIN_ID, "Users_walletAddress_here", (nfts -> {
       //todo: handle the list of nfts
       return Unit.INSTANCE;
     }), (error -> {
       //todo: handle error

       return Unit.INSTANCE;
     }));

   } catch (WalletSdkNotInitialisedException ex) {
     //This will occur if you call this function before initialization is successful.
     //Add your handling here.

   }
 }

Note: Replace “Users_walletAddress_here” with the actual walletAddress received in onSessionApproved.

Reference

A detailed reference for the getNfts function is listed here.

Important Information

To test your integration, please continue to the testing integration section.
We have also included the demo project for now.gg Wallet, which you can find here.

Start Integrating

Testing Integration