A quick guide on how to use the BDK-Kotlin 0.7.0 library to create a Bitcoin testnet wallet for your own testing purposes.
You can use the Padawan Wallet and dev-kit open-source projects as reference.
Wallet Creation
To create a wallet using BDK-Kotlin is really simple, with the Wallet class being really intuitive to use. To create a testnet wallet you will just have to call Wallet() with all the necessary information for a wallet to be created. As an example this is a snippet of the code used in Padawan Wallet :
val wallet: Wallet = Wallet(descriptor = descriptor, network = Network.TESTNET, databaseConfig = databaseConfig)
The variables required to build a valid wallet are descriptor, network and databaseConfig. We will quickly go through each one since they are simple to understand.
descriptor: String : This is the wallet descriptor that tells the wallet how to generate addresses.
network: Network : This is the network you want to connect to. In our case we want Network.TESTNET for testing purposes.
databaseConfig: DatabaseConfig : This is the database configuration for the wallet to store its data.
Finally you will have to call Wallet() with all the necessary parameters. This returns a Wallet object.
Wallet Recovery
To recover a wallet using BDK-Kotlin is also really simple. You will just have to call Wallet() with the mnemonic phrase instead of the descriptor. As an example this is a snippet of the code used in Padawan Wallet :
val wallet: Wallet = Wallet(mnemonic = mnemonic, network = Network.TESTNET, databaseConfig = databaseConfig)
The variables required to recover a wallet are mnemonic, network and databaseConfig. We will quickly go through each one since they are simple to understand.
mnemonic: String : This is the mnemonic phrase that was used to create the wallet.
network: Network : This is the network you want to connect to. In our case we want Network.TESTNET for testing purposes.
databaseConfig: DatabaseConfig : This is the database configuration for the wallet to store its data.
Finally you will have to call Wallet() with all the necessary parameters. This returns a Wallet object.
ExtendedKeyInfo
To get the ExtendedKeyInfo object from the wallet you will just have to call getExtendedKeyInfo() on the wallet object. As an example this is a snippet of the code used in Padawan Wallet :
val extendedKeyInfo: ExtendedKeyInfo = wallet.getExtendedKeyInfo()
The ExtendedKeyInfo object contains all the information about the wallet, including the descriptor, network, and other metadata.
Descriptor
To get the descriptor from the ExtendedKeyInfo object you will just have to call descriptor on the ExtendedKeyInfo object. As an example this is a snippet of the code used in Padawan Wallet :
val descriptor: String = extendedKeyInfo.descriptor
The descriptor is a string that tells the wallet how to generate addresses. It is used to create the wallet and can be used to recover the wallet.
Mnemonic
To get the mnemonic from the ExtendedKeyInfo object you will just have to call mnemonic on the ExtendedKeyInfo object. As an example this is a snippet of the code used in Padawan Wallet :
val mnemonic: String = extendedKeyInfo.mnemonic
The mnemonic is a string that is used to recover the wallet. It is generated when the wallet is created and can be used to recover the wallet.
Summary
To create a testnet wallet using BDK-Kotlin you will just have to call Wallet() with the descriptor, network, and database configuration. To recover a wallet you will just have to call Wallet() with the mnemonic phrase, network, and database configuration. The ExtendedKeyInfo object contains all the information about the wallet, including the descriptor and mnemonic.
Remember that to recover a wallet you just need the descriptor to let the scripts know how to generate the addresses, hence after retrieving the ExtendedKeyInfo object it is easy to see that the rest of the code remains the same.
