Examples with Wallet org.bitcoinj.wallet.Wallet used on opensource projects

Example 16 with Wallet

use of org.bitcoinj.wallet.Wallet in project bitcoin-wallet by bitcoin-wallet.

the class EncryptKeysDialogFragment method handleGo.

private void handleGo() {
    final String oldPassword = Strings.emptyToNull(oldPasswordView.getText().toString().trim());
    final String newPassword = Strings.emptyToNull(newPasswordView.getText().toString().trim());
    if (oldPassword != null && newPassword != null)
        log.info("changing spending password");
    else if (newPassword != null)
        log.info("setting spending password");
    else if (oldPassword != null)
        log.info("removing spending password");
    else
        throw new IllegalStateException();
    state = State.CRYPTING;
    updateView();
    backgroundHandler.post(() -> {
        // For the old key, we use the key crypter that was used to derive the password in the first
        // place.
        final KeyCrypter oldKeyCrypter = wallet.getKeyCrypter();
        final KeyParameter oldKey = oldKeyCrypter != null && oldPassword != null ? oldKeyCrypter.deriveKey(oldPassword) : null;
        // For the new key, we create a new key crypter according to the desired parameters.
        final KeyCrypterScrypt keyCrypter = new KeyCrypterScrypt(application.scryptIterationsTarget());
        final KeyParameter newKey = newPassword != null ? keyCrypter.deriveKey(newPassword) : null;
        handler.post(() -> {
            // Decrypt from old password
            if (wallet.isEncrypted()) {
                if (oldKey == null) {
                    log.info("wallet is encrypted, but did not provide spending password");
                    state = State.INPUT;
                    oldPasswordView.requestFocus();
                } else {
                    try {
                        wallet.decrypt(oldKey);
                        state = State.DONE;
                        log.info("wallet successfully decrypted");
                    } catch (final Wallet.BadWalletEncryptionKeyException x) {
                        log.info("wallet decryption failed, bad spending password: " + x.getMessage());
                        badPasswordView.setVisibility(View.VISIBLE);
                        state = State.INPUT;
                        oldPasswordView.requestFocus();
                    }
                }
            }
            // Use opportunity to maybe upgrade wallet
            if (wallet.isDeterministicUpgradeRequired(Constants.UPGRADE_OUTPUT_SCRIPT_TYPE) && !wallet.isEncrypted())
                wallet.upgradeToDeterministic(Constants.UPGRADE_OUTPUT_SCRIPT_TYPE, null);
            // Encrypt to new password
            if (newKey != null && !wallet.isEncrypted()) {
                wallet.encrypt(keyCrypter, newKey);
                config.updateLastEncryptKeysTime();
                log.info("wallet successfully encrypted, using key derived by new spending password ({} scrypt iterations)", keyCrypter.getScryptParameters().getN());
                state = State.DONE;
            }
            updateView();
            if (state == State.DONE) {
                WalletUtils.autoBackupWallet(activity, wallet);
                // trigger load manually because of missing callbacks for encryption state
                activityViewModel.walletEncrypted.load();
                handler.postDelayed(() -> dismiss(), 2000);
            }
        });
    });
}

Example 17 with Wallet

use of org.bitcoinj.wallet.Wallet in project bitcoin-wallet by bitcoin-wallet.

the class BlockchainService method onCreate.

@Override
public void onCreate() {
    serviceUpTime = Stopwatch.createStarted();
    log.debug(".onCreate()");
    super.onCreate();
    application = (WalletApplication) getApplication();
    config = application.getConfiguration();
    pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
    nm = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    wakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, getClass().getName());
    log.info("acquiring {}", wakeLock);
    wakeLock.acquire();
    connectivityNotification.setColor(getColor(R.color.fg_network_significant));
    connectivityNotification.setContentTitle(getString(config.isTrustedPeersOnly() ? R.string.notification_connectivity_syncing_trusted_peer : R.string.notification_connectivity_syncing_message));
    connectivityNotification.setContentIntent(PendingIntent.getActivity(BlockchainService.this, 0, new Intent(BlockchainService.this, WalletActivity.class), 0));
    connectivityNotification.setWhen(System.currentTimeMillis());
    connectivityNotification.setOngoing(true);
    connectivityNotification.setPriority(NotificationCompat.PRIORITY_LOW);
    startForeground(0);
    backgroundThread = new HandlerThread("backgroundThread", Process.THREAD_PRIORITY_BACKGROUND);
    backgroundThread.start();
    backgroundHandler = new Handler(backgroundThread.getLooper());
    addressBookDao = AddressBookDatabase.getDatabase(application).addressBookDao();
    blockChainFile = new File(getDir("blockstore", Context.MODE_PRIVATE), Constants.Files.BLOCKCHAIN_FILENAME);
    config.registerOnSharedPreferenceChangeListener(preferenceChangeListener);
    registerReceiver(deviceIdleModeReceiver, new IntentFilter(PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED));
    peerConnectivityListener = new PeerConnectivityListener();
    broadcastPeerState(0);
    final WalletBalanceLiveData walletBalance = new WalletBalanceLiveData(application);
    final SelectedExchangeRateLiveData exchangeRate = new SelectedExchangeRateLiveData(application);
    walletBalance.observe(this, balance -> {
        final ExchangeRateEntry rate = exchangeRate.getValue();
        if (balance != null)
            WalletBalanceWidgetProvider.updateWidgets(BlockchainService.this, balance, rate != null ? rate.exchangeRate() : null);
    });
    exchangeRate.observe(this, rate -> {
        final Coin balance = walletBalance.getValue();
        if (balance != null)
            WalletBalanceWidgetProvider.updateWidgets(BlockchainService.this, balance, rate != null ? rate.exchangeRate() : null);
    });
    wallet = new WalletLiveData(application);
    wallet.observe(this, new Observer<Wallet>() {

        @Override
        public void onChanged(final Wallet wallet) {
            BlockchainService.this.wallet.removeObserver(this);
            final boolean blockChainFileExists = blockChainFile.exists();
            if (!blockChainFileExists) {
                log.info("blockchain does not exist, resetting wallet");
                wallet.reset();
            }
            try {
                blockStore = new SPVBlockStore(Constants.NETWORK_PARAMETERS, blockChainFile, Constants.Files.BLOCKCHAIN_STORE_CAPACITY, true);
                // detect corruptions as early as possible
                blockStore.getChainHead();
                final long earliestKeyCreationTimeSecs = wallet.getEarliestKeyCreationTime();
                if (!blockChainFileExists && earliestKeyCreationTimeSecs > 0) {
                    try {
                        log.info("loading checkpoints for birthdate {} from '{}'", Utils.dateTimeFormat(earliestKeyCreationTimeSecs * 1000), Constants.Files.CHECKPOINTS_ASSET);
                        final Stopwatch watch = Stopwatch.createStarted();
                        final InputStream checkpointsInputStream = getAssets().open(Constants.Files.CHECKPOINTS_ASSET);
                        CheckpointManager.checkpoint(Constants.NETWORK_PARAMETERS, checkpointsInputStream, blockStore, earliestKeyCreationTimeSecs);
                        watch.stop();
                        log.info("checkpoints loaded, took {}", watch);
                    } catch (final IOException x) {
                        log.error("problem reading checkpoints, continuing without", x);
                    }
                }
            } catch (final BlockStoreException x) {
                blockChainFile.delete();
                final String msg = "blockstore cannot be created";
                log.error(msg, x);
                throw new Error(msg, x);
            }
            try {
                blockChain = new BlockChain(Constants.NETWORK_PARAMETERS, wallet, blockStore);
            } catch (final BlockStoreException x) {
                throw new Error("blockchain cannot be created", x);
            }
            observeLiveDatasThatAreDependentOnWalletAndBlockchain();
        }
    });
}

Example 18 with Wallet

use of org.bitcoinj.wallet.Wallet in project bitcoin-wallet by bitcoin-wallet.

the class SendCoinsFragment method signAndSendPayment.

private void signAndSendPayment(final KeyParameter encryptionKey) {
    setState(SendCoinsViewModel.State.SIGNING);
    // final payment intent
    final PaymentIntent finalPaymentIntent = viewModel.paymentIntent.mergeWithEditedValues(amountCalculatorLink.getAmount(), viewModel.validatedAddress != null ? viewModel.validatedAddress.address : null);
    final Coin finalAmount = finalPaymentIntent.getAmount();
    // prepare send request
    final Map<FeeCategory, Coin> fees = viewModel.dynamicFees.getValue();
    final Wallet wallet = walletActivityViewModel.wallet.getValue();
    final SendRequest sendRequest = finalPaymentIntent.toSendRequest();
    sendRequest.emptyWallet = viewModel.paymentIntent.mayEditAmount() && finalAmount.equals(wallet.getBalance(BalanceType.AVAILABLE));
    sendRequest.feePerKb = fees.get(viewModel.feeCategory);
    sendRequest.memo = viewModel.paymentIntent.memo;
    sendRequest.exchangeRate = amountCalculatorLink.getExchangeRate();
    sendRequest.aesKey = encryptionKey;
    final Coin fee = viewModel.dryrunTransaction.getFee();
    if (fee.isGreaterThan(finalAmount)) {
        setState(SendCoinsViewModel.State.INPUT);
        final MonetaryFormat btcFormat = config.getFormat();
        final DialogBuilder dialog = DialogBuilder.warn(activity, R.string.send_coins_fragment_significant_fee_title, R.string.send_coins_fragment_significant_fee_message, btcFormat.format(fee), btcFormat.format(finalAmount));
        dialog.setPositiveButton(R.string.send_coins_fragment_button_send, (d, which) -> sendPayment(sendRequest, finalAmount));
        dialog.setNegativeButton(R.string.button_cancel, null);
        dialog.show();
    } else {
        sendPayment(sendRequest, finalAmount);
    }
}

Example 19 with Wallet

use of org.bitcoinj.wallet.Wallet in project bitcoin-wallet by bitcoin-wallet.

the class SendCoinsFragment method updateView.

private void updateView() {
    final Wallet wallet = walletActivityViewModel.wallet.getValue();
    final Map<FeeCategory, Coin> fees = viewModel.dynamicFees.getValue();
    final BlockchainState blockchainState = application.blockchainState.getValue();
    final Map<String, AddressBookEntry> addressBook = AddressBookEntry.asMap(viewModel.addressBook.getValue());
    if (viewModel.paymentIntent != null) {
        final MonetaryFormat btcFormat = config.getFormat();
        getView().setVisibility(View.VISIBLE);
        if (viewModel.paymentIntent.hasPayee()) {
            payeeNameView.setVisibility(View.VISIBLE);
            payeeNameView.setText(viewModel.paymentIntent.payeeName);
            payeeVerifiedByView.setVisibility(View.VISIBLE);
            final String verifiedBy = viewModel.paymentIntent.payeeVerifiedBy != null ? viewModel.paymentIntent.payeeVerifiedBy : getString(R.string.send_coins_fragment_payee_verified_by_unknown);
            payeeVerifiedByView.setText(Constants.CHAR_CHECKMARK + String.format(getString(R.string.send_coins_fragment_payee_verified_by), verifiedBy));
        } else {
            payeeNameView.setVisibility(View.GONE);
            payeeVerifiedByView.setVisibility(View.GONE);
        }
        if (viewModel.paymentIntent.hasOutputs()) {
            payeeGroup.setVisibility(View.VISIBLE);
            receivingAddressView.setVisibility(View.GONE);
            receivingStaticView.setVisibility(!viewModel.paymentIntent.hasPayee() || viewModel.paymentIntent.payeeVerifiedBy == null ? View.VISIBLE : View.GONE);
            receivingStaticLabelView.setText(viewModel.paymentIntent.memo);
            if (viewModel.paymentIntent.hasAddress())
                receivingStaticAddressView.setText(WalletUtils.formatAddress(viewModel.paymentIntent.getAddress(), Constants.ADDRESS_FORMAT_GROUP_SIZE, Constants.ADDRESS_FORMAT_LINE_SIZE));
            else
                receivingStaticAddressView.setText(R.string.send_coins_fragment_receiving_address_complex);
        } else if (viewModel.validatedAddress != null) {
            payeeGroup.setVisibility(View.VISIBLE);
            receivingAddressView.setVisibility(View.GONE);
            receivingStaticView.setVisibility(View.VISIBLE);
            receivingStaticAddressView.setText(WalletUtils.formatAddress(viewModel.validatedAddress.address, Constants.ADDRESS_FORMAT_GROUP_SIZE, Constants.ADDRESS_FORMAT_LINE_SIZE));
            final String addressBookLabel = addressBookDao.resolveLabel(viewModel.validatedAddress.address.toString());
            final String staticLabel;
            if (addressBookLabel != null)
                staticLabel = addressBookLabel;
            else if (viewModel.validatedAddress.label != null)
                staticLabel = viewModel.validatedAddress.label;
            else
                staticLabel = getString(R.string.address_unlabeled);
            receivingStaticLabelView.setText(staticLabel);
            receivingStaticLabelView.setTextColor(activity.getColor(viewModel.validatedAddress.label != null ? R.color.fg_significant : R.color.fg_insignificant));
        } else if (viewModel.paymentIntent.standard == null) {
            payeeGroup.setVisibility(View.VISIBLE);
            receivingStaticView.setVisibility(View.GONE);
            receivingAddressView.setVisibility(View.VISIBLE);
        } else {
            payeeGroup.setVisibility(View.GONE);
        }
        receivingAddressView.setEnabled(viewModel.state == SendCoinsViewModel.State.INPUT);
        amountGroup.setVisibility(viewModel.paymentIntent.hasAmount() || (viewModel.state != null && viewModel.state.compareTo(SendCoinsViewModel.State.INPUT) >= 0) ? View.VISIBLE : View.GONE);
        amountCalculatorLink.setEnabled(viewModel.state == SendCoinsViewModel.State.INPUT && viewModel.paymentIntent.mayEditAmount());
        final boolean directPaymentVisible;
        if (viewModel.paymentIntent.hasPaymentUrl()) {
            if (viewModel.paymentIntent.isBluetoothPaymentUrl())
                directPaymentVisible = bluetoothAdapter != null;
            else
                directPaymentVisible = true;
        } else {
            directPaymentVisible = false;
        }
        directPaymentEnableView.setVisibility(directPaymentVisible ? View.VISIBLE : View.GONE);
        directPaymentEnableView.setEnabled(viewModel.state == SendCoinsViewModel.State.INPUT);
        hintView.setVisibility(View.GONE);
        if (viewModel.state == SendCoinsViewModel.State.INPUT) {
            if (blockchainState != null && blockchainState.replaying) {
                hintView.setTextColor(activity.getColor(R.color.fg_error));
                hintView.setVisibility(View.VISIBLE);
                hintView.setText(R.string.send_coins_fragment_hint_replaying);
            } else if (viewModel.paymentIntent.mayEditAddress() && viewModel.validatedAddress == null && !receivingAddressView.getText().toString().trim().isEmpty()) {
                hintView.setTextColor(activity.getColor(R.color.fg_error));
                hintView.setVisibility(View.VISIBLE);
                hintView.setText(R.string.send_coins_fragment_receiving_address_error);
            } else if (viewModel.dryrunException != null) {
                hintView.setTextColor(activity.getColor(R.color.fg_error));
                hintView.setVisibility(View.VISIBLE);
                if (viewModel.dryrunException instanceof DustySendRequested)
                    hintView.setText(getString(R.string.send_coins_fragment_hint_dusty_send));
                else if (viewModel.dryrunException instanceof InsufficientMoneyException)
                    hintView.setText(getString(R.string.send_coins_fragment_hint_insufficient_money, btcFormat.format(((InsufficientMoneyException) viewModel.dryrunException).missing)));
                else if (viewModel.dryrunException instanceof CouldNotAdjustDownwards)
                    hintView.setText(getString(R.string.send_coins_fragment_hint_empty_wallet_failed));
                else
                    hintView.setText(viewModel.dryrunException.toString());
            } else if (viewModel.dryrunTransaction != null && viewModel.dryrunTransaction.getFee() != null) {
                hintView.setVisibility(View.VISIBLE);
                final int hintResId;
                final int colorResId;
                if (viewModel.feeCategory == FeeCategory.ECONOMIC) {
                    hintResId = R.string.send_coins_fragment_hint_fee_economic;
                    colorResId = R.color.fg_less_significant;
                } else if (viewModel.feeCategory == FeeCategory.PRIORITY) {
                    hintResId = R.string.send_coins_fragment_hint_fee_priority;
                    colorResId = R.color.fg_less_significant;
                } else {
                    hintResId = R.string.send_coins_fragment_hint_fee;
                    colorResId = R.color.fg_insignificant;
                }
                hintView.setTextColor(activity.getColor(colorResId));
                hintView.setText(getString(hintResId, btcFormat.format(viewModel.dryrunTransaction.getFee())));
            } else if (viewModel.paymentIntent.mayEditAddress() && viewModel.validatedAddress != null && wallet != null && wallet.isAddressMine(viewModel.validatedAddress.address)) {
                hintView.setTextColor(activity.getColor(R.color.fg_insignificant));
                hintView.setVisibility(View.VISIBLE);
                hintView.setText(R.string.send_coins_fragment_receiving_address_own);
            }
        }
        final Transaction sentTransaction = viewModel.sentTransaction.getValue();
        if (sentTransaction != null && wallet != null) {
            sentTransactionView.setVisibility(View.VISIBLE);
            sentTransactionViewHolder.fullBind(new TransactionsAdapter.ListItem.TransactionItem(activity, sentTransaction, wallet, addressBook, btcFormat, application.maxConnectedPeers()));
        } else {
            sentTransactionView.setVisibility(View.GONE);
        }
        if (viewModel.directPaymentAck != null) {
            directPaymentMessageView.setVisibility(View.VISIBLE);
            directPaymentMessageView.setText(viewModel.directPaymentAck ? R.string.send_coins_fragment_direct_payment_ack : R.string.send_coins_fragment_direct_payment_nack);
        } else {
            directPaymentMessageView.setVisibility(View.GONE);
        }
        viewCancel.setEnabled(viewModel.state != SendCoinsViewModel.State.REQUEST_PAYMENT_REQUEST && viewModel.state != SendCoinsViewModel.State.DECRYPTING && viewModel.state != SendCoinsViewModel.State.SIGNING);
        viewGo.setEnabled(everythingPlausible() && viewModel.dryrunTransaction != null && wallet != null && fees != null && (blockchainState == null || !blockchainState.replaying));
        if (viewModel.state == null || viewModel.state == SendCoinsViewModel.State.REQUEST_PAYMENT_REQUEST) {
            viewCancel.setText(R.string.button_cancel);
            viewGo.setText(null);
        } else if (viewModel.state == SendCoinsViewModel.State.INPUT) {
            viewCancel.setText(R.string.button_cancel);
            viewGo.setText(R.string.send_coins_fragment_button_send);
        } else if (viewModel.state == SendCoinsViewModel.State.DECRYPTING) {
            viewCancel.setText(R.string.button_cancel);
            viewGo.setText(R.string.send_coins_fragment_state_decrypting);
        } else if (viewModel.state == SendCoinsViewModel.State.SIGNING) {
            viewCancel.setText(R.string.button_cancel);
            viewGo.setText(R.string.send_coins_preparation_msg);
        } else if (viewModel.state == SendCoinsViewModel.State.SENDING) {
            viewCancel.setText(R.string.send_coins_fragment_button_back);
            viewGo.setText(R.string.send_coins_sending_msg);
        } else if (viewModel.state == SendCoinsViewModel.State.SENT) {
            viewCancel.setText(R.string.send_coins_fragment_button_back);
            viewGo.setText(R.string.send_coins_sent_msg);
        } else if (viewModel.state == SendCoinsViewModel.State.FAILED) {
            viewCancel.setText(R.string.send_coins_fragment_button_back);
            viewGo.setText(R.string.send_coins_failed_msg);
        }
        final boolean privateKeyPasswordViewVisible = (viewModel.state == SendCoinsViewModel.State.INPUT || viewModel.state == SendCoinsViewModel.State.DECRYPTING) && wallet != null && wallet.isEncrypted();
        privateKeyPasswordViewGroup.setVisibility(privateKeyPasswordViewVisible ? View.VISIBLE : View.GONE);
        privateKeyPasswordView.setEnabled(viewModel.state == SendCoinsViewModel.State.INPUT);
        // focus linking
        final int activeAmountViewId = amountCalculatorLink.activeTextView().getId();
        receivingAddressView.setNextFocusDownId(activeAmountViewId);
        receivingAddressView.setNextFocusForwardId(activeAmountViewId);
        amountCalculatorLink.setNextFocusId(privateKeyPasswordViewVisible ? R.id.send_coins_private_key_password : R.id.send_coins_go);
        privateKeyPasswordView.setNextFocusUpId(activeAmountViewId);
        privateKeyPasswordView.setNextFocusDownId(R.id.send_coins_go);
        privateKeyPasswordView.setNextFocusForwardId(R.id.send_coins_go);
        viewGo.setNextFocusUpId(privateKeyPasswordViewVisible ? R.id.send_coins_private_key_password : activeAmountViewId);
    } else {
        getView().setVisibility(View.GONE);
    }
}

Example 20 with Wallet

use of org.bitcoinj.wallet.Wallet in project bitcoin-wallet by bitcoin-wallet.

the class SweepWalletFragment method requestWalletBalance.

private void requestWalletBalance() {
    viewModel.progress.setValue(getString(R.string.sweep_wallet_fragment_request_wallet_balance_progress));
    final RequestWalletBalanceTask.ResultCallback callback = new RequestWalletBalanceTask.ResultCallback() {

        @Override
        public void onResult(final Set<UTXO> utxos) {
            final Wallet wallet = walletActivityViewModel.wallet.getValue();
            viewModel.progress.setValue(null);
            // Filter UTXOs we've already spent and sort the rest.
            final Set<Transaction> walletTxns = wallet.getTransactions(false);
            final Set<UTXO> sortedUtxos = new TreeSet<>(UTXO_COMPARATOR);
            for (final UTXO utxo : utxos) if (!utxoSpentBy(walletTxns, utxo))
                sortedUtxos.add(utxo);
            // Fake transaction funding the wallet to sweep.
            final Map<Sha256Hash, Transaction> fakeTxns = new HashMap<>();
            for (final UTXO utxo : sortedUtxos) {
                Transaction fakeTx = fakeTxns.get(utxo.getHash());
                if (fakeTx == null) {
                    fakeTx = new FakeTransaction(Constants.NETWORK_PARAMETERS, utxo.getHash(), utxo.getHash());
                    fakeTx.getConfidence().setConfidenceType(ConfidenceType.BUILDING);
                    fakeTxns.put(fakeTx.getTxId(), fakeTx);
                }
                final TransactionOutput fakeOutput = new TransactionOutput(Constants.NETWORK_PARAMETERS, fakeTx, utxo.getValue(), utxo.getScript().getProgram());
                // Fill with output dummies as needed.
                while (fakeTx.getOutputs().size() < utxo.getIndex()) fakeTx.addOutput(new TransactionOutput(Constants.NETWORK_PARAMETERS, fakeTx, Coin.NEGATIVE_SATOSHI, new byte[] {}));
                // Add the actual output we will spend later.
                fakeTx.addOutput(fakeOutput);
            }
            final Wallet walletToSweep = viewModel.walletToSweep.getValue();
            walletToSweep.clearTransactions(0);
            for (final Transaction tx : fakeTxns.values()) walletToSweep.addWalletTransaction(new WalletTransaction(WalletTransaction.Pool.UNSPENT, tx));
            log.info("built wallet to sweep:\n{}", walletToSweep.toString(false, false, null, true, false, null));
            viewModel.walletToSweep.setValue(walletToSweep);
        }

        private boolean utxoSpentBy(final Set<Transaction> transactions, final UTXO utxo) {
            for (final Transaction tx : transactions) {
                for (final TransactionInput input : tx.getInputs()) {
                    final TransactionOutPoint outpoint = input.getOutpoint();
                    if (outpoint.getHash().equals(utxo.getHash()) && outpoint.getIndex() == utxo.getIndex())
                        return true;
                }
            }
            return false;
        }

        @Override
        public void onFail(final int messageResId, final Object... messageArgs) {
            viewModel.progress.setValue(null);
            viewModel.showDialogWithRetryRequestBalance.setValue(DialogEvent.warn(R.string.sweep_wallet_fragment_request_wallet_balance_failed_title, messageResId, messageArgs));
        }
    };
    final Wallet walletToSweep = viewModel.walletToSweep.getValue();
    final ECKey key = walletToSweep.getImportedKeys().iterator().next();
    new RequestWalletBalanceTask(backgroundHandler, callback).requestWalletBalance(activity.getAssets(), key);
}