Java tutorial
/* * Copyright 2015 the original author or authors. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package de.schildbach.wallet.ui.send; import static android.support.v4.util.Preconditions.checkNotNull; import java.util.Map; import javax.annotation.Nullable; import org.bitcoinj.core.Coin; import org.bitcoinj.core.Sha256Hash; import org.bitcoinj.core.Transaction; import org.bitcoinj.core.TransactionOutput; import org.bitcoinj.crypto.KeyCrypterException; import org.bitcoinj.wallet.KeyChain.KeyPurpose; import org.bitcoinj.wallet.SendRequest; import org.bitcoinj.wallet.Wallet; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.spongycastle.crypto.params.KeyParameter; import de.schildbach.wallet.Configuration; import de.schildbach.wallet.Constants; import de.schildbach.wallet.R; import de.schildbach.wallet.WalletApplication; import de.schildbach.wallet.data.DynamicFeeLiveData; import de.schildbach.wallet.service.BlockchainService; import de.schildbach.wallet.ui.AbstractWalletActivity; import de.schildbach.wallet.ui.DialogBuilder; import de.schildbach.wallet.util.WalletUtils; import android.app.AlertDialog; import android.app.Application; import android.app.Dialog; import android.arch.lifecycle.AndroidViewModel; import android.arch.lifecycle.Observer; import android.arch.lifecycle.ViewModelProviders; import android.content.Context; import android.content.DialogInterface; import android.content.DialogInterface.OnShowListener; import android.graphics.Typeface; import android.os.Bundle; import android.os.Handler; import android.os.HandlerThread; import android.os.Process; import android.support.v4.app.DialogFragment; import android.support.v4.app.FragmentManager; import android.text.Editable; import android.text.TextWatcher; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; /** * @author Andreas Schildbach */ public class RaiseFeeDialogFragment extends DialogFragment { private static final String FRAGMENT_TAG = RaiseFeeDialogFragment.class.getName(); private static final String KEY_TRANSACTION = "transaction"; public static void show(final FragmentManager fm, final Transaction tx) { final DialogFragment newFragment = instance(tx); newFragment.show(fm, FRAGMENT_TAG); } private static RaiseFeeDialogFragment instance(final Transaction tx) { final RaiseFeeDialogFragment fragment = new RaiseFeeDialogFragment(); final Bundle args = new Bundle(); args.putSerializable(KEY_TRANSACTION, tx.getHash().getBytes()); fragment.setArguments(args); return fragment; } private AbstractWalletActivity activity; private WalletApplication application; private Configuration config; private Wallet wallet; private Coin feeRaise = null; private Transaction transaction; @Nullable private AlertDialog dialog; private TextView messageView; private View passwordGroup; private EditText passwordView; private View badPasswordView; private Button positiveButton, negativeButton; private ViewModel viewModel; private HandlerThread backgroundThread; private Handler backgroundHandler; private enum State { INPUT, DECRYPTING, DONE } private State state = State.INPUT; private static final Logger log = LoggerFactory.getLogger(RaiseFeeDialogFragment.class); public static class ViewModel extends AndroidViewModel { private final WalletApplication application; private DynamicFeeLiveData dynamicFees; public ViewModel(final Application application) { super(application); this.application = (WalletApplication) application; } public DynamicFeeLiveData getDynamicFees() { if (dynamicFees == null) dynamicFees = new DynamicFeeLiveData(application); return dynamicFees; } } @Override public void onAttach(final Context context) { super.onAttach(context); this.activity = (AbstractWalletActivity) context; this.application = activity.getWalletApplication(); this.config = application.getConfiguration(); this.wallet = application.getWallet(); } @Override public void onCreate(final Bundle savedInstanceState) { super.onCreate(savedInstanceState); viewModel = ViewModelProviders.of(this).get(ViewModel.class); viewModel.getDynamicFees().observe(this, new Observer<Map<FeeCategory, Coin>>() { @Override public void onChanged(final Map<FeeCategory, Coin> dynamicFees) { // We basically have to pay fee for two transactions: // The transaction to raise the fee of and the CPFP transaction we're about to create. final int size = transaction.getMessageSize() + 192; feeRaise = dynamicFees.get(FeeCategory.PRIORITY).multiply(size).divide(1000); updateView(); } }); final Bundle args = getArguments(); final byte[] txHash = (byte[]) args.getSerializable(KEY_TRANSACTION); transaction = checkNotNull(wallet.getTransaction(Sha256Hash.wrap(txHash))); backgroundThread = new HandlerThread("backgroundThread", Process.THREAD_PRIORITY_BACKGROUND); backgroundThread.start(); backgroundHandler = new Handler(backgroundThread.getLooper()); } @Override public Dialog onCreateDialog(final Bundle savedInstanceState) { final View view = LayoutInflater.from(activity).inflate(R.layout.raise_fee_dialog, null); messageView = (TextView) view.findViewById(R.id.raise_fee_dialog_message); passwordGroup = view.findViewById(R.id.raise_fee_dialog_password_group); passwordView = (EditText) view.findViewById(R.id.raise_fee_dialog_password); passwordView.setText(null); badPasswordView = view.findViewById(R.id.raise_fee_dialog_bad_password); final DialogBuilder builder = new DialogBuilder(activity); builder.setTitle(R.string.raise_fee_dialog_title); builder.setView(view); // dummies, just to make buttons show builder.setPositiveButton(R.string.raise_fee_dialog_button_raise, null); builder.setNegativeButton(R.string.button_dismiss, null); builder.setCancelable(false); final AlertDialog dialog = builder.create(); dialog.setCanceledOnTouchOutside(false); dialog.setOnShowListener(new OnShowListener() { @Override public void onShow(final DialogInterface d) { positiveButton = dialog.getButton(DialogInterface.BUTTON_POSITIVE); negativeButton = dialog.getButton(DialogInterface.BUTTON_NEGATIVE); positiveButton.setTypeface(Typeface.DEFAULT_BOLD); positiveButton.setOnClickListener(new OnClickListener() { @Override public void onClick(final View v) { handleGo(); } }); negativeButton.setOnClickListener(new OnClickListener() { @Override public void onClick(final View v) { dismissAllowingStateLoss(); } }); passwordView.addTextChangedListener(textWatcher); RaiseFeeDialogFragment.this.dialog = dialog; updateView(); } }); log.info("showing raise fee dialog"); return dialog; } @Override public void onDismiss(final DialogInterface dialog) { this.dialog = null; wipePasswords(); super.onDismiss(dialog); } @Override public void onDestroy() { backgroundThread.getLooper().quit(); super.onDestroy(); } private void handleGo() { state = State.DECRYPTING; updateView(); if (wallet.isEncrypted()) { new DeriveKeyTask(backgroundHandler, application.scryptIterationsTarget()) { @Override protected void onSuccess(final KeyParameter encryptionKey, final boolean wasChanged) { if (wasChanged) WalletUtils.autoBackupWallet(activity, wallet); doRaiseFee(encryptionKey); } }.deriveKey(wallet, passwordView.getText().toString().trim()); updateView(); } else { doRaiseFee(null); } } private void doRaiseFee(final KeyParameter encryptionKey) { // construct child-pays-for-parent final TransactionOutput outputToSpend = checkNotNull(findSpendableOutput(wallet, transaction, feeRaise)); final Transaction transactionToSend = new Transaction(Constants.NETWORK_PARAMETERS); transactionToSend.addInput(outputToSpend); transactionToSend.addOutput(outputToSpend.getValue().subtract(feeRaise), wallet.freshAddress(KeyPurpose.CHANGE)); transactionToSend.setPurpose(Transaction.Purpose.RAISE_FEE); final SendRequest sendRequest = SendRequest.forTx(transactionToSend); sendRequest.aesKey = encryptionKey; try { wallet.signTransaction(sendRequest); log.info("raise fee: cpfp {}", transactionToSend); wallet.commitTx(transactionToSend); BlockchainService.broadcastTransaction(activity, transactionToSend); state = State.DONE; updateView(); dismiss(); } catch (final KeyCrypterException x) { badPasswordView.setVisibility(View.VISIBLE); state = State.INPUT; updateView(); passwordView.requestFocus(); log.info("raise fee: bad spending password"); } } private void wipePasswords() { passwordView.setText(null); } private void updateView() { if (dialog == null) return; final boolean needsPassword = wallet.isEncrypted(); if (feeRaise == null) { messageView.setText(R.string.raise_fee_dialog_determining_fee); passwordGroup.setVisibility(View.GONE); } else if (findSpendableOutput(wallet, transaction, feeRaise) == null) { messageView.setText(R.string.raise_fee_dialog_cant_raise); passwordGroup.setVisibility(View.GONE); } else { messageView.setText(getString(R.string.raise_fee_dialog_message, config.getFormat().format(feeRaise))); passwordGroup.setVisibility(needsPassword ? View.VISIBLE : View.GONE); } if (state == State.INPUT) { positiveButton.setText(R.string.raise_fee_dialog_button_raise); positiveButton.setEnabled((!needsPassword || passwordView.getText().toString().trim().length() > 0) && feeRaise != null && findSpendableOutput(wallet, transaction, feeRaise) != null); negativeButton.setEnabled(true); } else if (state == State.DECRYPTING) { positiveButton.setText(R.string.raise_fee_dialog_state_decrypting); positiveButton.setEnabled(false); negativeButton.setEnabled(false); } else if (state == State.DONE) { positiveButton.setText(R.string.raise_fee_dialog_state_done); positiveButton.setEnabled(false); negativeButton.setEnabled(false); } } private final TextWatcher textWatcher = new TextWatcher() { @Override public void onTextChanged(final CharSequence s, final int start, final int before, final int count) { badPasswordView.setVisibility(View.INVISIBLE); updateView(); } @Override public void beforeTextChanged(final CharSequence s, final int start, final int count, final int after) { } @Override public void afterTextChanged(final Editable s) { } }; public static boolean feeCanLikelyBeRaised(final Wallet wallet, final Transaction transaction) { if (transaction.getConfidence().getDepthInBlocks() > 0) return false; if (WalletUtils.isPayToManyTransaction(transaction)) return false; // We don't know dynamic fees here, so we need to guess. if (findSpendableOutput(wallet, transaction, Transaction.DEFAULT_TX_FEE) == null) return false; return true; } private static @Nullable TransactionOutput findSpendableOutput(final Wallet wallet, final Transaction transaction, final Coin minimumOutputValue) { for (final TransactionOutput output : transaction.getOutputs()) { if (output.isMine(wallet) && output.isAvailableForSpending() && output.getValue().isGreaterThan(minimumOutputValue)) return output; } return null; } }