Java tutorial
/* * Copyright 2014-2015 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; import javax.annotation.Nullable; import org.bitcoinj.crypto.KeyCrypterException; import org.bitcoinj.crypto.KeyCrypterScrypt; import org.bitcoinj.wallet.Wallet; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.spongycastle.crypto.params.KeyParameter; import com.google.common.base.Strings; import de.schildbach.wallet.WalletApplication; import de.schildbach.wallet_test.R; import android.app.Activity; import android.app.AlertDialog; import android.app.Dialog; import android.app.DialogFragment; import android.app.FragmentManager; 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.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.CheckBox; import android.widget.EditText; import android.widget.TextView; /** * @author Andreas Schildbach */ public class EncryptKeysDialogFragment extends DialogFragment { private static final String FRAGMENT_TAG = EncryptKeysDialogFragment.class.getName(); public static void show(final FragmentManager fm) { final DialogFragment newFragment = new EncryptKeysDialogFragment(); newFragment.show(fm, FRAGMENT_TAG); } private AbstractWalletActivity activity; private WalletApplication application; private Wallet wallet; @Nullable private AlertDialog dialog; private View oldPasswordGroup; private EditText oldPasswordView; private EditText newPasswordView; private View badPasswordView; private TextView passwordStrengthView; private CheckBox showView; private Button positiveButton, negativeButton; private final Handler handler = new Handler(); private HandlerThread backgroundThread; private Handler backgroundHandler; private enum State { INPUT, CRYPTING, DONE } private State state = State.INPUT; private static final Logger log = LoggerFactory.getLogger(EncryptKeysDialogFragment.class); 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) { } }; @Override public void onAttach(final Activity activity) { super.onAttach(activity); this.activity = (AbstractWalletActivity) activity; this.application = (WalletApplication) activity.getApplication(); this.wallet = application.getWallet(); } @Override public void onCreate(final Bundle savedInstanceState) { super.onCreate(savedInstanceState); 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.encrypt_keys_dialog, null); oldPasswordGroup = view.findViewById(R.id.encrypt_keys_dialog_password_old_group); oldPasswordView = (EditText) view.findViewById(R.id.encrypt_keys_dialog_password_old); oldPasswordView.setText(null); newPasswordView = (EditText) view.findViewById(R.id.encrypt_keys_dialog_password_new); newPasswordView.setText(null); badPasswordView = view.findViewById(R.id.encrypt_keys_dialog_bad_password); passwordStrengthView = (TextView) view.findViewById(R.id.encrypt_keys_dialog_password_strength); showView = (CheckBox) view.findViewById(R.id.encrypt_keys_dialog_show); final DialogBuilder builder = new DialogBuilder(activity); builder.setTitle(R.string.encrypt_keys_dialog_title); builder.setView(view); builder.setPositiveButton(R.string.button_ok, null); // dummy, just to make it show builder.setNegativeButton(R.string.button_cancel, 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(); } }); oldPasswordView.addTextChangedListener(textWatcher); newPasswordView.addTextChangedListener(textWatcher); showView = (CheckBox) dialog.findViewById(R.id.encrypt_keys_dialog_show); showView.setOnCheckedChangeListener( new ShowPasswordCheckListener(newPasswordView, oldPasswordView)); showView.setChecked(true); EncryptKeysDialogFragment.this.dialog = dialog; updateView(); } }); return dialog; } @Override public void onResume() { super.onResume(); updateView(); } @Override public void onDismiss(final DialogInterface dialog) { this.dialog = null; oldPasswordView.removeTextChangedListener(textWatcher); newPasswordView.removeTextChangedListener(textWatcher); showView.setOnCheckedChangeListener(null); wipePasswords(); super.onDismiss(dialog); } @Override public void onDestroy() { backgroundThread.getLooper().quit(); super.onDestroy(); } 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(new Runnable() { @Override public void run() { // For the old key, we use the key crypter that was used to derive the password in the first // place. final KeyParameter oldKey = oldPassword != null ? wallet.getKeyCrypter().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(new Runnable() { @Override public void run() { 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 KeyCrypterException x) { log.info("wallet decryption failed: " + x.getMessage()); badPasswordView.setVisibility(View.VISIBLE); state = State.INPUT; oldPasswordView.requestFocus(); } } } if (newKey != null && !wallet.isEncrypted()) { wallet.encrypt(keyCrypter, newKey); 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) { application.backupWallet(); delayedDismiss(); } } private void delayedDismiss() { handler.postDelayed(new Runnable() { @Override public void run() { dismiss(); } }, 2000); } }); } }); } private void wipePasswords() { oldPasswordView.setText(null); newPasswordView.setText(null); } private void updateView() { if (dialog == null) return; final boolean hasOldPassword = !oldPasswordView.getText().toString().trim().isEmpty(); final boolean hasPassword = !newPasswordView.getText().toString().trim().isEmpty(); oldPasswordGroup.setVisibility(wallet.isEncrypted() ? View.VISIBLE : View.GONE); oldPasswordView.setEnabled(state == State.INPUT); newPasswordView.setEnabled(state == State.INPUT); final int passwordLength = newPasswordView.getText().length(); passwordStrengthView .setVisibility(state == State.INPUT && passwordLength > 0 ? View.VISIBLE : View.INVISIBLE); if (passwordLength < 4) { passwordStrengthView.setText(R.string.encrypt_keys_dialog_password_strength_weak); passwordStrengthView.setTextColor(getResources().getColor(R.color.fg_password_strength_weak)); } else if (passwordLength < 6) { passwordStrengthView.setText(R.string.encrypt_keys_dialog_password_strength_fair); passwordStrengthView.setTextColor(getResources().getColor(R.color.fg_password_strength_fair)); } else if (passwordLength < 8) { passwordStrengthView.setText(R.string.encrypt_keys_dialog_password_strength_good); passwordStrengthView.setTextColor(getResources().getColor(R.color.fg_less_significant)); } else { passwordStrengthView.setText(R.string.encrypt_keys_dialog_password_strength_strong); passwordStrengthView.setTextColor(getResources().getColor(R.color.fg_password_strength_strong)); } showView.setEnabled(state == State.INPUT); if (state == State.INPUT) { if (wallet.isEncrypted()) { positiveButton.setText(hasPassword ? R.string.button_edit : R.string.button_remove); positiveButton.setEnabled(hasOldPassword); } else { positiveButton.setText(R.string.button_set); positiveButton.setEnabled(hasPassword); } negativeButton.setEnabled(true); } else if (state == State.CRYPTING) { positiveButton.setText(newPasswordView.getText().toString().trim().isEmpty() ? R.string.encrypt_keys_dialog_state_decrypting : R.string.encrypt_keys_dialog_state_encrypting); positiveButton.setEnabled(false); negativeButton.setEnabled(false); } else if (state == State.DONE) { positiveButton.setText(R.string.encrypt_keys_dialog_state_done); positiveButton.setEnabled(false); negativeButton.setEnabled(false); } } }