Java tutorial
/* * Copyright 2011-2013 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 java.math.BigInteger; import android.app.Activity; import android.app.AlertDialog; import android.app.Dialog; import android.content.DialogInterface; import android.content.SharedPreferences; import android.database.Cursor; import android.os.Bundle; import android.preference.PreferenceManager; import android.support.v4.app.DialogFragment; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.LoaderManager; import android.support.v4.content.Loader; import android.view.LayoutInflater; import android.view.View; import android.widget.TextView; import com.google.bitcoin.core.Utils; import de.schildbach.wallet.Constants; import de.schildbach.wallet.ExchangeRatesProvider; import de.schildbach.wallet.ExchangeRatesProvider.ExchangeRate; import de.schildbach.wallet.util.GenericUtils; import de.schildbach.wallet.util.WalletUtils; import de.schildbach.wallet_test.R; /** * @author Andreas Schildbach */ public final class AmountCalculatorFragment extends DialogFragment implements LoaderManager.LoaderCallbacks<Cursor> { public static interface Listener { void useCalculatedAmount(final BigInteger amount); } private static final String FRAGMENT_TAG = AmountCalculatorFragment.class.getName(); public static void calculate(final FragmentManager fm, final Listener listener) { final DialogFragment newFragment = new AmountCalculatorFragment(); newFragment.setTargetFragment((Fragment) listener, 0); newFragment.show(fm, FRAGMENT_TAG); } private AbstractWalletActivity activity; private LayoutInflater inflater; private SharedPreferences prefs; private LoaderManager loaderManager; private int precision; private ExchangeRate exchangeRate; private boolean exchangeDirection = true; private CurrencyAmountView btcAmountView, localAmountView; private TextView exchangeRateView; @Override public void onAttach(final Activity activity) { super.onAttach(activity); this.activity = (AbstractWalletActivity) activity; this.inflater = LayoutInflater.from(activity); this.prefs = PreferenceManager.getDefaultSharedPreferences(activity); this.loaderManager = getLoaderManager(); } @Override public Dialog onCreateDialog(final Bundle savedInstanceState) { precision = Integer.parseInt( prefs.getString(Constants.PREFS_KEY_BTC_PRECISION, Integer.toString(Constants.BTC_PRECISION))); final AlertDialog.Builder dialog = new AlertDialog.Builder(activity); dialog.setInverseBackgroundForced(true); dialog.setTitle(R.string.amount_calculator_dialog_title); final View view = inflater.inflate(R.layout.amount_calculator_dialog, null); btcAmountView = (CurrencyAmountView) view.findViewById(R.id.amount_calculator_row_btc); btcAmountView.setListener(new CurrencyAmountView.Listener() { public void changed() { if (btcAmountView.getAmount() != null) { exchangeDirection = true; updateAppearance(); } else { localAmountView.setHint(null); } } public void done() { AmountCalculatorFragment.this.done(); } public void focusChanged(final boolean hasFocus) { } }); localAmountView = (CurrencyAmountView) view.findViewById(R.id.amount_calculator_row_local); localAmountView.setPrecision(Constants.LOCAL_PRECISION); localAmountView.setListener(new CurrencyAmountView.Listener() { public void changed() { if (localAmountView.getAmount() != null) { exchangeDirection = false; updateAppearance(); } else { btcAmountView.setHint(null); } } public void done() { AmountCalculatorFragment.this.done(); } public void focusChanged(final boolean hasFocus) { } }); exchangeRateView = (TextView) view.findViewById(R.id.amount_calculator_rate); dialog.setView(view); dialog.setPositiveButton(R.string.amount_calculator_dialog_button_use, new DialogInterface.OnClickListener() { public void onClick(final DialogInterface dialog, final int whichButton) { done(); } }); dialog.setNegativeButton(R.string.button_cancel, new DialogInterface.OnClickListener() { public void onClick(final DialogInterface dialog, final int whichButton) { dismiss(); } }); updateAppearance(); loaderManager.initLoader(0, null, this); return dialog.create(); } private void updateAppearance() { if (exchangeRate != null) { localAmountView.setEnabled(true); localAmountView.setCurrencyCode(exchangeRate.currencyCode); if (exchangeDirection) { final BigInteger btcAmount = btcAmountView.getAmount(); if (btcAmount != null) { localAmountView.setAmount(null, false); localAmountView.setHint(WalletUtils.localValue(btcAmount, exchangeRate.rate)); btcAmountView.setHint(null); } } else { final BigInteger localAmount = localAmountView.getAmount(); if (localAmount != null) { btcAmountView.setAmount(null, false); btcAmountView.setHint(WalletUtils.btcValue(localAmount, exchangeRate.rate)); localAmountView.setHint(null); } } exchangeRateView.setText(getString(R.string.amount_calculator_dialog_exchange_rate, exchangeRate.currencyCode, GenericUtils.formatValue(WalletUtils.localValue(Utils.COIN, exchangeRate.rate), precision), exchangeRate.source)); } else { localAmountView.setEnabled(false); exchangeRateView.setText(R.string.amount_calculator_dialog_exchange_rate_not_available); } } private void done() { final BigInteger amount = exchangeDirection ? btcAmountView.getAmount() : WalletUtils.btcValue(localAmountView.getAmount(), exchangeRate.rate); ((Listener) getTargetFragment()).useCalculatedAmount(amount); dismiss(); } public Loader<Cursor> onCreateLoader(final int id, final Bundle args) { return new ExchangeRateLoader(activity); } public void onLoadFinished(final Loader<Cursor> loader, final Cursor data) { if (data != null) { data.moveToFirst(); exchangeRate = ExchangeRatesProvider.getExchangeRate(data); updateAppearance(); } } public void onLoaderReset(final Loader<Cursor> loader) { } }