AmountCalculatorFragment.java

/*
 * 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.digitalcoin.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.CursorLoader;
import android.support.v4.content.Loader;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.TextView;

import com.google.digitalcoin.core.Utils;

import de.schildbach.wallet.digitalcoin.Constants;
import de.schildbach.wallet.digitalcoin.ExchangeRatesProvider;
import de.schildbach.wallet.digitalcoin.ExchangeRatesProvider.ExchangeRate;
import de.schildbach.wallet.digitalcoin.util.WalletUtils;
import de.schildbach.wallet.digitalcoin.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 String exchangeCurrency;
	private int precision;

	private ExchangeRate exchangeRate;
	private boolean exchangeDirection = true;
	private CurrencyAmountView ltcAmountView, 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)
	{
		exchangeCurrency = prefs.getString(Constants.PREFS_KEY_EXCHANGE_CURRENCY, Constants.DEFAULT_EXCHANGE_CURRENCY);
		precision = Integer.parseInt(prefs.getString(Constants.PREFS_KEY_WDC_PRECISION, Integer.toString(Constants.WDC_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);

		ltcAmountView = (CurrencyAmountView) view.findViewById(R.id.amount_calculator_row_ltc);
		ltcAmountView.setListener(new CurrencyAmountView.Listener()
		{
			public void changed()
			{
				if (ltcAmountView.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.setCurrencyCode(exchangeCurrency);
		localAmountView.setPrecision(Constants.LOCAL_PRECISION);
		localAmountView.setListener(new CurrencyAmountView.Listener()
		{
			public void changed()
			{
				if (localAmountView.getAmount() != null)
				{
					exchangeDirection = false;

					updateAppearance();
				}
				else
				{
					ltcAmountView.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);

			if (exchangeDirection)
			{
				final BigInteger ltcAmount = ltcAmountView.getAmount();
				if (ltcAmount != null)
				{
					localAmountView.setAmount(null);
					localAmountView.setHint(WalletUtils.localValue(ltcAmount, exchangeRate.rate));
					ltcAmountView.setHint(null);
				}
			}
			else
			{
				final BigInteger localAmount = localAmountView.getAmount();
				if (localAmount != null)
				{
					ltcAmountView.setAmount(null);
					ltcAmountView.setHint(WalletUtils.ltcValue(localAmount, exchangeRate.rate));
					localAmountView.setHint(null);
				}
			}

			exchangeRateView.setText(getString(R.string.amount_calculator_dialog_exchange_rate, exchangeCurrency,
					WalletUtils.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 ? ltcAmountView.getAmount() : WalletUtils
				.ltcValue(localAmountView.getAmount(), exchangeRate.rate);

		((Listener) getTargetFragment()).useCalculatedAmount(amount);

		dismiss();
	}

	public Loader<Cursor> onCreateLoader(final int id, final Bundle args)
	{
		return new CursorLoader(activity, ExchangeRatesProvider.contentUri(activity.getPackageName()), null, ExchangeRatesProvider.KEY_CURRENCY_CODE,
				new String[] { exchangeCurrency }, null);
	}

	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)
	{
	}
}