Android Open Source - bgrates Convert Activity

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License

The source code is released under:

MIT License

Java Source Code

/*
 * The MIT License/*from  w ww .  j  a  v  a  2s.com*/
 *
 * Copyright (c) 2010 Petar Petrov
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package net.vexelon.bgrates;

import java.math.BigDecimal;
import java.math.MathContext;
import java.util.ArrayList;

import net.vexelon.bgrates.ConvertRow.RowType;

import android.app.Activity;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnKeyListener;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.AdapterView.OnItemSelectedListener;

public class ConvertActivity extends Activity {

  private final static String TAG = Defs.LOG_TAG;
  private ExchangeRate _myRates = null;
  private ArrayList<ConvertRow> _rows = null;
  private int[] _visibleCurrencies = null;
  private int _curSelectedRowId = -1;

  @Override
  protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.convert);

    // read rates from intent bundle
    _myRates = getIntent().getParcelableExtra(Defs.INT_EXCHANGERATES);

    _rows = new ArrayList<ConvertRow>(Defs.MAX_CONVERT_ROWS);
    _rows.add(new ConvertRow(R.id.Spinner4, R.id.EditText4, RowType.RowOthers));
    _rows.add(new ConvertRow(R.id.Spinner3, R.id.EditText3, RowType.RowOthers));
    _rows.add(new ConvertRow(R.id.Spinner2, R.id.EditText2, RowType.RowOthers));
    _rows.add(new ConvertRow(R.id.Spinner1, R.id.EditText1, RowType.RowBGN));

    // init dropdown convert options
    for (ConvertRow row : _rows) {
      _curSelectedRowId = row.getRowId(); // should select the Top one
      initRow(row);
    }

    // load last saved settings and adjust
    loadSettings();

    if ( _visibleCurrencies != null ) {
//      this.runOnUiThread(new Runnable() {
//        @Override
//        public void run() {
          int i = 0;
          for (ConvertRow row : _rows) {
            final Spinner spinner = (Spinner)findViewById(row.getSpinnerId());
            spinner.setSelection(_visibleCurrencies[i++]);
          }
//        }
//      }); // runOnUiThread
    }
  }

  @Override
  protected void onDestroy() {
    super.onDestroy();

    saveSettings();
  }

  /**
   * Read previously selected currencies for convert
   */
  private void loadSettings() {
    SharedPreferences prefs = this.getSharedPreferences(Defs.CONV_PREFS_NAME, 0);

    int count = prefs.getInt(Defs.CONV_PREFS_KEY_CONVITEMS_COUNT, Defs.MAX_CONVERT_ROWS);
    _visibleCurrencies = new int[count];

    for( int i = 0; i < count; i++ ) {
      String key = Defs.CONV_PREFS_KEY_ITEM + i;
      _visibleCurrencies[i] = prefs.getInt(key, 0);
    }
  }

  /**
   * Write currently selected currencies for convert
   */
  private void saveSettings() {
    SharedPreferences prefs = this.getSharedPreferences(Defs.CONV_PREFS_NAME, 0);
    SharedPreferences.Editor editor = prefs.edit();

    editor.putInt(Defs.CONV_PREFS_KEY_CONVITEMS_COUNT, Defs.MAX_CONVERT_ROWS);
    int i = 0;
    for (ConvertRow row : _rows) {
      Spinner spinner = (Spinner)findViewById(row.getSpinnerId());
      String key = Defs.CONV_PREFS_KEY_ITEM + i++;
      editor.putInt(key, spinner.getSelectedItemPosition());
    }

    editor.commit();
  }

  /**
   * Creates and inits UI elements (spinner & edittext) from logical row
   * @param ConvertRow - initialized ConvertRow object
   */
  private void initRow(ConvertRow row) {

    String[] items = null;

    switch(row.getRowType()) {
    case RowBGN:
      items = new String[] { "BGN" };

      // init the edit text box
      setResText(row.getEditTextId(), "1.00"); // default

      break;

    case RowOthers:
    default:
      items = _myRates.currenciesToStringArray();

      // init the edit text box
      setResText(row.getEditTextId(), "0.00");

      break;
    }

    // init the spinner
    final int thisRowId = row.getRowId();
    //Log.d(TAG, "Creating row " + thisRowId);

    Spinner spinner = (Spinner)findViewById(row.getSpinnerId());
//    ArrayAdapter<String> adapter = new ArrayAdapter<String>(
//        this, android.R.layout.simple_spinner_item, items );
    ConvertCurrencyAdapter adapter = new ConvertCurrencyAdapter(this, android.R.layout.simple_spinner_item, items);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(adapter);

    spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
      @Override
      public void onItemSelected(AdapterView<?> parent, View view,
          int pos, long listRow) {
        // calculate and refresh
        updateResult(_curSelectedRowId);
      }

      @Override
      public void onNothingSelected(AdapterView<?> arg0) {
        // do nothing
      }
    });

    // init edit text
    EditText editText = (EditText)findViewById(row.getEditTextId());
    editText.setOnKeyListener(new OnKeyListener() {
      @Override
      public boolean onKey(View v, int keyCode, KeyEvent event) {
        _curSelectedRowId = thisRowId;
        updateResult(_curSelectedRowId);
        return false;
      }

    });
    editText.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
        _curSelectedRowId = thisRowId;
        updateResult(_curSelectedRowId);
      }
    });
  }

  /**
   * Do convert calculations and display results
   * @param rowId - the logical row which activated the update
   */
  private void updateResult(int rowId) {
    //Log.d(TAG, "Update Result, caller row is " + rowId);

    // find caller row
    ConvertRow callerRow = null;

    for (ConvertRow row : _rows) {
      if ( row.getRowId() == rowId ) {
        callerRow = row;
        break;
      }
    }

    if ( callerRow == null ) { // something went wrong !
      //Log.e(TAG, "Failed to find caller row !");
      return;
    }

    Spinner callerRowSpinner = (Spinner)findViewById(callerRow.getSpinnerId());
    String callerRowCode = (String) callerRowSpinner.getItemAtPosition(callerRowSpinner.getSelectedItemPosition());
    //Log.d(TAG, "Caller Row Code is " + callerRowCode);

    BigDecimal sum;
    MathContext mc = new MathContext(Defs.SCALE_CALCULATIONS);

    try {
      sum = new BigDecimal( getResText(callerRow.getEditTextId()).toString(), mc );
      //Log.d(TAG, "Sum is " + sum.toPlainString());
    }
    catch(NumberFormatException e) {
      Log.e(TAG, "Failed to convert value from String!", e);
      return; // invalid number
    }

    BigDecimal rate, ratio, result;
    CurrencyInfo currency = null;

    try {

      // update all rows (except the caller row)
      for (ConvertRow row : _rows) {
        if ( row.getRowId() != callerRow.getRowId() ) {

          switch(row.getRowType()) {
          case RowBGN:
            //Log.d(TAG, "Updating RowBGN !");

            // convert from caller row currency to BGN currency
            currency = _myRates.getCurrencyByCode(callerRowCode);
            rate = new BigDecimal(currency.getRate(), mc);
            ratio = new BigDecimal(currency.getRatio(), mc);
            try {
              result = rate.divide(ratio, mc).multiply(sum, mc); //result = rate / ratio * sum;
            }
            catch(Exception e) {
//              Log.d(TAG, e.toString());
              result = BigDecimal.ZERO;
            }
            //Log.d(TAG, String.format("rate: %1$s, ratio: %2$s, result: %3$s, sum: %4$s", rate.toPlainString(), ratio.toPlainString(), result.toPlainString(), sum.toPlainString()));
            setResText(row.getEditTextId(), Utils.scaleNumber(result, Defs.SCALE_SHOW_SHORT));
            break;

          case RowOthers:

            // get selected currency from row's spinner
            Spinner spinner = (Spinner)findViewById(row.getSpinnerId());
            String code = (String) spinner.getItemAtPosition(spinner.getSelectedItemPosition());
            //Log.d(TAG, "Updating RowOthers - " + code);

            if ( callerRow.getRowType() == RowType.RowBGN ) { // simply convert from BGN currency to selected row currency
              currency = _myRates.getCurrencyByCode(code);
              rate = new BigDecimal(currency.getRate(), mc);
              ratio = new BigDecimal(currency.getRatio(), mc);
              try {
                result = sum.divide(rate, mc).multiply(ratio, mc);
              }
              catch(Exception e) {
//                Log.e(TAG, e.toString());
                result = BigDecimal.ZERO;
              }
              setResText(row.getEditTextId(), Utils.scaleNumber(result, Defs.SCALE_SHOW_SHORT));
            }
            else { // more complex calculations

              // Step 1 - Convert from caller row currency to BGN currency
              currency = _myRates.getCurrencyByCode(callerRowCode);
              rate = new BigDecimal(currency.getRate(), mc);
              ratio = new BigDecimal(currency.getRatio(), mc);
              try {
                result = rate.divide(ratio, mc).multiply(sum, mc);
              }
              catch(Exception e) {
//                Log.e(TAG, e.toString());
                result = BigDecimal.ZERO;
              }
              //sum = result;

              // Step 2 - Convert from BGN currency to selected row currency
              currency = _myRates.getCurrencyByCode(code);
              rate = new BigDecimal(currency.getRate(), mc);
              ratio = new BigDecimal(currency.getRatio(), mc);
              try {
                result = result.multiply(ratio.divide(rate, mc), mc); //result = sum * ratio / rate;
              }
              catch(Exception e) {
//                Log.e(TAG, e.toString());
                result = BigDecimal.ZERO;
              }

              // Step 3 - Display results
              setResText(row.getEditTextId(), Utils.scaleNumber(result, Defs.SCALE_SHOW_SHORT));
            }
            break;
          } // end switch
        } // end if
      } // end for
    } catch (NumberFormatException e) {
      Log.e(TAG, "", e);
    }
  }


  private void setResText(int id, CharSequence text) {
    TextView tx = (TextView)findViewById(id);
    if ( tx != null )
      tx.setText(text);
  }

  private CharSequence getResText(int id) {
    TextView tx = (TextView)findViewById(id);
    if ( tx != null )
      return tx.getText();

    return null;
  }

  private void appendResText(int id, CharSequence text) {
    TextView tx = (TextView)findViewById(id);
    if ( tx != null )
      tx.setText(tx.getText().toString() + text);
  }
}

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