Android Open Source - SOWGcalc S O W Gcalc

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License

The source code is released under:

GNU General Public License

Java Source Code

/**
 *  SOWGware, Copyright 2010/*from w  w  w.  j  av a  2s  .  com*/
 * 
 *  This file is part of SOWGcalc.

    SOWGcalc 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.

    SOWGcalc 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 SOWGcalc.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.sowg.calc;

import java.util.Arrays;
import java.util.HashSet;

import android.app.Activity;
import android.graphics.Typeface;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.ImageButton;
import android.view.KeyEvent;
import android.view.View;

public class SOWGcalc extends Activity {
  private final char[] repChars = {'+', Constants.DIV_CHAR, Constants.MULT_CHAR, '^'};
  private final char[] nonClearChars = {'+', '-', Constants.DIV_CHAR, Constants.MULT_CHAR, '^', '!'};
  private final char[] doubles = {'.'};
  private final String[] masterClearValues = { Constants.NAN_STRING, Character.toString(Constants.INFINITY_CHAR) };
  
  private final SOWGNumberKeyListener keyL = new SOWGNumberKeyListener();
  
  private HashSet<String> masterClearSet;
  private boolean clearItFirst = false;
  private boolean masterClear = false;
  
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        EditText output = (EditText)findViewById(R.id.output);

        //set key override
        output.setKeyListener(keyL);

        //focus
        output.setSelected(true);

        //set font
        Typeface font = Typeface.createFromAsset(getAssets(), "outputfont.ttf");
        output.setTypeface(font);

        //input master clear hash set with values from string[]
        masterClearSet = new HashSet<String>(Arrays.asList(masterClearValues));
    }

    //listener for text buttons
    public void buttonClickListener(View v)
    {
      //new characters to be input
      ImageButton b = (ImageButton)v;
      String newChars = b.getTag().toString();
      char lastNewChar = newChars.charAt(newChars.length() - 1);
      char firstNewChar = newChars.charAt(0);

      //handle clearing it before, e.g. if equals was just clicked - note auto-override with master clear
      if (masterClear || (clearItFirst && !Helper.charInList(firstNewChar, nonClearChars)))
      {
        clearListener(v);
      }
      //make sure to reset these flags no matter what
      masterClear = false;
      clearItFirst = false;

      //get the output field
      EditText output = (EditText) findViewById(R.id.output);
        //output.setTextSize((float)output.getMeasuredHeight() / 2.0f);

      //current text in field
      String currText = output.getText().toString();

      //indices for selection
      int start = Math.min(output.getSelectionStart(), output.getSelectionEnd());
      int end = Math.max(output.getSelectionStart(), output.getSelectionEnd());

      //check the last char for add/replace
      if (currText.length() > 0)
      {
        char toCheck = output.getText().charAt(Math.max(0, end - 1));
        if (!addOrReplace(toCheck, lastNewChar))
        {
          //simply go 1 before in the index for replace
          start--;
        }
      }

      //temporarily allow all text
      output.setKeyListener(null);

      //insert
      try
      {
        output.getText().replace(start, end, newChars);
      }
      catch(Exception e)
      {

      }

      //reinstate key restrictions
      output.setKeyListener(keyL);
    }

    //equals button listener
    public void equalsListener(View v)
    {
      //quick master clear check
      if (masterClear)
      {
        clearListener(v);
      }
      
      setOutput(getCalcResult());
    }
    
    //C button
    public void clearListener(View v)
    {      
      EditText output = (EditText) findViewById(R.id.output);
      output.setText("");
    }
    
    //backspace button
    public void backspaceListener(View v)
    {      
      EditText output = (EditText) findViewById(R.id.output);
      keyL.backspace(output, output.getEditableText(), 0, new KeyEvent(0, 0));
    }
    
    //MC button
    public void MCListener(View v)
    {
      Memory.clear();
    }
    
    //MR button
    public void MRListener(View v)
    {      
      setOutput(Helper.doubleFormatted(Memory.recall()));
    }
    
    //M+ button
    public void MPlusListener(View v)
    {
      //= first
      equalsListener(v);

      try
      {
        Memory.plus(Double.parseDouble(getCalcText()));
    }
    catch (Exception e)
    {
      //clear output on bad input
      clearListener(v);
    }
    }

    //M- button
    public void MMinusListener(View v)
    {
      //= first
      equalsListener(v);
      
      try
      {
        Memory.minus(Double.parseDouble(getCalcText()));
      }
      catch (Exception e)
      {
        //clear output on bad input
        clearListener(v);
      }
    }
    
    //set the output window with a specific string
    private void setOutput(String val)
    {
      EditText output = (EditText) findViewById(R.id.output);

      //temporarily allow all text
      output.setKeyListener(null);
      
      try
      {
        //feed into grammar parser
        output.setText(val);
        output.setSelection(output.getText().length());
    }
    catch(Exception e)
    {
      
    }
      
      //reinstate key restrictions
      output.setKeyListener(keyL);
      
      //set the clear flag
      clearItFirst = true;
      masterClear = masterClearSet.contains(output.getText().toString());
    }
    
    //pass in a string expression, get a result
    private String getCalcResult()
    {
      //feed it through a parentheses checker
      String correctedText = Helper.addParentheses(getCalcText());
      
      //return the evaluated result
      return CalcGrammar.evalGrammar(correctedText);
    }
    
    //retrieve contents of calculator output view
    private String getCalcText()
    {
      //get the calculator string
      EditText output = (EditText) findViewById(R.id.output);
      String calcText = output.getText().toString();

      return calcText;
    }

    //do we add to the string or replace the last char instead?
    private boolean addOrReplace(char lastChar, char toAdd)
    {
      boolean add = true;
      
      //these characters should be replaced with each other      
      if (Helper.charInList(lastChar, repChars) && Helper.charInList(toAdd, repChars))
      {
        add = false;
      }
      
      //these characters shouldn't produce doubles      
      for (char c : doubles)
      {
        if (c == lastChar && c == toAdd)
        {
          add = false;
          break;
        }
      }
      
      return add;
    }
}

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