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ehrenb on 05/28/11

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Last Edited at 05/28/11 09:33am

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Basic Android Calculator

/ Published in: Java

This is a current side project. I make changes (mainly adding new things) about once a week (when I have time).

Notes: GUI in XML(not here), Eclipse Android plug-in, some images not here

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package newProject.test;
//Code by ehrenb
import android.app.Activity;
import android.os.Bundle;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.RadioButton;
import android.widget.Toast;
import java.util.ArrayList;
import android.widget.*;
//import java.util.ArrayList;

//needs error checking for number parsing**

public class myMenu extends Activity {
	private EditText inputNums;
	private TextView resultBox;

@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		inputNums = (EditText) findViewById(R.id.input);
		resultBox = (TextView) findViewById(R.id.results);
	//	requestWindowFeature(Window.FEATURE_CUSTOM_TITLE); 
	}
	
//int[] storage = new int[10];
//ArrayList<Double> storage=new ArrayList<Double>();
double numToCalc=0;

// This method is called at button click because we assigned the name to the
	// "On Click property" of the button
	public void myClickHandler(View view) {
		switch (view.getId()) {
		}
		//initialize all the buttons
		Button addButton = (Button) findViewById(R.id.addButton);
		Button multButton = (Button) findViewById(R.id.multButton);
		Button subtractButton = (Button) findViewById(R.id.subtract);
		Button divideButton = (Button) findViewById(R.id.divideButton);
		Button factorsButton = (Button) findViewById(R.id.factorsButton);

if (inputNums.getText().length() == 0) {
				Toast.makeText(this, "Please enter a valid number",
						Toast.LENGTH_LONG).show();
				return; //return is a MUST...force close without
				//parse for numbers, not just a blank input

}

//Code by ehrenb
			// check for non-numeric values
			//abstracted from: 
			//src = http://www.ehow.com/how_7718014_error-check-fields-java.html
			for(int i= 0; i < inputNums.getText().length(); i++) {
			if(!Character.isDigit(inputNums.getText().charAt(i)))
				Toast.makeText(this, "Please enter a valid number",
						Toast.LENGTH_LONG).show();
			
			return;
			}
			
			
			
			
			double inputValue = Double.parseDouble(inputNums.getText().toString());
			
			if (addButton.isPressed()) {
			
				//storage.add(inputValue); //add parsed double to arraylist
				//numToCalc = inputValue;

//inputNums.setText(inputValue.);
				//inputNums.append("+"); //add + to the textView
				//permNum=add(inputValue);
				resultBox.setText(String
						.valueOf(add(inputValue)));	//do addition calculations
				
				inputNums.setText("");//clear the textfield
			} 
			if (multButton.isPressed()){
				numToCalc = inputValue;
				 //add parsed double to arraylist
				//inputNums.setText(inputValue.);
				//inputNums.append("+"); //add + to the textView
				//storage.add(inputValue);
				//storage.add(inputValue);
				//permNum=resultValue;
				resultBox.setText(String
						.valueOf(multiply(inputValue)));	//do addition calculations
				
				inputNums.setText("");//clear the textfield
			}
			
			if(subtractButton.isPressed() ){
				
				resultBox.setText(String.valueOf(subtract(inputValue)));	//do addition calculations
				
				inputNums.setText("");//clear the textfield
				
			}
			// Switch to the other button
//			if (fahrenheitButton.isChecked()) {
//				fahrenheitButton.setChecked(false);
//				celsiusButton.setChecked(true);
//			} else {
//				fahrenheitButton.setChecked(true);
//				celsiusButton.setChecked(false);
//			}
			
			if (divideButton.isPressed()){
				numToCalc = inputValue;

resultBox.setText(String
						.valueOf(divide(inputValue)));	//do division calculations
				
				inputNums.setText("");//clear the textfield
			}
			
			if (factorsButton.isPressed()){
				resultBox.setText(String.valueOf(findFactors(inputValue)));
		}
	}

// add
	int numOfAdds=0;
	
	private double add(double addNum) {

//int temp = storage.size();
		
		double total =0;
//		if (temp == 0) // if array is empty, do nothing
//		{
//
//		}
//		else
		{
			double resultValue = Double.parseDouble(resultBox.getText().toString());
			double inputValue = Double.parseDouble(inputNums.getText().toString());

//	total=numToCalc+resultValue;
			total = addNum+resultValue;
			//permNum=total;
//		for (int i=0; i<temp; i++) //loop adds up every item in the array
//		{
//			total = total +storage.get(i);
//			
//		}
//		storage.clear();//standard template for calc functions: clear the arrayList, then add 
//		storage.add(total);
		}
		numOfAdds++;
		return (total);
	}

int multiplicationInit=1;
	int numOfMultis=0;//FIX - counts amt of multiplications done in the program
	
	private double multiply(double multiplyNum)
	{
		double inputValue = Double.parseDouble(inputNums.getText().toString());
		double resultValue = Double.parseDouble(resultBox.getText().toString());

double product=0;
		product=multiplyNum*resultValue;

if (numOfMultis==0 && resultValue==0 && numOfAdds==0 && numOfSubtract==0  && numOfDivide==0)
			//if it is absolutely the first calculation <<FIX!! If it is BOTH: The first Calculation & the resultBox=0 > it is ABSOLUTELY the first calculation.
			//previous problem: if(numOfMultis==0) only checks to see when the first multiplication is, not what the values are
			//still testing
			//seek to optimize this later--IE- no number of calculations counted
		{			
			
			product = multiplyNum*multiplicationInit;//workaround
		}
		
		
		else //assuming we have already done something to the resultValue 
			//then we dont need to worry about the case of multiplying product*0
		{
		product = multiplyNum*resultValue;//multiply normally
		}
		numOfMultis++;
		return product;
	}
	
	int numOfSubtract=0;
	int numOfDivide=0;
	private double subtract(double subtractNum)
	{
		double total =0;
		double resultValue = Double.parseDouble(resultBox.getText().toString());

total=resultValue-subtractNum;
		numOfSubtract++;
		return total;
	}

private double divide(double divideNum)
	{
		double resultValue = Double.parseDouble(resultBox.getText().toString());
		numOfDivide++;
		return resultValue/divideNum;
		
	}
	
	private String findFactors(double factNum)
	{
		ArrayList tempArray = new ArrayList();
		for(int i = 1; i <= factNum/2; i++)
			{
			     if(factNum % i == 0)// if the remainder of num5 and a number is 0..it is a factor!
			    	 tempArray.add(i);
			          //System.out.print(i + " ");
			}
		return tempArray.toString();
	}
	
//MULTIPLCATION NOTES:
//**Calculations are done off of the resultValue
	//Since the result value has to initially be 0, we must compensate
	//and make resultValue=1 in the case that the user multiplies first
	//instead of add/sub/div
	//If we were to keep resultValue=0, we would run into a problem where; if multiplying first(assuming resultValue hasnt been touched), our calculation would be forced to =0 
	// because by default, resultValue must=0. IE 1*0=0
	
	//goals:maintain universal resultValue
	//problems: if subtracting say 3-3=0. If we attempt to multiply after that, we will encounter an issue b/c it will force the 0 to be a 1.  
	//Solution: compensate again in the functions that require it (force 1 to be a 0?)
	//above problem fixed
//Code by ehrenb

}

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