Simple Calculator

Hey guys this is asimple implementation of calculator in Xamarin Forms Cross Platform
Enjoy the code: :D
Step1: Your MainPage.xaml will look like this

	<?xml version="1.0" encoding="utf-8" ?>
	<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
	xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
	xmlns:local="clr-namespace:XamarinCalculator"
	x:Class="XamarinCalculator.MainPage">
	<ContentPage.Padding>
	<OnPlatform x:TypeArguments="Thickness">
	<OnPlatform.iOS>0,20,0,0</OnPlatform.iOS>
	</OnPlatform>
	</ContentPage.Padding>
	<ContentPage.Resources>
	<ResourceDictionary>
	<Style x:Key ="infostyle" TargetType="Button">
	<Setter Property="WidthRequest" Value="60" />
	<Setter Property="HeightRequest" Value="60"/>
	<Setter Property="BorderRadius" Value="30"/>
	<Setter Property="TextColor" Value="White"/>
	<Setter Property="FontSize" Value="36"/>
	</Style>
	</ResourceDictionary>
	</ContentPage.Resources>
	<Grid Padding="5,0" RowSpacing="5" ColumnSpacing="5" >
	<Grid.RowDefinitions>
	<RowDefinition Height="2*" />
	<RowDefinition Height="*" />
	<RowDefinition Height="*" />
	<RowDefinition Height="*" />
	<RowDefinition Height="*" />
	<RowDefinition Height="*" />
	</Grid.RowDefinitions>
	<Grid.ColumnDefinitions>
	<ColumnDefinition Width="*" />
	<ColumnDefinition Width="*" />
	<ColumnDefinition Width="*" />
	<ColumnDefinition Width="*" />
	</Grid.ColumnDefinitions>
	<Label x:Name="resultText" FontSize="48" FontAttributes="Bold" BackgroundColor="Black" Text="0"
	TextColor="White" HorizontalTextAlignment="End" VerticalTextAlignment="Center"
	LineBreakMode="NoWrap" Grid.ColumnSpan="4" />
	<Button Text="AC" Grid.Row="1" Grid.Column="0" Style="{StaticResource infostyle}" BackgroundColor="#808080" Clicked="OnClear" />
	<Button Text="√" Grid.Row="1" Grid.Column="1" Style="{StaticResource infostyle}" BackgroundColor="#808080" FontSize="36" Clicked="OnSquareRoot"/>
	<Button BorderRadius="30" Text="%" Grid.Row="1" Grid.Column="2" Style="{StaticResource infostyle}" BackgroundColor="#808080" Clicked="OnPercentage"/>
	<Button Text="7" Grid.Row="2" Grid.Column="0" BackgroundColor="#2e2e2e" Clicked="OnSelectNumber" Style="{StaticResource infostyle}"/>
	<Button Text="8" Grid.Row="2" Grid.Column="1" BackgroundColor="#2e2e2e" Clicked="OnSelectNumber" Style="{StaticResource infostyle}" />
	<Button Text="9" Grid.Row="2" Grid.Column="2" BackgroundColor="#2e2e2e" Clicked="OnSelectNumber" Style="{StaticResource infostyle}" />
	<Button Text="4" Grid.Row="3" Grid.Column="0" BackgroundColor="#2e2e2e" Clicked="OnSelectNumber" Style="{StaticResource infostyle}"/>
	<Button Text="5" Grid.Row="3" Grid.Column="1" BackgroundColor="#2e2e2e" Clicked="OnSelectNumber" Style="{StaticResource infostyle}" />
	<Button Text="6" Grid.Row="3" Grid.Column="2" BackgroundColor="#2e2e2e" Clicked="OnSelectNumber" Style="{StaticResource infostyle}" />
	<Button Text="1" Grid.Row="4" Grid.Column="0" BackgroundColor="#2e2e2e" Clicked="OnSelectNumber" Style="{StaticResource infostyle}"/>
	<Button Text="2" Grid.Row="4" Grid.Column="1" BackgroundColor="#2e2e2e" Clicked="OnSelectNumber" Style="{StaticResource infostyle}"/>
	<Button Text="3" Grid.Row="4" Grid.Column="2" BackgroundColor="#2e2e2e" Clicked="OnSelectNumber" Style="{StaticResource infostyle}" />
	<Button Text="0" Grid.Row="5" Grid.Column="0" Grid.ColumnSpan="2" BackgroundColor="#2e2e2e" Clicked="OnSelectNumber" Style="{StaticResource infostyle}"/>
	<Button Text="x2" Grid.Row="5" Grid.Column="2" BackgroundColor="#2e2e2e" Clicked="squareclicked" Style="{StaticResource infostyle}" />
	<Button Text="=" Grid.Row="5" Grid.Column="3" BackgroundColor="#EE7600" Clicked="OnCalculate" Style="{StaticResource infostyle}"/>
	<Button Text="÷" Grid.Row="1" Grid.Column="3" BackgroundColor="#EE7600" Clicked="OnSelectOperator" Style="{StaticResource infostyle}"/>
	<Button Text="*" Grid.Row="2" Grid.Column="3" BackgroundColor="#EE7600" Clicked="OnSelectOperator" Style="{StaticResource infostyle}" />
	<Button Text="-" Grid.Row="3" Grid.Column="3" BackgroundColor="#EE7600" Clicked="OnSelectOperator" Style="{StaticResource infostyle}" />
	<Button Text="+" Grid.Row="4" Grid.Column="3" BackgroundColor="#EE7600" Clicked="OnSelectOperator" Style="{StaticResource infostyle}" />
	</Grid>
	</ContentPage>

view raw MainPage.xaml hosted with ❤ by GitHub

Step2: Your MainPage.xaml.cs will look like this

	using System;
	using System.Collections.Generic;
	using System.Linq;
	using System.Text;
	using System.Threading.Tasks;
	using Xamarin.Forms;
	namespace XamarinCalculator
	{
	public partial class MainPage : ContentPage
	{
	int currentState = 1;
	string myoperator;
	double firstNumber, secondNumber;
	public MainPage()
	{
	InitializeComponent();
	OnClear(this, null);
	}
	void OnSelectNumber(object sender, EventArgs e)
	{
	Button button = (Button)sender;
	string pressed = button.Text;
	//validation before button is pressed
	//if the current result is 0 in text box then we will direct the calculator to exclude 0 when pressing busttons
	if (this.resultText.Text == "0" || currentState < 0 )//at first current state is 1
	{
	this.resultText.Text = "";//here the text value will be cleared when pressing button
	if (currentState < 0) //at first current value is 1 so this condition is excluded
	currentState *= -1;
	}
	this.resultText.Text += pressed;// this condition is called when current state is greater and text box will aquire the pressed
	double number;//if we are going to assign two dynamic number for a given variable using try parse method
	if (double.TryParse(this.resultText.Text, out number))
	{
	this.resultText.Text = number.ToString("N0");
	if (currentState == 1)
	{
	firstNumber = number;//at first current state will be 1 and it will assign first number with the pressed number variable
	}
	else
	{
	secondNumber = number;//it will be implemented as the number of current state changes i.e. 2
	}
	}
	}
	void OnSelectOperator(object sender, EventArgs e)//event is called when the select operator is called
	{
	currentState = -2;
	Button button = (Button)sender;
	string pressed = button.Text;
	myoperator = pressed;
	}
	void OnClear(object sender, EventArgs e)// this method is called when we press the AC button
	{
	firstNumber = 0;
	secondNumber = 0;
	currentState = 1;
	this.resultText.Text = "0";
	}
	void OnPercentage(object sender,EventArgs e) //This method is useful when we are going to find out percentage of last rsulting variable or the initial variable
	{
	if ((currentState == -1) || (currentState == 1))//please use some break point to check when we are going to get current state value as -1 or 1
	{
	//var result = OperatorHelper.MyPercentage(firstNumber, myoperator);
	var result = firstNumber / 100;
	this.resultText.Text = result.ToString();
	firstNumber = result;
	currentState = -1;
	}
	}
	void OnCalculate(object sender, EventArgs e) //This method is called when we have both first number and second number and we are going to evaluate those number
	{
	if (currentState == 2)
	{
	var result = OperatorHelper.Calculate(firstNumber, secondNumber, myoperator);
	this.resultText.Text = result.ToString();
	firstNumber = result;
	currentState = -1;
	}
	}
	void OnSquareRoot(object sender, EventArgs e) //We call this event when we have one resulting number or initial number ,we are going to find out the square root of that number
	{
	if ((currentState == -1)||(currentState == 1))
	{
	//var result = OperatorHelper.MySquareRoot(firstNumber, myoperator);
	var result = Math.Sqrt(firstNumber);
	this.resultText.Text = result.ToString();
	firstNumber = result;
	currentState = -1;
	}
	}
	private void squareclicked(object sender, EventArgs e)//We call this method when we have one resulting number or initial number ,we are going to find out the square root of that number
	{
	if ((currentState == -1) || (currentState == 1))
	{
	//var result = OperatorHelper.MySquare(firstNumber, myoperator);
	var result = firstNumber * firstNumber;
	this.resultText.Text = result.ToString();
	firstNumber = result;
	currentState = -1;
	}
	}
	}
	}

view raw MainPage.xaml.cs hosted with ❤ by GitHub

Step3: Your OperatorHelper.cs will lookLike this

	using System;
	using System.Collections.Generic;
	using System.Text;
	namespace XamarinCalculator
	{
	public static class OperatorHelper
	{
	public static double Calculate(double value1 , double value2 , string myoperator)
	{
	double result = 0;
	switch(myoperator)
	{
	case "÷":
	result = value1 / value2;
	break;
	case "*":
	result = value1 * value2;
	break;
	case "+":
	result = value1 + value2;
	break;
	case "-":
	result = value1 - value2;
	break;
	}
	return result;
	}
	}
	}

view raw OperatorHelper.cs hosted with ❤ by GitHub

Step4: You can change Android MainActivity.cs to get round buttons like this:(Not Recommended to implement)

	using System;
	using Android.App;
	using Android.Content.PM;
	using Android.Runtime;
	using Android.Views;
	using Android.Widget;
	using Android.OS;
	namespace XamarinCalculator.Droid
	{
	[Activity(Label = "XamarinCalculator", Icon = "@drawable/icon", Theme = "@style/MainTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
	public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsApplicationActivity
	{
	protected override void OnCreate(Bundle bundle)
	{
	//TabLayoutResource = Resource.Layout.Tabbar;
	//ToolbarResource = Resource.Layout.Toolbar;
	base.OnCreate(bundle);
	global::Xamarin.Forms.Forms.Init(this, bundle);
	LoadApplication(new App());
	}
	}
	}

view raw MainActivity.cs hosted with ❤ by GitHub