//This example requires the 'Xamarin.Android GUI' option to be enabled
//This is a calculator using Mono.CSharp.Evaluator to evaluate expressions
//+ref=Mono.CSharp.dll
using System;
using System.Text.RegularExpressions;
using System.IO;
using Mono.CSharp;
using Android.Widget;
using Android.Content;
using Android.Views.InputMethods;
using System.Threading.Tasks;
using NativeUiLib; //This adds the UI controls
namespace CSharp_Shell
{
public static class Program
{
static Evaluator evaluator;
static StringWriter sw; //Results and errors are printed here
static string evalCodeStart = "public static class Calc { public static void Eval(){ result=";
static EditText txtDisplay; //calculator display/result line
static TextView lblError; //calculator evaluation error line
static LinearLayout layNumpad;
static LinearLayout layArithmetics;
public static void Main()
{
var layMain = new LinearLayout(); //Primary layout
layMain.Orientation = Orientation.Vertical;
txtDisplay = layMain.AddEditText(true);
txtDisplay.Click += txtDisplay_Click;
lblError = layMain.AddTextView(true);
var hpx = Ui.Context.Resources.DisplayMetrics.HeightPixels * 0.1;
txtDisplay.SetMinHeight((int)hpx);
var layHor = new LinearLayout(); //This layout will contains 2 others
layHor.Orientation = Orientation.Horizontal;
layMain.AddView(layHor); //Add to primary layout
layNumpad = GenerateNumpad();
layArithmetics = GenerateArithmetics();
layHor.AddView(layNumpad);
layHor.AddView(layArithmetics);
//Set layNumpad and layArithmetics to take up a specific percantage of space
var np= new LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.WrapContent);
np.Weight = 0.85f;//Take up 85% of parent layout (parent layout is width=fill_parent)
layNumpad.LayoutParameters = np;
var ap= new LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.WrapContent);
ap.Weight = 0.25f; //Take up 25% of parent layout
layArithmetics.LayoutParameters = ap;
layMain.Show(); //Show primary layout
txtDisplay_Click(null, null);//Hide keyboard popup
}
//Hide the keyboard on click
private static async void txtDisplay_Click(object sender, EventArgs args)
{
var im = ((InputMethodManager)Ui.Context.GetSystemService(Context.InputMethodService));
await Task.Delay(10); //Hiding keyboard doesn't work without a delay
im.HideSoftInputFromWindow(txtDisplay.WindowToken, Android.Views.InputMethods.HideSoftInputFlags.None);
}
private static LinearLayout GenerateNumpad()
{
//This layout is basically a table with 6 rows and 3 columns
var linNum = new LinearLayout();
linNum.Orientation = Orientation.Vertical;
var linRow1 = new LinearLayout();
linRow1.Orientation = Orientation.Horizontal;
linRow1.AddView(NewCalcButton("1"));
linRow1.AddView(NewCalcButton("2"));
linRow1.AddView(NewCalcButton("3"));
var linRow2 = new LinearLayout();
linRow2.Orientation = Orientation.Horizontal;
linRow2.AddView(NewCalcButton("4"));
linRow2.AddView(NewCalcButton("5"));
linRow2.AddView(NewCalcButton("6"));
var linRow3 = new LinearLayout();
linRow3.Orientation = Orientation.Horizontal;
linRow3.AddView(NewCalcButton("7"));
linRow3.AddView(NewCalcButton("8"));
linRow3.AddView(NewCalcButton("9"));
var linRow4 = new LinearLayout();
linRow4.Orientation = Orientation.Horizontal;
linRow4.AddView(NewCalcButton("0"));
linRow4.AddView(NewCalcButton("."));
linRow4.AddView(NewCalcButton("="));
var linRow5 = new LinearLayout();
linRow5.Orientation = Orientation.Horizontal;
linRow5.AddView(NewCalcButton("("));
linRow5.AddView(NewCalcButton(")"));
linRow5.AddView(NewCalcButton("%"));
var linRow6 = new LinearLayout();
linRow6.Orientation = Orientation.Horizontal;
linRow6.AddView(NewCalcButton("sqrt"));
linRow6.AddView(NewCalcButton("pow"));
linRow6.AddView(NewCalcButton("mod"));
linNum.AddView(linRow1);
linNum.AddView(linRow2);
linNum.AddView(linRow3);
linNum.AddView(linRow4);
linNum.AddView(linRow5);
linNum.AddView(linRow6);
return linNum;
}
private static LinearLayout GenerateArithmetics()
{
var linArth = new LinearLayout();
linArth.Orientation = Orientation.Vertical;
linArth.AddView(NewCalcButton("+"));
linArth.AddView(NewCalcButton("-"));
linArth.AddView(NewCalcButton("*"));
linArth.AddView(NewCalcButton("/"));
linArth.AddView(NewCalcButton("DEL"));
linArth.AddView(NewCalcButton("CLR"));
return linArth;
}
//Helper method for adding buttons to the calculator
private static Button NewCalcButton(string text)
{
var btn = new Button();
btn.Text = text;
btn.Click += PerformButtonAction;
return btn;
}
//Decide what to do when a button is pressed
private static void PerformButtonAction(object sender, EventArgs args)
{
var btn = (Button)sender;
if (btn.Text == "=") Task.Run(()=> Calculate(txtDisplay.Text));
else if (btn.Text == "CLR")
{
txtDisplay.Text = string.Empty;
lblError.Text=string.Empty;
}
else if (btn.Text == "DEL") //Remove character at cursor
{
if (txtDisplay.Text.Length == 0) return;
var ind = txtDisplay.SelectionStart;
txtDisplay.Text = txtDisplay.Text.Remove(ind - 1, 1);
txtDisplay.SetSelection(--ind);
}
else
{
var text = btn.Text;
var ind = txtDisplay.SelectionStart;
if (text == "pow") text = "pow(,)";
else if (text == "sqrt") text = "sqrt()";
else if (text == "mod") text = "mod()";
txtDisplay.Text = txtDisplay.Text.Insert(ind, text);
txtDisplay.SetSelection(ind + text.Length);
}
}
private static void Calculate(string expr)
{
try
{
InitEvaluator();
//Convert shorthand pseudo-methods into real ones
expr = expr.Split('=')[0];
expr = expr.Replace("pow", "Math.Pow");
expr = expr.Replace("sqrt", "Math.Sqrt");
expr = expr.Replace("mod", "Math.Abs");
var ok = evaluator.Run(evalCodeStart + expr + ";}}"); //Create evaluation class
if (!ok) throw new ApplicationException(sw.ToString());
ok = evaluator.Run("Calc.Eval()"); //Start evaluatuion
if (!ok || !string.IsNullOrWhiteSpace(sw.ToString()))
{
//throw exception due to evaluation error.
throw new ApplicationException(sw.ToString());
}
//Show the result
Ui.RunOnUiThread(()=>
{
txtDisplay.Text = txtDisplay.Text.Split('=')[0] + "=" + GetEvalResult();
txtDisplay.SetSelection(txtDisplay.Text.Length);
lblError.Text = string.Empty;
});
}
catch(Exception ex)
{
//Show the exception message
Ui.RunOnUiThread(()=>
{
lblError.Text = ex.Message;
if (ex.InnerException != null)
{
lblError.Text += ex.InnerException.Message;
}
});
}
}
//Get evaluator result variable and process it for display
private static string GetEvalResult()
{
var errorRegex = @"\((\d*),\s*(\d*)\):(.*)";
var res = evaluator.GetVars().Replace("object result = ", string.Empty).Trim();
if (Regex.IsMatch(res, errorRegex))
{
var offset = evalCodeStart.Length + "using System;\nobject result;".Length;
var matches = Regex.Matches(res, errorRegex);
res = string.Empty;
foreach (Match match in matches)
{
var pos = int.Parse(match.Groups[2].Value) - offset;
var error = match.Groups[3].Value;
res += $"{pos}: {error}";
}
}
return res;
}
private static void InitEvaluator()
{
sw = new StringWriter();
var setting = new CompilerSettings();
var pr = new ConsoleReportPrinter(sw);
var ctx = new CompilerContext(setting, pr);
evaluator = new Evaluator(ctx);
evaluator.Run("using System;"); //We probably need this
evaluator.Run("object result;"); //Result variable, very important.
}
}
}
