A self generating Android program

This is a more or less insane DroidScript program I prepared as a demo for a seminar on dynamic languages. The program generates a main activity with a list from which you can launch 10000 generated activities. The theme I had in mind was "Fortune Cards", but all I had time to do was a coloured oval. If I get some more time I will improve the program.

I recommend that you try with a smaller number if you want to run the program, say 100. I wanted to show that it is possible to create a really big program in JavaScript on Android in terms of the size of the scrolling list and the number of activities, and still get good performance.

var DroidScriptFileHandler = Packages.comikit.droidscript.DroidScriptFileHandler;
var Intent = Packages.android.content.Intent;

function createAppScript()
{
    return """function onCreate(bundle)
    {
        var lang = Packages.java.lang;
        var android = Packages.android;
        var widget = Packages.android.widget;

        var listView = new widget.ListView(Activity);
        
        var numberOfCards = 10000;
        var cards = lang.reflect.Array.newInstance(lang.String, numberOfCards);
        for (var i = 0; i < numberOfCards; ++i)
        {
            cards[i] = "Card " + (i + 1);
        }

        var arrayAdapter =
            new widget.ArrayAdapter(Activity,
               android.R.layout.simple_list_item_1,
               cards);

        listView.setAdapter(arrayAdapter);
        
        listView.setOnItemClickListener(function(parent, view, position, id) {
            var Intent = Packages.android.content.Intent;
            var DroidScriptFileHandler = Packages.comikit.droidscript.DroidScriptFileHandler;
            var script = DroidScriptFileHandler.create().readStringFromFileOrUrl(
                "droidscript/generated/Card" + position + ".js");
            var intent = new Intent();
            intent.setClassName(Activity, "comikit.droidscript.DroidScriptActivity");
            intent.putExtra("Script", script);
            Activity.startActivity(intent);
        });

        Activity.setContentView(listView);
    }
    """;
}

function createCardScript()
{
    function random255() { return Math.random() * 255; }
        
    var script = """function onCreate(bundle)
    {
        var lang = Packages.java.lang;
        var android = Packages.android;
        var widget = Packages.android.widget;
        var Morph = Packages.comikit.droidscript.Morph;
        var Paint = Packages.android.graphics.Paint;
        var Color = Packages.android.graphics.Color;
        var RectF = Packages.android.graphics.RectF;
                
        var morph = new Morph(Activity);
        var width = 100;
        var height = 100;
        
        morph.setOnDrawListener(function(canvas)
        {""";
     
     var red = random255();
     var green = random255();
     var blue = random255();
     
     script += """
         var brushColor = Color.rgb(""" 
            + red + ", " + green + ", " + blue + """);
         var paint = new Paint();
         paint.setColor(brushColor);
         paint.setStyle(Paint.Style.FILL);
         paint.setAntiAlias(true);
         canvas.drawOval(
             new RectF(
                 0,
                 0,
                 width,
                 height),
                 paint);""";
                
     script += """});
        
        morph.setOnSizeChangedListener(function(w, h, oldw, oldh)
        {
            width = w;
            height = h;
            morph.invalidate();
        });
        
        Activity.setContentView(morph);
    }""";
    
    return script;
}

function launch(script)
{
    var intent = new Intent();
    intent.setClassName(Activity, "comikit.droidscript.DroidScriptActivity");
    intent.putExtra("Script", script);
    Activity.startActivity(intent);
}

// Create directory
var directory = "droidscript/generated/";
var fileHandler = DroidScriptFileHandler.create();
fileHandler.externalStorageCreateDirectory("droidscript/generated/");
    
// Generate main script
fileHandler.writeStringToFile(directory + "CardApp.js", createAppScript());

// Generate card scripts
for (var i = 0; i < 10000; ++i)
{
    fileHandler.writeStringToFile(
        directory + "Card" + i + ".js", createCardScript());
}

// I suggest you first run the above code in the editor at droidscript.se, 
// then launch the app. And I strongly recommend to try a smaller number 
// of "cards", say 100.

// Launch app
launch(DroidScriptFileHandler.create().readStringFromFileOrUrl(
    "droidscript/generated/CardApp.js"));