Week Two Notes

Loops

Allows you to make code that is reusable and compact, so you don't have to write it out multiple times.

Two Types of Loops

// FOR LOOP

//it is customary to use the letter i as the variable in the for loop, if you have multiples the next would be j , k

// for variable - setting a condition - incrimentor

for (var i:int = 0; i < 3; i++ ) {
    trace("hello");
}

Output: 
hello
hello
hello
// < 3 (going to run it 3 times), ++ incriment operator, this will trace hello 3 times into the output panel
// you could do number instead of int but int is faster to write
// 0 is because you are setting the number from which it starts counting

for (var i:int = 0; i < 3; i++ ) {
    trace("hello");
}

for (var j:int = 0; j < 4; j++) {
    trace(j);
} 

Output: 
hello
hello
hello
0
1
2
3

for (var i:int = 0; i < 3; i++ ) {
    trace("hello");
}

for (var j:int = 0; j < 4; j++) {
    trace(j);
}

for (var k:int = 4; k > 0; k--) {
    trace(k);
} 

//counts backwards


Output: 
hello
hello
hello
0
1
2
3
4
3
2
1



// WHILE LOOP 
// for loops run a set number of times, while loops run while a condition is true (based on a condition)

var num:Number = 0;
while  (num < 0.5) {
   
}
// If you ran this it would go on and on because we have not set a condition for the while loop

var num:Number = 0; 
while  (num < 0.5) { 
    num = Math.random(); 
    trace(num); 
}   

Output: 
// in this example as long as the number is greater than .5 it keeps going,

ARRAYS

//ARRAYS
//store multiple values in one single variable. An array is an object in flash, just like movieclips. So it is more than just a type it is an object.

//Arrays always start counting at 0

var myFirstArray:Array = new Array();
myFirstArray[0] = "poop";
trace(myFirstArray); 

Output: 
poop

//next we mix up the types of data we can put into the array

var myFirstArray:Array = new Array();
myFirstArray[0] = "poop";
myFirstArray[1] = "cat";
myFirstArray[2] = 35;

trace(myFirstArray);  

//another way to write it

var mySecondArray:Array = ["123 Main St.", "Pooptown", "USA", 94566]
trace(mySecondArray);  

//

Output: (of both)
poop,cat,35
123 Main St.,Pooptown,USA,94566
//you only get a line break for each trace command

// it is more common to get values out of an array vs in (like the above examples)

var mySecondArray:Array = ["123 Main St.", "Pooptown", "USA", 94566]
trace(mySecondArray[2]);  

//get the second position of the array

Output
USA

//PUSH 

//this is a way to add values into an existing array

//whatever you put inside the array it will add it onto the end of the array

mySecondArray.push("Earth");
trace(mySecondArary); 

//POP

mySecondArray.pop();
trace(mySecondArray);

//it pops of the last value of the array

Output (of both) 
123 Main St.,Pooptown,USA,94566,Earth
123 Main St.,Pooptown,USA,94566

//indexOf

//method or function (when a function is part of an object it is called a method)

var mySecondArray:Array = ["123 Main St.", "Pooptown", "USA", 94566] 
trace(mySecondArray); 


trace(myFirstArray.indexOf("cat"));
//indexOf will return a 1 if it finds the information

//if we search for something and it does not find it, it will return -1 forexample ("Cat")

Output
 poop,cat,35
1

 //FOR LOOP with an ARRAY

var mySecondArray:Array = ["123 Main St.", "Pooptown", "USA", 94566]

for (var m:int = 0; m<mySecondArray.length; m++) {
     trace(mySecondArray[m]);
     
     } 

//you could have m<4, but in case you don't remember how many values you can put the arrayname.length

//[m] you could put a number in there and it would trace out that position 4 times.

Output
123 Main St.
Pooptown
USA
94566

-----------------------------------------------------------------------------------
                                                         BREAK TIME
-------------------------------------------------------------------------------------

Three types of programming:
Sequential, Procedural, and Object Orient Programming.
Up to this point we have been using sequential coding.

Custom Functions

//FUNCTIONS

//you define the function, then you call it

function showMessage() {
    trace("hello")
}

//this will not output anything, because we have to call the function

function showMessage() {
    trace("hello dogface")
} 

showMessage();
showMessage(); 

//it will output how ever many times you call it

Output 
hello dogface
hello dogface

//now we are going to write it in a more dynamic way, we are going to tell it (read more down below)

function showMessage(theMessage:String):void { 
    trace(theMessage); 
} 

showMessage("hello");
showMessage("Buttface");

Output
hello
Buttface

//passing a parameter from the call into a variable that will catch that parameter

//the parameter "hello" gets stored in the variable theMessage

//it only exists in that function, it is called a local variable

//with in that function we can use that variable anytime we want

//now we can also have it run and return a value back to us for later use
function celciusToFarenheit(theCelciusNumber:Number):Number {
    return (9/5)*theCelciusNumber +32;
   
}
var theFarenheitNumber:Number = celciusToFarenheit(28);
trace(theFarenheitNumber);

//creating variable theCelciusNumber that is a Number
//:Number):Number since we are passing something as opposed to passing nothing like  :String):void
//since it is returning a value to use we need to create something to store that value into
//create a new variable theFarenheitNumber to store the value




----------------------------------------------------------------------------------
-----------------------NEW FILE-----------------------------------------------
---------------------------------------------------------------------------------
//MOUSE EVENTS
make a pentagon on the stage
make it a movieclip
give it an instance name: pentagon01_mc

//in the AS we need to create an even listener

//when the event happens/is triggered then the event handler occurs

pentagon01_mc.addEventListener(MouseEvent.CLICK, onClick);

function onClick(event:MouseEvent):void {
    trace("click");
   
}

//the eventlistener sends an  event to the handler, we named it event but we could have named it whatever we wanted such as (evt:mouseEvent)

OUTPUT 

run the script
when we click on pentagon01_mc the output panel shows click



import flash.events.MouseEvent;

pentagon01_mc.addEventListener(MouseEvent.CLICK, onClick);

function onClick(event:MouseEvent):void {
pentagon01_mc.rotation += 10;

}  


OUTPUT  
when you click on the pentagon, it rotates on the registration point


//if you need to change the registration point, you go to the library, select it, cut and paste and the point will move to the middle.
//if you need to move it back the corner you can copy and paste it and use the guides to eyeball the position, or you can set the x and y values in the properties.


//when you create a new listener you have to create a new handler to handle it
//this changes the alpha down to 80 percent 


import flash.events.MouseEvent;

pentagon01_mc.addEventListener(MouseEvent.CLICK, onClick); 
pentagon01_mc.addEventListener(MouseEvent.ROLL_OVER, onRoll); 

function onClick(event:MouseEvent):void {
    pentagon01_mc.rotation += 10;
   
}

function onRoll(event:MouseEvent):void {
    pentagon01_mc.alpha = .8;
}

//next create a third event to make the transparency come back

import flash.events.MouseEvent;

pentagon01_mc.addEventListener(MouseEvent.CLICK, onClick);
pentagon01_mc.addEventListener(MouseEvent.ROLL_OVER, onRoll);
pentagon01_mc.addEventListener(MouseEvent.MOUSE_OUT, onMouseOut); 

function onClick(event:MouseEvent):void {
    pentagon01_mc.rotation += 10;
   
} 

function onRoll(event:MouseEvent):void {
    pentagon01_mc.alpha = .8;
} 

function onMouseOut(event:MouseEvent):void {
    pentagon01_mc.alpha = 1;
}




//KEYBOARD BOARD EVENT

stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyPress);
function onKeyPress(event:KeyboardEvent):void {
    trace("key pressed: " + event.keyCode);

//you can have a key up or a key down, they are basically the same except you might want key up if you are making a game and you have the user hold a key and do stuff

OUTPUT (depends on what keys you pressed)

key pressed: 83

key pressed: 68

key pressed: 70

key pressed: 65

key pressed: 83

stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyPress);
function onKeyPress(event:KeyboardEvent):void {
    trace("key pressed: " + event.keyCode);
    if  (event.keyCode == 40) {
        trace("down");
    }
}

Output

key pressed: 40

down

// next add else if for the other arrow keys and else for everything else

stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyPress);

function onKeyPress(event:KeyboardEvent):void {

    //trace("key pressed: " + event.keyCode);

    if  (event.keyCode == 40) {

        trace("down");

    } else if (event.keyCode == Keyboard.UP) {

        trace("up");

    } else if (event.keyCode == Keyboard.LEFT) {

        trace("left");

    } else if (event.keyCode == Keyboard.RIGHT) {

        trace("right");

    } else {

        trace("you suck");

    }

}

OUTPUT

up
right
left
down
you suck

stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyPress);
function onKeyPress(event:KeyboardEvent):void {
    //trace("key pressed: " + event.keyCode);
    if  (event.keyCode == 40) {
        //trace("down");
        pentagon01_mc.y +=20;
    } else if (event.keyCode == Keyboard.UP) {
        //trace("up");
        pentagon01_mc.y -=20;
    } else if (event.keyCode == Keyboard.LEFT) {
        //trace("left");
        pentagon01_mc.x -=20;
    } else if (event.keyCode == Keyboard.RIGHT) {
        //trace("right");
        pentagon01_mc.x +=20;
    } else {
        trace("you suck");
    }
}


OUTPUT
You can use the arrow keys to move the shape around



HOMEWORK : Read Chapter 3