Hi,

I've just started learning flex using OReilly "Programming Flex 3.0". After completing three chapters and starting fourth (ActionScript), and not having enough patience to wait till completing chapter 22 I started to practice :)

One bit that I have most worries about right now is the the dual coding mode (MXML vs ActionScript)

Please have a look at my code below (it compiles via mxmlc design.mxml, second file 'code.as' should be in same directory) and advise if the separation I used between visual design and code is appropriate.

Also - if some smart guy could show me how to recode same example with *.as being a class file [package?] it would be highly appreciated. I got lost with creating directory structure for package - and did not find it most intuitive, especially for small project that has two files like my example.

Code: design.mxml

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
 <mx:Script source="code.as"/>
 <mx:VBox>
  <mx:TextInput creationComplete="initializeCalculator()" id="txtScreen"/>
  <mx:HBox>
   <mx:Button click="click('7')" id="btn7" label="7"/>
   <mx:Button click="click('8')" id="btn8" label="8"/>
   <mx:Button click="click('9')" id="btn9" label="9"/>
   <mx:Button click="click('C')" id="btnClear" label="C"/>
  </mx:HBox>
  <mx:HBox>
   <mx:Button click="click('4')" id="btn4" label="4"/>
   <mx:Button click="click('5')" id="btn5" label="5"/>
   <mx:Button click="click('6')" id="btn6" label="6"/>
   <mx:Button click="click('/')" id="btnDivide" label="/"/>
  </mx:HBox>
  <mx:HBox>
   <mx:Button click="click('1')" id="btn1" label="1"/>
   <mx:Button click="click('2')" id="btn2" label="2"/>
   <mx:Button click="click('3')" id="btn3" label="3"/>
   <mx:Button click="click('*')" id="btnMultiply" label="*"/>
  </mx:HBox>
  <mx:HBox>
   <mx:Button click="click('0')" id="btn0" label="0"/>
   <mx:Button click="click('=')" id="btnEqual" label="="/>
   <mx:Button click="click('-')" id="btnMinus" label="-"/>
   <mx:Button click="click('+')" id="btnPlus" label="+"/>
  </mx:HBox>
 </mx:VBox>
</mx:Application>

code: code.as

public var res:int = 0;
public var previousOperator:String = "";
public var previousRes:int=0;

public function initializeCalculator():void{
 txtScreen.text = res.toString();
}
public function click(code:String):void{ 
 if (code=="1" || code=="2" || code=="3" || code=="4" || code=="5" ||
   code=="6" || code=="7" || code=="8" || code=="9" || code=="0"){
  res = res*10 + int(code);
  txtScreen.text = res.toString();
 }
 else if (code=="C"){
  res = 0;
  previousOperator ="";
  previousRes = 0;
  txtScreen.text = res.toString();
 }
 else{
  calculate(code);
 }
}
public function calculate(operator:String):void{
 var tmpRes:int;
 if (previousOperator=="+"){
  tmpRes = previousRes + res;
 }
 else if (previousOperator=="-"){
  tmpRes = previousRes - res;
 }
 else if (previousOperator=="/"){
  tmpRes = previousRes / res;
 }
 else if (previousOperator=="*"){
  tmpRes = previousRes * res;
 }
else{
 tmpRes = res;
}
 previousOperator = operator;
 previousRes = tmpRes;
 txtScreen.text = previousRes.toString();
res = 0;
 if (previousOperator=="=")
 {
  res = tmpRes;
  txtScreen.text=res.toString();
 }
}

PS. If you have comments that this calculator does not calculate properly, they are also appreciated, yet most important are comments on best practices in Flex.