最近老师让学Flex，于是跟着教学视频做了一个计算器的小程序。刚学，有很多不懂的，请大家多多指教~

【界面】

计算器.png

功能：可以实现加减乘除四种运算方法，以及开方、乘方、取反数等功能。

【代码】

声明变量

private var hasClickFloat:Boolean=false;
private var num:Number;
private var hasOver:Boolean=false;                         
private var cal:String;

函数部分

• 初始化函数

//init
protected function application1_creationCompleteHandler():void{
    result.text="0";
    hasClickFloat=false;
    hasOver=false;
}

• addNumber函数

//append new number
private function addNumber(str:String):void{
    //if not a number
    if(result.text=="NaN"){
        result.text=str; 
    }
    //if result is 0,that str
    else if(result.text=="0"){
         result.text=str; 
    //if over,replace
    }else if(hasOver==true){
        result.text=str;
    //if digits greater than 9
    }else{
        if(result.text.length>=9){
            return;
        }else{
            result.text=result.text+str;
        }
    }
}

• saveNumber函数

//when input calculator,save the previous number
private function saveNumber(str:String):void{
    //let can be input minus
    if(str=="-" && result.text=="0"){
        result.text="-";
        return;
    }
    //when input calculator,let the value begin from 0
    cal=str;                    
    num=Number(result.text);                    
    result.text="0";                    
    hasOver=true;       
}

• addFloat函数

//append a float
private function addFloat():void{
    if(hasClickFloat==true){
        return;
    }else{
        result.text=result.text+".";
        hasClickFloat=true;
    }
}

• 开方函数

//extract
private function pingFang():void{
    result.text=String(Math.sqrt(Number(result.text)))
}

• 平方函数

//square
private function chengFang():void{
    result.text=String((Number(result.text))*(Number(result.text)));
}

• 取反数函数

//inverse number
private function fanShu():void{
    if(result.text=="0"){
        result.text="NaN";
    }else{
        result.text=String(1/Number(result.text));
    }
}

这里要判断下0没有反数哦。

• 输入运算符函数

private function doCal():void{
    if(cal=="+"){
        result.text=String(num+Number(result.text));
    }else if(cal=="-"){
        result.text=String(num-Number(result.text));
    }else if(cal=="*"){
        result.text=String(num*Number(result.text));
    }else if(cal=="/"){
        if(result.text=="0"){
            result.text=="NaN";
        }else {
            result.text=String(num/Number(result.text));
        }
    }
}

• 布局部分代码

<s:HGroup width="100%" height="30" paddingLeft="5" paddingRight="5" verticalAlign="middle" horizontalAlign="center">
    <s:Button label="S" width="40" click="pingFang();"/>
    <s:Button label="G" width="40" click="chengFang();"/>
    <s:Button label="N" width="40" click="fanShu();"/>
    <s:Button label="C" width="40" click="application1_creationCompleteHandler()"/>
</s:HGroup>
<s:HGroup width="100%" height="30">
<s:HGroup width="100%" height="30" paddingLeft="5" paddingRight="5" verticalAlign="middle" horizontalAlign="center">
    <s:Button label="1" width="40" click="addNumber('1')"/>
    <s:Button label="2" width="40" click="addNumber('2')"/>
    <s:Button label="3" width="40" click="addNumber('3')"/>
    <s:Button label="=" width="40" click="doCal();"/>
</s:HGroup>
</s:HGroup>
<s:HGroup width="100%" height="30">
<s:HGroup width="100%" height="30" paddingLeft="5" paddingRight="5" verticalAlign="middle" horizontalAlign="center">
    <s:Button label="4" width="40" click="addNumber('4')"/>
    <s:Button label="5" width="40" click="addNumber('5')"/>
    <s:Button label="6" width="40" click="addNumber('6')"/>
    <s:Button label="+" width="40" click="saveNumber('+');"/>
</s:HGroup>
</s:HGroup>
<s:HGroup width="100%" height="30">
<s:HGroup width="100%" height="30" paddingLeft="5" paddingRight="5" verticalAlign="middle" horizontalAlign="center">
    <s:Button label="7" width="40" click="addNumber('7')"/>
    <s:Button label="8" width="40" click="addNumber('8')"/>
    <s:Button label="9" width="40" click="addNumber('9')"/>
    <s:Button label="-" width="40" click="saveNumber('-');"/>
</s:HGroup>
</s:HGroup>
<s:HGroup width="100%" height="30">
<s:HGroup width="100%" height="30" paddingLeft="5" paddingRight="5" verticalAlign="middle" horizontalAlign="center">
    <s:Button label="0" width="40" click="addNumber('0')"/>
    <s:Button label="." width="40" click="addFloat();"/>
    <s:Button label="/" width="40" click="saveNumber('/');"/>
    <s:Button label="*" width="40" click="saveNumber('*');"/>
</s:HGroup>