Question

我正在尝试在AS3中创建基本功能。

我有一个这样的课程：

package tax 
{
    public class Calculator
    {

        public function Calculator() 
        {
        }

        private var grwage:Number;
        private var taxes:Number;
        private var superannuation:Number;
        private var insurance:Number;
        private var net:Number;

        public function getGrwage():Number {
            return grwage;
        } 

        public function setGrwage(grwage:Number):void {
            this.grwage = grwage;
        }

        public function getTaxes():Number {
            return grwage;
        } 

        public function setTaxes(taxes:Number):void {
            this.taxes = grwage * 0.2;
        }

        public function getSup():Number {
            return superannuation;
        } 

        public function setSup(superannuation:Number):void {
            this.superannuation = superannuation * 0.05;
        }

        public function getIns():Number {
            return insurance;
        } 

        public function setIns(insurance:Number):void {
            this.insurance = insurance * 0.1;
        }

        public function getNet():Number {
            return net;
        } 

        public function setNet(net:Number):void {
            this.net = grwage - taxes - superannuation - insurance;
        }

    }
}

只是一些吸气剂和制定者。

在我的mxml文件中：

        import tax.Calculator;

                    public var calculate:Calculator = new Calculator();

        calculate.setGrwage(1000);
        trace(calculate.getTaxes());
        trace(calculate.getSup());
        trace(calculate.getIns());
        trace(calculate.getNet());

我收到错误1120当我尝试访问计算时访问未找到的属性。你有什么想法吗？

感谢。

Answer 1

我猜你们在吸气剂和制定者之间混淆了一些东西。如果变量依赖于另一个变量，则必须在其getter中编写计算。此变量不应作为私有成员存在，并且必须始终通过适当的getter来访问它。

例如：

public function getNet():Number {
    return getGrwage() - getTaxes() - getSup() - getIns();
}

所以在这里，你只需要一个setter（setGrwage），你可以删除其他的setter并将计算放在getter中。

请注意，AS3中的setter和getter更合适syntax。

class GetSet 
{ 
    private var privateProperty:String; 

    public function get publicAccess():String 
    { 
        return privateProperty; 
    } 

    public function set publicAccess(setValue:String):void 
    { 
        privateProperty = setValue; 
    } 
}

Answer 2

您班级有多个问题。所以我们重新设计它你遇到的主要问题是你在访问它们之前没有启动变量，因为它们有一个NULL值，闪存播放器会把这个错误抛给你。正如您在构造函数中看到的，我将默认值设置为0，以便它们永远不会为NULL。

package tax {
    public class Calculator{

        private var _grwage:Number;
        private var _taxes:Number;
        private var _superannuation:Number;
        private var _insurance:Number;

        public function Calculator() {
          this._grwage = 0;
          this._taxes = 0;
          this._superannuation = 0;
          this._insurance = 0;
        }

        public function get grwage():Number {
            return this._grwage;
        } 

        public function set grwage(val:Number):void {
            this._grwage = val;
        }

        public function get taxes():Number {
            return this._taxes;
        } 

        public function set taxes(val:Number):void {
            this._taxes = val * 0.2;
        }

        public function get superannuation():Number {
            return this._superannuation;
        } 

        public function set superannuation(val:Number):void {
            this._superannuation = val * 0.05;
        }

        public function get insurance():Number {
            return this._insurance;
        } 

        public function set insurance(val:Number):void {
            this._insurance = val* 0.1;
        }

        public function get net():Number {
            return this._grwage -  this._taxes -  this._superannuation -  this._insurance;
        }

    }
}

    import tax.Calculator;
    public var calculate:Calculator = new Calculator();
     //Now due to the fact we are using true setter/getter methods.
    calculate.grwage = 1000;
    trace( calculate.taxes); // should be 0 as we are defaulting to the initial value
    trace( calculate.superannuation );// should be 0 as we are defaulting to the initial value
    trace( calculate.insurance );// should be 0 as we are defaulting to the initial value
    trace( calculate.net );// should be 1000 as we are defaulting to the initial values of everything but grwage

Answer 3

这里的答案都很好，但他们都错过了主要观点：

您在设置之前尝试获取变量。

import tax.Calculator;

public var calculate:Calculator = new Calculator();

calculate.setGrwage(1000);
trace(calculate.getTaxes());
trace(calculate.getSup());
trace(calculate.getIns());
trace(calculate.getNet());

这会引发错误（由于您设置课程的方式），因为您在尝试使用它们之前从未调用setSup()，setIns()和setNet()。

虽然你的课可能不是以最好的方式写的，但它在语法上是合理的。

尝试在getter之前调用每个setter。我想你会解决你的问题。

AS3 1120实例化时出错

3 个答案: