圆数问题flex [英] Round Number problem flex

问题描述

这段代码有问题:

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
                   xmlns:s="library://ns.adobe.com/flex/spark"
                   xmlns:mx="library://ns.adobe.com/flex/mx"
                   showStatusBar="false"
                   width="250" height="31">
<s:layout>
    <s:HorizontalLayout gap="10" paddingBottom="10" paddingLeft="10" paddingRight="10"
                        paddingTop="10" verticalAlign="middle"/>
</s:layout>
<fx:Script>
    <![CDATA[
        [Bindable]
        private var i:Number = 1.0;

        private function click(e:MouseEvent):void
        {
            if (e.currentTarget == plus)
                i += .1;
            if (e.currentTarget == minus)
                i -= .1;
        }
    ]]>
</fx:Script>
<s:Button id="plus" width="30" label="+" click="click(event)"/>
<s:Button id="minus" width="30" label="-" click="click(event)"/>
<s:Label text="{i}"/>

当我点击+"时，我得到
1.1(确定)
1.2000000000000002(而不是1.2)
1.3000000000000003(而不是1.3)
1.4000000000000004(而不是1.4)
1.5000000000000004(而不是1.5)
1.6000000000000005(而不是1.6)
1.7000000000000006(而不是1.7)
1.8000000000000007(而不是1.8)
1.9000000000000008(而不是1.9)
2.000000000000001(而不是2.0)
...
当我点击-"时，我得到
0.9(好)
0.8(好)
0.7000000000000001(而不是0.7)
0.6000000000000001(而不是0.6)
0.5000000000000001(而不是0.5)
0.40000000000000013(而不是0.4)
0.30000000000000016(而不是0.3)
0.20000000000000015(而不是0.2)
0.10000000000000014(而不是0.1)
1.3877787807814457e-16(而不是0.0)
...
我通过

When I click on '+' I get
1.1 (OK)
1.2000000000000002 (instead of 1.2)
1.3000000000000003 (instead of 1.3)
1.4000000000000004 (instead of 1.4)
1.5000000000000004 (instead of 1.5)
1.6000000000000005 (instead of 1.6)
1.7000000000000006 (instead of 1.7)
1.8000000000000007 (instead of 1.8)
1.9000000000000008 (instead of 1.9)
2.000000000000001 (instead of 2.0)
...
And when I click on '-' I get
0.9 (OK)
0.8 (OK)
0.7000000000000001 (instead of 0.7)
0.6000000000000001 (instead of 0.6)
0.5000000000000001 (instead of 0.5)
0.40000000000000013 (instead of 0.4)
0.30000000000000016 (instead of 0.3)
0.20000000000000015 (instead of 0.2)
0.10000000000000014 (instead of 0.1)
1.3877787807814457e-16 (instead of 0.0)
...
I change my function by

private function click(e:MouseEvent):void
{
    if (e.currentTarget == plus)
        i = Math.floor((i + 0.1) * 10) / 10;
    if (e.currentTarget == minus)
        i = Math.floor((i - 0.1) * 10) / 10;
}

当我只点击+"或只点击-"时，我得到了正确的数字
但是如果我点击-"直到 0.7 和+"，它会保持在 0.7
当我单击-"时相同的附加，直到+"时为 0.9，它保持为 0.8

I get the right number when I click on only '+' or only on '-'
But if I click '-' until 0.7 and '+', it stays at 0.7
The same append when I click '-' until 0.9 when '+', it stay to 0.8

为什么?如何将数字增加或减少 0.1?

Why? How can I do to increment or decrement a Number by 0.1?

推荐答案

尝试使用:

private function click(e:MouseEvent):void
{
    if (e.currentTarget == plus)
        i = Math.round((i + 0.1) * 10) / 10;
    if (e.currentTarget == minus)
        i = Math.round((i - 0.1) * 10) / 10;
}

或者在 Flex 4.5 的情况下:

Or in case of Flex 4.5:

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
                   xmlns:s="library://ns.adobe.com/flex/spark"
                   xmlns:mx="library://ns.adobe.com/flex/mx"
                   showStatusBar="false"
                   width="250" height="31">
<s:layout>
    <s:HorizontalLayout gap="10" paddingBottom="10" paddingLeft="10" paddingRight="10"
                        paddingTop="10" verticalAlign="middle"/>
</s:layout>
<fx:Script>
    <![CDATA[
        [Bindable]
        private var i:Number = 1.0;

        private function click(e:MouseEvent):void
        {
            if (e.currentTarget == plus)
                i += .1;
            if (e.currentTarget == minus)
                i -= .1;
        }
    ]]>
</fx:Script>
<fx:Declarations>
    <s:NumberFormatter id="numberFormatter" trailingZeros="true" fractionalDigits="1" />
</fx:Declarations><s:Button id="plus" width="30" label="+" click="click(event)"/>
<s:Button id="minus" width="30" label="-" click="click(event)"/>
<s:Label text="{numberFormatter.format(i)}"/>
</s:WindowedApplication>

或者在 Flex 4 的情况下:

Or in case of Flex 4:

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
                   xmlns:s="library://ns.adobe.com/flex/spark"
                   xmlns:mx="library://ns.adobe.com/flex/mx"
                   showStatusBar="false"
                   width="250" height="31">
<s:layout>
    <s:HorizontalLayout gap="10" paddingBottom="10" paddingLeft="10" paddingRight="10"
                        paddingTop="10" verticalAlign="middle"/>
</s:layout>
<fx:Script>
    <![CDATA[
        [Bindable]
        private var i:Number = 1.0;

        private function click(e:MouseEvent):void
        {
            if (e.currentTarget == plus)
                i += .1;
            if (e.currentTarget == minus)
                i -= .1;
        }
    ]]>
</fx:Script>
<fx:Declarations>
    <mx:NumberFormatter id="numberFormatter" precision="1" rounding="nearest" />
</fx:Declarations><s:Button id="plus" width="30" label="+" click="click(event)"/>
<s:Button id="minus" width="30" label="-" click="click(event)"/>
<s:Label text="{numberFormatter.format(i)}"/>
</s:WindowedApplication>

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