Your chart has only one line or multiple lines? If you can ellaborate little more or paste your sample code here, that would help to understand your problem precisely.

It mainly depends on your data, it's attributes to dynamically assign these attributes based on slider selection, at runtime.

Hopefully, this shall solve your purpose. This gets your line series dynamically:

<?xml version="1.0"?>

<!-- charts/BasicLineStroke.mxml -->

<s:Application

    xmlns:fx="http://ns.adobe.com/mxml/2009"

    xmlns:mx="library://ns.adobe.com/flex/mx"

    xmlns:s="library://ns.adobe.com/flex/spark"

    creationComplete="drawChart()"

    height="100%" width="100%">

    <fx:Script>

        <![CDATA[

            import mx.charts.series.LineSeries;

            import mx.events.FlexEvent;

            import mx.events.SliderEvent;

            import mx.rpc.events.ResultEvent;

            import spark.events.IndexChangeEvent;

            protected function drawChart():void

            {

                // TODO Auto-generated method stub

                var ls:LineSeries = new LineSeries();

                ls.yField='@'+String(cb.selectedItem.@attributeName);

                ls.displayName=String(cb.selectedItem.@desc);

                var seriesArray:Array = []; // you can push all your line series here, if you have more than one also

                seriesArray.push(ls);

                myChart.series = seriesArray;

            }

        ]]>

    </fx:Script>

    <fx:Declarations>

        <fx:XML id="myXML" xmlns="">

            <root>

                <row month="Jan" seriesA="200" seriesB="545" seriesC="234"/>

                <row month="Feb" seriesA="234" seriesB="123" seriesC="865"/>

                <row month="Mar" seriesA="753" seriesB="456" seriesC="345"/>

                <row month="Apr" seriesA="123" seriesB="322" seriesC="846"/>

            </root>

        </fx:XML>

    </fx:Declarations>

    <s:layout>

        <s:VerticalLayout/>

    </s:layout>

    <s:Panel title="Line Chart" width="100%" height="100%">

        <s:layout>

            <s:VerticalLayout/>

        </s:layout>

        <s:ComboBox id="cb" change="drawChart()" selectedIndex="0" labelField="@desc">

            <s:dataProvider>

                <s:XMLListCollection>

                    <fx:XMLList xmlns="">

                        <row attributeName="seriesA" desc="Series A"/>

                        <row attributeName="seriesB" desc="Series B"/>

                        <row attributeName="seriesC" desc="Series C"/>

                    </fx:XMLList>

                </s:XMLListCollection>

            </s:dataProvider>

        </s:ComboBox>

        <mx:LineChart id="myChart"

                      dataProvider="{myXML.row}"

                      showDataTips="true" width="100%" height="100%">

            <mx:horizontalAxis>

                <mx:CategoryAxis categoryField="@month"/>

            </mx:horizontalAxis>

        </mx:LineChart>

        <mx:Legend dataProvider="{myChart}"/>

    </s:Panel>

</s:Application>

Try this. I hope this is what you wanted.

<?xml version="1.0" encoding="utf-8"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" minWidth="955" minHeight="600"

                width="100%" height="100%" layout="vertical" horizontalAlign="left" verticalAlign="middle"

                creationComplete="application1_creationCompleteHandler(event)">

    <mx:Script>

        <![CDATA[

            import mx.events.FlexEvent;

            import mx.events.SliderEvent;

            [Bindable]private var dataValues:Array = [];

            protected function application1_creationCompleteHandler(event:FlexEvent):void

            {

                // TODO Auto-generated method stub

                for each(var node:XML in xml.ROOT)

                {

                    dataValues.push(String(node.TXTA));

                }

                dataValues.sort(Array.NUMERIC);

                hSlider.values = dataValues;

                hSlider.minimum = dataValues[0];

                hSlider.maximum = dataValues[dataValues.length-1];

                hSlider.labels = dataValues;

                hSlider.snapInterval = 10;

                hSlider.tickInterval = 10;

                hSlider_changeHandler();

            }

            protected function hSlider_changeHandler():void

            {

                // TODO Auto-generated method stub

                for each(var node:XML in xml.ROOT)

                {

                    if(Number(node.TXTA) == hSlider.value)

                    {

                        sliderXML = new XML('<ROOTS>'+node.toXMLString()+'</ROOTS>');

                        break;

                    }

                }

                barchart2.dataProvider = sliderXML.ROOT;

            }

        ]]>

    </mx:Script>

    <mx:HSlider id="hSlider" width="100%" change="hSlider_changeHandler()" />

    <mx:HBox width="100%" height="100%">

        <mx:VBox width="50%" height="100%">

            <mx:BarChart  id="barchart1" type="stacked"  showDataTips="true" dataProvider="{xml.ROOT}" >

                <mx:verticalAxis>

                    <mx:CategoryAxis categoryField="name"/>

                </mx:verticalAxis>

                <mx:series>

                    <mx:BarSeries  xField="TXTA" />

                </mx:series>

            </mx:BarChart>

        </mx:VBox>

        <mx:VBox width="50%" height="100%">

            <mx:BarChart  id="barchart2" type="stacked"  showDataTips="true" >

                <mx:verticalAxis>

                    <mx:CategoryAxis categoryField="name"/>

                </mx:verticalAxis>

                <mx:series>

                    <mx:BarSeries  xField="TXTA" />

                </mx:series>

            </mx:BarChart>

        </mx:VBox>

    </mx:HBox>

    <mx:XML id="sliderXML"/>

    <mx:XML id="xml" xmlns="">

        <ROOTS>

            <ROOT>

                <name>Assignment</name>

                <TXTA>10</TXTA>

            </ROOT>

            <ROOT>

                <name>Discussion</name>

                <TXTA>20</TXTA>

            </ROOT>

            <ROOT>

                <name>class</name>

                <TXTA>30</TXTA>

            </ROOT>

            <ROOT>

                <name>Co-study</name>

                <TXTA>40</TXTA>

            </ROOT>

            <ROOT>

                <name>Self-study</name>

                <TXTA>50</TXTA>

            </ROOT>

        </ROOTS>

    </mx:XML>

</mx:Application>

Add fill function for your bar series for colour change:

private static const DEFAULT_VALUE:Number = 30;

            private function barSeries_fillFunc(item:ChartItem, index:Number):IFill {

                var currItem:BarSeriesItem = BarSeriesItem(item);

                if(Number(currItem.item.TXTA) >= DEFAULT_VALUE)

                {

                    return new SolidColor(0xFF0000, 1.0);//if TXTA value is 30 or more, show in RED

                }else

                {

                    return new SolidColor(0x00FF00, 1.0);// if TXTA value is less than 30, show in GREEN

                }

            }

<mx:BarChart  id="barchart2" type="stacked"  showDataTips="true" >

                <mx:verticalAxis>

                    <mx:CategoryAxis categoryField="name"/>

                </mx:verticalAxis>

                <mx:series>

                    <mx:BarSeries  xField="TXTA" fillFunction="barSeries_fillFunc" />

                </mx:series>

            </mx:BarChart>

One more thing how to enable the multi browser support for flex application..

Flex application depends on flash player, whichever browser has flash player, flex application works on it. This feature is what makes it browser independent.

how to design the application that suitable to all monitor size

For this you need to specify your containers' size in terms of percentage(width = "25%" height="80%")

You need to import those classes.

Add following two lines on top:

import mx.charts.ChartItem;           

import mx.graphics.IFill;

            import mx.charts.series.items.BarSeriesItem;

            import mx.events.FlexEvent;

            import mx.events.SliderEvent;

            import mx.charts.ChartItem;

            import mx.graphics.IFill;

            import mx.graphics.SolidColor;