Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/04/30/always-displaying-the-selected-text-in-a-textinput-in-flex/ -->
<mx:Application name="TextInput_getTextField_alwaysShowSelection_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.core.UITextField;
            import mx.controls.TextInput;

            private function init(evt:Event):void {
                var ti:TextInput = evt.currentTarget as TextInput;
                var tf:UITextField = ti.mx_internal::getTextField();
                tf.alwaysShowSelection = true;
            }
        ]]>
    </mx:Script>

    <mx:TextInput id="textInput"
            text="The quick brown fox jumps over the lazy dog."
            selectionBeginIndex="4" selectionEndIndex="9"
            initialize="init(event);" />
    <mx:Button label="Submit" />

</mx:Application>

View source is enabled in the following example.

 

Full code after the jump.

<?xml version="1.0" encoding="utf-8"?>
<mx:Application name="TextArea_tabStops_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            private function init1():void {
                var tf:TextFormat = new TextFormat();
                tf.tabStops = [100, 200, 300, 400];

                textArea1.mx_internal::getTextField().setTextFormat(tf);
            }

            private function init3():void {
                textArea3.htmlText = "<TEXTFORMAT TABSTOPS='100,200,300,400'><P>The quick<TAB/>brown fox<TAB/>jumps over<TAB/>the lazy<TAB/>dog.</P><P>The<TAB/>quick brown<TAB/>fox jumps<TAB/>over the<TAB/>lazy dog.</P></TEXTFORMAT>";
            }

            private function init4():void {
                var tf:TextFormat = new TextFormat();
                tf.tabStops = [100, 200, 300, 400];

                textArea4.mx_internal::getTextField().defaultTextFormat = tf;
                textArea4.text = "The quick\\tbrown fox\\tjumps over\\tthe lazy\\tdog.\\nThe\\tquick brown\\tfox jumps\\tover the\\tlazy dog.";

                textArea4.validateNow();
                trace(textArea4.htmlText);
            }
        ]]>
    </mx:Script>

    <mx:TextArea id="textArea1"
            condenseWhite="true"
            width="500"
            creationComplete="init1();">
        <mx:htmlText>
            <![CDATA[
                <p>The quick<tab/>brown fox<tab/>jumps over<tab/>the lazy<tab/>dog.</p><p>The<tab/>quick brown<tab/>fox jumps<tab/>over the<tab/>lazy dog.</p>
            ]]>
        </mx:htmlText>
    </mx:TextArea>

    <mx:TextArea id="textArea2"
            condenseWhite="true"
            width="500">
        <mx:htmlText>
            <![CDATA[
                <TEXTFORMAT TABSTOPS="100,200,300,400"><P>The quick<TAB/>brown fox<TAB/>jumps over<TAB/>the lazy<TAB/>dog.</P><P>The<TAB/>quick brown<TAB/>fox jumps<TAB/>over the<TAB/>lazy dog.</P></TEXTFORMAT>
            ]]>
        </mx:htmlText>
    </mx:TextArea>

    <mx:TextArea id="textArea3"
            condenseWhite="true"
            width="500"
            initialize="init3();" />

    <mx:TextArea id="textArea4"
            width="500"
            initialize="init4();" />

</mx:Application>

 

You can also find the version number by doing one of the following:
(a) Viewing the flex-sdk-description.xml file in your Flex SDK’s root directory:

<?xml version="1.0"?>
<flex-sdk-description>
    <name>Flex 4.0</name>
    <version>4.0.0</version>
    <build>3934</build>
</flex-sdk-description>

(b) At a command prompt, navigate to your Flex SDK’s /bin/ directory and type mxmlc -version:

C:\\dev\\flexSDKs\\4.0.0.3934\\bin>mxmlc -version
Version 4.0.0 build 3934

Full code after the jump.

Since this example uses the mx_internal namespace, you can’t always depend on this behavior to work in future versions of the Flex SDK. Use at your own risk.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/10/29/determining-your-flex-sdk-version-number/ -->
<mx:Application name="mx_internal_VERSION_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Label text="{mx_internal::VERSION}" />

</mx:Application>

View source is enabled in the following example.

Due to popular demand, here is the “same” example in a more ActionScript friendly format:

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/10/29/determining-your-flex-sdk-version-number/ -->
<mx:Application name="mx_internal_VERSION_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white"
        initialize="init();">

    <mx:Script>
        <![CDATA[
            import mx.controls.Label;

            private var lbl:Label;

            private function init():void {
                lbl = new Label();
                lbl.text = mx_internal::VERSION;
                addChild(lbl);
            }
        ]]>
    </mx:Script>

</mx:Application>

Or, you can use data binding (and not get a warning) by using the use namespace, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/10/29/determining-your-flex-sdk-version-number/ -->
<mx:Application name="mx_internal_VERSION_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            use namespace mx_internal;
        ]]>
    </mx:Script>

    <mx:Label text="{VERSION}" />

</mx:Application>

 

Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/05/08/determining-the-number-of-lines-in-a-textarea-control-in-flex/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.utils.StringUtil;

            private function textArea_change(evt:Event):void {
                callLater(updateStats, [evt]);
            }

            private function updateStats(evt:Event):void {
                var nLines:uint = textArea.mx_internal::getTextField().numLines;
                var nChars:uint = textArea.length;
                var str:String = "{0} characters; {1} lines";
                panel.status = StringUtil.substitute(str,
                                    nChars,
                                    nLines);
            }
        ]]>
    </mx:Script>

    <mx:String id="str" source="lorem.txt" />

    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="width (%):">
                <mx:HSlider id="slider"
                        minimum="50"
                        maximum="100"
                        value="100"
                        liveDragging="true"
                        snapInterval="1"
                        tickInterval="10" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:Panel id="panel"
            percentWidth="{slider.value}"
            height="100%">
        <mx:TextArea id="textArea"
                htmlText="{str}"
                condenseWhite="true"
                width="100%"
                height="100%"
                change="textArea_change(event);"
                resize="textArea_change(event);" />
    </mx:Panel>

</mx:Application>

View source is enabled in the following example.

 

Download source (ZIP, 2K) | View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/07/21/setting-an-icon-in-an-alert-control/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        creationComplete="showAlert();"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.controls.Alert;
            import mx.events.CloseEvent;

            // Embed the error.png image.
            [Bindable]
            [Embed(source='assets/error.png')]
            private var Icon:Class;

            private var a:Alert;

            private function showAlert():void {
                var titleText:String = "WARNING";
                var messageText:String = "Are you sure you would like to erase the Internet?\\n\\nPress OK to continue, or Cancel to abort.";
                /* Display the Alert, show the OK and Cancel buttons,
                    and show an icon represented by the Icon binding. */
                a = Alert.show(messageText, titleText, Alert.OK | Alert.CANCEL, null, doClose, Icon);
            }

            private function doClose(evt:CloseEvent):void {
                // do nothing.
            }
        ]]>
    </mx:Script>

    <mx:Button label="Launch Alert" click="showAlert();" />

</mx:Application>

View source enabled in the following example.

The second example uses the mx_internal namespace to access a couple of internal properties (descriptions taken from the documented source code):

alertForm — The internal AlertForm object that contains the text, icon, and buttons of the Alert control.
buttons — An Array that contains any Buttons appearing in the Alert control.

Since this example uses the mx_internal namespace, you can’t always depend on this behavior to work in future versions of the Flex SDK. Use at your own risk.

Download source (ZIP, 4K) | View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/07/21/setting-an-icon-in-an-alert-control/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        creationComplete="showAlert();"
        backgroundColor="white" >

    <mx:Script>
        <![CDATA[
            import mx.controls.Alert;
            import mx.events.CloseEvent;

            [Bindable]
            [Embed(source='assets/error.png')]
            private var Icon:Class;

            [Bindable]
            [Embed(source='assets/tick.png')]
            private var TickIcon:Class;

            [Bindable]
            [Embed(source='assets/cross.png')]
            private var CrossIcon:Class;

            private var a:Alert;

            private function showAlert():void {
                /* Set button width so it is large enough to accomodate
                    an icon and default button labels. */
                Alert.buttonWidth = 100;

                var titleText:String = "WARNING";
                var messageText:String = "Are you sure you would like to erase the Internet?\\n\\nPress OK to continue, or Cancel to abort.";
                /* Display the Alert, show the OK and Cancel buttons,
                    and show an icon represented by the Icon binding. */
                a = Alert.show(messageText, titleText, Alert.OK | Alert.CANCEL, null, doClose, Icon);

                /* Get a reference to the Alert control's internal
                    buttons array. */
                var buttonArray:Array = a.mx_internal::alertForm.mx_internal::buttons;

                /* Set the first button to the TickIcon class, and the
                    second icon to the CrossIcon class. */
                buttonArray[0].setStyle("icon", TickIcon);
                buttonArray[1].setStyle("icon", CrossIcon);

                progressBar.visible = false;
            }

            private function doClose(evt:CloseEvent):void {
                if (evt.detail == Alert.OK) {
                    progressBar.visible = true;
                } else if (evt.detail == Alert.CANCEL) {
                    // do nothing.
                }
            }
        ]]>
    </mx:Script>

    <mx:Button label="Launch Alert"
            click="showAlert();" />

    <mx:ProgressBar id="progressBar"
            label="Deleting..."
            indeterminate="true"
            visible="false" />

</mx:Application>

View source enabled in the following example.