User feedback with maxChar attribute on TextInput

Question

I have a textinput with maxChars=6
i would like to have some sort of user feedback when they attempt to type the 7th char.  (red border, tooltip, etc...)
what would be the ideal way to achieve this?
I don't see where there is an event dispatched when a user tries to type the 7th char ?

Answer 1

Hi there,
The change event would be a solution but a slightly more efficient solution would be to simply listen for a keyDown event. Here's a fast example that hopefully will help you get on the right track:
<?xml version="1.0" encoding="utf-8"?>
<mx:Application
    xmlns:mx            ="http://www.adobe.com/2006/mxml"
    backgroundColor     ="#FFFFFF"
    layout              ="absolute">
    <mx:Script>
        <![CDATA[
            import mx.controls.Alert;
            import mx.events.FlexEvent;
            import mx.controls.TextInput;
            private static const ALLOWED_MAX_CHARS:int = 6;
            private function onInputFieldFill(event:KeyboardEvent):void
                if (event.charCode != Keyboard.LEFT &&
                    event.charCode != Keyboard.RIGHT &&
                    event.charCode != Keyboard.UP &&
                    event.charCode != Keyboard.DOWN)
                    var target:TextInput = event.currentTarget as TextInput;
                    if (target.text.length > ALLOWED_MAX_CHARS - 1)
                        target.text = target.text.slice(0, ALLOWED_MAX_CHARS);
                        Alert.show("You tried to add 7 characters!", "ERROR");
        ]]>
    </mx:Script>
    <mx:VBox
        width               ="100%"
        height              ="100%"
        horizontalAlign     ="center"
        verticalAlign       ="middle">
        <mx:TextInput
            id              ="userInputField"
            keyDown         ="onInputFieldFill(event)"/>
    </mx:VBox>
</mx:Application>
The code I posted is not perfect, it's an older file of mine that I have found and edited a bit so don't use it as it is.
Blog: http://blog.wisebisoft.com
With best regards,
Barna Biro