I forget to mention in my previous post that the project cleaning doesn't help.

But setting the text property stopped the RTE.

New code :

_label = new Label();

_label.horizontalCenter = 0;

_label.y = 140;

_label.text = "Loading"; // <-- the line that made it

_label.styleName = "loadingLabel";

addChild(_label);

I am getting this error on a very simple (simplest ever?) Air App.

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

<s:WindowedApplication

    xmlns:fx="http://www.adobe.com/2006/mxml"

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

    initialize="onLoad()">

    <fx:Script>

        <![CDATA[

            private function onLoad():void {

            }           

        ]]>

    </fx:Script>

</s:WindowedApplication>

I do not get this on compilation, but on runtime.

[SWF] TestStuff.swf - 2,111,726 bytes after decompression
TypeError: Error #2007: Parameter justificationStyle must be non-null.
    at flash.text.engine::EastAsianJustifier/set justificationStyle()
    at spark.components::Label/createTextLines()[E:\dev\4.x\frameworks\proje cts\spark\src\spark\components\Label.as:802]
    at spark.components::Label/http://www.adobe.com/2006/flex/mx/internal::composeTextLines()[E:\dev\4.x\frameworks\projects\spark\src\spark\components\Label.as: 474]
    at spark.components.supportClasses::TextBase/measure()[E:\dev\4.x\framew orks\projects\spark\src\spark\components\supportClasses\TextBase.as:53 3]
    at mx.core::UIComponent/measureSizes()[E:\dev\4.x\frameworks\projects\fr amework\src\mx\core\UIComponent.as:8216]
    at mx.core::UIComponent/validateSize()[E:\dev\4.x\frameworks\projects\fr amework\src\mx\core\UIComponent.as:8140]
    at mx.managers::LayoutManager/validateSize()[E:\dev\4.x\frameworks\proje cts\framework\src\mx\managers\LayoutManager.as:617]
    at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.x\framewo rks\projects\framework\src\mx\managers\LayoutManager.as:709]
    at mx.managers::LayoutManager/doPhasedInstantiationCallback()[E:\dev\4.x \frameworks\projects\framework\src\mx\managers\LayoutManager.as:1072]

Hi,

I have found another way to reproduce this problem. Weiguo's namespace suggestion doesn't apply to this case.

Essentially I extend the spark Window class and call open() in constructor, like this:

package test

{

          import spark.components.Window;

          public class ExtWindow extends Window

          {

                    public function ExtWindow()

                    {

                              super();

                              open();

                    }

          }

}

Then the following simple application throws the error discussed in this thread

<?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"

                                                     xmlns:test="test.*">

          <fx:Declarations>

                    <test:ExtWindow>

                              <s:Label text="test"/>

                    </test:ExtWindow>

          </fx:Declarations>

</s:WindowedApplication>

That's exactly what I had trouble with, I wanted to add a Label (Spark) to a Sprite Visual Element (I am doing something for mobile and the View needs some other stuff so I used a SVE instead of a Sprite)... that causes problems... here is a good explanation, hope it helps...

                    It's not being displayed because you're not adding Label (which is a UIComponent and works with the component lifecycle) to another UIComponent that will actually instantiate it properly. Your SpriteVisualElement is not made to have UIComponents within it, it's made to have sprites which can draw itself. Label is waiting for 'invalidateDisplayList' to be called so that it can draw itself.

                    Either do a force draw or use a UIComponent as the container for Label.

                              http://stackoverflow.com/questions/6549374/flex-spritevisualelement-can-not -add-as-a-child-spark-label