Flex 3 to Flex 4 conversion problems and solutions

My recently work project has Flex front-end for UI design. Following problems I faced when it is compiled by converting to Flex 4 SDK from Flex 3 SDK . I would like to share this information with all of you.

Problem	Solution
Error: The style 'dropShadowEnabled' is only supported by type 'flexlib.containers.SuperTabNavigator' with the theme(s) 'halo'.	Use dropShadowVisible  propert y instead  dropShadowEnabled
Error: The style 'borderThickness' is only supported by type 'mx.containers.VBox' with the theme(s) 'halo'.	Use borderWeight  property in BorderContainer component in Spark theme
Error: The style 'themeColor' is only supported by type 'mx.containers.VBox' with the theme(s) 'halo'.	Use ChromeColor instead of themeColor
Error: The style 'backgroundImage' is only supported by type 'mx.containers.Canvas' with the theme(s) 'halo'.	Use BorderContainer component to set background image in spark theme like this  by enclosing your component    <s:BorderContainer backgroundImage="@Embed(source='/com/tranzfinity/images/login-screen.jpg')"> <mx:Canvas  …./> </s:BorderContainer>y enclosing your componentd image in spark theme in Flex 4
Error: Incorrect number of arguments.  Expected 3.	Try with adding null value for required arguments
Error: Access of undefined property sortCompareFunction function within mx.DataGridColumn	Ex: sortCompareFunction= "caseinsensitivesort('displayname')" Use it like this, sortCompareFunction=" {caseinsensitivesort('displayname')}" (put method name enclosing curly bracket)
Error: Type was not found or was not a compile-time constant	Add Flex 4 -flexlib.swc into project  libs

 

Most of the Flex 3 to Flex 4 conversion problems occurs due to different default themes in Flex verions

    Flex 3  default theme is Halo theme,

    Flex 4 default theme is Spark theme.

If you want to appear Halo theme as default theme in Flax 4, use this configuration changes in flex-config.xml (flex_sdk_4\frameworks\flex-config.xml)  file in flex-sdk-4 .

<theme>

<!-- The Flex 4 default theme is Spark. -->

<!-- <filename>themes/Spark/spark.css</filename> -->

<filename>themes/Halo/halo.swc</filename>

</theme>

Solution for some of Flex programming problems: The class not found in jar file: mxmlc.jar

This error may occur when you switch from Flex 3 SDK to Flex 4 SDK.

To resolve this error,
copy the {FLEX_HOME}/ant/lib/flexTasks.jar file from Flex 4 SDK and replace the existing flexTasks.jar in  Ant's lib directory ({ANT_HOME}/lib)