RE: [flexcoders] Flex2B3 :: viewMtrics - borderMetrics :: What changed

[Gordon Smith]

It sounds like you don't have a correct understanding of object references. A lot of different variables can contain references to (or "point" to) the same object instance. A Container instance has a reference to an EdgeMetrics instance. When you execute       var v:EdgeMetrics = super.viewMetrics;   your local variable v now contains a reference to the SAME EdgeMetrics instance that the Container is using; v and some var in the Container instance are "sharing" the same object. When you then assign       v.left =  ...   you are modifying the shared EdgeMetrics instance.   Here''s a simple example of this using Arrays:       var a1:Array = [ "foo" ];     var a2 = a1;     a2[0] = "bar";     trace(a1[0]); // traces "bar", not "foo", because a1 and a2 are two references to the same Array object   In AS3 as in most languages, Arrays, Objects, and all subclasses of them are passed and returned "by reference", not "by value", because they are potentially large and it is much more efficient to pass just a 4-byte address of an object in memory rather than copying all the data inside the object. If you need your own copy, you have to make a copy. That's what a method like clone() is for. We could have implemented the viewMetrics property to make a copy, but we chose not to for performance reasons. The documentation probably isn't always clear about whether an API returns a copy or a reference to the original object.   - Gordon   From: flexcoders@yahoogroups.com [mailto:flexcoders@yahoogroups.com] On Behalf Of Michael Schmalle Sent: Thursday, May 18, 2006 2:28 PM To: flexcoders@yahoogroups.com Subject: Re: [flexcoders] Flex2B3 :: viewMtrics - borderMetrics :: What changed   > you shouldn't be modifying it. Gordon, this is the delema, I'm not modifing it. I am 'getting' it. I am 'modifying' viewmetrics to add the heights of added bars into the Window. Oh well, sounds like it's something that I have backasswarded, I will figure it out. Thanks for your time peoplz Peace, Mike On 5/18/06, Gordon Smith <[EMAIL PROTECTED]> wrote: I don't think we changed anything... properties that return an EdgeMetrics all return a reference to the actual EdgeMetrics object used by the container, you shouldn't be modifying it. EdgeMetrics has a clone() method for making your own copy. - Gordon -----Original Message----- From: flexcoders@yahoogroups.com [mailto: flexcoders@yahoogroups.com] On Behalf Of Manish Jethani Sent: Thursday, May 18, 2006 8:33 AM To: flexcoders@yahoogroups.com Subject: Re: [flexcoders] Flex2B3 :: viewMtrics - borderMetrics :: What changed On 5/18/06, Michael Schmalle <[EMAIL PROTECTED]> wrote: > Please refer to this post for more information. > > Flex2B3 :: Container subclass :: viewMetrics - borderMetrics Okay, this one:     override public function get viewMetrics():EdgeMetrics     {          var v:EdgeMetrics = super.viewMetrics;          var b:EdgeMetrics = borderMetrics;          trace("viewMetrics", v.left)          trace("borderMetrics", b.left)         if (dragEnabled) {              if (direction == "horizontal") {                  v.left = draggerButton.width;              } else {                  v.top = draggerButton.height;              }          }          return v;     } > There is something that is fishy. I am NOT changing border metrics but, when I go to qeury it after viewMetrics has run, it holds the actual viewMetrics values not the simple values of 1 or 2 for solid, outset etc... Not sure why that's happening (don't have access to source at the moment), but could you try making a *copy* of viewMetrics instead of modifying the value returned by super.viewMetrics? -- Flexcoders Mailing List FAQ: http://groups.yahoo.com/group/flexcoders/files/flexcodersFAQ.txt Search Archives: http://www.mail-archive.com/flexcoders%40yahoogroups.com Yahoo! Groups Links -- Flexcoders Mailing List FAQ: http://groups.yahoo.com/group/flexcoders/files/flexcodersFAQ.txt Search Archives: http://www.mail-archive.com/flexcoders%40yahoogroups.com SPONSORED LINKS Web site design development Computer software development Software design and development Macromedia flex Software development best practice     YAHOO! GROUPS LINKS    Visit your group "flexcoders" on the web.    To unsubscribe from this group, send an email to:   [EMAIL PROTECTED]    Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.   -- What goes up, does come down. -- Flexcoders Mailing List FAQ: http://groups.yahoo.com/group/flexcoders/files/flexcodersFAQ.txt Search Archives: http://www.mail-archive.com/flexcoders%40yahoogroups.com SPONSORED LINKS Web site design development Computer software development Software design and development Macromedia flex Software development best practice YAHOO! GROUPS LINKS  Visit your group "flexcoders" on the web.    To unsubscribe from this group, send an email to:  [EMAIL PROTECTED]    Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.