Currently i write a lil' component to display class hierachies. I wrote my own
TreeDataDescriptor. SInce i work with my own class-, packages- and
interface-descriptor
classes to describe the structure, i encapsule some ArrayCollection. In order
to display the
structures in a tree, i need to melt them together in one ArrayCollection. So
far so good...
Since i want not to create a new ArrayCollection everytime the
ITreeDataDescriptor#getChildren is called, i thought to create one
ArrayCollection and
remove all items when the function is called. I thought it would be ok to
create a new field
(typed: ArrayCollection) for the class. But actually the forces my component to
crash.
Here's the code:
<pre><code>
public function getChildren(node:Object, model:Object=null):ICollectionView {
trace(this._className+"#getChildren");
try {
if(node is PackageDescriptor) {
this._children.sort = null;
/*try {
this._children.removeAll();
this._children.refresh();
} catch (e:Error) {
trace("Error: "+e.message)
} catch (e1:StackOverflowError) {
trace("StackOverflowError: "+e1.message);
} catch (e2:CollectionViewError) {
trace("CollectionViewError: "+e2.message);
} catch (e3:ArgumentError) {
trace("ArgumentError: "+e2.message);
}*/
trace("\tnode.className:
"+PackageDescriptor(node).className);
this._children = new ArrayCollection();
var packageDescriptor:PackageDescriptor =
PackageDescriptor(node);
for (var i:uint = 0;
i<packageDescriptor.packages.length; i++) {
this._children.addItem(PackageDescriptor(packageDescriptor.packages.getItemAt(i)));
}
for (var j:uint = 0;
j<packageDescriptor.classes.length; j++) {
this._children.addItem(ClassDescriptor(packageDescriptor.classes.getItemAt(j)));
}
for (var k:uint = 0;
k<packageDescriptor.interfaces.length; k++) {
this._children.addItem(InterfaceDescriptor(packageDescriptor.interfaces.getItemAt(k)));
}
/*for (var l:uint = 0; l<this._children.length; l++) {
trace("\t\t"+l+":
"+this._children.getItemAt(l).name);
}*/
return this._children;
}
} catch (e:Error) {
trace("Error: "+e.message)
} catch (e1:StackOverflowError) {
trace("StackOverflowError: "+e1.message);
} catch (e2:CollectionViewError) {
trace("CollectionViewError: "+e2.message);
} finally {
return _children;
}
}</code></pre>
So why is it at this point wrong to call removeAll to remove all references
from the
ArrayCollection instead of creating a new ArrayCollection all the time? The
code above
compiles. If i uncomment the first try/ctach statement, the application crashes.
