Hi,
while digging into nifty gui i have come to a problem which i do not understand.
I create a window element with onStartScreenEffect (move in from top border).
Window works and i can drag it around, but every time i start dragging, the onStartScreenEffect ist triggered.
After setting some breakpoints i found out that the start effect is triggered from somewhere in the DraggableControl, here the stack trace:
Thread [LWJGL Renderer Thread] (Suspended (breakpoint at line 261 in EffectProcessor))
EffectProcessor.startEffect(Effect, String, String) line: 261
EffectProcessor.activate(EndNotify, String, String) line: 153
EffectManager.startEffect(EffectEventId, Element, TimeProvider, EndNotify, String) line: 87
Element.startEffectInternal(EffectEventId, EndNotify, String) line: 1040
Element.startEffectDoIt(EffectEventId, EndNotify, String, boolean) line: 1000
Element.startEffect(EffectEventId, EndNotify, String) line: 950
Element.startEffect(EffectEventId, EndNotify) line: 946
Screen.addPopup(Element, Element) line: 164
Nifty.showPopup(Screen, String, Element) line: 782
DraggableControl$1.perform() line: 146
Nifty$EndOfFrameElementAction.perform() line: 1004
Nifty.executeEndOfFrameElementActions() line: 376
Nifty.handleDynamicElements() line: 295
Nifty.access$1400(Nifty) line: 72
Nifty$NiftyInputConsumerImpl.processEvent(NiftyMouseInputEvent) line: 1345
Nifty$NiftyInputConsumerImpl.processMouseEvent(int, int, int, int, boolean) line: 1311
InputSystemJme.onMouseButtonEventQueued(MouseButtonEvent, NiftyInputConsumer) line: 128
InputSystemJme.forwardEvents(NiftyInputConsumer) line: 171
Nifty.update() line: 227
InputSystemJme.endInput() line: 94
InputManager.processQueue() line: 773
InputManager.update(float) line: 837
ModelViewer(Application).update() line: 567
ModelViewer.update() line: 316
LwjglDisplay(LwjglAbstractDisplay).runLoop() line: 144
LwjglDisplay.runLoop() line: 185
LwjglDisplay(LwjglAbstractDisplay).run() line: 218
Thread.run() line: 679
Here the code i use to build the window:
[java]
WindowBuilder window_builder = new WindowBuilder(NiftyConstants.SETTINGS_ID, NiftyConstants.SETTINGS_ID)
{
{
width("320");
height("200");
alignCenter();
valignCenter();
onStartScreenEffect(new EffectBuilder("move")
{
{
length(150);
inherit();
neverStopRendering(true);
effectParameter("mode", "in");
effectParameter("direction", "top");
}
});
onEndScreenEffect(new EffectBuilder("move")
{
{
length(150);
inherit();
neverStopRendering(true);
effectParameter("mode", "out");
effectParameter("direction", "bottom");
}
});
}
};
[/java]
Should there not be any effect on a window element, or what am i doing wrong here?
uhm, I think that this is a “odd” feature 
internally the window control (or any draggable) is using niftys popup mechanism. when a popup is being shown the onStartScreen effect will be triggered automatically.
what you can do - as a workaround - is to use a custom effect instead of the onStartScreen effect and trigger that one from code.
aah ok, that explains. already found out it has something to do with the popup mechanism, but was not sure.
Thank you for your answer.
But how should i implement the custom effect to be triggered on start/end?
Are custom effects in general explained somewhere?
And will this not be triggered by popup too?
Sorry for these questions, but i am pretty new to nifty and just getting started.
Ok, first the general explanation of custom effects:
Instead of writting: “onStartScreenEffect” you can use “onCustomEffect”. This will not start the effect automatically because you can decide when the effect should start. When you want to activate the effect you get the Element with the attached effect first, something like:
[java]Element e = screen.findElementByName(")[/java]
and then use:
[java]e.startEffect(EffectEventId.onCustom);[/java]
to start the custom effect.
You should be able to add this at the time where you show/build the actual window.