It is possible for a VisualElement to transition from one IStyle state to another using transition properties. However, I have not been able to figure an obvious way to make an element animate its initial appearance on-screen, for example to fade-in when first displayed or animate its position coming up from the bottom.
Is there a way to accomplish this?
You can do
myElement.RegisterCallback<AttachToPanelEvent>(e =>
{
myElement.AddToClassList("class-with-appear-transition");
});
If that doesn’t work, you can use the GeometryChangedEvent instead. Note that this event can be called for a variety of other reasons.
This still has the issue where you need to set up the element in it’s hidden state in the UI Builder, so when it loads it can then immediately be shown. Which is obviously non-ideal.
The only other solution I can think of is to, in code:
Which seems like a hack…