event when the component show up in the screen

[jwjiwon]

Hello all
I wonder if there is an event when the component show up in the screen.
I mean, not the moment when the component is made, but the moment when the component start to appear the screen so that user can see the component.

For example, I made a long list. and I add the button after the list.
and I read through the list until the button show up!
then the event occurs because button show up in the screen!

is there such kind of event?
If there is not, is there suggestion to how to make it?

[mitchellsimoens]

The painted event should fire when a component is drawn on the screen (even if it is hidden) like in a card layout.

[jwjiwon]

Yeah I found the event show and painted, but that is fired when the component is drawn on the virtual screen. even if users can not see it, it is fired.
the event I want to use is the event fired when the component is actually show up in the real computer screen.
can you see the difference?

for example, like the picture below.
untitled.jpg


it's on the same panel but, the event is fired when user really see the button 'more...'.

Any idea?

[mitchellsimoens]

There is no event when an element or component comes into view, There is a scrollend event on an element that you may be able to listen to.

[rdougan]

Yeah, there is no easy way to do this if it is inside a scrolling container. You will need to listen to the scroller events as Mitchell suggested and check when the item is actually within the bounds of the screen.

[jwjiwon]

as you said, it is not easy job to make in this way.
but it is closer!!
do you think is there a way to check the component within the bounds of the screen?

really,
I keep thinking about it, and I got an idea that the last few components of the list have
the scrolling event... but it feels not right for me.
and I also thought about using carousel, and tried, but
the carousel goes the other card even I didn't scroll the list fully yet.