Hero image transition

[andhie]

Fixes #66

[nic0lette]

Hi @andhie ! This is really cool! Thanks for working on it. I do have a few comments:

First, it looks like you've changed (slightly) click handling when adding the shared element transition. I wonder if you could revert that, so this PR is exclusively about the shared element transition.

If you slow the animation down (Developer options -> Transition animation scale + Animator duration scale, set both to 5x) you can see the transition feels a bit off. Specifically, while the image from the plant list moves to the header position smoothly, the fragment pops in with all the details first, and so the image looks like it slides over the fragment.

This is in contrast with the example animations from the Material Design website: https://material.io/design/components/lists.html#behavior -- The hero image should move and expand, either revealing the text as it expands or having the text fade in afterwards, so it looks as though the plant details fragment is unfolding from the plant item.

Does that make sense?

[andhie]

i have revert the click listener code.
for the MD anim you mentioned, its the Condensed Transition type. it doesnt animate the hero image. which approach would be preferable? the one moving the hero image or the condensed transition
https://material.io/design/motion/customization.html#condensing-transitions

[nic0lette]

Hi @andhie :) That makes sense. I think the animation that's on the right side (captioned with "The list item and focal element transition...") is close to what I was thinking about, and feels closer to what you had, since the hero image was animating up.

Does that help?

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[googlebot]

CLAs look good, thanks!

[andhie]

@nic0lette i've tweak a little transition animation.
there are areas i'm not satisfied with.

Enter Transition: the collapsingtoolbar title appears after everything completed
Return Transition: the text can still be seen for a brief moment during Fade

do you have any suggestions to improving this?

[nic0lette]

Sorry for the slow reply :)

I took a look at this and I think the enter transition needs to fade the moving header image as it settles into place so that the collapsing toolbar (with the text) can be seen. (At least, what I think is happening is that the moving image is covering the toolbar and so, until it's removed at the end, the title isn't visible).

Unfortunately I'm still learning these things and so I wasn't able to quickly verify this, but you may be able to :)

[andhie]

Good news: i have done a test, it's as you mentioned, the moving image overlay is covering/hovering over the actual image+title and only appear when the overlay disappears.
Bad news: i have no idea how to proceed or have any hint to solve this.

[andhie]

Changes in #315 makes the title appearing out of order is now invalid.