Half expanded Collapsing toolbar

Question

How can I create a half-expanded toolbar? Something like that WhatsApp profile page.

I've tried scrollBy and scrollTo, but they don't seem to work.

Even dispatchNestedScroll, onNesterScroll and onNestedPreScroll don't seem to work.

can you please make it more clear ? – Ajeet Yadav Mar 01 '19 at 06:59 — Ajeet Yadav, Mar 01 '19 at 06:59
Did you find a solution until now? – flauschtrud May 20 '20 at 17:56 — flauschtrud, May 20 '20 at 17:56

score 2 · Accepted Answer · answered May 20 '20 at 21:11

2

I managed to solve this problem by adapting this answer: https://stackoverflow.com/a/34920495/5369519 and using the following code:

nestedScrollView.post(() -> {
        int appBarHeight = appBar.getHeight()/2;
        nestedScrollView.startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL);
        nestedScrollView.dispatchNestedPreScroll(0, appBarHeight, null, null);
        nestedScrollView.dispatchNestedScroll(0, 0, 0, 0, new int[]{0, -appBarHeight});
    });

This simulates scrolling halfway down. Just using NestedScrollView.scrollTo() is not enough to trigger the scroll events for the parent.

answered May 20 '20 at 21:11

flauschtrud

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I already found an answer long ago. But this answer sums up what I did. I made the nestedScrollView scroll 50$ the height of the appbar, making the appbar half collapsed – Ahmad Sattout May 21 '20 at 13:08
Did you also encounter problems with a flickering UI? I added a question for this problem here: https://stackoverflow.com/q/61938816/5369519 – flauschtrud May 21 '20 at 20:55
No not at all, it was a fine implementation. – Ahmad Sattout May 22 '20 at 09:43

score 0 · Answer 2 · answered Mar 01 '19 at 07:02

0

To create the collapsing toolbar, CollapsingToolbarLayout integrates with AppBarLayout, CoordinatorLayout, Toolbar, and a scrollable content view, such as RecyclerView

answered Mar 01 '19 at 07:02

Ajeet Yadav

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Yes, I'm aware of that, my question is scrolling the toolbar to mid way of it's collapsing state – Ahmad Sattout Mar 01 '19 at 08:14

Half expanded Collapsing toolbar

2 Answers2