Develop Reference

Have an item stick to the bottom of a RecyclerView

I have a vertically scrollable list using a RecyclerView. The layout I'm trying to implement is that when you scroll down far enough and reach a specific item, if you keep scrolling past this item it will stick to the bottom of the screen while the rest of the list continues to scroll behind it. Currently it's implemented by having a scroll listener on the RecyclerView and manually adjusting the position of the sticky view as required, but this is hacky and hard to build on.
Is there an easier way to have this kind of layout? I am currently investigating using a CoordinatorLayout but I'm not sure if it's the right tool for the job.

You can accomplish this using a CoordinatorLayout with a custom behaviour. The behaviour should be applied to the sticky view and make it appear/disappear as the RecyclerView scrolls. You have to override onStartNestedScroll in your behaviour to return true to receive calls for scroll changes.

Recyclerview - how to disable vertical scrolling on item swipe (fling)

Simple question - how to disable recyclerview scrolling while swiping its item? I created OnTouchListener inside recyclerView item view holder, but it catches swipe events only if user makes straight horizontal line. Otherwise recycler list is scrolling. Any ideas?

I am not using ItemTouchHelper because it doesnt quite do what I want. I solved this by checking the source to it and finding the call to:
getParent().requestDisallowInterceptTouchEvent(true)
Call that when you determine the user has started swiping (i.e., moved more than a few pixels). Then don't forget it to call it again with false when the swipe is done.

I'm facing the opposite problem. If you are using the ItemTouchHelper, do this
mItemTouchHelper.startSwipe(myViewHolder);
This would force the swipe instead of the scroll.

Animating a View while ListView is scrolling not working

I'm trying to achieve the effect that the Google+ Android app has where there is a View that sits at the bottom of the screen, and when the user scrolls the ListView that sits behind it UP the View animates down, off screen. When the user scrolls the ListView down, even slightly, the View animates back up, on screen.
I've set up a GestureDetector, that is giving me callbacks for the scroll event on my ListView, and the callbacks are constant as I scroll so I know that part is working.
In my callback I'm trying to use the ViewPropertyAnimator to animate my y value as such:
headerView.animate().yBy(distanceY).start();
Nothing happens until I stop scrolling. Is there any way to throw this animation in with the ListView scroll on the UI thread? I get the feeling it's waiting.

I've been fighting this one also. The trick I ended up using was to replace
headerView.animate().yBy(distanceY).start();
with
headerView.setTranslationY(floatValue);
Hope this helps!

ViewPager in a ListView - how to lock the scrolling axis?

I have a ViewPager widget in every row of a ListView. This provides a shelf-like UI, so the user can scroll around searching for a shelf vertically, and then scroll horizontally amongst the contents of a shelf. This works.
But the scrolling experience is terrible: if I start to drag a shelf's ViewPager, scroll it horizontally, and accidentally drag a bit upwards/downwards, then the ListView "traps" this dragging action, and start to scroll vertically, ending my horizontal drag. In this state, the drag action won't "return" to the ViewPager, the ListView has it, and that's it. I have to start another drag action to affect the ViewPager again. So I guess the ListView has precedence in these cases.
How can this be fixed? I'd like to achieve the exact opposite: If the ViewPager inside a list row starts reacting to a horizontal drag, then it should trap that action, and this drag should stop affecting the ListView, no matter how the user moves his/her finger vertically. Can this be done?

I've found a solution in this thread. There the problem is to handle touch events properly for a HorizontalScrollView inside a regular ScrollView, but the solution to that problem seems to apply to this one too.

Android: Detect when ScrollView has finished scrolling and bouncing back?

I have a ScrollView which has two hidden images, one at the top and one at the bottom. In between there is a bunch of visible content.
What I need to do is make these images hidden by default but when you scroll all the way up or all the way down you could see them as you're scrolling. But then as soon as you stop scrolling it should bounce back to the visible area so that the hidden images aren't showing.
Basically I'm trying to imitate the bounce scrolling feature of the iphone UIScrollView.
I have my ScrollView all setup and I do a scroll at the beginning so as to hide the top hidden image. Now all I need to do is detect when a scrolling has ended, figure out the Y position, and check whether a hidden image is shown. If it is, I would just programmatically scroll the view back so that the hidden image is hidden.
I hope all that made sense.
So anyways, I know how to programmatically scroll a ScrollView. Now what I need is some sort of callback to tell me when a ScrollView ended scrolling and also a way to get the ScrollView's current 'Y' position. Are there any such methods I could use?
I looked through the ScrollView docs but nothing jumped out at me. I'm still not very familiar with the Android naming schemes so maybe I missed something obvious somewhere.
Anyways, any help would be appreciated here. Cheers.

You can use an OnTouchListener to detect when the user presses/releases the list.
You can also use the onScrollStateChanged method of the OnScrollListener class (most likely in conjunction with a touch listener) to detect changes in the SCROLL_STATE - when the list has stopped scrolling the state will change from a state that is not SCROLL_STATE_IDLE to SCROLL_STATE_IDLE.
Alternatively if you are using 2.3 or above you can use an OverScroller to get the desired effect (see Modifying Android OverScroll for how to change the over scroll effect to an iPhone like one).