Develop Reference

Android scroll list programmatically with animation

I want to scroll a list view by x pixels
list.scrollListBy(x) works, but the default scrolling animations are missing
Is there any api to scroll list with animation,
I cannot use smoothScrollBy and its other varients, because it wont scroll if the element is already visible.

If you are using RecyclerView, you can call the method
list.scrollToPosition(int position)
to scroll to a particular position on the list. Let's say there are 50 positions on the list, and your phone screen is showing first 10 positions of the list. Then you can call
list.scrollToPosition(40);
to scroll to the 40th position. There will be a slightly smooth effect.

How to smoothly scroll to a position and make it appear at beginning in RecyclerView?

I have tried RecyclerView.smoothScrollToPosition(int position), but it's not what I want. It scrolls to a position so that the child get into the viewport; it can either appear at the beginning or the end. Moreover, if the view is already in the viewport, it won't do anything!
What I need to do is to scroll to a position and make it appear at very beginning of RecyclerView so as to arouse user's attention. How can I do with it?

You can use mRecyclerView.scrollToPosition(Position); to display the list item at top. However it will go to the specified position very quickly without any scrolling effect.

Center aligned selection with animation in ListView (?)

I need a component that works like the picture below but I'm having trouble coming up with some kind of decent solution that works.
I want the list to have a center locked selection but being scrollable with the d-pad. This is for an application running on a TV so no need for touch scroll. So when pressing down on the remote d-pad the list will scroll and a new item will size up and the current selected one will size down and the new selection will still be in the middle.
I've tried doing this using a ListView that I extended and programmatically scrolling when pressing down or up. On scroll finished I called notifyDatasetChanged() on the ListView for re-inflating of the childs and in the ListViews adapters getView() I made the animation of the view located at the current selected position.
This is not optimal since I need to call notifyDatasetChanged(), which re-inflates all visible views, for the animation to apply. The UI becomes laggy when doing this and scrolling fast. It's also not possible to make som kind of compress animation when current selected item goes out of selection. There is also some trouble with the end items (read views) such the first or last in the list when doing animation of them, the may sometimes go out of screen.
I think that his must have been done before and maybe I'm missing it when searching for an answer.
Have anyone done something similar or do you have some suggestions of how this can be achieved? Maybe I'm just starting of with the wrong component here..
Regards,
Kristoffer

Determine if the list view is about to stop scrolling?

I need to do some animations in a listview after it is flinged and is about to stop.I have a listview which is going to be of a fixed height(well dont ask me why), and whenever the scroll stops , it should have three elements visible. What i do now is detect when the list reaches SCROLL_STATE_IDLE and if i have two elements visible at that time, i use smoothScrollToPosition and reach a state of 3 items visible and it works fine, but what i would like to do is detect when the scroll is about to stop and stop the scroll programatically when there are three items visible. Is that even possible... Any code snippets, pseudo code, algo would help me.

You can set an OnScrollListener, and then store the value from absListView.getScrollY() each sample and compare it the previous sample to compute the velocity of the scroll. Once that drops below a threshold you define, you can take over scrolling.

How to find scrollview scrolled position dynamically in Android?

Hi,I am new to android.my requirement is when user scrolling the scroll view,based on scrolled height i want to change images on screen. for this i want the event which will call immediately when scroll is changing,and once user reach end position i want set it to first position programatically. it is continuous loop.

You may use the listView instead of scrollView. So you can use onScrollChangeListener.