I have a "Dynamic" ExpandableListView. That is to say child are only load when there is click on there parent.
So I use onGroupExpand to load list. It works but I must expand myself the group with
expandableList.expandGroup(groupPosition);
The problem is that, when I click on parent, the group expands but the view go back to the first position. That is to say : I scroll, I click on parent, group expand, view go back to the first parent, so I must scroll again to see the group I click before.
I try to use expandableList.scrollTo(x,y); But it doesn't work.
I am having a similar problem. I found this method that lets you scroll based on an item position :
mList.smoothScrollToPosition(pos);
The downside is I have to call this from my groupClickListener() and in order to get it to work I have to put it inside of a runnable and delay it by part of a second otherwise it will do nothing. This means my list scrolls one way then stops and scrolls back to where it was, which looks weird. But its the only thing I've come up with thus far.
Related
I am trying to scroll and request focus to an off screen element from a recycler view. I have a list of 15 languages. When app starts the user can select one language from the recycler. Then if the app starts again the recycler scrolls and request focusto that item.
But imagine the user selects the last language from the list which is not showed in the recycler when the app starts. How to scroll and therefore reqeust focus to that element which is not currently showed in the recycler?
I expected to do something like recycler.scrollToPosition(14) and then scrollToPosition(14) , but the index is outof bunds... I guess thats because the element is not created yet. Any idea?
I had similar scenario and below code worked for me:
(rv_your_recycler_view.layoutManager as LinearLayoutManager).scrollToPositionWithOffset(position, offset)
Just set offset to 0 and position to 14, this will get you last item.
P.S. If it doesn't work check if your recyclerview's bottom constraint tied up to parent's bottom.
app:layout_constraintBottom_toBottomOf="parent"
If you try to scroll and set the focus at the same time then it may fail. While the scrolling will proceed, the request for the focus will fail if the item is not yet present in the RecyclerView. (As you state.)
The solution is to separate the two activities. Scroll to the position as you do now, but set the focus when the item is bound to the view holder in the adapter. This will require you to keep track of which item has the focus so that it can be referenced in the adapter.
I have a situation involving animation of listview's item appearances.
I have a few views in a ScollView , the last of which is the listview. I have attached an appearence animation of the row (a fade in animation).
The problem I have is that when the screen is loaded , the getView() of listview already executes for the initial items , even though the listview is not currently in view.
Hence when a user scroll downs , he sees the list plainly.
I am unsure how to go about this situation . Is there any callback that can be invoked when a row from a listview becomes visible on screen ? .
Yes there is a callback (OnScrollChangeListener), first visible index and last visible index etc. You can achieve what you are trying to using combination of these.
But you need to try that yourself first. No one can simply write a code for you.
You can learn about listview here
EDIT
It's on swedish, but this is what i got with list view.
Every listview item has a empty Linearlayout that i add a view to when i press the down arrow button. the problem is that every fifth item gets this or i can only click on the first 5.
I dont get why they make ListView so complicated. i want to be able to get a child that is in the list without seening it!
The Problem
My way to add the view makes every fifth item to add the view when i only want one position to have this "Mängd" row.
Why Can i only edit listitems when they are visible on the screen.
The child will be static at 5 items even though i got like 20 item....
Is there any way to only say that item 1 will have this and not
position - firstvisibleposition
i think this is the problem with the listview
My code is not understandable at the time because of other things so i hope you get my problem anyways.
This is my main question
It seems like the thing i add to position 0 also happens to 6 and 12 Why is ListView this wierd ?
Just like a ListView but instead it doesn't scroll. Its content is added programatically via an ArrayAdapter. Is there any view that can be used for this purpose?
PS: Not LinearLayout, since it doesn't get its content from an adapter (I want the observer pattern)
Edit: Let me explain a little bit more. Suppose you need a list of items, but the list itself is not scrollable, what is scrollable is the screen.
That being said, the list of items should show ALL items, not a limited amount based on a fixed height. The way to go is LinearLayout as it is both non-scrollable and shows all items within itself.
But there is a third requierement. You don't want to add(View) directly, but instead, you want something similar to an ArrayAdapter so that you have a control of the items and their position, so you can handle on item click events based on their position. As far as I know, this can't be done using a LinearLayout. So my question is, does any view exist for this purpose?
You could try using a ListView, but disable scrolling, as described here
Put your layout inside a ScrollView and yes you have to use a Linearlayout. You need to set tag for each of your view that you add dynamically and whenever your view is clicked you can get it's position by view.getTag() and perform the required operation.
Note : Adding views at run time may affect performance.
I'm having a strange issue. I need to implement swipe to delete in my listview. When user swipes left/right, I need to animate a delete button into/out of the screen and then on delete button click I need to delete that item from listview.
I am using Commonswares [TouchList] (https://github.com/commonsguy/cwac-touchlist/tree/master/src/com/commonsware/cwac/tlv) library to achieve that. In onFling method it gets the position of the swiped row and send it to onRemove method in my activity. I can delete the item accurately. But if i animate the row at swiped position, multiple rows get effected. I am not able to fix this issue nor am I able to find any help.
Any help will be appreciated.
I had a similar issue to this which was down to Android's view recycling.
(A good explanation of it is available here)
To resolve I simply reset the animation in the item's OnResume method as I didn't need to retain the animation for the item which has scrolled out of view.