I am using a scroll listener to detect the end of the Listview.The list initially has 20 items. When the end is reached I populate the list with 10 more items from the DB. At the same time I remove the top 10 items which aren't visible. Since I delete the top 10 items the newly added items are shown on screen and the scroll listener detects end of list and populates 10 more items. So my two problems are
1) How do I stop the position of the item I am currently viewing from changing ?
2) How to prevent the onScrollListener from being called multiple times ?
I guess if you could help me with the first problem, the second would automatically be taken care of.
By the way ,I call notifyDatasetchanged to update the content of the adapter. Kindly help, and thanks.
Related
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 ?
I have a problem with deleting items from ListView.
I am using a subclass of BaseExpandableListAdapter.
The problem is that when I am deleting an item, I change the underlying data, after which I call notifyDataSetChanged. All seems ok. But the refresh of the ListView does not happen immediately. So, if somebody keeps checking/un-cheking some of my items, they will point to data that there is no longer in adapter (but they are still displayed in the ListView).
Example :
Say I have a ListView with 3 views and 3 items in the adapter (1, 2, 3):
I select item 3 and press delete. Now they are 3 views and 2 items in the adapter
Call notifyDataSetChanged (note that the ListView still has 3 views since it did not had time to refresh)
I keep selecting the 3rd item which will query my adapter for an item which is no longer there
My question is how do I deal with this situation ? It seems to be a gap between the time the notifyDataSetChanged is called and the ListView is refreshed and within that gap, we need to check that all the requests received in the adapter are still valid.
Try to delete your list item like.
filelist.remove("your selected item position".intValue());
This may solve your problem.
BACKGROUND:
I have a grid of 36 buttons, lets say a 6 rows & 6 columns numbered 1 to 36, displayed 2 rows at a time via a GridView and custom Adapter
The grid displays fine, and all of the scrolling works properly.
QUESTION:
I want to be able to click on an item, have it removed from the grid and the remain items shuffle up into place. Currently I am able to disable the item disabled, set its visibility to INVISIBLE or GONE, but none of these will actually remove it from the display.
Suggestions?
Specifically, you need to remove the corresponding object from the data set of the underlying adapter and then call adapter.notifyDataSetChanged(). This isn't going to provide you with an animation, though, if that was part of this question.
It may be interesting to try a tween animation for the item in question and then finally remove it from your adapter at the end. I'm not well-versed in animation, so I'm not sure how well this will work in an AdapterView.
You should be able to update the adapter, and then call notifyDataSetChanged to force the grid view to be updated.
I have a ListView which displays 5 listitems. When the user selects the last item (5th item), a hit goes to server and the next set of 5 items is displayed.
I have implemented the code for displaying the first 5 items. I am also able to fetch the next set of items from the server, but the items are not updated in the ListView.
If required I can share the sample code.
Kindly provide hints/sample source code.
Did you try clearing the list items first and then update the list elements?
In order to commit the updates you should call notifyDataSetChanged() ..