It's easy to remove, add and insert an item from the listview adapter object, but I don't think I see a direct method to update an item in the listview adapter. Obviously, I could simply replace via remove/add, but I want to make sure I'm not missing something obvious.
Right now, I'm simply updating the underlying Item Array and refresh the entire listview by recreating/assigning the adapter (probably also not very elegant).
I hope the question is clear enough.
If you are using ArrayList in adapter class for update In ArrayList there is method called set() which update the item in arraylist after updation call notifyItemchanged() which update an item in listview
Check this link
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during getView()
I set the layout to each item in the list.
However there are some items I want to remove from my ArrayList and also not draw in the list.
My code goes like:
getView() {
if (condition a)
{
myArrayList.remove(currentIndex);
return;
}
doMoreLayouting();
}
Is this the right way?
Does it do any hurt when you remove an item from the collection during list drawing?
Does it do any hurt when you remove an item from the collection during
list drawing?
Yes it will, the main problem is that first the item in the collection will get deleted but what if the item is already called by the getView and you are deleting it after it is drawn then there is your first problem it wont get deleted, because you need to call notifyDataSetChanged to call the getView all over again to delete it from the listView.
Second is that what if each item in your list need to delete somewhere in your array then it will call an call getView again and again which is not wise in performance of you application.
I would recommend deleting it from the method of your adapter and make sure that you gather all the data that needs to be delete and call notifyDataSetChanged only once for performance wise.
Is there is any equivalent to ItemAdded event in android listview?
basically I want to check if the new item has some attributes or values then I will do some coloring on it.
I don't want to loop over all items once loading is done, even though I have no idea how to do it :)
You need to update the data that is used in the adapter in your listview.
After updating the data.. there is one method in adapter called notifyDataSetChanged() which will refresh the adapter.
Now in adapter's getView() method,
implement the logic that can change the color..
Hope it will help you..!!
How can I recreate listView?
I have listView with items containing few TextViews and I want, to reaload ListView and hide part of those TextViews from every row. I tried setting new adapter, clearing adapter (it makes listView empty), invalidating listView, using notifyDataSetChanged(). Nothing forced ListView to recreate items.
Use a ArrayAdapter backed by an ArrayList. To change the data, just update the data in the list and call adapter.notifyDataSetChanged() - Robby Pond
Also please check Google I/O 2010 - The world of ListView
I use below code to update listview.
setListAdapter(MyAdapter);
MyAdapter.notifyDataSetChanged();
getListView().setEmptyView(empty);
But each time update, the list always show top one.
I want to let it only update data, but not focus on top.
How to do it?
Use a ArrayAdapter backed by an ArrayList. To change the data, just update the data in the list and call
MyAdapter.notifyDataSetChanged().
Although you can call notifyDataSetChanged() on SimpleAdapter too.
You need to add listview.setSelection(your_collection.size());. This will make the last item in the ListView as selected when you refresh the ListView. Also call this after refereshing the ListView.
How to remove item from a list view? how to reload the list after removal?
Here you can find all the informations.
Anyway you can call
mListAdapter.remove(x); // to remove an item
and
mListAdapter.invalidate(); // to refresh the content
or
mListAdapter.notifyDataSetChanged();
Please, there's no need to write with multiple question marks like that. Removing items from your ListView depends on how you put in the items in the beginning. Edit your question to provide some details on how you did that. Updating your list afterwards can be done with notifyDataSetChanged() called by your ListView adapter.
Remove from the adapter, and the list will refresh automatically.