I have a listview and a corresponding listview adapter.
The views displayed in the Listview have I written myself and it's a framelayout with one button and one imagebutton. The imagebutton is a red cross that deletes the entry and the regular button selects the entry.
When the user presses the regular button, that item is selected and I want to show this to the user by setting the background of that item to green. The application stores which item the user selected and the next time the listview is rendered, THAT item should be selected and green.
Notice that there should be one and EXACTLY one selected item in my listview at all times.
In the getView(.. method in my adaper, it's very easy to change color of the button when the user clicks it. But the button that was green before the user clicked is impossible for me to reference.
I tried storing a reference the previously selected button, but it never repainted
I tried removing and adding the data item from the list to trigger notifyDataSetChanged but it never repainted
I tried setChoiceMode(ListView.CHOICE_MODE_SINGLE), but that led nowhere because I don't know how to catch the choice in my getView method and paint differently depending on wheter it's selected or not.
All guides I see suggest using notifyDataSetChanged. However, the underlying data is NOT changed in this case and it is not correct (or possible) solution.
So I think that my problem boils down to: HOW can I reference another view in my listview??
(And Yes, I have seen this post: Highlight selected item in ListView on Android . It describes my problem and is answered with "and then change the color of previous selected item's background back to normal" but I still can't refer to the PREVIOUS selected item.
Thanks!
Why don't you use Radio Buttons ? This is exactly the design you need. You can add a "red cross" on each line to delete the line. The selected line is unique and you can iterate on RadioButton.isChecked(); of your RadioGroup to set the background color accordingly.
Related
I'm stuck on a little problem.
When I click on a row in my RecyclerView, I'd like to change its color to some other color (i.e.: red).
Then, if I click this row again, I would like to set its color back to the normal one (i.e.: white).
Then, if I click on a second row or n-th row, I would like to do the same.
I've tried to work on the RecyclerView Adapter class, in my ViewHolder I tried some ideas counting user clicks, setting a boolean to check the colored rows, and getAdapterPosition to know what is the row's position... but actually all my tries failed!
Would you please help me with that problem?
It seems that I'm close to the solution, but need a little help
You're going to need to keep track of which items were selected on the list (otherwise any changes to the view will simply be recycled).
Keep a list of selected items within your adapter. In the adapter's onBindViewHolder you can check against the list and if the list contains the view/item, you can color the view accordingly.
Edit: Refer here for a working example
How to properly highlight selected item on RecyclerView?
I have created a custom ListView.. every element of my ListView constructing from a layout.
My layout will have some TextViews and a ToggleButton. My ListView will have some 50 elemnts and my device screen can show 2 elements at a time.
Now if we select ToggleButton on a Item and scroll down my ListView , the selected item will be out of screen and when I come back to the previous selected item I am observinf that selection for that toggle button is gone.
I know that this is a normal behavior in android that It will construct the elements which is currently displaying.
But I want to keep that value.. Is there any way that we preserve selection. or can I tell ListView to donot construct every time.. memory is a not a issue for my application.
Please let me know if there's any good solution for this.
You could store the states of the checkbox in a map with the position as the key. So whenever the list reloads after scroll, it loads based on the hashmap state. You should write this logic in the getView()
I have a ListView with a custom adapter. I'd like to visually mark the list element the user clicked on by changing it's background permanently (until the user clicks on another element that is). How do I achieve that? I believe that there's a built-in feature inside LisView for this, but I had no luck finding it yet.
By default ListView animates the background color of the list-element clicked, I just want that modified color to "stay". I've already set the ListView's ChoiceMode to single choice, but it doesn't affect it visually.
Have you tried ListView.setSelector?
i have a simple list view control
my queries are:
1) how to set first row selected on start (after fill data in list view)
2) when i navigate by hardware button i got AdapterView.OnItemSelectedListener and color of row background change, but when i click i not get any OnItemSelectedListener and no row selected. How to select row on click.
3) when i change focus list row selection removed,
please any one with any solution, code example or articles
i search but no susses
with regards
Chandra Kant Singh
how to set first row selected on start
(after fill data in list view)
Call setSelection() on the ListView. However, this only will have a visual effect if the user entered your activity via the pointing device (trackball, D-pad, etc.).
How to select row on click.
You don't.
when i change focus list row selection
removed,
If I understand what you mean by "change focus", this is working as designed.
Please review this article on touch mode and the use of the "selected" state, then adjust your UI design to follow Android conventions. Selection is only used when the user navigates with the pointing device, not when the user uses the touch screen.
In Android, I want to present the user with a list. When an item on the list is selected some action is performed, and this list item is no longer selectable. It is also 'grayed out' or the like to indicate that it cannot be selected the next time the list is displayed. I have seen the isSelectable() override in Adapter, but I believe this causes the item to be treated as a separator, which causes visual problems. And I have not found a way to 'gray out' an item. Any ideas? Thanks...
As far as graying out an item. I'm not sure if this is the best way, but it's what I do:
view.setAlpha(75);
view.setBackgroundColor(Color.GRAY);
I'm basically making the item transparent and then setting the background color to gray. If you're reusing your list items you should also change them back to their original state if the condition is not met, i.e.:
view.setAlpha(255);
view.setBackgroundColor(Color.WHITE);
that is, if your original state was no transparency and the background color was white.
You need the view to be disabled. If you are creating the views just call .setDisabled(boolean) on the top view. Setting the list item to be disabled doesn't work very well in my experience.
Here is the solution I am using. I set up an OnItemClickListener for my ListView. When an item in the list is clicked, I take the passed in View and call setEnabled(false) on it. This will gray out the item. However, subsequent clicks on this item will still call the onItemClick method. So, you will need to check on each click if the item is enabled/disabled and act accordingly.