Develop Reference

Get spinner selected item inside RecyclerView

I have added Spinner inside RecyclerView , when i am trying to get spinner selected item data, its getting another/wrong position data, any one suggest me to get correct selected item and position from Spinner onItemSelected
Here is my code
#Override
public void onBindViewHolder(final QuestionHolder holder, final int position) {
if (position % 2 == 1)
holder.itemView.setBackgroundColor(Color.parseColor("#F8F8F8"));
adapter = new ArrayAdapter<Option>(binding.getRoot().getContext(),
R.layout.item_spinner, questionList.get(position).getOptions());
adapter.setDropDownViewResource(R.layout.item_spinner);
binding.optionSpinner.setAdapter(adapter);
binding.serialNo.setText((position + 1) + ".");
binding.setQuestion(questionList.get(position));
binding.executePendingBindings();
binding.optionSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(holder.itemView.getContext(), position+" : "+binding.optionSpinner.getSelectedItem().toString(), Toast.LENGTH_SHORT).show();
spinnerData.setSelectedData(position, binding.optionSpinner.getSelectedItem().toString());
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
}

I think you have to try this
showSpinnerList.setOnItemSelectedListener(new
AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int
position, long id) {
// On selecting a spinner item
String item = parent.getItemAtPosition(position).toString();
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
// todo for nothing selected
}
});

Check this, can be helpful and may fix your problem. If this won't fix your problem at least you get rid of Lint error. Lint error “Do not treat position as fixed; only use immediately…”. So everywhere you are using final int position** change it to getAdapterPosition();
The documentation of RecyclerView.Adapter.onBindViewHolder()
states:
Note that unlike ListView, RecyclerView will not call this method
again if the position of the item changes in the data set unless the
item itself is invalidated or the new position cannot be determined.
For this reason, you should only use the position parameter while
acquiring the related data item inside this method and should not keep
a copy of it. If you need the position of an item later on (e.g. in a
click listener), use getAdapterPosition() which will have the updated
adapter position
So, technically items may be re-arranged and binding will not be
necessary because items are not invalidated yet. The position
variable received holds true only for the scope of bind function and
will not always point to correct position in the data set. That's why
the function getAdapterPosition() must be called everytime updated
position is needed.
IMHO, mLastPosition = holder.getAdapterPosition(); is still
potentially wrong. Because item may be re-arranged and mLastPosition
still points to old position.
About why lint is silent, perhaps Lint rule is not that thorough. Its
only checking whether position parameter is being copied or not.

How to disable all elements (also the ones not currently visible in the screen) in a listview?

I have a ListView with a set of elements. When I click one of the I would like to disable all the others. If I click again on the selected item all the other items are enabled again.
I tried the different proposed solution without success. I hope someone can help me.
This is my code:
//action to take when a presentation is selected
listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, final View view,
int position, long id) {
//disable the other items when one is selected
if(position!=selectedPresentation){
for(int i=0;i<parent.getCount();i++){
if(i!=position)//disable all the items except the select one
parent.getChildAt(i).setEnabled(false);
}
selectedPresentation=position;
}else if(selectedPresentation==position){
//enable again all the items
for(int i=0;i<parent.getCount();i++){
parent.getChildAt(i).setEnabled(true);
}
selectedPresentation=-1;
}
Where selectedPresentation is a global variable storing the selected item. If no item is selected its value is -1.
Thank you for your help!

Make your own subclass of ArrayAdapter that has AreAllItemsEnabled() return false, and define isEnabled(int position) to return false for a given item in your the ones you want to disable.
In your custom ArrayAdapter overide isEnabled method as following
#Override
public boolean isEnabled(int position) {
return false;
}
other option
Don't implement onItemclickListener. This will not give you any update of item click. Only register onClick listener to views.

You may take another object of the List(Arraylist) which is populating elements in listview then on click copy the corresponding position data to new arraylist you made and then notifyDataSet and when you click again you populate listview with original list so it will apear again....Just do this trick it might work for you

parent.getChildeAt() only work for visible Item.
you should change something in adapter.
if make custom adapter then you can do some thing like #ṁᾶƔƏň ツ answer, but if you use default adapter you can change adapter's arraylist that before you pass it to adapter.
put boolean in it (in arraylist) and in on item click true/false it for all item.

I wrote this solution and seems it works fine!
listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, final View view,
int position, long id) {
//disable the other items when one is selected
Toast.makeText(context, "onClick called",Toast.LENGTH_SHORT).show(); // this will flash up twice
if(position!=selectedPresentation){
selectedPresentation=position;
for(int i=0;i<adapter.getCount();i++){
if(i!=position)//disable all the items except the select one
adapter.isEnabled(i);
}
}else if(selectedPresentation==position){
//enable again all the items
selectedPresentation=-1;
for(int i=0;i<adapter.getCount();i++){
adapter.isEnabled(i);
}
}
And in my adapter I wrote:
public boolean isEnabled(int position) {
if(selectedPresentation==-1 || selectedPresentation==position)
return true;
return false;
Now my concern is how to show the items in the listView as disabled

Android: ListView.getChildAt() throws null

Sometimes, when I call goToLast() it throws me a null exception in vista=lista.getChildAt(), it happens when the list is full, I dont know why I have this code:
private void goToLast() {
lista.post(new Runnable() {
#Override
public void run() {
lista.setSelection(mensajes.getCount() - 1);
View vista = lista.getChildAt(mensajes.getCount() - 1);
TextView txtMensaje = (TextView)vista.findViewById(R.id.txtMensajeLista);
txtMensaje.setBackgroundColor(Color.RED);
}
});
}

You should log lista.getChildCount(), see how many children the ListView has. ListView recycles views, which means it only hold limit number of views.
So if you want to get the last view, you should do something like this
private void goToLast() {
lista.post(new Runnable() {
#Override
public void run() {
lista.setSelection(mensajes.getCount() - 1);
// Figure out the last position of the view on the list.
int lastViewIndex = lista.getChildCount() - 1;
View vista = lista.getChildAt(lastViewIndex);
TextView txtMensaje = (TextView)vista.findViewById(R.id.txtMensajeLista);
txtMensaje.setBackgroundColor(Color.RED);
}
});
}

ListView.getChildAt() position is different to the position in your adapter. ListView recycles its views, so if you have more items in your adapter, than can fit on the screen it will not create views for all of those, but only the ones that are visible. If you want to update an item in the ListView you need to update it in the adapter and call notifyDataSetChanged()

How to change other items in a Android ListView when one item is clicked

I have a ListView that contains items with checkboxes that should behave sometimes like a CHOICE_MODE_MULTIPLE and sometimes like a CHOICE_MODE_SINGLE. What I mean is for certain items in the list, when selected certain other items needs to be deselected whilst other can remain selected.
So when item A is checked I can find in my data the item B that needs to be unchecked but how do I get the UI to refresh to show this as I (I believe) cannot find the actual View that represents B but just it's data?

It sounds like you're off to a good start. You're right that you should be manipulating the underlying data source for item B when A is clicked.
Two tips that may help you:
Your getView() method in the Adapter should be looking at your data source and changing convertView based on what it finds. You cannot find the actual View that represents B because in a ListView, the Views are recycled and get reused as different data needs to be displayed. Basically, when an item is scrolled off the list, the View that was used gets passed to the getView() function as convertView, ready to handle the next element's data. For this reason, you should probably never directly change a View in a ListView based on user input, but rather the underlying data.
You can call notifyDataSetChanged() from within your adapter to signal that somewhere the underlying data has been changed and getView() should be called again for the elements currently displayed in your list.
If you're still having trouble, feel free to post some code that illustrates the specific problem that you're having. It's much easier to provide concrete advice when the problem is better defined. Hope this helps!

you can use singleChoice alartDialog, i have used like:
private int i = 0; // this is global
private final CharSequence[] items = {"Breakfast", "Lunch", "Dinner"}; // this is global
Button settings = (Button)view.findViewById(R.id.settings);
settings.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(final View v) {
AlertDialog.Builder builder = new AlertDialog.Builder(v.getContext());
//Title of Popup
builder.setTitle("Settings");
builder.setSingleChoiceItems(items, i,
new DialogInterface.OnClickListener() {
// When you click the radio button
public void onClick(DialogInterface dialog, int item){
i=item;
}
});
builder.setPositiveButton("Confirm",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int item) {
if (i == 0) {
//it means 1st item is checked, so do your code
}
if (i == 1) {
//it means 2nd item is checked, so do your code
} /// for more item do if statement
}
});
//When you click Cancel, Leaves PopUp.
builder.setNegativeButton("Cancel", null);
builder.create().show();
}
});
i have initialized i=0, so that for the very first time when user click on settings button, the first item is selected. and after then when user select other item, i have saved the i value so that next time when user click settings button, i can show user his/her previously selected item is selected.

I come across and solve this question today.
public class ItemChooceActivity extends Activity implements OnItemClickListener {
private int chosenOne = -1;
class Madapter extends BaseAdapter {
.....
.....
#Override
public View getView(final int position, View convertView,
ViewGroup parent) {
// TODO Auto-generated method stub
if (chosenOne != position) {
set the view in A style
} else {
set the view in B style
}
return convertView;
}
}
#Override
public void onItemClick(AdapterView<?> arg0, View view, int position,
long arg3) {
,,,,
chosenOne = position;
adapter.notifyDataSetChanged();
,,,
}
}

How to scroll ExpandableListView in properly position when group is clicked

I have a ExpandableListView in my activity that works properly. I set in my adapter a clickListener on RelativeLayout, so when I click on it, my group get expanded. My group list is a ArrayList, my children is a HashMap> where Integer is groupPosition of ArrayList. Children is a comment list that any user can see. The user can add a comment by EditText at end of comment list. My goal is to position at top of screen the groupView clicked. I tried to do this but my problem is:
My first group has 10 comments. If i expand the first group I can see them and the position of my group clicked is right. If I try to expand my fourth group, when the first is already expanded, the ExpandableListView position on my screen goes to the fourth children of first group and not on fourth group just expanded. After if I scroll down the list the fourth group is open, but I would to position on the fourth group and not on fourth children of first group. All works properly if I open only group without comments...
small part of method getGroupView:
scanCommFav=(RelativeLayout)v.findViewById(R.id.feedcell_scancommentfavorite);
scanCommFav.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v)
{
if(!isExp)
{
if(mess==0)
{
setIdx(idx);
addIndex(idx);
getCommentNoList();
}
else
{
callCommentScript(snapId);
setIdx(idx);
addIndex(idx);
}
}
else if(isExp)
{
setIdx(idx);
removeIndex(idx);
closeGroup(idx);
}
}
});
addIndex(idx) and removeIndex, add and remove in LinkedList the position of groups open. setIdx(idx) set to int variable the group position that I use for different purpose.
this is openGroup():
private void openGroup(int pos)
{
feedlistView.setSelectedGroup(pos);
}
this is closeGroup():
private void closeGroup(int idx)
{
feedlistView.collapseGroup(idx);
}
this is my listener:
feedlistView.setOnItemSelectedListener(new OnItemSelectedListener(){
#Override
public void onItemSelected(AdapterView<?> arg0, View view,int position, long id) {
if(ExpandableListView.getPackedPositionForGroup(position)==ExpandableListView.PACKED_POSITION_TYPE_GROUP)
{
int pos = feedlistView.getSelectedItemPosition();
feedlistView.expandGroup(pos);
}
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
I tried also to implement setOnGroupClickListener but doesn't works. Somebody has any idea?
Thanks

I solved saving Instance State and restoring Istance State every time I set my customer adapter to my Expandable ListView in this way:
Parcelable state = myExpList.onSaveIstanceState();
myExpList.setAdapter(myAdapter);
myExpList.onRestoreIstanceState();
after in my method openGroup(int position)
myExpList.expandGroup(position);
myExpList.setSelectedGroup(position);
I didn't use setOnItemSelectedListener.