I know there are no default selection methods in recyclerview class, But I have tried in following way,
public void onBindViewHolder(ViewHolder holder, final int position) {
holder.mTextView.setText(fonts.get(position).getName());
holder.checkBox.setChecked(fonts.get(position).isSelected());
holder.checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if(isChecked) {
for (int i = 0; i < fonts.size(); i++) {
fonts.get(i).setSelected(false);
}
fonts.get(position).setSelected(isChecked);
}
}
});
}
While trying this code, I got expected output, But completely not.
I will explain this with images.
By default, the first item is selected from my adapter
Then I am trying to select 2nd and then 3rd, and then 4th and finally 5th one,
Here 5th only should be selected, but all five are getting selected.
If I scroll the list to bottom and come again to top,
I got what I expected,
How can I overcome this issue? And some time If I scroll the list very fast some other item gets selected. How to overcome this problem too?
Update
While I am trying to use notifyDataSetChanged()
after fonts.get(position).setSelected(isChecked);
I got following exception,
java.lang.IllegalStateException: Cannot call this method while RecyclerView is computing a layout or scrolling
at android.support.v7.widget.RecyclerView.assertNotInLayoutOrScroll(RecyclerView.java:1462)
at android.support.v7.widget.RecyclerView$RecyclerViewDataObserver.onChanged(RecyclerView.java:2982)
at android.support.v7.widget.RecyclerView$AdapterDataObservable.notifyChanged(RecyclerView.java:7493)
at android.support.v7.widget.RecyclerView$Adapter.notifyDataSetChanged(RecyclerView.java:4338)
at com.app.myapp.screens.RecycleAdapter.onRowSelect(RecycleAdapter.java:111)
This question is related to
android
android-recyclerview
The solution for the issue:
public class yourRecyclerViewAdapter extends RecyclerView.Adapter<yourRecyclerViewAdapter.yourViewHolder> {
private static CheckBox lastChecked = null;
private static int lastCheckedPos = 0;
public void onBindViewHolder(ViewHolder holder, final int position) {
holder.mTextView.setText(fonts.get(position).getName());
holder.checkBox.setChecked(fonts.get(position).isSelected());
holder.checkBox.setTag(new Integer(position));
//for default check in first item
if(position == 0 && fonts.get(0).isSelected() && holder.checkBox.isChecked())
{
lastChecked = holder.checkBox;
lastCheckedPos = 0;
}
holder.checkBox.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
CheckBox cb = (CheckBox)v;
int clickedPos = ((Integer)cb.getTag()).intValue();
if(cb.isChecked())
{
if(lastChecked != null)
{
lastChecked.setChecked(false);
fonts.get(lastCheckedPos).setSelected(false);
}
lastChecked = cb;
lastCheckedPos = clickedPos;
}
else
lastChecked = null;
fonts.get(clickedPos).setSelected(cb.isChecked);
}
});
}
}
Hope this help!
public class GetStudentAdapter extends
RecyclerView.Adapter<GetStudentAdapter.MyViewHolder> {
private List<GetStudentModel> getStudentList;
Context context;
RecyclerView recyclerView;
public class MyViewHolder extends RecyclerView.ViewHolder {
TextView textStudentName;
RadioButton rbSelect;
public MyViewHolder(View view) {
super(view);
textStudentName = (TextView) view.findViewById(R.id.textStudentName);
rbSelect = (RadioButton) view.findViewById(R.id.rbSelect);
}
}
public GetStudentAdapter(Context context, RecyclerView recyclerView, List<GetStudentModel> getStudentList) {
this.getStudentList = getStudentList;
this.recyclerView = recyclerView;
this.context = context;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.select_student_list_item, parent, false);
return new MyViewHolder(itemView);
}
@Override
public void onBindViewHolder(final MyViewHolder holder, final int position) {
holder.textStudentName.setText(getStudentList.get(position).getName());
holder.rbSelect.setChecked(getStudentList.get(position).isSelected());
holder.rbSelect.setTag(position); // This line is important.
holder.rbSelect.setOnClickListener(onStateChangedListener(holder.rbSelect, position));
}
@Override
public int getItemCount() {
return getStudentList.size();
}
private View.OnClickListener onStateChangedListener(final RadioButton checkBox, final int position) {
return new View.OnClickListener() {
@Override
public void onClick(View v) {
if (checkBox.isChecked()) {
for (int i = 0; i < getStudentList.size(); i++) {
getStudentList.get(i).setSelected(false);
}
getStudentList.get(position).setSelected(checkBox.isChecked());
notifyDataSetChanged();
} else {
}
}
};
}
}
This is how the Adapter class looks like :
public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewHolder>{
Context context;
ArrayList<RouteDetailsFromFirestore> routeDetailsFromFirestoreArrayList_;
public int lastSelectedPosition=-1;
public MyRecyclerViewAdapter(Context context, ArrayList<RouteDetailsFromFirestore> routeDetailsFromFirestoreArrayList)
{
this.context = context;
this.routeDetailsFromFirestoreArrayList_ = routeDetailsFromFirestoreArrayList;
}
@NonNull
@Override
public MyRecyclerViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i)
{
// LayoutInflater layoutInflater = LayoutInflater.from(mainActivity_.getBaseContext());
LayoutInflater layoutInflater = LayoutInflater.from(viewGroup.getContext());
View view = layoutInflater.inflate(R.layout.route_details, viewGroup, false);
return new MyRecyclerViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull final MyRecyclerViewHolder myRecyclerViewHolder, final int i) {
/* This is the part where the appropriate checking and unchecking of radio button happens appropriately */
myRecyclerViewHolder.mRadioButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
if(b) {
if (lastSelectedPosition != -1) {
/* Getting the reference to the previously checked radio button and then unchecking it.lastSelectedPosition has the index of the previously selected radioButton */
//RadioButton rb = (RadioButton) ((MainActivity) context).linearLayoutManager.getChildAt(lastSelectedPosition).findViewById(R.id.rbRadioButton);
RadioButton rb = (RadioButton) ((MainActivity) myRecyclerViewHolder.mRadioButton.getContext()).linearLayoutManager.getChildAt(lastSelectedPosition).findViewById(R.id.rbRadioButton);
rb.setChecked(false);
}
lastSelectedPosition = i;
/* Checking the currently selected radio button */
myRecyclerViewHolder.mRadioButton.setChecked(true);
}
}
});
}
@Override
public int getItemCount() {
return routeDetailsFromFirestoreArrayList_.size();
}
} // End of Adapter Class
Inside MainActivity.java we call the ctor of Adapter class like this. The context passed is of MainActivity to the Adapter ctor :
myRecyclerViewAdapter = new MyRecyclerViewAdapter(MainActivity.this, routeDetailsList);
Please try this... This works for me..
In adapter,take a sparse boolean array.
SparseBooleanArray sparseBooleanArray;
In constructor initialise this,
sparseBooleanArray=new SparseBooleanArray();
In bind holder add,
@Override
public void onBindViewHolder(DispositionViewHolder holder, final int position) {
holder.tv_disposition.setText(dispList.get(position).getName());
if(sparseBooleanArray.get(position,false))
{
holder.rd_disp.setChecked(true);
}
else
{
holder.rd_disp.setChecked(false);
}
setClickListner(holder,position);
}
private void setClickListner(final DispositionViewHolder holder, final int position) {
holder.rd_disp.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
sparseBooleanArray.clear();
sparseBooleanArray.put(position, true);
notifyDataSetChanged();
}
});
}
rd_disp is radio button in xml file.
So when the recycler view load the items,in bindView Holder it check whether the sparseBooleanArray contain the value "true" correspnding to its position.
If the value returned is true then we set the radio button selection true.Else we set the selection false. In onclickHolder I have cleared the sparseArray and set the value true corresponding to that position. When I call notify datasetChange it again call the onBindViewHolder and the condition are checked again. This makes our selection to only select particular radio.
This might help for those who want a single radiobutton to work --> Radio Button RecycleView - Gist
If lambda expressions aren't supported, use this instead:
View.OnClickListener listener = new View.OnClickListener() {
@Override
public void onClick(View v) {
notifyItemChanged(mSelectedItem); // to update last selected item.
mSelectedItem = getAdapterPosition();
}
};
Cheers
The following might be helpful for RecyclerView with Single Choice.
Three steps to do that, 1) Declare a global integer variable,
private int mSelectedItem = -1;
2) in onBindViewHolder
mRadio.setChecked(position == mSelectedItem);
3) in onClickListener
mSelectedItem = getAdapterPosition();
notifyItemRangeChanged(0, mSingleCheckList.size());
mAdapter.onItemHolderClick(SingleCheckViewHolder.this);
You need to clear the OnCheckedChangeListener
before setting setChecked()
:
@Override
public void onBindViewHolder(final ViewHolder holder, int position) {
holder.mRadioButton.setOnCheckedChangeListener(null);
holder.mRadioButton.setChecked(position == mCheckedPosition);
holder.mRadioButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
mCheckedPosition = position;
notifyDataSetChanged();
}
});
}
This way it won't trigger the java.lang.IllegalStateException: Cannot call this method while RecyclerView is computing a layout or scrolling
error.
This happens because RecyclerView, as the name suggests, does a good job at recycling its ViewHolders. This means that every ViewHolder, when it goes out of sight (actually, it takes a little more than going out of sight, but it makes sense to simplify it that way), it is recycled; this implies that the RecyclerView takes this ViewHolder that is already inflated and replaces its elements with the elements of another item in your data set.
Now, what is going on here is that once you scroll down and your first, selected, ViewHolders go out of sight, they are being recycled and used for other positions of your data set. Once you go up again, the ViewHolders that were bound to the first 5 items are not necessarely the same, now.
This is why you should keep an internal variable in your adapter that remembers the selection state of each item. This way, in the onBindViewHolder
method, you can know if the item whose ViewHolder is currently being bound was selected or not, and modify a View accordingly, in this case your RadioButton's state (though I would suggest to use a CheckBox if you plan on selecting multiple items).
If you want to learn more about RecyclerView and its inner workings, I invite you to check FancyAdapters, a project I started on GitHub. It is a collection of adapters that implement selection, drag&drop of elements and swipe to dismiss capabilities. Maybe by checking the code you can obtain a good understanding on how RecyclerView works.
It's quite late, but I'm still posting it as it may help someone else.
Use the code below as a reference to check a single item in RecyclerView:
/**
* Created by subrahmanyam on 28-01-2016, 04:02 PM.
*/
public class SampleAdapter extends RecyclerView.Adapter<SampleAdapter.ViewHolder> {
private final String[] list;
private int lastCheckedPosition = -1;
public SampleAdapter(String[] list) {
this.list = list;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = View.inflate(parent.getContext(), R.layout.sample_layout, null);
ViewHolder holder = new ViewHolder(view);
return holder;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.choiceName.setText(list[position]);
holder.radioButton.setChecked(position == lastCheckedPosition);
}
@Override
public int getItemCount() {
return list.length;
}
public class ViewHolder extends RecyclerView.ViewHolder {
@Bind(R.id.choice_name)
TextView choiceName;
@Bind(R.id.choice_select)
RadioButton radioButton;
public ViewHolder(View itemView) {
super(itemView);
ButterKnife.bind(this, itemView);
radioButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int copyOfLastCheckedPosition = lastCheckedPosition;
lastCheckedPosition = getAdapterPosition();
notifyItemChanged(copyOfLastCheckedPosition);
notifyItemChanged(lastCheckedPosition);
}
});
}
}
}
So, after spending so many days over this, this is what I came up with which worked for me, and is good practice as well,
code
@Override
public void onTicketSelect(int position) {
for (ListType listName : list) {
listName.setmSelectedConstant(0);
}
8. Outside this, make the selected position constant 1:
code
list.get(position).setmSelectedConstant(1);
adapter.notifyDataSetChanged();
immediately after this.code
if (listVarInAdapter.get(position).getmSelectedConstant() == 1) {
holder.checkIcon.setChecked(true);
selectedTicketType = dataSetList.get(position);}
else {
commonHolder.checkCircularIcon.setChecked(false);
}
This is how its looks
Inside your Adapter
private int selectedPosition = -1;
And onBindViewHolder
@Override
public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
if (selectedPosition == position) {
holder.itemView.setSelected(true); //using selector drawable
holder.tvText.setTextColor(ContextCompat.getColor(holder.tvText.getContext(),R.color.white));
} else {
holder.itemView.setSelected(false);
holder.tvText.setTextColor(ContextCompat.getColor(holder.tvText.getContext(),R.color.black));
}
holder.itemView.setOnClickListener(v -> {
if (selectedPosition >= 0)
notifyItemChanged(selectedPosition);
selectedPosition = holder.getAdapterPosition();
notifyItemChanged(selectedPosition);
});
}
Thats it! As you can see i am just Notifying(updating) previous selected item and newly selected item
My Drawable set it as a background for recyclerview child views
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_focused="false" android:state_selected="true">
<shape android:shape="rectangle">
<solid android:color="@color/blue" />
</shape>
</item>
just use mCheckedPosition
save status
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.checkBox.setChecked(position == mCheckedPostion);
holder.checkBox.setOnClickListener(v -> {
if (position == mCheckedPostion) {
holder.checkBox.setChecked(false);
mCheckedPostion = -1;
} else {
mCheckedPostion = position;
notifyDataSetChanged();
}
});
}
I want to share the similar thing I have achieved, may be it will help someone.
below code is from the application to select an address from a list of addresses that are displayed in cardview(cvAddress)
, so that on click of particular item(cardview)
the imageView
inside the item should set to different resource(select/unselect)
@Override
public void onBindViewHolder(final AddressHolder holder, final int position)
{
holderList.add(holder);
holder.tvAddress.setText(addresses.get(position).getAddress());
holder.cvAddress.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
selectCurrItem(position);
}
});
}
private void selectCurrItem(int position)
{
int size = holderList.size();
for(int i = 0; i<size; i++)
{
if(i==position)
holderList.get(i).ivSelect.setImageResource(R.drawable.select);
else
holderList.get(i).ivSelect.setImageResource(R.drawable.unselect);
}
}
I don't know this is best solution or not but this worked for me.
Looks like there are two things at play here:
I will address each separately.
Basically, in onBindViewHolder
you are given an already initialized ViewHolder
, which already contains a view. That ViewHolder
may or may not have been previously bound to some data!
Note this bit of code right here:
holder.checkBox.setChecked(fonts.get(position).isSelected());
If the holder has been previously bound, then the checkbox already has a listener for when the checked state changes! That listener is being triggered at this point, which is what was causing your IllegalStateException
.
An easy solution would be to remove the listener before calling setChecked
. An elegant solution would require more knowledge of your views - I encourage you to look for a nicer way of handling this.
The listener in your code is changing the state of the data without notifying the adapter of any subsequent changes. I don't know how your views are working so this may or may not be an issue. Typically when the state of your data changes, you need to let the adapter know about it.
RecyclerView.Adapter
has many options to choose from, including notifyItemChanged
, which tells it that a particular item has changed state. This might be good for your use
if(isChecked) {
for (int i = 0; i < fonts.size(); i++) {
if (i == position) continue;
Font f = fonts.get(i);
if (f.isSelected()) {
f.setSelected(false);
notifyItemChanged(i); // Tell the adapter this item is updated
}
}
fonts.get(position).setSelected(isChecked);
notifyItemChanged(position);
}
This simple one worked for me
private RadioButton lastCheckedRB = null;
...
@Override
public void onBindViewHolder(final CoachListViewHolder holder, final int position) {
holder.priceRadioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
RadioButton checked_rb = (RadioButton) group.findViewById(checkedId);
if (lastCheckedRB != null && lastCheckedRB != checked_rb) {
lastCheckedRB.setChecked(false);
}
//store the clicked radiobutton
lastCheckedRB = checked_rb;
}
});
Source: Stackoverflow.com