This is what you're looking for.
I had this problem too. And like you, the answer is very hard to find. But there IS an easy way to get the ViewHolder from a specific position (something you'll probably do a lot in the Adapter).
myRecyclerView.findViewHolderForAdapterPosition(pos);
NOTE: If the View has been recycled, this will return null
. Thanks to Michael for quickly catching my important omission.
I suppose you are using a LinearLayoutManager
to show the list. It has a nice method called findViewByPosition
that
Finds the view which represents the given adapter position.
All you need is the adapter position of the item you are interested in.
edit: as noted by Paul Woitaschek in the comments, findViewByPosition
is a method of LayoutManager
so it would work with all LayoutManagers (i.e. StaggeredGridLayoutManager
, etc.)
If you want the View
, make sure to access the itemView
property of the ViewHolder like so: myRecyclerView.findViewHolderForAdapterPosition(pos).itemView;
You can use use both
recyclerViewInstance.findViewHolderForAdapterPosition(adapterPosition)
and
recyclerViewInstance.findViewHolderForLayoutPosition(layoutPosition)
.
Be sure that RecyclerView view uses two type of positions
Adapter position: Position of an item in the adapter. This is the position from the Adapter's perspective.
Layout position: Position of an item in the latest layout calculation. This is the position from the LayoutManager's perspective.
You should use getAdapterPosition()
for findViewHolderForAdapterPosition(adapterPosition)
and getLayoutPosition()
for findViewHolderForLayoutPosition(layoutPosition)
.
Take a member variable to hold previously selected item position in recyclerview adapter and other member variable to check whether user is clicking for first time or not.
Sample code and screen shots are attached for more information at the bottom.
public class MainActivity extends AppCompatActivity {
private RecyclerView mRecyclerList = null;
private RecyclerAdapter adapter = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerList = (RecyclerView) findViewById(R.id.recyclerList);
}
@Override
protected void onStart() {
RecyclerView.LayoutManager layoutManager = null;
String[] daysArray = new String[15];
String[] datesArray = new String[15];
super.onStart();
for (int i = 0; i < daysArray.length; i++){
daysArray[i] = "Sunday";
datesArray[i] = "12 Feb 2017";
}
adapter = new RecyclerAdapter(mRecyclerList, daysArray, datesArray);
layoutManager = new LinearLayoutManager(MainActivity.this);
mRecyclerList.setAdapter(adapter);
mRecyclerList.setLayoutManager(layoutManager);
}
}
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.MyCardViewHolder>{
private final String TAG = "RecyclerAdapter";
private Context mContext = null;
private TextView mDaysTxt = null, mDateTxt = null;
private LinearLayout mDateContainerLayout = null;
private String[] daysArray = null, datesArray = null;
private RecyclerView mRecyclerList = null;
private int previousPosition = 0;
private boolean flagFirstItemSelected = false;
public RecyclerAdapter(RecyclerView mRecyclerList, String[] daysArray, String[] datesArray){
this.mRecyclerList = mRecyclerList;
this.daysArray = daysArray;
this.datesArray = datesArray;
}
@Override
public MyCardViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater layoutInflater = null;
View view = null;
MyCardViewHolder cardViewHolder = null;
mContext = parent.getContext();
layoutInflater = LayoutInflater.from(mContext);
view = layoutInflater.inflate(R.layout.date_card_row, parent, false);
cardViewHolder = new MyCardViewHolder(view);
return cardViewHolder;
}
@Override
public void onBindViewHolder(MyCardViewHolder holder, final int position) {
mDaysTxt = holder.mDaysTxt;
mDateTxt = holder.mDateTxt;
mDateContainerLayout = holder.mDateContainerLayout;
mDaysTxt.setText(daysArray[position]);
mDateTxt.setText(datesArray[position]);
if (!flagFirstItemSelected){
mDateContainerLayout.setBackgroundColor(Color.GREEN);
flagFirstItemSelected = true;
}else {
mDateContainerLayout.setBackground(null);
}
}
@Override
public int getItemCount() {
return daysArray.length;
}
class MyCardViewHolder extends RecyclerView.ViewHolder{
TextView mDaysTxt = null, mDateTxt = null;
LinearLayout mDateContainerLayout = null;
LinearLayout linearLayout = null;
View view = null;
MyCardViewHolder myCardViewHolder = null;
public MyCardViewHolder(View itemView) {
super(itemView);
mDaysTxt = (TextView) itemView.findViewById(R.id.daysTxt);
mDateTxt = (TextView) itemView.findViewById(R.id.dateTxt);
mDateContainerLayout = (LinearLayout) itemView.findViewById(R.id.dateContainerLayout);
mDateContainerLayout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
LinearLayout linearLayout = null;
View view = null;
if (getAdapterPosition() == previousPosition){
view = mRecyclerList.findViewHolderForAdapterPosition(previousPosition).itemView;
linearLayout = (LinearLayout) view.findViewById(R.id.dateContainerLayout);
linearLayout.setBackgroundColor(Color.GREEN);
previousPosition = getAdapterPosition();
}else {
view = mRecyclerList.findViewHolderForAdapterPosition(previousPosition).itemView;
linearLayout = (LinearLayout) view.findViewById(R.id.dateContainerLayout);
linearLayout.setBackground(null);
view = mRecyclerList.findViewHolderForAdapterPosition(getAdapterPosition()).itemView;
linearLayout = (LinearLayout) view.findViewById(R.id.dateContainerLayout);
linearLayout.setBackgroundColor(Color.GREEN);
previousPosition = getAdapterPosition();
}
}
});
}
}
}
You can simply use "findViewHolderForAdapterPosition" method of recycler view and you will get a viewHolder object from that then typecast that viewholder into your adapter viewholder so you can directly access your viewholder's views
following is the sample code for kotlin
val viewHolder = recyclerView.findViewHolderForAdapterPosition(position)
val textview=(viewHolder as YourViewHolder).yourTextView
You can make ArrayList of ViewHolder :
ArrayList<MyViewHolder> myViewHolders = new ArrayList<>();
ArrayList<MyViewHolder> myViewHolders2 = new ArrayList<>();
and, all store ViewHolder(s) in the list like :
@Override
public void onBindViewHolder(@NonNull final MyViewHolder holder, final int position) {
final String str = arrayList.get(position);
myViewHolders.add(position,holder);
}
and add/remove other ViewHolder in the ArrayList as per your requirement.
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