How to get all RecyclerView ViewHolder?

kai hello picture kai hello · Apr 14, 2016 · Viewed 20.3k times · Source

I want to change all items' text color when I click on one of them. My problem is that the color is changing only on visible items. The color of invisible items does not change at all.

New: Also I would like to know how to change the color of the clicked item only.

EffectPanelRecyclerViewAdapter.java:

public class EffectPanelRecyclerViewAdapter extends RecyclerView.Adapter<EffectPanelRecyclerViewAdapter.ViewHolder> {
private ArrayList<String> mDataset = null;
private MyItemClickListener mItemClickListener;

public EffectPanelRecyclerViewAdapter(ArrayList<String> datats) {
    mDataset = datats;
}


public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    public TextView mTextView;
    private MyItemClickListener mListener;

    public ViewHolder(View v, MyItemClickListener listener) {
        super(v);
        mListener = listener;
        mTextView = (TextView) v.findViewById(R.id.tv);
        v.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if (mListener != null) {
            Log.d("hello", "getAdapterPosition=" + getAdapterPosition());
            mListener.onItemClick(v, getAdapterPosition());
        }
    }

}

@Override
public int getItemCount() {
    return mDataset.size();
}

public interface MyItemClickListener {
    public void onItemClick(View view, int postion);
}

/**
 * ViewHolder
 */
@Override
public EffectPanelRecyclerViewAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    // create a new view
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item, parent, false);
    // set the view's size, margins, paddings and layout parameters
    ViewHolder vh = new ViewHolder(v, mItemClickListener);
    Log.d("hello", "onCreateViewHolder");
    return vh;
}

@Override
public void onBindViewHolder(ViewHolder holder, final int position) {
    Log.d("hello", "onBindViewHolder,position=" + position);
    ViewHolder mHolder = (ViewHolder) holder;
    mHolder.mTextView.setText(mDataset.get(position));
    mHolder.mTextView.setTag(position);
    mHolder.mTextView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            mItemClickListener.onItemClick(v, position);
        }
    });
}

public void setOnItemClickListener(MyItemClickListener listener) {
    this.mItemClickListener = listener;
}

}

MainActivity.java:

public class MainActivity extends AppCompatActivity {

private ArrayList<String> mDatas;
private RecyclerView mRecyclerView;
private EffectPanelRecyclerViewAdapter mAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initDatas();
    mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerview_horizontal);
    final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
    linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
    mRecyclerView.setLayoutManager(linearLayoutManager);
    mAdapter = new EffectPanelRecyclerViewAdapter(mDatas);
    mRecyclerView.setAdapter(mAdapter);
    mAdapter.setOnItemClickListener(new EffectPanelRecyclerViewAdapter.MyItemClickListener() {
        @Override
        public void onItemClick(View view, int position) {
            Toast.makeText(MainActivity.this, "position=" + position, Toast.LENGTH_SHORT).show();
            //I want to change all item text color.How to do it ?
            for (int i = 0; i < mAdapter.getItemCount(); i++) {
                EffectPanelRecyclerViewAdapter.ViewHolder viewHolder = (EffectPanelRecyclerViewAdapter.ViewHolder) mRecyclerView.findViewHolderForAdapterPosition(i);
                if (viewHolder != null) {
                    viewHolder.mTextView.setTextColor(Color.RED);
                    Log.d("hellotom", "if i=" + i);
                } else {
                    Log.d("hellotom", "else i=" + i);
                }
            }
        }
    });
}

private void initDatas() {
    mDatas = new ArrayList();
    for (int i = 0; i < 10; i++) {
        mDatas.add(i, "i=" + i);
    }
}

}

activity_main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

<android.support.v7.widget.RecyclerView
    android:id="@+id/id_recyclerview_horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_centerVertical="true"
    android:paddingBottom="18dp"
    android:paddingTop="15dp"
    android:scrollbars="none" />

item.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content">

<TextView
    android:id="@+id/tv"
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:drawableTop="@drawable/ic_launcher_select"
    android:textColor="@color/select_color"
    android:gravity="center"
    android:text="@string/app_name" />

Answer

Ralph Bergmann picture Ralph Bergmann · Apr 14, 2016

Store a flag in your adapter class like this private boolean clicked = false;. In the onclicklistener set it to true and call notifiyDatasetChanged()

In the onBindViewHolder method add a if like this

if (clicked)
   viewHolder.mTextView.setTextColor(Color.RED); 
else
   viewHolder.mTextView.setTextColor(Color.BLUE);