kai hello kai hello - 1 month ago 17
Android Question

How to get all RecyclerView ViewHolder?

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

it is not tested!!!

public class EffectPanelRecyclerViewAdapter extends
    RecyclerView.Adapter<EffectPanelRecyclerViewAdapter.ViewHolder> {

    private ArrayList<DataClass> mDataset = null;

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

    /**
     * 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);
        Log.d("hello", "onCreateViewHolder");
        return vh;
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, final int position) {

        Log.d("hello", "onBindViewHolder,position=" + position);
        holder.mTextView.setText(mDataset.get(position).text);
        holder.mTextView.setTextColor(mDataset.get(position).clicked ? Color.RED : Color.BLUE);
        holder.mTextView.setTag(position);
        holder.mTextView.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                mDataset.get(position).clicked = true;
                notifyItemChanged(position);
            }
        });
    }

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


    private static class DataClass {

        public String  text;
        public boolean clicked;
    }


    private static class ViewHolder extends RecyclerView.ViewHolder {

        public TextView mTextView;

        public ViewHolder(View v) {
            super(v);
            mTextView = (TextView) v.findViewById(R.id.tv);
        }
    }
}