content: /*
   * Copyright (c) 2016 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.example.android.tvleanback.presenter;
  
  import android.content.Context;
  import android.graphics.drawable.Drawable;
  import androidx.leanback.widget.HeaderItem;
  import androidx.leanback.widget.ListRow;
  import androidx.leanback.widget.Presenter;
  import androidx.leanback.widget.RowHeaderPresenter;
  import android.view.LayoutInflater;
  import android.view.View;
  import android.view.ViewGroup;
  import android.widget.ImageView;
  import android.widget.TextView;
  
  import com.example.android.tvleanback.R;
  
  public class IconHeaderItemPresenter extends RowHeaderPresenter {
  
      private float mUnselectedAlpha;
  
      @Override
      public ViewHolder onCreateViewHolder(ViewGroup viewGroup) {
          mUnselectedAlpha = viewGroup.getResources()
                  .getFraction(R.fraction.lb_browse_header_unselect_alpha, 1, 1);
          LayoutInflater inflater = (LayoutInflater) viewGroup.getContext()
                  .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
  
          View view = inflater.inflate(R.layout.icon_header_item, null);
          view.setAlpha(mUnselectedAlpha); // Initialize icons to be at half-opacity.
  
          return new ViewHolder(view);
      }
  
      @Override
      public void onBindViewHolder(Presenter.ViewHolder viewHolder, Object item) {
          HeaderItem headerItem = ((ListRow) item).getHeaderItem();
          View rootView = viewHolder.view;
          rootView.setFocusable(true);
  
          ImageView iconView = (ImageView) rootView.findViewById(R.id.header_icon);
          Drawable icon = rootView.getResources().getDrawable(R.drawable.android_header, null);
          iconView.setImageDrawable(icon);
  
          TextView label = (TextView) rootView.findViewById(R.id.header_label);
          label.setText(headerItem.getName());
      }
  
      @Override
      public void onUnbindViewHolder(Presenter.ViewHolder viewHolder) {
          // no op
      }
  
      // TODO: This is a temporary fix. Remove me when leanback onCreateViewHolder no longer sets the
      // mUnselectAlpha, and also assumes the xml inflation will return a RowHeaderView.
      @Override
      protected void onSelectLevelChanged(RowHeaderPresenter.ViewHolder holder) {
          holder.view.setAlpha(mUnselectedAlpha + holder.getSelectLevel() *
                  (1.0f - mUnselectedAlpha));
      }
  }
  