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.android.internal.widget;
  
  import android.annotation.IdRes;
  import android.content.Context;
  import android.util.AttributeSet;
  import android.view.View;
  import android.view.ViewGroup;
  import android.widget.AdapterView;
  import android.widget.ListAdapter;
  import android.widget.ListView;
  import android.widget.HeaderViewListAdapter;
  
  import java.util.ArrayList;
  import java.util.function.Predicate;
  
  public class WatchHeaderListView extends ListView {
      private View mTopPanel;
  
      public WatchHeaderListView(Context context, AttributeSet attrs) {
          super(context, attrs);
      }
  
      public WatchHeaderListView(Context context, AttributeSet attrs, int defStyleAttr) {
          super(context, attrs, defStyleAttr);
      }
  
      public WatchHeaderListView(
              Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
          super(context, attrs, defStyleAttr, defStyleRes);
      }
  
      @Override
      protected HeaderViewListAdapter wrapHeaderListAdapterInternal(
              ArrayList<ListView.FixedViewInfo> headerViewInfos,
              ArrayList<ListView.FixedViewInfo> footerViewInfos,
              ListAdapter adapter) {
          return new WatchHeaderListAdapter(headerViewInfos, footerViewInfos, adapter);
      }
  
      @Override
      public void addView(View child, ViewGroup.LayoutParams params) {
          if (mTopPanel == null) {
              setTopPanel(child);
          } else {
              throw new IllegalStateException("WatchHeaderListView can host only one header");
          }
      }
  
      public void setTopPanel(View v) {
          mTopPanel = v;
          wrapAdapterIfNecessary();
      }
  
      @Override
      public void setAdapter(ListAdapter adapter) {
          super.setAdapter(adapter);
          wrapAdapterIfNecessary();
      }
  
      @Override
      protected View findViewTraversal(@IdRes int id) {
          View v = super.findViewTraversal(id);
          if (v == null && mTopPanel != null && !mTopPanel.isRootNamespace()) {
              return mTopPanel.findViewById(id);
          }
          return v;
      }
  
      @Override
      protected View findViewWithTagTraversal(Object tag) {
          View v = super.findViewWithTagTraversal(tag);
          if (v == null && mTopPanel != null && !mTopPanel.isRootNamespace()) {
              return mTopPanel.findViewWithTag(tag);
          }
          return v;
      }
  
      @Override
      protected <T extends View> T findViewByPredicateTraversal(
              Predicate<View> predicate, View childToSkip) {
          View v = super.findViewByPredicateTraversal(predicate, childToSkip);
          if (v == null && mTopPanel != null && mTopPanel != childToSkip
                  && !mTopPanel.isRootNamespace()) {
              return (T) mTopPanel.findViewByPredicate(predicate);
          }
          return (T) v;
      }
  
      @Override
      public int getHeaderViewsCount() {
          return mTopPanel == null ? super.getHeaderViewsCount()
                  : super.getHeaderViewsCount() + (mTopPanel.getVisibility() == GONE ? 0 : 1);
      }
  
      private void wrapAdapterIfNecessary() {
          ListAdapter adapter = getAdapter();
          if (adapter != null && mTopPanel != null) {
              if (!(adapter instanceof WatchHeaderListAdapter)) {
                  wrapHeaderListAdapterInternal();
              }
  
              ((WatchHeaderListAdapter) getAdapter()).setTopPanel(mTopPanel);
              dispatchDataSetObserverOnChangedInternal();
          }
      }
  
      private static class WatchHeaderListAdapter extends HeaderViewListAdapter {
          private View mTopPanel;
  
          public WatchHeaderListAdapter(
                  ArrayList<ListView.FixedViewInfo> headerViewInfos,
                  ArrayList<ListView.FixedViewInfo> footerViewInfos,
                  ListAdapter adapter) {
              super(headerViewInfos, footerViewInfos, adapter);
          }
  
          public void setTopPanel(View v) {
              mTopPanel = v;
          }
  
          private int getTopPanelCount() {
              return (mTopPanel == null || mTopPanel.getVisibility() == GONE) ? 0 : 1;
          }
  
          @Override
          public int getCount() {
              return super.getCount() + getTopPanelCount();
          }
  
          @Override
          public boolean areAllItemsEnabled() {
              return getTopPanelCount() == 0 && super.areAllItemsEnabled();
          }
  
          @Override
          public boolean isEnabled(int position) {
              int topPanelCount = getTopPanelCount();
              return position < topPanelCount ? false : super.isEnabled(position - topPanelCount);
          }
  
          @Override
          public Object getItem(int position) {
              int topPanelCount = getTopPanelCount();
              return position < topPanelCount ? null : super.getItem(position - topPanelCount);
          }
  
          @Override
          public long getItemId(int position) {
              int numHeaders = getHeadersCount() + getTopPanelCount();
              if (getWrappedAdapter() != null && position >= numHeaders) {
                  int adjPosition = position - numHeaders;
                  int adapterCount = getWrappedAdapter().getCount();
                  if (adjPosition < adapterCount) {
                      return getWrappedAdapter().getItemId(adjPosition);
                  }
              }
              return -1;
          }
  
          @Override
          public View getView(int position, View convertView, ViewGroup parent) {
              int topPanelCount = getTopPanelCount();
              return position < topPanelCount
                      ? mTopPanel : super.getView(position - topPanelCount, convertView, parent);
          }
  
          @Override
          public int getItemViewType(int position) {
              int numHeaders = getHeadersCount() + getTopPanelCount();
              if (getWrappedAdapter() != null && position >= numHeaders) {
                  int adjPosition = position - numHeaders;
                  int adapterCount = getWrappedAdapter().getCount();
                  if (adjPosition < adapterCount) {
                      return getWrappedAdapter().getItemViewType(adjPosition);
                  }
              }
  
              return AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER;
          }
      }
  }
  