[Download Home] Displaying offline page bundle per day

chrome/android/java/src/org/chromium/chrome/browser/widget/DateDividedAdapter.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.widget;
 
 import android.os.AsyncTask;
+import android.support.annotation.Nullable;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.RecyclerView.Adapter;
 import android.support.v7.widget.RecyclerView.ViewHolder;
 import android.text.format.DateUtils;
 import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.TextView;
 
@@ skipping 124 matching lines @@
             mTextView.setText(builder);
         }
     }
 
     protected static class BasicViewHolder extends RecyclerView.ViewHolder {
         public BasicViewHolder(View itemView) {
             super(itemView);
         }
     }
 
+    protected static class SubsectionHeaderViewHolder extends RecyclerView.ViewHolder {
+        private View mView;
+
+        public SubsectionHeaderViewHolder(View itemView) {
+            super(itemView);
+            mView = itemView;
+        }
+
+        public View getView() {
+            return mView;
+        }
+    }
+
     /**
      * A bucket of items with the same date.
      */
-    protected static class ItemGroup {
+    public static class ItemGroup {
         private final Date mDate;
         private final List<TimedItem> mItems = new ArrayList<>();
 
         /** Index of the header, relative to the full list.  Must be set only once.*/
         private int mIndex;
 
         private boolean mIsSorted;
         private boolean mIsListHeader;
         private boolean mIsListFooter;
 
@@ skipping 54 matching lines @@
             if (index == 0 || mIsListHeader || mIsListFooter) return null;
 
             sortIfNeeded();
             return mItems.get(index - 1);
         }
 
         /**
          * Rather than sorting the list each time a new item is added, the list is sorted when
          * something requires a correct ordering of the items.
          */
-        private void sortIfNeeded() {
+        protected void sortIfNeeded() {
             if (mIsSorted) return;
             mIsSorted = true;
 
             Collections.sort(mItems, new Comparator<TimedItem>() {
                 @Override
                 public int compare(TimedItem lhs, TimedItem rhs) {
-                    // More recent items are listed first.  Ideally we'd use Long.compare, but that
-                    // is an API level 19 call for some inexplicable reason.
-                    long timeDelta = lhs.getTimestamp() - rhs.getTimestamp();
-                    if (timeDelta > 0) {
-                        return -1;
-                    } else if (timeDelta == 0) {
-                        return 0;
-                    } else {
-                        return 1;
-                    }
+                    return compareItem(lhs, rhs);
                 }
             });
         }
+
+        protected int compareItem(TimedItem lhs, TimedItem rhs) {
+            // More recent items are listed first.  Ideally we'd use Long.compare, but that
+            // is an API level 19 call for some inexplicable reason.
+            long timeDelta = lhs.getTimestamp() - rhs.getTimestamp();
+            if (timeDelta > 0) {
+                return -1;
+            } else if (timeDelta == 0) {
+                return 0;
+            } else {
+                return 1;
+            }
+        }
     }
 
     // Cached async tasks to get the two Calendar objects, which are used when comparing dates.
     private static final AsyncTask<Void, Void, Calendar> sCal1 = createCalendar();
     private static final AsyncTask<Void, Void, Calendar> sCal2 = createCalendar();
 
     public static final int TYPE_FOOTER = -2;
     public static final int TYPE_HEADER = -1;
     public static final int TYPE_DATE = 0;
     public static final int TYPE_NORMAL = 1;
+    public static final int TYPE_SUBSECTION_HEADER = 2;
 
     private int mSize;
     private boolean mHasListHeader;
     private boolean mHasListFooter;
 
     private SortedSet<ItemGroup> mGroups = new TreeSet<>(new Comparator<ItemGroup>() {
         @Override
         public int compare(ItemGroup lhs, ItemGroup rhs) {
             if (lhs == rhs) return 0;
 
             // There should only be at most one list header and one list footer in the SortedSet.
             if (lhs.mIsListHeader || rhs.mIsListFooter) return -1;
             if (lhs.mIsListFooter || rhs.mIsListHeader) return 1;
 
             return compareDate(lhs.mDate, rhs.mDate);
         }
     });
 
     /**
      * Creates a {@link ViewHolder} in the given view parent.
      * @see #onCreateViewHolder(ViewGroup, int)
      */
     protected abstract ViewHolder createViewHolder(ViewGroup parent);
 
     /**
      * Creates a {@link BasicViewHolder} in the given view parent for the header.
      * @see #onCreateViewHolder(ViewGroup, int)
      */
+    @Nullable
     protected BasicViewHolder createHeader(ViewGroup parent) {
         return null;
     }
 
     /**
      * Creates a {@link BasicViewHolder} in the given view parent for the footer.
      * See {@link #onCreateViewHolder(ViewGroup, int)}.
      */
+    @Nullable
     protected BasicViewHolder createFooter(ViewGroup parent) {
         return null;
     }
 
     /**
      * Creates a {@link DateViewHolder} in the given view parent.
      * @see #onCreateViewHolder(ViewGroup, int)
      */
     protected DateViewHolder createDateViewHolder(ViewGroup parent) {
         return new DateViewHolder(LayoutInflater.from(parent.getContext()).inflate(
                 getTimedItemViewResId(), parent, false));
     }
 
     /**
+     * Creates a {@link ViewHolder} for a subsection in the given view parent.
+     * @see #onCreateViewHolder(ViewGroup, int)
+     */
+    @Nullable
+    protected SubsectionHeaderViewHolder createSubsectionHeader(ViewGroup parent) {
+        return null;
+    }
+
+    /**
+     * Helper function to determine whether an item is a subsection header.
+     * @param timedItem The item

[Theresa, 2017/02/17 23:56:35]

nit: add a period at the end of this line

[shaktisahu, 2017/02/18 00:39:46]

Done.

+     * @return Whether the item is a subsection header.
+     */
+    protected boolean isSubsectionHeader(TimedItem timedItem) {
+        return false;
+    }
+
+    /**
      * Binds the {@link ViewHolder} with the given {@link TimedItem}.
      * @see #onBindViewHolder(ViewHolder, int)
      */
     protected abstract void bindViewHolderForTimedItem(ViewHolder viewHolder, TimedItem item);
 
     /**
+     * Binds the {@link SubsectionHeaderViewHolder} with the given {@link TimedItem}.
+     * @see #onBindViewHolder(ViewHolder, int)
+     */
+    protected void bindViewHolderForSubsectionHeader(
+            SubsectionHeaderViewHolder holder, TimedItem timedItem) {}
+
+    /**
      * Gets the resource id of the view showing the date header.
      * Contract for subclasses: this view should be a {@link TextView}.
      */
     protected abstract int getTimedItemViewResId();
 
     /**
      * Loads a list of {@link TimedItem}s to this adapter. Previous data will not be removed. Call
      * {@link #clear(boolean)} to remove previous items.
      */
     public void loadItems(List<? extends TimedItem> timedItems) {
         for (TimedItem timedItem : timedItems) {
             Date date = new Date(timedItem.getTimestamp());
             boolean found = false;
             for (ItemGroup group : mGroups) {
                 if (group.isSameDay(date)) {
                     found = true;
                     group.addItem(timedItem);
                     mSize++;
                     break;
                 }
             }
             if (!found) {
                 // Create a new ItemGroup with the date for the new item. This increases the
                 // size by two because we add new views for the date and the item itself.
-                ItemGroup newGroup = new ItemGroup(timedItem.getTimestamp());
+                ItemGroup newGroup = createGroup(timedItem.getTimestamp());
                 newGroup.addItem(timedItem);
                 mGroups.add(newGroup);
                 mSize += 2;
             }
         }
 
         setGroupPositions();
         notifyDataSetChanged();
     }
 
     /**
+     * Creates and returns an item group for a given day.
+     * @param timestamp A timestamp from which the date is determined.
+     * @return The item group.
+     */
+    protected ItemGroup createGroup(long timestamp) {
+        return new ItemGroup(timestamp);
+    }
+
+    /**
      * Tells each group where they start in the list.
      */
     private void setGroupPositions() {
         int startIndex = 0;
         for (ItemGroup group : mGroups) {
             group.resetPosition();
             group.setPosition(startIndex);
             startIndex += group.size();
         }
     }
@@ skipping 88 matching lines @@
      */
     public Pair<Date, TimedItem> getItemAt(int position) {
         Pair<ItemGroup, Integer> pair = getGroupAt(position);
         ItemGroup group = pair.first;
         return new Pair<>(group.mDate, group.getItemAt(pair.second));
     }
 
     @Override
     public final int getItemViewType(int position) {
         Pair<ItemGroup, Integer> pair = getGroupAt(position);
+        ItemGroup group = pair.first;
         if (pair.second == TYPE_HEADER) {
             return TYPE_HEADER;
         } else if (pair.second == TYPE_FOOTER) {
             return TYPE_FOOTER;
         } else if (pair.second == 0) {
             return TYPE_DATE;
+        } else if (isSubsectionHeader(group.getItemAt(pair.second))) {
+            return TYPE_SUBSECTION_HEADER;
         } else {
             return TYPE_NORMAL;
         }
     }
 
     @Override
     public final RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
         if (viewType == TYPE_DATE) {
             return createDateViewHolder(parent);
         } else if (viewType == TYPE_NORMAL) {
             return createViewHolder(parent);
         } else if (viewType == TYPE_HEADER) {
             return createHeader(parent);
         } else if (viewType == TYPE_FOOTER) {
             return createFooter(parent);
+        } else if (viewType == TYPE_SUBSECTION_HEADER) {
+            return createSubsectionHeader(parent);
         }
         assert false;
         return null;
     }
 
     @Override
     public final void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
         Pair<Date, TimedItem> pair = getItemAt(position);
         if (holder instanceof DateViewHolder) {
             ((DateViewHolder) holder).setDate(pair.first);
+        } else if (holder instanceof SubsectionHeaderViewHolder) {
+            bindViewHolderForSubsectionHeader((SubsectionHeaderViewHolder) holder, pair.second);
         } else if (!(holder instanceof BasicViewHolder)) {
             bindViewHolderForTimedItem(holder, pair.second);
         }
     }
 
     @Override
     public final int getItemCount() {
         return mSize;
     }
 
@@ skipping 55 matching lines @@
         long dayOfYear = calendar.get(Calendar.DAY_OF_YEAR);
         long year = calendar.get(Calendar.YEAR);
         return (year << 16) + dayOfYear;
     }
 
     /**
      * Compares two {@link Date}s. Note if you already have two {@link Calendar} objects, use
      * {@link #compareCalendar(Calendar, Calendar)} instead.
      * @return 0 if date1 and date2 are in the same day; 1 if date1 is before date2; -1 otherwise.
      */
-    private static int compareDate(Date date1, Date date2) {
+    protected static int compareDate(Date date1, Date date2) {
         Pair<Calendar, Calendar> pair = getCachedCalendars();
         Calendar cal1 = pair.first, cal2 = pair.second;
         cal1.setTime(date1);
         cal2.setTime(date2);
         return compareCalendar(cal1, cal2);
     }
 
     /**
      * @return 0 if cal1 and cal2 are in the same day; 1 if cal1 happens before cal2; -1 otherwise.
      */
@@ skipping 30 matching lines @@
      */
     private static AsyncTask<Void, Void, Calendar> createCalendar() {
         return new AsyncTask<Void, Void, Calendar>() {
             @Override
             protected Calendar doInBackground(Void... unused) {
                 return Calendar.getInstance();
             }
         }.execute();
     }
 }