[Download Home] Displaying offline page bundle per day

chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadItemGroup.java

+// Copyright 2017 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.download.ui;
+
+import org.chromium.chrome.browser.download.ui.DownloadHistoryItemWrapper.OfflinePageItemWrapper;
+import org.chromium.chrome.browser.widget.DateDividedAdapter;
+import org.chromium.chrome.browser.widget.DateDividedAdapter.TimedItem;
+
+/**
+ * A bucket of downloaded items with the same date.
+ */
+public class DownloadItemGroup extends DateDividedAdapter.ItemGroup {
+    private int mNumSuggestedOfflinePages;
+    private boolean mIsSuggestedOfflinePagesSectionExpanded;
+
+    /** The header representing the offline pages that are automatically downloaded */
+    private TimedItem mSuggestedOfflinePagesHeader;
+
+    public DownloadItemGroup(long timestamp) {
+        super(timestamp);
+        mNumSuggestedOfflinePages = 0;
+        mIsSuggestedOfflinePagesSectionExpanded = false;
+    }
+
+    public boolean isSuggestedOfflinePagesSectionExpanded() {
+        return mIsSuggestedOfflinePagesSectionExpanded;
+    }
+
+    public void setIsSuggestedOfflinePagesSectionExpanded(boolean expanded) {
+        mIsSuggestedOfflinePagesSectionExpanded = expanded;
+    }
+
+    public int getSuggestedOfflinePageCount() {

[Theresa, 2017/02/03 19:53:06]

nit: public methods need JavaDocs

[shaktisahu, 2017/02/04 18:57:43]

Done.

+        return mNumSuggestedOfflinePages;
+    }
+
+    private TimedItem getSuggestedOfflinePagesHeader() {
+        if (mSuggestedOfflinePagesHeader == null) {
+            mSuggestedOfflinePagesHeader = new TimedItem() {
+                private Long mStableId;
+
+                @Override
+                public long getTimestamp() {
+                    return getDate().getTime();
+                }
+
+                @Override
+                public long getStableId() {
+                    if (mStableId == null) {
+                        // Generate a stable ID based on timestamp.
+                        mStableId = 0xFFFFFFFF00000000L + getTimestamp() & 0x0FFFFFFFF;
+                    }
+                    return mStableId;
+                }
+            };
+        }
+        return mSuggestedOfflinePagesHeader;
+    }
+
+    @Override
+    public void addItem(TimedItem item) {
+        super.addItem(item);
+        if (isSuggestedOfflinePage(item)) {
+            mNumSuggestedOfflinePages++;
+        }
+    }
+
+    @Override
+    public void removeItem(TimedItem item) {
+        super.removeItem(item);
+        if (isSuggestedOfflinePage(item)) {
+            mNumSuggestedOfflinePages--;
+        }
+    }
+
+    @Override
+    protected void setPositionForItems(int startIndex) {
+        int index = startIndex;
+        boolean firstSuggestedItem = false;
+        for (TimedItem item : mItems) {
+            if (isSuggestedOfflinePage(item)) {
+                if (!firstSuggestedItem) {
+                    index += 1;

[Theresa, 2017/02/03 19:53:06]

A comment here explaining why we skip a position for the first suggested item
would be helpful.

[shaktisahu, 2017/02/04 18:57:43]

Done.

+                    firstSuggestedItem = true;
+                }
+                if (!isSuggestedOfflinePagesSectionExpanded()) continue;

[Theresa, 2017/02/03 19:53:06]

Should we break if the suggested offline page section isn't expanded instead of
checking for each of the remaining items?

[shaktisahu, 2017/02/04 18:57:43]

Done. Yes.

+            }
+            item.setPosition(index);
+            index += 1;
+        }
+    }
+
+    @Override
+    public int size() {
+        int size = super.size();
+        if (mNumSuggestedOfflinePages > 0) {

[Theresa, 2017/02/03 19:53:06]

Do we add everything to the adapter whether or not the section is expanded? Can
you walk me through the logic of how suggested offline pages are hidden when the
section is not expanded?

[shaktisahu, 2017/02/04 18:57:43]

We only add the visible items to the adapter. The adapter invokes
getItemAt(position) and we supply that item by finding the appropriate item from
mItems. 

+            size += 1;
+            if (!isSuggestedOfflinePagesSectionExpanded()) {
+                size -= mNumSuggestedOfflinePages;
+            }
+        }
+
+        return size;
+    }
+
+    public long getSuggestedOfflinePagesFileSize() {
+        long size = 0;
+        for (TimedItem item : mItems) {
+            if (isSuggestedOfflinePage(item)) {
+                size += ((DownloadHistoryItemWrapper) item).getFileSize();
+            }
+        }
+        return size;
+    }
+
+    private boolean isSuggestedOfflinePagesSectionHeader(int index) {
+        return index == (mItems.size() - mNumSuggestedOfflinePages + 1)
+                && mNumSuggestedOfflinePages > 0;
+    }
+
+    @Override
+    public TimedItem getItemAt(int index) {
+        // 0 is allocated to the date header. The list header has no items.
+        if (index == 0) return null;
+
+        sortIfNeeded();
+
+        // The suggested pages start at the end of the group.
+        if (index <= mItems.size() - mNumSuggestedOfflinePages) {
+            return mItems.get(index - 1);
+        } else {
+            if (mNumSuggestedOfflinePages > 0
+                    && index == mItems.size() - mNumSuggestedOfflinePages + 1) {
+                return getSuggestedOfflinePagesHeader();
+            } else if (isSuggestedOfflinePagesSectionExpanded()) {
+                return mItems.get(index - 2);
+            } else {
+                assert false;
+                return null;
+            }
+        }
+    }
+
+    @Override
+    public int getItemViewType(int position) {
+        if (isSuggestedOfflinePagesSectionHeader(position)) {
+            return DateDividedAdapter.TYPE_SUGGESTED_OFFLINE_PAGES_HEADER;
+        } else {
+            return DateDividedAdapter.TYPE_NORMAL;
+        }
+    }
+
+    @Override
+    public int compareItem(TimedItem lhs, TimedItem rhs) {
+        if (isSuggestedOfflinePage(lhs) && !isSuggestedOfflinePage(rhs)) return 1;
+        if (!isSuggestedOfflinePage(lhs) && isSuggestedOfflinePage(rhs)) return -1;
+
+        return super.compareItem(lhs, rhs);
+    }
+
+    private boolean isSuggestedOfflinePage(TimedItem timedItem) {
+        if (timedItem instanceof OfflinePageItemWrapper) {
+            return ((OfflinePageItemWrapper) timedItem).isSuggested();
+        }
+
+        return false;
+    }
+}