[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. It also holds the suggested offline items which
+ * are shown at the end of the list for that 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;
+    }
+
+    /** @return Whether the suggested pages are expanded. */
+    public boolean isSuggestedOfflinePagesSectionExpanded() {
+        return mIsSuggestedOfflinePagesSectionExpanded;
+    }
+
+    /**
+     * Expands or collapses the suggested offline pages.
+     * @param expanded Whether the suggested pages should be shown.
+     */
+    public void setIsSuggestedOfflinePagesSectionExpanded(boolean expanded) {
+        mIsSuggestedOfflinePagesSectionExpanded = expanded;
+    }
+
+    /** @return The total number of suggested pages for this date. */
+    public int getSuggestedOfflinePageCount() {
+        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--;
+        }
+    }
+
+    /**
+     * The visible items for the group are set to their respective positions in the list view.
+     * Invisible (collpased) items are skipped.
+     */
+    @Override
+    protected void setPositionForItems(int startIndex) {
+        int index = startIndex;
+        boolean firstSuggestedItem = true;
+        for (TimedItem item : mItems) {
+            if (isSuggestedOfflinePage(item)) {
+                // Skip one position for the header at the beginning of the suggested items section.
+                if (firstSuggestedItem) {
+                    index += 1;
+                    firstSuggestedItem = false;
+                }
+                if (!isSuggestedOfflinePagesSectionExpanded()) break;
+            }
+            item.setPosition(index);
+            index += 1;
+        }
+    }
+
+    @Override
+    protected void setPositionForFirstAndLastInGroup() {
+        TimedItem first = mItems.get(0);
+        first.setIsFirstInGroup(true);
+
+        TimedItem last = mItems.get(mItems.size() - 1);
+        if (!isSuggestedOfflinePagesSectionExpanded() && mNumSuggestedOfflinePages > 0) {
+            last = getSuggestedOfflinePagesHeader();
+        }
+
+        last.setIsLastInGroup(true);
+    }
+
+    @Override
+    public int size() {
+        int size = super.size();
+
+        // The size should match the number of rows in the list view. So, adjust the size depending
+        // on whether the suggested items section is expanded or collapsed.
+        if (mNumSuggestedOfflinePages > 0) {
+            // First item of the suggested pages section is the section header.
+            size += 1;
+            if (!isSuggestedOfflinePagesSectionExpanded()) {
+                size -= mNumSuggestedOfflinePages;
+            }
+        }
+
+        return size;
+    }
+
+    /** @return The total file size of the suggested pages for this date. */
+    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;

[Theresa, 2017/02/07 00:09:05]

The history view is going to have a list header view soon (when the space
display moves out of the drawer and in-line, I can send you mocks if you're
interested), so it would be ideal if this method kept more of the logic from its
super class version (specifically the parts that check if the group is a list
header or list footer).

[shaktisahu, 2017/02/07 23:35:12]

Done.

+
+        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) {

[Theresa, 2017/02/07 00:09:05]

Could this be extracted to something like getOfflinePagesSectionHeaderPosition()
and shared with isSuggestedOfflinePagesSectionHeader()?

[shaktisahu, 2017/02/07 23:35:12]

Done.

+                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_SUBSECTION_HEADER;
+        } else {
+            return super.getItemViewType(position);
+        }
+    }
+
+    @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;
+    }
+}