Ntp: show footer with learn more link.

BUG=637257

Review-Url: https://codereview.chromium.org/2275693003
Cr-Commit-Position: refs/heads/master@{#414738}

chrome/android/java/res/layout/new_tab_page_footer.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!-- 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. -->
+
+<TextView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:textColor="@color/snippets_text_color"
+    android:textSize="12sp"
+    android:textStyle="italic"
+    android:padding="12dp"
+    android:gravity="center" />

chrome/android/java/res/layout/new_tab_page_snippets_header.xml

@@ -5,7 +5,6 @@
 
 <TextView
     xmlns:android="http://schemas.android.com/apk/res/android"
-    android:id="@+id/suggestions_section_header"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:textColor="@color/snippets_list_header_text_color"

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java

@@ -249,6 +249,14 @@ public class NewTabPage
             }
         }
 
+        @Override
+        public void onLearnMoreClicked() {
+            if (mIsDestroyed) return;
+            // TODO(mvanouwerkerk): UMA logging.
+            String url = "https://support.google.com/chrome/?p=new_tab";
+            openUrl(WindowOpenDisposition.CURRENT_TAB, url);
+        }
+
         @TargetApi(Build.VERSION_CODES.LOLLIPOP)
         private boolean switchToExistingTab(String url) {
             String matchPattern = CommandLine.getInstance().getSwitchValue(

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java

@@ -258,6 +258,11 @@ public class NewTabPageView extends FrameLayout
          * called whenever a ContextMenu is closed.
          */
         void removeContextMenuCloseCallback(Callback<Menu> callback);
+
+        /**
+         * Handles clicks on the "learn more" link in the footer.
+         */
+        void onLearnMoreClicked();
     }
 
     /**

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardViewHolder.java

@@ -210,6 +210,7 @@ public class CardViewHolder extends NewTabPageViewHolder {
     /**
      * Override this to provide a context menu for the card. This method will not be called if the
      * card is currently peeking.
+     * @param menu The menu to add menu items to.
      */
     protected void createContextMenu(ContextMenu menu) {}
 
@@ -291,6 +292,7 @@ public class CardViewHolder extends NewTabPageViewHolder {
             case NewTabPageItem.VIEW_TYPE_HEADER:
             case NewTabPageItem.VIEW_TYPE_SPACING:
             case NewTabPageItem.VIEW_TYPE_PROGRESS:
+            case NewTabPageItem.VIEW_TYPE_FOOTER:
                 return false;
             default:
                 assert false;

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/Footer.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.ntp.cards;
+
+import android.text.method.LinkMovementMethod;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.ntp.NewTabPageView.NewTabPageManager;
+import org.chromium.ui.text.NoUnderlineClickableSpan;
+import org.chromium.ui.text.SpanApplier;
+
+/**
+ * A footer to show some text and a link to learn more.
+ */
+public class Footer extends SingleItemGroup {
+    @Override
+    public int getType() {
+        return NewTabPageItem.VIEW_TYPE_FOOTER;
+    }
+
+    /**
+     * The {@code ViewHolder} for the {@link Footer}.
+     */
+    public static class ViewHolder extends NewTabPageViewHolder {
+        public ViewHolder(ViewGroup root, final NewTabPageManager manager) {
+            super(LayoutInflater.from(root.getContext())
+                            .inflate(R.layout.new_tab_page_footer, root, false));
+
+            NoUnderlineClickableSpan link = new NoUnderlineClickableSpan() {
+                @Override
+                public void onClick(View view) {
+                    // TODO(mvanouwerkerk): Ensure this can be activated when using TalkBack.
+                    manager.onLearnMoreClicked();
+                }
+            };
+
+            TextView textView = (TextView) itemView;
+            textView.setText(SpanApplier.applySpans(
+                    root.getResources().getString(R.string.ntp_learn_more_about_suggested_content),
+                    new SpanApplier.SpanInfo("<link>", "</link>", link)));
+            textView.setMovementMethod(LinkMovementMethod.getInstance());
+        }
+    }
+}

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapter.java

@@ -59,6 +59,7 @@ public class NewTabPageAdapter extends Adapter<NewTabPageViewHolder>
      */
     private final List<ItemGroup> mGroups = new ArrayList<>();
     private final AboveTheFoldItem mAboveTheFold = new AboveTheFoldItem();
+    private final Footer mFooter = new Footer();
     private final SpacingItem mBottomSpacer = new SpacingItem();
 
     /** Maps suggestion categories to sections, with stable iteration ordering. */
@@ -266,6 +267,10 @@ public class NewTabPageAdapter extends Adapter<NewTabPageViewHolder>
             return new ActionItem.ViewHolder(mRecyclerView, mNewTabPageManager, mUiConfig);
         }
 
+        if (viewType == NewTabPageItem.VIEW_TYPE_FOOTER) {
+            return new Footer.ViewHolder(mRecyclerView, mNewTabPageManager);
+        }
+
         return null;
     }
 
@@ -299,10 +304,7 @@ public class NewTabPageAdapter extends Adapter<NewTabPageViewHolder>
     }
 
     public int getLastContentItemPosition() {
-        // TODO(mvanouwerkerk): Don't rely on getBottomSpacerPosition() here.
-        int bottomSpacerPosition = getBottomSpacerPosition();
-        if (bottomSpacerPosition == RecyclerView.NO_POSITION) return RecyclerView.NO_POSITION;
-        return bottomSpacerPosition - 1;
+        return getGroupPositionOffset(mFooter);
     }
 
     public int getBottomSpacerPosition() {
@@ -336,6 +338,7 @@ public class NewTabPageAdapter extends Adapter<NewTabPageViewHolder>
         // TODO(treib,bauerb): Preserve the order of categories we got from getCategories.
         mGroups.addAll(mSections.values());
         if (!mSections.isEmpty()) {
+            mGroups.add(mFooter);
             mGroups.add(mBottomSpacer);
         }
 

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageItem.java

@@ -64,6 +64,12 @@ public interface NewTabPageItem {
      */
     public static final int VIEW_TYPE_ACTION = 7;
 
+    /**
+     * View type for a {@link Footer}.
+     * @see Adapter#getItemViewType(int)
+     */
+    public static final int VIEW_TYPE_FOOTER = 8;
+
     /**
       * Returns the type ({@link ViewType}) of this list item. This is so we can
       * distinguish between different elements that are held in a single RecyclerView holder.

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageRecyclerView.java

@@ -246,7 +246,7 @@ public class NewTabPageRecyclerView extends RecyclerView {
 
     /**
      * Finds the view holder for the first header.
-     * @return The {@link ViewHolder} of the header, or null if it is not present.
+     * @return The {@code ViewHolder} of the header, or null if it is not present.
      */
     private SectionHeaderViewHolder findFirstHeader() {
         ViewHolder viewHolder =
@@ -258,7 +258,7 @@ public class NewTabPageRecyclerView extends RecyclerView {
 
     /**
      * Finds the view holder for the first card.
-     * @return The {@link ViewHolder} for the first card, or null if it is not present.
+     * @return The {@code ViewHolder} for the first card, or null if it is not present.
      */
     private CardViewHolder findFirstCard() {
         ViewHolder viewHolder =
@@ -269,21 +269,20 @@ public class NewTabPageRecyclerView extends RecyclerView {
     }
 
     /**
-     * Finds the view holder for the last content item: a card or status indicator.
-     * @return The {@link ViewHolder} of the last content item, or null if it is not present.
+     * Finds the view holder for the last content item: the footer.
+     * @return The {@code ViewHolder} of the last content item, or null if it is not present.
      */
     private ViewHolder findLastContentItem() {
         ViewHolder viewHolder = findViewHolderForAdapterPosition(
                 getNewTabPageAdapter().getLastContentItemPosition());
-        if (viewHolder instanceof CardViewHolder) return viewHolder;
-        if (viewHolder instanceof ProgressViewHolder) return viewHolder;
+        if (viewHolder instanceof Footer.ViewHolder) return viewHolder;
 
         return null;
     }
 
     /**
      * Finds the view holder for the bottom spacer.
-     * @return The {@link ViewHolder} of the bottom spacer, or null if it is not present.
+     * @return The {@code ViewHolder} of the bottom spacer, or null if it is not present.
      */
     private ViewHolder findBottomSpacer() {
         return findViewHolderForAdapterPosition(getNewTabPageAdapter().getBottomSpacerPosition());

chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SectionHeaderViewHolder.java

@@ -23,7 +23,6 @@ public class SectionHeaderViewHolder extends NewTabPageViewHolder {
 
     private final int mMaxSnippetHeaderHeight;
     private final int mMaxPeekPadding;
-    private final TextView mHeaderTextView;
     private final NewTabPageRecyclerView mRecyclerView;
 
     private SectionHeader mHeaderListItem;
@@ -37,7 +36,6 @@ public class SectionHeaderViewHolder extends NewTabPageViewHolder {
         mMaxPeekPadding = itemView.getResources().getDimensionPixelSize(
                 R.dimen.snippets_padding_and_peeking_card_height);
 
-        mHeaderTextView = (TextView) itemView.findViewById(R.id.suggestions_section_header);
         mRecyclerView = recyclerView;
         MarginResizer.createWithViewAdapter(itemView, config);
     }
@@ -45,7 +43,7 @@ public class SectionHeaderViewHolder extends NewTabPageViewHolder {
     @Override
     public void onBindViewHolder(NewTabPageItem header) {
         mHeaderListItem = (SectionHeader) header;
-        mHeaderTextView.setText(mHeaderListItem.getHeaderText());
+        ((TextView) itemView).setText(mHeaderListItem.getHeaderText());
         updateDisplay(0, false);
     }
 

chrome/android/java/strings/android_chrome_strings.grd

@@ -1979,6 +1979,9 @@ To obtain new licenses, connect to the internet and play your downloaded content
       <message name="IDS_ACCESSIBILITY_NTP_OFFLINE_BADGE" desc="Content description for the badge that indicates offline availability of a most visited item on the new tab page.">
         Available offline
       </message>
+      <message name="IDS_NTP_LEARN_MORE_ABOUT_SUGGESTED_CONTENT" desc="Text in the footer of the New Tab Page. Part of the text is a link to a help center page where the user can learn more about suggested content.">
+        <ph name="BEGIN_LINK">&lt;link&gt;</ph>Learn more<ph name="END_LINK">&lt;/link&gt;</ph> about suggested content
+      </message>
 
       <!-- Toolbar button strings -->
       <message name="IDS_OPEN_TABS" desc="Text for button to enter the tab switcher and show tabs that are open on this device">

chrome/android/java_sources.gni

@@ -546,6 +546,7 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/ntp/cards/CardViewHolder.java",
   "java/src/org/chromium/chrome/browser/ntp/cards/DisplayStyleObserverAdapter.java",
   "java/src/org/chromium/chrome/browser/ntp/cards/ItemGroup.java",
+  "java/src/org/chromium/chrome/browser/ntp/cards/Footer.java",
   "java/src/org/chromium/chrome/browser/ntp/cards/MarginResizer.java",
   "java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapter.java",
   "java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageItem.java",

chrome/android/javatests/src/org/chromium/chrome/browser/ntp/snippets/ArticleSnippetsTest.java

@@ -332,5 +332,10 @@ public class ArticleSnippetsTest extends ChromeActivityTestCaseBase<ChromeActivi
         public void removeContextMenuCloseCallback(Callback<Menu> callback) {
             throw new UnsupportedOperationException();
         }
+
+        @Override
+        public void onLearnMoreClicked() {
+            throw new UnsupportedOperationException();
+        }
     }
 }