📰 Add visibility change triggers for bottom sheet content

chrome/android/java/src/org/chromium/chrome/browser/suggestions/SuggestionsBottomSheetContent.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.suggestions;
 
 import android.annotation.SuppressLint;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.RecyclerView.OnScrollListener;
 import android.view.LayoutInflater;
@@ skipping 15 matching lines @@
 import org.chromium.chrome.browser.ntp.snippets.SuggestionsSource;
 import org.chromium.chrome.browser.offlinepages.OfflinePageBridge;
 import org.chromium.chrome.browser.omnibox.LocationBar;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.snackbar.SnackbarManager;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.widget.FadingShadow;
 import org.chromium.chrome.browser.widget.FadingShadowView;
 import org.chromium.chrome.browser.widget.bottomsheet.BottomSheet;
 import org.chromium.chrome.browser.widget.bottomsheet.BottomSheetContentController;
-import org.chromium.chrome.browser.widget.bottomsheet.BottomSheetObserver;
-import org.chromium.chrome.browser.widget.bottomsheet.EmptyBottomSheetObserver;
 import org.chromium.chrome.browser.widget.displaystyle.UiConfig;
 import org.chromium.ui.widget.Toast;
 
 import java.util.List;
 import java.util.Locale;
 
 /**
  * Provides content to be displayed inside of the Home tab of bottom sheet.
  */
 public class SuggestionsBottomSheetContent implements BottomSheet.BottomSheetContent {
     private static SuggestionsSource sSuggestionsSourceForTesting;
     private static SuggestionsEventReporter sEventReporterForTesting;
 
     private final View mView;
     private final FadingShadowView mShadowView;
     private final SuggestionsRecyclerView mRecyclerView;
     private final ContextMenuManager mContextMenuManager;
     private final SuggestionsUiDelegateImpl mSuggestionsUiDelegate;
     private final TileGroup.Delegate mTileGroupDelegate;
-    private final BottomSheet mBottomSheet;
-    private final BottomSheetObserver mBottomSheetObserver;
+    private final SuggestionsSheetVisibilityChangeObserver mBottomSheetObserver;
 
     public SuggestionsBottomSheetContent(final ChromeActivity activity, final BottomSheet sheet,
             TabModelSelector tabModelSelector, SnackbarManager snackbarManager) {
         Profile profile = Profile.getLastUsedProfile();
         SuggestionsNavigationDelegate navigationDelegate =
                 new SuggestionsNavigationDelegateImpl(activity, profile, sheet, tabModelSelector);
         mTileGroupDelegate = new TileGroupDelegateImpl(
                 activity, profile, tabModelSelector, navigationDelegate, snackbarManager);
         mSuggestionsUiDelegate = createSuggestionsDelegate(
                 profile, navigationDelegate, sheet, activity.getReferencePool());
@@ skipping 18 matching lines @@
             }
         });
 
         UiConfig uiConfig = new UiConfig(mRecyclerView);
 
         final NewTabPageAdapter adapter = new NewTabPageAdapter(mSuggestionsUiDelegate,
                 /* aboveTheFoldView = */ null, uiConfig, OfflinePageBridge.getForProfile(profile),
                 mContextMenuManager, mTileGroupDelegate);
         mRecyclerView.init(uiConfig, mContextMenuManager, adapter);
 
-        mBottomSheetObserver = new EmptyBottomSheetObserver() {
+        mBottomSheetObserver = new SuggestionsSheetVisibilityChangeObserver(this, activity) {
             @Override
             public void onSheetOpened() {
                 mRecyclerView.scrollToPosition(0);
-                prepareSuggestionsForReveal(adapter);
-
+                adapter.refreshSuggestions();
+                mSuggestionsUiDelegate.getEventReporter().onSurfaceOpened();
                 mRecyclerView.getScrollEventReporter().reset();
 
                 if (ChromeFeatureList.isEnabled(
                             ChromeFeatureList.CONTEXTUAL_SUGGESTIONS_CAROUSEL)) {
-                    updateContextualSuggestions(mBottomSheet.getActiveTab().getUrl());
+                    updateContextualSuggestions(sheet.getActiveTab().getUrl());
                 }
+
+                super.onSheetOpened();
             }
 
             @Override
-            public void onSheetClosed() {
+            public void onContentShown() {
+                SuggestionsMetrics.recordSurfaceVisible();
+            }
+
+            @Override
+            public void onContentHidden() {
                 SuggestionsMetrics.recordSurfaceHidden();
             }
 
+            @Override
+            public void onContentStateChanged(@BottomSheet.SheetState int contentState) {
+                if (contentState == BottomSheet.SHEET_STATE_HALF) {
+                    SuggestionsMetrics.recordSurfaceHalfVisible();
+                } else if (contentState == BottomSheet.SHEET_STATE_FULL) {
+                    SuggestionsMetrics.recordSurfaceFullyVisible();
+                }
+            }
         };
-        mBottomSheet = activity.getBottomSheet();
-        mBottomSheet.addObserver(mBottomSheetObserver);
-
-        if (mBottomSheet.isSheetOpen()) prepareSuggestionsForReveal(adapter);
 
         mShadowView = (FadingShadowView) mView.findViewById(R.id.shadow);
         mShadowView.init(
                 ApiCompatibilityUtils.getColor(mView.getResources(), R.color.toolbar_shadow_color),
                 FadingShadow.POSITION_TOP);
 
         mRecyclerView.addOnScrollListener(new OnScrollListener() {
             @Override
             public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                 boolean shadowVisible = mRecyclerView.canScrollVertically(-1);
@@ skipping 31 matching lines @@
         return false;
     }
 
     @Override
     public int getVerticalScrollOffset() {
         return mRecyclerView.computeVerticalScrollOffset();
     }
 
     @Override
     public void destroy() {
-        mBottomSheet.removeObserver(mBottomSheetObserver);
+        mBottomSheetObserver.onDestroy();
         mSuggestionsUiDelegate.onDestroy();
         mTileGroupDelegate.destroy();
     }
 
     @Override
     public int getType() {
         return BottomSheetContentController.TYPE_SUGGESTIONS;
     }
 
-    /** Called when the UI is revlealed, prepares the list of suggestions. */
-    private void prepareSuggestionsForReveal(NewTabPageAdapter adapter) {
-        adapter.refreshSuggestions();
-        mSuggestionsUiDelegate.getEventReporter().onSurfaceOpened();
-        SuggestionsMetrics.recordSurfaceVisible();
-    }
-
     private void updateContextualSuggestions(String url) {
         mSuggestionsUiDelegate.getSuggestionsSource().fetchContextualSuggestions(
                 url, new Callback<List<SnippetArticle>>() {
                     @Override
                     public void onResult(List<SnippetArticle> result) {
                         String text = String.format(
                                 Locale.US, "Received %d contextual suggestions", result.size());
                         Toast.makeText(mRecyclerView.getContext(), text, Toast.LENGTH_SHORT).show();
                     }
                 });
@@ skipping 27 matching lines @@
             eventReporter = sEventReporterForTesting;
         }
 
         SuggestionsUiDelegateImpl delegate = new SuggestionsUiDelegateImpl(
                 suggestionsSource, eventReporter, navigationDelegate, profile, host, referencePool);
         if (snippetsBridge != null) delegate.addDestructionObserver(snippetsBridge);
 
         return delegate;
     }
 }