🍝🏠 Refactor MostVisited UI management, extract it for reuse in Home.

chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGroup.java

Index: chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGroup.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGroup.java b/chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGroup.java
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index 0000000000000000000000000000000000000000..655e154c6e5206371716d4c150b1ee0c511e8d76
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+++ b/chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGroup.java
@@ -0,0 +1,367 @@
+// 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.content.Context;
+import android.content.res.Resources;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.Color;
+import android.graphics.drawable.BitmapDrawable;
+import android.support.annotation.Nullable;
+import android.support.v4.graphics.drawable.RoundedBitmapDrawable;
+import android.support.v4.graphics.drawable.RoundedBitmapDrawableFactory;
+import android.text.TextUtils;
+import android.view.ContextMenu;
+import android.view.ContextMenu.ContextMenuInfo;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.view.View.OnCreateContextMenuListener;
+import android.view.ViewGroup;
+
+import org.chromium.base.ApiCompatibilityUtils;
+import org.chromium.base.Callback;
+import org.chromium.base.ContextUtils;
+import org.chromium.base.Log;
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.favicon.LargeIconBridge.LargeIconCallback;
+import org.chromium.chrome.browser.ntp.ContextMenuManager;
+import org.chromium.chrome.browser.ntp.ContextMenuManager.ContextMenuItemId;
+import org.chromium.chrome.browser.ntp.MostVisitedItemView;
+import org.chromium.chrome.browser.ntp.MostVisitedTileType;
+import org.chromium.chrome.browser.ntp.TitleUtil;
+import org.chromium.chrome.browser.profiles.MostVisitedSites.MostVisitedURLsObserver;
+import org.chromium.chrome.browser.widget.RoundedIconGenerator;
+import org.chromium.ui.mojom.WindowOpenDisposition;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * The model and controller for a group of site suggestion tiles.
+ */
+public class TileGroup implements MostVisitedURLsObserver {
+    /**
+     * Performs work in other parts of the system that the {@link TileGroup} should not know about.
+     */
+    public interface Delegate {
+        void removeMostVisitedItem(Tile tile);
+
+        void openMostVisitedItem(int windowDisposition, Tile tile);
+
+        /**
+         * Gets the list of most visited sites.
+         * @param observer The observer to be notified with the list of sites.
+         * @param maxResults The maximum number of sites to retrieve.
+         */
+        void setMostVisitedURLsObserver(MostVisitedURLsObserver observer, int maxResults);
+
+        /**
+         * Called when the NTP has completely finished loading (all views will be inflated
+         * and any dependent resources will have been loaded).
+         * @param tiles The tiles owned by the {@link TileGroup}. Used to record metrics.
+         */
+        void onLoadingComplete(Tile[] tiles);
+
+        /**
+         * To be called before this instance is abandoned to the garbage collector so it can do any
+         * necessary cleanups. This instance must not be used after this method is called.
+         */
+        void destroy();
+    }
+
+    /**
+     * An observer for events in the {@link TileGroup}.
+     */
+    public interface Observer {
+        /**
+         * Called when the first data has been received and processed.
+         */
+        void onInitialTileDataLoaded();
+
+        /**
+         * Called when any of the tile data has changed, such as an icon, url, or title.
+         */
+        void onTileDataChanged();
+
+        /**
+         * Called when the number of tiles has changed.
+         */
+        void onTileCountChanged();
+
+        /**
+         * Called when a tile icon has changed.
+         * @param tile The tile for which the icon has changed.
+         */
+        void onTileIconChanged(Tile tile);
+
+        /**
+         * Called when an asynchronous loading task has started.
+         */
+        void onLoadTaskAdded();
+
+        /**
+         * Called when an asynchronous loading task has completed.
+         */
+        void onLoadTaskCompleted();
+    }
+
+    private static final String TAG = "TileGroup";
+
+    private static final int ICON_CORNER_RADIUS_DP = 4;
+    private static final int ICON_TEXT_SIZE_DP = 20;
+    private static final int ICON_MIN_SIZE_PX = 48;
+
+    private final Context mContext;
+    private final SuggestionsUiDelegate mUiDelegate;
+    private final ContextMenuManager mContextMenuManager;
+    private final Delegate mTileGroupDelegate;
+    private final Observer mObserver;
+    private final RoundedIconGenerator mIconGenerator;
+
+    private Tile[] mTiles;
+    private int mMinIconSize;
+    private int mDesiredIconSize;
+    boolean mHasReceivedData;
+
+    public TileGroup(SuggestionsUiDelegate uiDelegate, ContextMenuManager contextMenuManager,
+            Delegate tileGroupDelegate, Observer observer) {
+        mContext = ContextUtils.getApplicationContext();
+        mUiDelegate = uiDelegate;
+        mContextMenuManager = contextMenuManager;
+        mTileGroupDelegate = tileGroupDelegate;
+        mObserver = observer;
+
+        Resources resources = mContext.getResources();
+        mDesiredIconSize = resources.getDimensionPixelSize(R.dimen.most_visited_icon_size);
+        // On ldpi devices, mDesiredIconSize could be even smaller than ICON_MIN_SIZE_PX.
+        mMinIconSize = Math.min(mDesiredIconSize, ICON_MIN_SIZE_PX);
+        int desiredIconSizeDp =
+                Math.round(mDesiredIconSize / resources.getDisplayMetrics().density);
+        int iconColor =
+                ApiCompatibilityUtils.getColor(resources, R.color.default_favicon_background_color);
+        mIconGenerator = new RoundedIconGenerator(mContext, desiredIconSizeDp, desiredIconSizeDp,
+                ICON_CORNER_RADIUS_DP, iconColor, ICON_TEXT_SIZE_DP);
+    }
+
+    @Override
+    public void onMostVisitedURLsAvailable(final String[] titles, final String[] urls,
+            final String[] whitelistIconPaths, final int[] sources) {
+        // If no tiles have been built yet, this is the initial load. Build the tiles immediately so
+        // the layout is stable during initial rendering. They can be
+        // replaced later if there are offline urls, but that will not affect the layout widths and
+        // heights. A stable layout enables reliable scroll position initialization.
+        if (!mHasReceivedData) {
+            buildTiles(titles, urls, whitelistIconPaths, null, sources);
+        }
+
+        // TODO(https://crbug.com/607573): We should show offline-available content in a nonblocking
+        // way so that responsiveness of the NTP does not depend on ready availability of offline
+        // pages.
+        Set<String> urlSet = new HashSet<>(Arrays.asList(urls));
+        mUiDelegate.getUrlsAvailableOffline(urlSet, new Callback<Set<String>>() {
+            @Override
+            public void onResult(Set<String> offlineUrls) {
+                buildTiles(titles, urls, whitelistIconPaths, offlineUrls, sources);
+            }
+        });
+    }
+
+    @Override
+    public void onIconMadeAvailable(String siteUrl) {
+        // Get a large icon for the matching tile.
+        for (Tile tile : mTiles) {
+            if (tile.getUrl().equals(siteUrl)) {
+                LargeIconCallback iconCallback =
+                        new LargeIconCallbackImpl(tile, /* trackLoadTask = */ false);
+                mUiDelegate.getLargeIconForUrl(siteUrl, mMinIconSize, iconCallback);
+                break;
+            }
+        }
+    }
+
+    /**
+     * Instructs this instance to start listening for data. The {@link TileGroup.Observer} may be
+     * called immediately if new data is received synchronously.
+     * @param maxResults The maximum number of sites to retrieve.
+     */
+    public void startObserving(int maxResults) {
+        mTileGroupDelegate.setMostVisitedURLsObserver(this, maxResults);
+    }
+
+    public void renderTileViews(ViewGroup parentView, boolean trackLoadTasks) {
+        parentView.removeAllViews();
+
+        for (final Tile tile : mTiles) {
+            View tileView = buildTileView(tile, parentView, trackLoadTasks);
+
+            tileView.setOnClickListener(new OnClickListener() {
+                @Override
+                public void onClick(View view) {
+                    mTileGroupDelegate.openMostVisitedItem(WindowOpenDisposition.CURRENT_TAB, tile);
+                }
+            });
+
+            tileView.setOnCreateContextMenuListener(new OnCreateContextMenuListener() {
+                @Override
+                public void onCreateContextMenu(
+                        ContextMenu menu, View view, ContextMenuInfo menuInfo) {
+                    mContextMenuManager.createContextMenu(
+                            menu, view, new ContextMenuManager.Delegate() {
+                                @Override
+                                public void openItem(int windowDisposition) {
+                                    mTileGroupDelegate.openMostVisitedItem(windowDisposition, tile);
+                                }
+
+                                @Override
+                                public void removeItem() {
+                                    mTileGroupDelegate.removeMostVisitedItem(tile);
+                                }
+
+                                @Override
+                                public String getUrl() {
+                                    return tile.getUrl();
+                                }
+
+                                @Override
+                                public boolean isItemSupported(@ContextMenuItemId int menuItemId) {
+                                    return true;
+                                }
+
+                                @Override
+                                public void onContextMenuCreated() {}
+                            });
+                }
+            });
+
+            parentView.addView(tileView);
+        }
+    }
+
+    public Tile[] getTiles() {
+        return Arrays.copyOf(mTiles, mTiles.length);
+    }
+
+    public boolean hasReceivedData() {
+        return mHasReceivedData;
+    }
+
+    private void buildTiles(String[] titles, String[] urls, String[] whitelistIconPaths,
+            @Nullable Set<String> offlineUrls, int[] sources) {
+        Tile[] oldTiles = mTiles;
+        int oldTileCount = oldTiles == null ? 0 : oldTiles.length;
+        mTiles = new Tile[titles.length];
+
+        boolean isInitialLoad = !mHasReceivedData;
+        mHasReceivedData = true;
+
+        // Add the tile views to the layout.
+        for (int i = 0; i < titles.length; i++) {
+            String url = urls[i];
+            String title = titles[i];
+            String whitelistIconPath = whitelistIconPaths[i];
+            int source = sources[i];
+            boolean offlineAvailable = offlineUrls != null && offlineUrls.contains(url);
+
+            // Look for an existing tile to reuse.
+            // TODO(mvanouwerkerk): Ensure we don't create views and load icons more often than
+            // necessary.
+            Tile tile = null;
+            for (int j = 0; j < oldTileCount; j++) {
+                Tile oldTile = oldTiles[j];
+                if (oldTile != null && TextUtils.equals(url, oldTile.getUrl())
+                        && TextUtils.equals(title, oldTile.getTitle())
+                        && offlineAvailable == oldTile.isOfflineAvailable()
+                        && whitelistIconPath.equals(oldTile.getWhitelistIconPath())) {
+                    tile = oldTile;
+                    tile.setIndex(i);
+                    oldTiles[j] = null;
+                    break;
+                }
+            }
+
+            // If nothing can be reused, create a new tile.
+            if (tile == null) {
+                tile = new Tile(title, url, whitelistIconPath, offlineAvailable, i, source);
+            }
+            mTiles[i] = tile;
+        }
+
+        if (oldTileCount != mTiles.length) mObserver.onTileCountChanged();
+        if (isInitialLoad) {
+            mObserver.onLoadTaskCompleted();
+            mObserver.onInitialTileDataLoaded();
+        }
+        mObserver.onTileDataChanged();
+    }
+
+    private View buildTileView(Tile tile, ViewGroup parentView, boolean trackLoadTask) {
+        MostVisitedItemView view =
+                (MostVisitedItemView) LayoutInflater.from(parentView.getContext())
+                        .inflate(R.layout.most_visited_item, parentView, false);
+        view.setTitle(TitleUtil.getTitleForDisplay(tile.getTitle(), tile.getUrl()));
+        view.setOfflineAvailable(tile.isOfflineAvailable());
+        view.setIcon(tile.getIcon());
+        view.setUrl(tile.getUrl());
+
+        LargeIconCallback iconCallback = new LargeIconCallbackImpl(tile, trackLoadTask);
+        if (trackLoadTask) mObserver.onLoadTaskAdded();
+        if (!loadWhitelistIcon(tile, iconCallback)) {
+            mUiDelegate.getLargeIconForUrl(tile.getUrl(), mMinIconSize, iconCallback);
+        }
+
+        return view;
+    }
+
+    private boolean loadWhitelistIcon(Tile tile, LargeIconCallback iconCallback) {
+        if (tile.getWhitelistIconPath().isEmpty()) return false;
+
+        // TODO(mvanouwerkerk): Consider using an AsyncTask to reduce rendering jank.
+        Bitmap bitmap = BitmapFactory.decodeFile(tile.getWhitelistIconPath());
+        if (bitmap == null) {
+            Log.d(TAG, "Image decoding failed: %s", tile.getWhitelistIconPath());
+            return false;
+        }
+        iconCallback.onLargeIconAvailable(bitmap, Color.BLACK, false);
+        return true;
+    }
+
+    private class LargeIconCallbackImpl implements LargeIconCallback {
+        private final Tile mTile;
+        private final boolean mTrackLoadTask;
+
+        private LargeIconCallbackImpl(Tile tile, boolean trackLoadTask) {
+            mTile = tile;
+            mTrackLoadTask = trackLoadTask;
+        }
+
+        @Override
+        public void onLargeIconAvailable(
+                @Nullable Bitmap icon, int fallbackColor, boolean isFallbackColorDefault) {
+            if (icon == null) {
+                mIconGenerator.setBackgroundColor(fallbackColor);
+                icon = mIconGenerator.generateIconForUrl(mTile.getUrl());
+                mTile.setIcon(new BitmapDrawable(mContext.getResources(), icon));
+                mTile.setTileType(isFallbackColorDefault ? MostVisitedTileType.ICON_DEFAULT
+                                                         : MostVisitedTileType.ICON_COLOR);
+            } else {
+                RoundedBitmapDrawable roundedIcon =
+                        RoundedBitmapDrawableFactory.create(mContext.getResources(), icon);
+                int cornerRadius = Math.round(ICON_CORNER_RADIUS_DP
+                        * mContext.getResources().getDisplayMetrics().density * icon.getWidth()
+                        / mDesiredIconSize);
+                roundedIcon.setCornerRadius(cornerRadius);
+                roundedIcon.setAntiAlias(true);
+                roundedIcon.setFilterBitmap(true);
+                mTile.setIcon(roundedIcon);
+                mTile.setTileType(MostVisitedTileType.ICON_REAL);
+            }
+            mObserver.onTileIconChanged(mTile);
+            if (mTrackLoadTask) mObserver.onLoadTaskCompleted();
+        }
+    }
+}