Snap for 4707594 from 7e6aeee1cb8d64ad271a25c0bc8e0bbe4068ca9f to pi-release

Change-Id: Ib1d47f18ce32d565e28a1f522307fc30a2783782

13 files changed, 1165 insertions, 73 deletions

diff --git a/res/layout/fragment_playback.xml b/res/layout/fragment_playback.xml
index e37a712..601844f 100644
--- a/res/layout/fragment_playback.xml
+++ b/res/layout/fragment_playback.xml
@@ -56,12 +56,9 @@
         android:id="@+id/browse_list"
         android:layout_width="match_parent"
         android:layout_height="0dp"
-        android:layout_weight="1"
-        app:showPagedListViewDivider="true"
-        app:listDividerColor="@color/car_list_divider_inverse"
+        android:layout_marginBottom="@dimen/car_padding_4"
+        app:showPagedListViewDivider="false"
         app:layout_behavior="@string/appbar_scrolling_view_behavior"
-        app:dividerStartMargin="@dimen/car_keyline_1"
-        app:dividerEndMargin="@dimen/car_keyline_1"
         app:layout_constraintTop_toBottomOf="@+id/metadata_container"
         app:layout_constraintBottom_toTopOf="@+id/playback_controls"/>
 
diff --git a/res/layout/media_browse_grid_item.xml b/res/layout/media_browse_grid_item.xml
new file mode 100644
index 0000000..086f11a
--- /dev/null
+++ b/res/layout/media_browse_grid_item.xml
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/container"
+    android:orientation="vertical"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content">
+
+    <com.android.car.media.common.FixedRatioImageView
+        android:id="@+id/thumbnail"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:scaleType="centerCrop"
+        app:aspect_ratio="1"/>
+
+    <TextView
+        android:id="@+id/title"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="@dimen/car_padding_2"
+        android:ellipsize="end"
+        android:maxLines="1"
+        android:textAppearance="@style/TextAppearance.Car.Body2.Light"/>
+
+</LinearLayout>
\ No newline at end of file
diff --git a/res/layout/media_browse_header_item.xml b/res/layout/media_browse_header_item.xml
new file mode 100644
index 0000000..b4db506
--- /dev/null
+++ b/res/layout/media_browse_header_item.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/container"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content">
+    <TextView
+        android:id="@+id/title"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:includeFontPadding="false"
+        android:textAppearance="@style/TextAppearance.Car.Body1.Light"/>
+</FrameLayout>
\ No newline at end of file
diff --git a/res/layout/media_browse_list_item.xml b/res/layout/media_browse_list_item.xml
new file mode 100644
index 0000000..f20b20d
--- /dev/null
+++ b/res/layout/media_browse_list_item.xml
@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/container"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:focusable="true"
+    android:orientation="horizontal">
+    <ImageView
+        android:id="@+id/thumbnail"
+        android:layout_width="@dimen/car_drawer_list_item_icon_size"
+        android:layout_height="@dimen/car_drawer_list_item_icon_size"
+        android:layout_marginEnd="@dimen/car_drawer_list_item_icon_end_margin"
+        android:layout_gravity="center_vertical"
+        android:scaleType="centerCrop" />
+    <LinearLayout
+        android:id="@+id/text_container"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_weight="1"
+        android:layout_gravity="center_vertical"
+        android:orientation="vertical" >
+        <TextView
+            android:id="@+id/title"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginBottom="@dimen/car_padding_1"
+            android:includeFontPadding="false"
+            android:ellipsize="end"
+            android:maxLines="1"
+            android:textAppearance="@style/TextAppearance.Car.Body1.Light" />
+        <TextView
+            android:id="@+id/subtitle"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:includeFontPadding="false"
+            android:ellipsize="end"
+            android:maxLines="1"
+            android:textAppearance="@style/TextAppearance.Car.Body2.Light" />
+    </LinearLayout>
+</LinearLayout>
diff --git a/res/layout/media_browse_more_footer.xml b/res/layout/media_browse_more_footer.xml
new file mode 100644
index 0000000..ea79378
--- /dev/null
+++ b/res/layout/media_browse_more_footer.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/container"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content">
+    <TextView
+        android:id="@+id/title"
+        android:text="@string/media_browse_more"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="@dimen/car_padding_1"
+        android:includeFontPadding="false"
+        android:textAppearance="@style/TextAppearance.Car.Body1.Light"/>
+</FrameLayout>
diff --git a/res/layout/media_browse_panel_item.xml b/res/layout/media_browse_panel_item.xml
new file mode 100644
index 0000000..3b56c36
--- /dev/null
+++ b/res/layout/media_browse_panel_item.xml
@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/container"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:focusable="true"
+    android:orientation="horizontal">
+    <ImageView
+        android:id="@+id/thumbnail"
+        android:layout_width="@dimen/car_drawer_list_item_icon_size"
+        android:layout_height="@dimen/car_drawer_list_item_icon_size"
+        android:layout_marginEnd="@dimen/car_drawer_list_item_icon_end_margin"
+        android:layout_gravity="center_vertical"
+        android:scaleType="centerCrop" />
+    <LinearLayout
+        android:id="@+id/text_container"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_weight="1"
+        android:layout_gravity="center_vertical"
+        android:orientation="vertical" >
+        <TextView
+            android:id="@+id/title"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginBottom="@dimen/car_text_vertical_margin"
+            android:maxLines="1"
+            android:textAppearance="?attr/drawerItemTitleTextAppearance" />
+        <TextView
+            android:id="@+id/subtitle"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:ellipsize="end"
+            android:maxLines="1"
+            android:textAppearance="?attr/drawerItemBodyTextAppearance" />
+    </LinearLayout>
+</LinearLayout>
\ No newline at end of file
diff --git a/res/values/strings.xml b/res/values/strings.xml
index dbe3930..84d60fd 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -26,4 +26,6 @@
     <string name="loading">Getting your selection&#8230;</string>
     <!-- The text for unknown playback error. [CHAR LIMIT=50] -->
     <string name="unknown_error">Something went wrong</string>
+    <!-- Text of the button displayed at the bottom of a media browse section to provide access to additional items. [CHAR LIMIT=100] -->
+    <string name="media_browse_more">More …</string>
 </resources>
diff --git a/src/com/android/car/media/PlaybackFragment.java b/src/com/android/car/media/PlaybackFragment.java
index 69ca0b0..bf1e9ec 100644
--- a/src/com/android/car/media/PlaybackFragment.java
+++ b/src/com/android/car/media/PlaybackFragment.java
@@ -1,12 +1,11 @@
 package com.android.car.media;
 
-import static java.security.AccessController.getContext;
-
-import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.PorterDuff;
+import android.media.browse.MediaBrowser;
 import android.os.Bundle;
 import android.support.v4.app.Fragment;
+import android.support.v7.widget.GridLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.util.TypedValue;
 import android.view.LayoutInflater;
@@ -16,29 +15,29 @@ import android.widget.ImageView;
 import android.widget.SeekBar;
 import android.widget.TextView;
 
-import com.android.car.apps.common.ImageUtils;
+import com.android.car.media.browse.BrowseAdapter;
+import com.android.car.media.browse.ContentForwardStrategy;
+import com.android.car.media.common.GridSpacingItemDecoration;
 import com.android.car.media.common.MediaItemMetadata;
+import com.android.car.media.common.MediaSource;
 import com.android.car.media.common.PlaybackControls;
 import com.android.car.media.common.PlaybackModel;
 
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.util.Date;
-import java.util.List;
 import java.util.Locale;
+import java.util.Objects;
 
-import androidx.car.widget.ListItem;
-import androidx.car.widget.ListItemAdapter;
-import androidx.car.widget.ListItemProvider;
 import androidx.car.widget.PagedListView;
-import androidx.car.widget.TextListItem;
 
 /**
  * A {@link Fragment} that implements both the playback and the content forward browsing experience.
  * It observes a {@link PlaybackModel} and updates its information depending on the currently
- * playing media source through the {@link MediaSession} API.
+ * playing media source through the {@link android.media.session.MediaSession} API.
  */
-public class PlaybackFragment extends Fragment {
+public class PlaybackFragment extends Fragment implements PlaybackModel.PlaybackObserver,
+        MediaSource.Observer, BrowseAdapter.Observer {
     private static final String TAG = "PlaybackFragment";
     private static final DateFormat TIME_FORMAT = new SimpleDateFormat("m:ss", Locale.US);
 
@@ -51,64 +50,18 @@ public class PlaybackFragment extends Fragment {
     private TextView mSubtitle;
     private SeekBar mSeekbar;
     private PagedListView mBrowseList;
-    private ListItemAdapter mMediaAdapter;
     private int mBackgroundRawImageSize;
     private float mBackgroundBlurRadius;
     private float mBackgroundBlurScale;
-
-    private PlaybackModel.PlaybackObserver mObserver = new PlaybackModel.PlaybackObserver() {
-        @Override
-        public void onPlaybackStateChanged() {
-            updateState();
-        }
-
-        @Override
-        public void onSourceChanged() {
-            updateState();
-            updateMetadata();
-            updateAccentColor();
-            updateBrowse();
-        }
-
-        @Override
-        public void onMetadataChanged() {
-            updateMetadata();
-        }
-    };
-
-    private ListItemProvider mMediaItemsProvider = new ListItemProvider() {
-        @Override
-        public ListItem get(int position) {
-            if (mModel == null || !mModel.hasQueue()) {
-                return null;
-            }
-            List<MediaItemMetadata> queue = mModel.getQueue();
-            if (position < 0 || position >= queue.size()) {
-                return null;
-            }
-            MediaItemMetadata item = queue.get(position);
-            TextListItem textListItem = new TextListItem(getContext());
-            textListItem.setTitle(item.getTitle().toString());
-            textListItem.setBody(item.getSubtitle().toString());
-            textListItem.setOnClickListener(v -> mModel.onSkipToQueueItem(item.getQueueId()));
-            return textListItem;
-        }
-
-        @Override
-        public int size() {
-            if (mModel == null || !mModel.hasQueue()) {
-                return 0;
-            }
-            return mModel.getQueue().size();
-        }
-    };
+    private MediaSource mMediaSource;
+    private BrowseAdapter mBrowseAdapter;
 
     @Override
     public View onCreateView(LayoutInflater inflater, final ViewGroup container,
             Bundle savedInstanceState) {
         View view = inflater.inflate(R.layout.fragment_playback, container, false);
         mModel = new PlaybackModel(getContext());
-        mModel.registerObserver(mObserver);
+        mModel.registerObserver(this);
         mAlbumBackground = view.findViewById(R.id.album_background);
         mPlaybackControls = view.findViewById(R.id.playback_controls);
         mPlaybackControls.setModel(mModel);
@@ -120,12 +73,14 @@ public class PlaybackFragment extends Fragment {
         mSeekbar = view.findViewById(R.id.seek_bar);
         mTime = view.findViewById(R.id.time);
         mBrowseList = view.findViewById(R.id.browse_list);
-        mMediaAdapter = new ListItemAdapter(getContext(), mMediaItemsProvider);
-        mBrowseList.setAdapter(mMediaAdapter);
-        RecyclerView recyclerView = mBrowseList.findViewById(R.id.recycler_view);
+        GridLayoutManager gridLayoutManager = new GridLayoutManager(getContext(), 4);
+        RecyclerView recyclerView = mBrowseList.getRecyclerView();
+        recyclerView.setLayoutManager(gridLayoutManager);
         recyclerView.setVerticalFadingEdgeEnabled(true);
         recyclerView.setFadingEdgeLength(getResources()
-                .getDimensionPixelSize(R.dimen.car_padding_3));
+                .getDimensionPixelSize(R.dimen.car_padding_4));
+        recyclerView.addItemDecoration(new GridSpacingItemDecoration(getResources()
+                .getDimensionPixelSize(R.dimen.car_padding_4)));
         TypedValue outValue = new TypedValue();
         getResources().getValue(R.dimen.playback_background_blur_radius, outValue, true);
         mBackgroundBlurRadius = outValue.getFloat();
@@ -140,14 +95,42 @@ public class PlaybackFragment extends Fragment {
     public void onStart() {
         super.onStart();
         mModel.start();
-        mMediaAdapter.start();
+        if (mMediaSource != null) {
+            mMediaSource.subscribe(this);
+        }
+        if (mBrowseAdapter != null) {
+            mBrowseAdapter.start();
+        }
     }
 
     @Override
     public void onStop() {
         super.onStop();
         mModel.stop();
-        mMediaAdapter.stop();
+        if (mMediaSource != null) {
+            mMediaSource.unsubscribe(this);
+        }
+        if (mBrowseAdapter != null) {
+            mBrowseAdapter.stop();
+        }
+    }
+
+    @Override
+    public void onPlaybackStateChanged() {
+        updateState();
+    }
+
+    @Override
+    public void onSourceChanged() {
+        updateState();
+        updateMetadata();
+        updateAccentColor();
+        updateBrowse();
+    }
+
+    @Override
+    public void onMetadataChanged() {
+        updateMetadata();
     }
 
     private void updateState() {
@@ -159,6 +142,10 @@ public class PlaybackFragment extends Fragment {
             mSeekbar.removeCallbacks(mSeekBarRunnable);
         }
         mBrowseList.setVisibility(mModel.hasQueue() ? View.VISIBLE : View.GONE);
+
+        if (mBrowseAdapter != null) {
+            mBrowseAdapter.setQueue(mModel.getQueue(), mModel.getQueueTitle());
+        }
     }
 
     private void updateMetadata() {
@@ -186,7 +173,8 @@ public class PlaybackFragment extends Fragment {
     }
 
     private void updateAccentColor() {
-        int color = mModel.getAccentColor();
+        int defaultColor = getResources().getColor(android.R.color.background_dark, null);
+        int color = mModel.getMediaSource().getAccentColor(defaultColor);
         mSeekbar.getProgressDrawable().setColorFilter(color, PorterDuff.Mode.SRC_IN);
     }
 
@@ -225,7 +213,75 @@ public class PlaybackFragment extends Fragment {
     }
 
     private void updateBrowse() {
+        MediaSource newSource = mModel.getMediaSource();
+        if (Objects.equals(mMediaSource, newSource)) {
+            return;
+        }
+        if (mMediaSource != null) {
+            mMediaSource.unsubscribe(this);
+        }
+        mMediaSource = newSource;
+        mMediaSource.subscribe(this);
         MediaManager.getInstance(getContext())
-                .setMediaClientComponent(mModel.getMediaBrowseServiceComponent());
+                .setMediaClientComponent(mMediaSource.getBrowseServiceComponentName());
+    }
+
+    @Override
+    public void onBrowseConnected(MediaBrowser mediaBrowser) {
+        if (mBrowseAdapter != null) {
+            mBrowseAdapter.stop();
+            mBrowseAdapter = null;
+        }
+        if (mediaBrowser == null) {
+            mBrowseList.setVisibility(View.GONE);
+            // TODO(b/77647430) implement intermediate states.
+            return;
+        }
+        mBrowseAdapter = new BrowseAdapter(getContext(), mediaBrowser, null,
+                ContentForwardStrategy.DEFAULT_STRATEGY);
+        mBrowseList.setAdapter(mBrowseAdapter);
+        mBrowseAdapter.registerObserver(this);
+        mBrowseAdapter.start();
+    }
+
+    @Override
+    public void onBrowseDisconnected() {
+        mBrowseAdapter.stop();
+    }
+
+    @Override
+    public void onDirty() {
+        mBrowseAdapter.update();
+        if (mBrowseAdapter.getItemCount() > 0) {
+            mBrowseList.setVisibility(View.VISIBLE);
+        } else {
+            mBrowseList.setVisibility(View.GONE);
+            // TODO(b/77647430) implement intermediate states.
+        }
+    }
+
+    @Override
+    public void onPlayableItemClicked(MediaItemMetadata item) {
+        mModel.onPlayItem(item.getId());
+    }
+
+    @Override
+    public void onBrowseableItemClicked(MediaItemMetadata item) {
+        // TODO(b/77527398): Drill down in the navigation.
+    }
+
+    @Override
+    public void onMoreButtonClicked(MediaItemMetadata item) {
+        // TODO(b/77527398): Drill down in the navigation
+    }
+
+    @Override
+    public void onQueueTitleClicked() {
+        // TODO(b/77527398): Show full queue
+    }
+
+    @Override
+    public void onQueueItemClicked(MediaItemMetadata item) {
+        mModel.onSkipToQueueItem(item.getQueueId());
     }
 }
diff --git a/src/com/android/car/media/browse/BrowseAdapter.java b/src/com/android/car/media/browse/BrowseAdapter.java
new file mode 100644
index 0000000..be50b9b
--- /dev/null
+++ b/src/com/android/car/media/browse/BrowseAdapter.java
@@ -0,0 +1,542 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.car.media.browse;
+
+import android.content.Context;
+import android.media.browse.MediaBrowser;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.v7.util.DiffUtil;
+import android.support.v7.widget.GridLayoutManager;
+import android.support.v7.widget.RecyclerView;
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
+import com.android.car.media.common.MediaItemMetadata;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Objects;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+
+/**
+ * A {@link RecyclerView.Adapter} that can be used to display a single level of a
+ * {@link android.service.media.MediaBrowserService} media tree into a
+ * {@link androidx.car.widget.PagedListView} or any other {@link RecyclerView}.
+ *
+ * <p>This adapter assumes that the attached {@link RecyclerView} uses a {@link GridLayoutManager},
+ * as it can use both grid and list elements to produce the desired representation.
+ *
+ * <p> The actual strategy to group and expand media items has to be supplied by providing an
+ * instance of {@link ContentForwardStrategy}.
+ *
+ * <p> The adapter will only start updating once {@link #start()} is invoked. At this point, the
+ * provided {@link MediaBrowser} must be already in connected state.
+ *
+ * <p>Resources and asynchronous data loading must be released by callign {@link #stop()}.
+ *
+ * <p>No views will be actually updated until {@link #update()} is invoked (normally as a result of
+ * the {@link Observer#onDirty()} event. This way, the consumer of this adapter has the opportunity
+ * to decide whether updates should be displayd immediately, or if they should be delayed to
+ * prevent flickering.
+ *
+ * <p>Consumers of this adapter should use {@link #registerObserver(Observer)} to receive updates.
+ */
+public class BrowseAdapter extends RecyclerView.Adapter<BrowseViewHolder> {
+    private static final String TAG = "MediaBrowseAdapter";
+    @NonNull
+    private final Context mContext;
+    private final MediaBrowser mMediaBrowser;
+    private final MediaItemMetadata mParentMediaItem;
+    private final ContentForwardStrategy mCFBStrategy;
+    private LinkedHashMap<String, MediaItemState> mItemStates = new LinkedHashMap<>();
+    private List<BrowseViewData> mViewData = new ArrayList<>();
+    private String mParentMediaItemId;
+    private List<Observer> mObservers = new ArrayList<>();
+    private List<MediaItemMetadata> mQueue;
+    private CharSequence mQueueTitle;
+    private int mMaxSpanSize = 1;
+    private BrowseViewData.State mState = BrowseViewData.State.IDLE;
+
+    /**
+     * An {@link BrowseAdapter} observer.
+     */
+    public interface Observer {
+        /**
+         * Callback invoked anytime there is more information to be displayed, or if there is a
+         * change in the overall state of the adapter.
+         */
+        void onDirty();
+
+        /**
+         * Callback invoked when a user clicks on a playable item.
+         */
+        void onPlayableItemClicked(MediaItemMetadata item);
+
+        /**
+         * Callback invoked when a user clicks on a browsable item.
+         */
+        void onBrowseableItemClicked(MediaItemMetadata item);
+
+        /**
+         * Callback invoked when a user clicks on a the "more items" button on a section.
+         */
+        void onMoreButtonClicked(MediaItemMetadata item);
+
+        /**
+         * Callback invoked when the user clicks on the title of the queue.
+         */
+        void onQueueTitleClicked();
+
+        /**
+         * Callback invoked when the user clicks on a queue item.
+         */
+        void onQueueItemClicked(MediaItemMetadata item);
+    }
+
+    private MediaBrowser.SubscriptionCallback mSubscriptionCallback =
+        new MediaBrowser.SubscriptionCallback() {
+            @Override
+            public void onChildrenLoaded(String parentId, List<MediaBrowser.MediaItem> children) {
+                onItemsLoaded(parentId, children);
+            }
+
+            @Override
+            public void onChildrenLoaded(String parentId, List<MediaBrowser.MediaItem> children,
+                    Bundle options) {
+                onItemsLoaded(parentId, children);
+            }
+
+            @Override
+            public void onError(String parentId) {
+                onLoadingError(parentId);
+            }
+
+            @Override
+            public void onError(String parentId, Bundle options) {
+                onLoadingError(parentId);
+            }
+        };
+
+
+    /**
+     * Represents the loading state of children of a single {@link MediaItemMetadata} in the
+     * {@link BrowseAdapter}
+     */
+    private class MediaItemState {
+        /**
+         * {@link com.android.car.media.common.MediaItemMetadata} whose children are being loaded
+         */
+        final MediaItemMetadata mItem;
+        /** Current loading state for this item */
+        BrowseViewData.State mState = BrowseViewData.State.LOADING;
+        /** Playable children of the given item */
+        List<MediaItemMetadata> mPlayableChildren = new ArrayList<>();
+        /** Browsable children of the given item */
+        List<MediaItemMetadata> mBrowsableChildren = new ArrayList<>();
+        /** Whether we are subscribed to updates for this item or not */
+        boolean mIsSubscribed;
+
+        MediaItemState(MediaBrowser.MediaItem item) {
+            mItem = new MediaItemMetadata(item);
+        }
+
+        void setChildren(List<MediaBrowser.MediaItem> children) {
+            mPlayableChildren.clear();
+            mBrowsableChildren.clear();
+            for (MediaBrowser.MediaItem child : children) {
+                if (child.isBrowsable()) {
+                    // Browsable items could also be playable
+                    mBrowsableChildren.add(new MediaItemMetadata(child));
+                } else if (child.isPlayable()) {
+                    mPlayableChildren.add(new MediaItemMetadata(child));
+                }
+            }
+        }
+    }
+
+    /**
+     * Creates a {@link BrowseAdapter} that displays the children of the given media tree node.
+     *
+     * @param mediaBrowser the {@link MediaBrowser} to get data from.
+     * @param parentItem the node to display children of, or NULL if the
+     * @param strategy a {@link ContentForwardStrategy} that would determine which items would be
+     *                 expanded and how.
+     */
+    public BrowseAdapter(Context context, @NonNull MediaBrowser mediaBrowser,
+            @Nullable MediaItemMetadata parentItem, @NonNull ContentForwardStrategy strategy) {
+        mContext = context;
+        mMediaBrowser = mediaBrowser;
+        mParentMediaItem = parentItem;
+        mCFBStrategy = strategy;
+    }
+
+    /**
+     * Initiates or resumes the data loading process and subscribes to updates. The client can use
+     * {@link #registerObserver(Observer)} to receive updates on the progress.
+     */
+    public void start() {
+        mParentMediaItemId = mParentMediaItem != null
+                ? mParentMediaItem.getId()
+                : mMediaBrowser.getRoot();
+        mMediaBrowser.subscribe(mParentMediaItemId, mSubscriptionCallback);
+        for (MediaItemState itemState : mItemStates.values()) {
+            subscribe(itemState);
+        }
+    }
+
+    /**
+     * Stops the data loading and releases any subscriptions.
+     */
+    public void stop() {
+        if (mParentMediaItemId == null) {
+            // Not started
+            return;
+        }
+        mMediaBrowser.unsubscribe(mParentMediaItemId, mSubscriptionCallback);
+        for (MediaItemState itemState : mItemStates.values()) {
+            unsubscribe(itemState);
+        }
+        mParentMediaItemId = null;
+    }
+
+    /**
+     * Sets media queue items into this adapter.
+     */
+    public void setQueue(List<MediaItemMetadata> items, CharSequence queueTitle) {
+        mQueue = items;
+        mQueueTitle = queueTitle;
+        notify(Observer::onDirty);
+    }
+
+    /**
+     * Registers an {@link Observer}
+     */
+    public void registerObserver(Observer observer) {
+        mObservers.add(observer);
+    }
+
+    /**
+     * Unregisters an {@link Observer}
+     */
+    public void unregisterObserver(Observer observer) {
+        mObservers.remove(observer);
+    }
+
+    /**
+     * @return the global loading state. Consumers can use this state to determine if more
+     * information is still pending to arrive or not. This method will report
+     * {@link BrowseViewData.State#ERROR} only if the list of immediate children fails to load.
+     */
+    public BrowseViewData.State getState() {
+        return mState;
+    }
+
+    /**
+     * Sets the number of columns that items can take. This method only needs to be used if the
+     * attached {@link RecyclerView} is NOT using a {@link GridLayoutManager}. This class will
+     * automatically determine this value on {@link #onAttachedToRecyclerView(RecyclerView)}
+     * otherwise.
+     */
+    public void setMaxSpanSize(int maxSpanSize) {
+        mMaxSpanSize = maxSpanSize;
+    }
+
+    /**
+     * @return a {@link GridLayoutManager.SpanSizeLookup} that can be used to obtain the span size
+     * of each item in this adapter. This method is only needed if the {@link RecyclerView} is NOT
+     * using a {@link GridLayoutManager}. This class will automatically use it on\
+     * {@link #onAttachedToRecyclerView(RecyclerView)} otherwise.
+     */
+    public GridLayoutManager.SpanSizeLookup getSpanSizeLookup() {
+        return new GridLayoutManager.SpanSizeLookup() {
+            @Override
+            public int getSpanSize(int position) {
+                BrowseItemViewType viewType = mViewData.get(position).mViewType;
+                return viewType.getSpanSize(mMaxSpanSize);
+            }
+        };
+    }
+
+    /**
+     * Updates the {@link RecyclerView} with newly loaded information. This normally should be
+     * invoked as a result of a {@link Observer#onDirty()} callback.
+     *
+     * This method is idempotent and can be used at any time (even delayed if needed). Additions,
+     * removals and insertions would be notified to the {@link RecyclerView} so it can be
+     * animated appropriately.
+     */
+    public void update() {
+        List<BrowseViewData> newItems = generateViewData(mItemStates.values());
+        List<BrowseViewData> oldItems = mViewData;
+        mViewData = newItems;
+        DiffUtil.DiffResult result = DiffUtil.calculateDiff(createDiffUtil(oldItems, newItems));
+        result.dispatchUpdatesTo(this);
+    }
+
+    private void subscribe(MediaItemState state) {
+        if (!state.mIsSubscribed && state.mItem.isBrowsable()) {
+            mMediaBrowser.subscribe(state.mItem.getId(), mSubscriptionCallback);
+            state.mIsSubscribed = true;
+        }
+    }
+
+    private void unsubscribe(MediaItemState state) {
+        if (state.mIsSubscribed) {
+            mMediaBrowser.unsubscribe(state.mItem.getId(), mSubscriptionCallback);
+            state.mIsSubscribed = false;
+        }
+    }
+
+    @NonNull
+    @Override
+    public BrowseViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        int layoutId = BrowseItemViewType.values()[viewType].getLayoutId();
+        View view = LayoutInflater.from(mContext).inflate(layoutId, parent, false);
+        return new BrowseViewHolder(view);
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull BrowseViewHolder holder, int position) {
+        BrowseViewData viewData = mViewData.get(position);
+        holder.bind(mContext, viewData);
+    }
+
+    @Override
+    public int getItemCount() {
+        return mViewData.size();
+    }
+
+    @Override
+    public int getItemViewType(int position) {
+        return mViewData.get(position).mViewType.ordinal();
+    }
+
+    private void onItemsLoaded(String parentId, List<MediaBrowser.MediaItem> children) {
+        if (parentId.equals(mParentMediaItemId)) {
+            // Direct children from the requested media item id. Update subscription list.
+            LinkedHashMap<String, MediaItemState> newItemStates = new LinkedHashMap<>();
+            for (MediaBrowser.MediaItem item : children) {
+                MediaItemState itemState = mItemStates.get(item.getMediaId());
+                if (itemState != null) {
+                    // Reuse existing section.
+                    newItemStates.put(item.getMediaId(), itemState);
+                    mItemStates.remove(item.getMediaId());
+                } else {
+                    // New section, subscribe to it.
+                    itemState = new MediaItemState(item);
+                    newItemStates.put(item.getMediaId(), itemState);
+                    subscribe(itemState);
+                }
+            }
+            // Remove unused sections
+            for (MediaItemState itemState : mItemStates.values()) {
+                unsubscribe(itemState);
+            }
+            mItemStates = newItemStates;
+        } else {
+            MediaItemState itemState = mItemStates.get(parentId);
+            if (itemState == null) {
+                Log.w(TAG, "Loaded children for a section we don't have: " + parentId);
+                return;
+            }
+            itemState.setChildren(children);
+            itemState.mState = BrowseViewData.State.LOADED;
+        }
+        updateGlobalState();
+        notify(Observer::onDirty);
+    }
+
+    private void notify(Consumer<Observer> notification) {
+        for (Observer observer : mObservers) {
+            notification.accept(observer);
+        }
+    }
+
+    private void onLoadingError(String parentId) {
+        if (parentId.equals(mParentMediaItemId)) {
+            mState = BrowseViewData.State.ERROR;
+        } else {
+            MediaItemState state = mItemStates.get(parentId);
+            if (state == null) {
+                Log.w(TAG, "Error loading children for a section we don't have: " + parentId);
+                return;
+            }
+            state.setChildren(new ArrayList<>());
+            state.mState = BrowseViewData.State.ERROR;
+        }
+        updateGlobalState();
+        notify(Observer::onDirty);
+    }
+
+    private void updateGlobalState() {
+        for (MediaItemState state: mItemStates.values()) {
+            if (state.mState == BrowseViewData.State.LOADING) {
+                mState = BrowseViewData.State.LOADING;
+                return;
+            }
+        }
+        mState = BrowseViewData.State.LOADED;
+    }
+
+    private DiffUtil.Callback createDiffUtil(List<BrowseViewData> oldList,
+            List<BrowseViewData> newList) {
+        return new DiffUtil.Callback() {
+            @Override
+            public int getOldListSize() {
+                return oldList.size();
+            }
+
+            @Override
+            public int getNewListSize() {
+                return newList.size();
+            }
+
+            @Override
+            public boolean areItemsTheSame(int oldPos, int newPos) {
+                BrowseViewData oldItem = oldList.get(oldPos);
+                BrowseViewData newItem = newList.get(newPos);
+
+                return Objects.equals(oldItem.mMediaItem, newItem.mMediaItem)
+                        && Objects.equals(oldItem.mText, newItem.mText);
+            }
+
+            @Override
+            public boolean areContentsTheSame(int oldPos, int newPos) {
+                BrowseViewData oldItem = oldList.get(oldPos);
+                BrowseViewData newItem = newList.get(newPos);
+
+                return oldItem.equals(newItem);
+            }
+        };
+    }
+
+    @Override
+    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
+        if (recyclerView.getLayoutManager() instanceof GridLayoutManager) {
+            GridLayoutManager manager = (GridLayoutManager) recyclerView.getLayoutManager();
+            mMaxSpanSize = manager.getSpanCount();
+            manager.setSpanSizeLookup(getSpanSizeLookup());
+        }
+    }
+
+    private class ItemsBuilder {
+        private List<BrowseViewData> result = new ArrayList<>();
+
+        void addItem(MediaItemMetadata item, BrowseViewData.State state,
+                BrowseItemViewType viewType, Consumer<Observer> notification) {
+            result.add(new BrowseViewData(item, viewType, state,
+                    view -> BrowseAdapter.this.notify(notification)));
+        }
+
+        void addItems(List<MediaItemMetadata> items, BrowseItemViewType viewType, int maxRows) {
+            int spanSize = viewType.getSpanSize(mMaxSpanSize);
+            int maxChildren = maxRows * (mMaxSpanSize / spanSize);
+            result.addAll(items.stream()
+                    .limit(maxChildren)
+                    .map(item -> {
+                        Consumer<Observer> notification = item.getQueueId() != null
+                                ? observer -> observer.onQueueItemClicked(item)
+                                : item.isBrowsable()
+                                        ? observer -> observer.onBrowseableItemClicked(item)
+                                        : observer -> observer.onPlayableItemClicked(item);
+                        return new BrowseViewData(item, viewType, null, view ->
+                                BrowseAdapter.this.notify(notification));
+                    })
+                    .collect(Collectors.toList()));
+        }
+
+        void addTitle(CharSequence title, Consumer<Observer> notification) {
+            result.add(new BrowseViewData(title, BrowseItemViewType.HEADER,
+                    view -> BrowseAdapter.this.notify(notification)));
+
+        }
+
+        void addBrowseBlock(MediaItemMetadata header, BrowseViewData.State state,
+                List<MediaItemMetadata> items, BrowseItemViewType viewType, int maxChildren,
+                boolean showHeader, boolean showMoreFooter) {
+            if (showHeader) {
+                addItem(header, state, BrowseItemViewType.HEADER, null);
+            }
+            addItems(items, viewType, maxChildren);
+            if (showMoreFooter) {
+                addItem(header, null, BrowseItemViewType.MORE_FOOTER,
+                        observer -> observer.onMoreButtonClicked(header));
+            }
+        }
+
+        List<BrowseViewData> build() {
+            return result;
+        }
+    }
+
+    /**
+     * Flatten the given collection of item states into a list of {@link BrowseViewData}s. To avoid
+     * flickering, the flatting will stop at the first "loading" section, avoiding unnecessary
+     * insertion animations during the initial data load.
+     */
+    private List<BrowseViewData> generateViewData(Collection<MediaItemState> itemStates) {
+        ItemsBuilder itemsBuilder = new ItemsBuilder();
+
+        if (mQueue != null && !mQueue.isEmpty() && mCFBStrategy.getMaxQueueRows() > 0
+                && mCFBStrategy.getQueueViewType() != null) {
+            if (mQueueTitle != null) {
+                itemsBuilder.addTitle(mQueueTitle, Observer::onQueueTitleClicked);
+            }
+            itemsBuilder.addItems(mQueue, mCFBStrategy.getQueueViewType(),
+                    mCFBStrategy.getMaxQueueRows());
+        }
+        for (MediaItemState itemState : itemStates) {
+            MediaItemMetadata item = itemState.mItem;
+            if (itemState.mItem.isBrowsable()) {
+                if (!itemState.mBrowsableChildren.isEmpty()
+                        && !itemState.mPlayableChildren.isEmpty()
+                        || !mCFBStrategy.shouldBeExpanded(item)) {
+                    itemsBuilder.addItem(item, itemState.mState,
+                            mCFBStrategy.getBrowsableViewType(mParentMediaItem), null);
+                } else if (!itemState.mPlayableChildren.isEmpty()) {
+                    itemsBuilder.addBrowseBlock(item,
+                            itemState.mState,
+                            itemState.mPlayableChildren,
+                            mCFBStrategy.getPlayableViewType(item),
+                            mCFBStrategy.getMaxRows(item, mCFBStrategy.getPlayableViewType(item)),
+                            mCFBStrategy.showMoreButton(item),
+                            mCFBStrategy.includeHeader(item));
+                } else if (!itemState.mBrowsableChildren.isEmpty()) {
+                    itemsBuilder.addBrowseBlock(item,
+                            itemState.mState,
+                            itemState.mBrowsableChildren,
+                            mCFBStrategy.getBrowsableViewType(item),
+                            mCFBStrategy.getMaxRows(item, mCFBStrategy.getBrowsableViewType(item)),
+                            mCFBStrategy.showMoreButton(item),
+                            mCFBStrategy.includeHeader(item));
+                }
+            } else if (item.isPlayable()) {
+                itemsBuilder.addItem(item, itemState.mState,
+                        mCFBStrategy.getPlayableViewType(mParentMediaItem), null);
+            }
+        }
+
+        return itemsBuilder.build();
+    }
+}
diff --git a/src/com/android/car/media/browse/BrowseItemViewType.java b/src/com/android/car/media/browse/BrowseItemViewType.java
new file mode 100644
index 0000000..cfbdee7
--- /dev/null
+++ b/src/com/android/car/media/browse/BrowseItemViewType.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.car.media.browse;
+
+import android.support.annotation.LayoutRes;
+
+/**
+ * Possible view types that would be used by the {@link BrowseAdapter}.
+ */
+public enum BrowseItemViewType {
+    /** A section header */
+    HEADER(com.android.car.media.common.R.layout.media_browse_header_item),
+    /** A grid item including an image and a title */
+    GRID_ITEM(com.android.car.media.common.R.layout.media_browse_grid_item, 1),
+    /** A list item including title and subtitle */
+    LIST_ITEM(com.android.car.media.common.R.layout.media_browse_list_item),
+    /** An item in a panel of items (menu) */
+    PANEL_ITEM(com.android.car.media.common.R.layout.media_browse_panel_item),
+    /** A footer that can be used to navigate to an expanded version of a section */
+    MORE_FOOTER(com.android.car.media.common.R.layout.media_browse_more_footer),
+    ;
+    private final @LayoutRes int mLayoutId;
+    private final int mSpanSize;
+
+    /**
+     * {@link BrowseItemViewType} that take the whole width of the
+     * {@link android.support.v7.widget.RecyclerView}
+     */
+    BrowseItemViewType(@LayoutRes int layoutId) {
+        mLayoutId = layoutId;
+        mSpanSize = -1;
+    }
+
+    /**
+     * {@link BrowseItemViewType} that only takes the given number of columns.
+     */
+    BrowseItemViewType(@LayoutRes int layoutId, int spanSize) {
+        mLayoutId = layoutId;
+        mSpanSize = spanSize;
+    }
+
+    /**
+     * @param maxSpanSize maximum number of columns of the underlying grid
+     * @return number of columns this view wants to use.
+     */
+    public int getSpanSize(int maxSpanSize) {
+        return mSpanSize < 0 ? maxSpanSize : mSpanSize;
+    }
+
+    /**
+     * @return layout that should be inflated to generate this view type.
+     */
+    public @LayoutRes int getLayoutId() {
+        return mLayoutId;
+    }
+}
diff --git a/src/com/android/car/media/browse/BrowseViewData.java b/src/com/android/car/media/browse/BrowseViewData.java
new file mode 100644
index 0000000..31d0588
--- /dev/null
+++ b/src/com/android/car/media/browse/BrowseViewData.java
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.car.media.browse;
+
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.view.View;
+
+import com.android.car.media.common.MediaItemMetadata;
+
+import java.util.Objects;
+
+/**
+ * Information necessary to update a {@link BrowseViewHolder}
+ */
+class BrowseViewData {
+    /** {@link com.android.car.media.common.MediaItemMetadata} associated with this item */
+    public final MediaItemMetadata mMediaItem;
+    /** View type associated with this item */
+    @NonNull public final BrowseItemViewType mViewType;
+    /** Current state of this item */
+    public final State mState;
+    /** Text associated with this item */
+    public final CharSequence mText;
+    /** Click listener to set for this item */
+    public final View.OnClickListener mOnClickListener;
+
+    /**
+     * Possible states of a view
+     */
+    public enum State {
+        /** Loading of this item hasn't started yet */
+        IDLE,
+        /** There is pending information before this item can be displayed */
+        LOADING,
+        /** It was not possible to load metadata for this item */
+        ERROR,
+        /** Metadata for this items has been correctly loaded */
+        LOADED
+    }
+
+    /**
+     * Creates a {@link BrowseViewData} for a particular {@link MediaItemMetadata}.
+     *
+     * @param mediaItem {@link MediaItemMetadata} metadata
+     * @param viewType view type to use to represent this item
+     * @param state current item state
+     * @param onClickListener optional {@link android.view.View.OnClickListener}
+     */
+    BrowseViewData(MediaItemMetadata mediaItem, @NonNull BrowseItemViewType viewType,
+            @NonNull State state, View.OnClickListener onClickListener) {
+        mMediaItem = mediaItem;
+        mViewType = viewType;
+        mState = state;
+        mText = null;
+        mOnClickListener = onClickListener;
+    }
+
+    /**
+     * Creates a {@link BrowseViewData} for a given text (normally used for headers or footers)
+     * @param text text to set
+     * @param viewType view type to use
+     * @param onClickListener optional {@link android.view.View.OnClickListener}
+     */
+    BrowseViewData(@NonNull CharSequence text, @NonNull BrowseItemViewType viewType,
+            View.OnClickListener onClickListener) {
+        mText = text;
+        mViewType = viewType;
+        mMediaItem = null;
+        mState = null;
+        mOnClickListener = onClickListener;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        BrowseViewData item = (BrowseViewData) o;
+        return Objects.equals(mMediaItem, item.mMediaItem) &&
+                mState == item.mState &&
+                mViewType == item.mViewType;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(mMediaItem, mState, mViewType);
+    }
+}
diff --git a/src/com/android/car/media/browse/BrowseViewHolder.java b/src/com/android/car/media/browse/BrowseViewHolder.java
new file mode 100644
index 0000000..28ec64c
--- /dev/null
+++ b/src/com/android/car/media/browse/BrowseViewHolder.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.car.media.browse;
+
+import android.content.Context;
+import android.support.v7.widget.RecyclerView;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import com.android.car.media.common.MediaItemMetadata;
+
+/**
+ * Generic {@link RecyclerView.ViewHolder} to use for all views in the {@link BrowseAdapter}
+ */
+class BrowseViewHolder extends RecyclerView.ViewHolder {
+    final TextView mTitle;
+    final TextView mSubtitle;
+    final ImageView mAlbumArt;
+    final ViewGroup mContainer;
+
+    /**
+     * Creates a {@link BrowseViewHolder} for the given view.
+     */
+    BrowseViewHolder(View itemView) {
+        super(itemView);
+        mTitle = itemView.findViewById(com.android.car.media.common.R.id.title);
+        mSubtitle = itemView.findViewById(com.android.car.media.common.R.id.subtitle);
+        mAlbumArt = itemView.findViewById(com.android.car.media.common.R.id.thumbnail);
+        mContainer = itemView.findViewById(com.android.car.media.common.R.id.container);
+    }
+
+    /**
+     * Updates this {@link BrowseViewHolder} with the given data
+     */
+    public void bind(Context context, BrowseViewData data) {
+        if (mTitle != null) {
+            mTitle.setText(data.mText != null
+                    ? data.mText : data.mMediaItem != null
+                    ? data.mMediaItem.getTitle()
+                    : null);
+        }
+        if (mSubtitle != null) {
+            mSubtitle.setText(data.mMediaItem != null
+                    ? data.mMediaItem.getSubtitle()
+                    : null);
+        }
+        if (mAlbumArt != null) {
+            MediaItemMetadata.updateImageView(context, data.mMediaItem, mAlbumArt, 0);
+        }
+        if (mContainer != null && data.mOnClickListener != null) {
+            mContainer.setOnClickListener(data.mOnClickListener);
+        }
+    }
+}
diff --git a/src/com/android/car/media/browse/ContentForwardStrategy.java b/src/com/android/car/media/browse/ContentForwardStrategy.java
new file mode 100644
index 0000000..7720366
--- /dev/null
+++ b/src/com/android/car/media/browse/ContentForwardStrategy.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.car.media.browse;
+
+import com.android.car.media.common.MediaItemMetadata;
+
+/**
+ * Strategy used to group and expand media items in the {@link BrowseAdapter}
+ */
+public interface ContentForwardStrategy {
+    /**
+     * @return true if a header should be included when expanding the given media item into a
+     * section. Only used if {@link #shouldBeExpanded(MediaItemMetadata)} returns true.
+     */
+    boolean includeHeader(MediaItemMetadata mediaItem);
+
+    /**
+     * @return maximum number of rows to use when when expanding the given media item into a
+     * section. The number can be different depending on the {@link BrowseItemViewType} that
+     * will be used to represent media item children (i.e.: we might allow more rows for lists
+     * than for grids). Only used if {@link #shouldBeExpanded(MediaItemMetadata)} returns true.
+     */
+    int getMaxRows(MediaItemMetadata mediaItem, BrowseItemViewType viewType);
+
+    /**
+     * @return whether the given media item should be expanded or not. If not expanded, the item
+     * will be displayed according to its parent preferred view type.
+     */
+    boolean shouldBeExpanded(MediaItemMetadata mediaItem);
+
+    /**
+     * @return view type to use to render browsable children of the given media item. Only used if
+     * {@link #shouldBeExpanded(MediaItemMetadata)} returns true.
+     */
+    BrowseItemViewType getBrowsableViewType(MediaItemMetadata mediaItem);
+
+    /**
+     * @return view type to use to render playable children fo the given media item. Only used if
+     * {@link #shouldBeExpanded(MediaItemMetadata)} returns true.
+     */
+    BrowseItemViewType getPlayableViewType(MediaItemMetadata mediaItem);
+
+    /**
+     * @return true if a "more" button should be displayed as a footer for a section displaying the
+     * given media item, in case that there item has more children than the ones that can be
+     * displayed according to {@link #getMaxQueueRows()}. Only used if
+     * {@link #shouldBeExpanded(MediaItemMetadata)} returns true.
+     */
+    boolean showMoreButton(MediaItemMetadata mediaItem);
+
+    /**
+     * @return maximum number of items to show for the media queue, if one is provided.
+     */
+    int getMaxQueueRows();
+
+    /**
+     * @return view type to use to display queue items.
+     */
+    BrowseItemViewType getQueueViewType();
+
+    /**
+     * Default strategy
+     * TODO(b/77646944): Expand this implementation to honor the media source expectations.
+     */
+    ContentForwardStrategy DEFAULT_STRATEGY = new ContentForwardStrategy() {
+        @Override
+        public boolean includeHeader(MediaItemMetadata mediaItem) {
+            return false;
+        }
+
+        @Override
+        public int getMaxRows(MediaItemMetadata mediaItem, BrowseItemViewType viewType) {
+            return viewType == BrowseItemViewType.GRID_ITEM ? 2 : 8;
+        }
+
+        @Override
+        public boolean shouldBeExpanded(MediaItemMetadata mediaItem) {
+            return true;
+        }
+
+        @Override
+        public BrowseItemViewType getBrowsableViewType(MediaItemMetadata mediaItem) {
+            return BrowseItemViewType.PANEL_ITEM;
+        }
+
+        @Override
+        public BrowseItemViewType getPlayableViewType(MediaItemMetadata mediaItem) {
+            return BrowseItemViewType.GRID_ITEM;
+        }
+
+        @Override
+        public boolean showMoreButton(MediaItemMetadata mediaItem) {
+            return true;
+        }
+
+        @Override
+        public int getMaxQueueRows() {
+            return 8;
+        }
+
+        @Override
+        public BrowseItemViewType getQueueViewType() {
+            return BrowseItemViewType.LIST_ITEM;
+        }
+    };
+}