src/com/android/car/media/BrowseViewController.java - platform/packages/apps/Car/Media - Git at Google

 /*
  * 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;

 import static com.android.car.apps.common.util.ViewUtils.removeFromParent;

 import android.content.res.Resources;
 import android.os.Handler;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ImageView;
 import android.widget.TextView;

 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.fragment.app.FragmentActivity;
 import androidx.lifecycle.Observer;
 import androidx.lifecycle.ViewModelProviders;
 import androidx.recyclerview.widget.RecyclerView;

 import com.android.car.apps.common.util.FutureData;
 import com.android.car.apps.common.util.ViewUtils;
 import com.android.car.media.browse.BrowseAdapter;
 import com.android.car.media.browse.LimitedBrowseAdapter;
 import com.android.car.media.common.MediaItemMetadata;
 import com.android.car.media.common.browse.MediaBrowserViewModelImpl;
 import com.android.car.media.common.browse.MediaItemsRepository.MediaItemsLiveData;
 import com.android.car.media.common.source.MediaSource;
 import com.android.car.ui.FocusArea;
 import com.android.car.ui.baselayout.Insets;
 import com.android.car.ui.recyclerview.CarUiRecyclerView;
 import com.android.car.uxr.LifeCycleObserverUxrContentLimiter;
 import com.android.car.uxr.UxrContentLimiterImpl;

 import java.util.Collection;
 import java.util.List;

 /**
  * A view controller that displays the media item children of a {@link MediaItemMetadata}.
  * The controller manages a recycler view where the items can be displayed as a list or a grid, as
  * well as an error icon and a message used to indicate loading and errors.
  * The content view is initialized with 0 alpha and needs to be animated or set to to full opacity
  * to become visible.
  */
 public class BrowseViewController {
     private static final String TAG = "BrowseViewController";

     private final Callbacks mCallbacks;
     private final FocusArea mFocusArea;
     private final MediaItemMetadata mParentItem;
     private final MediaItemsLiveData mMediaItems;
     private final boolean mDisplayMediaItems;
     private final LifeCycleObserverUxrContentLimiter mUxrContentLimiter;
     private final View mContent;
     private final CarUiRecyclerView mBrowseList;
     private final ImageView mErrorIcon;
     private final TextView mMessage;
     private final LimitedBrowseAdapter mLimitedBrowseAdapter;

     private final int mFadeDuration;
     private final int mLoadingIndicatorDelay;

     private final boolean mSetFocusAreaHighlightBottom;

     private final Handler mHandler = new Handler();

     private final MediaActivity.ViewModel mViewModel;

     private final BrowseAdapter.Observer mBrowseAdapterObserver = new BrowseAdapter.Observer() {

         @Override
         protected void onPlayableItemClicked(@NonNull MediaItemMetadata item) {
             mCallbacks.onPlayableItemClicked(item);
         }

         @Override
         protected void onBrowsableItemClicked(@NonNull MediaItemMetadata item) {
             mCallbacks.onBrowsableItemClicked(item);
         }
     };

     /**
      * The bottom padding of the FocusArea highlight.
      */
     private int mFocusAreaHighlightBottomPadding;

     /**
      * Callbacks (implemented by the host)
      */
     public interface Callbacks {
         /**
          * Method invoked when the user clicks on a playable item
          *
          * @param item item to be played.
          */
         void onPlayableItemClicked(@NonNull MediaItemMetadata item);

         /** Invoked when the user clicks on a browsable item. */
         void onBrowsableItemClicked(@NonNull MediaItemMetadata item);

         /** Invoked when child nodes have been removed from this controller. */
         void onChildrenNodesRemoved(@NonNull BrowseViewController controller,
                 @NonNull Collection<MediaItemMetadata> removedNodes);

         FragmentActivity getActivity();
     }

     private FragmentActivity getActivity() {
         return mCallbacks.getActivity();
     }

     /**
      * Creates a controller to display the children of the given parent {@link MediaItemMetadata}.
      * This parent node can have been obtained from the browse tree, or from browsing the search
      * results.
      */
     static BrowseViewController newBrowseController(Callbacks callbacks, ViewGroup container,
             @NonNull MediaItemMetadata parentItem, MediaItemsLiveData mediaItems,
             int rootBrowsableHint, int rootPlayableHint) {
         return new BrowseViewController(callbacks, container, parentItem, mediaItems,
                 rootBrowsableHint, rootPlayableHint, true);
     }

     /** Creates a controller to display the top results of a search query (in a list). */
     static BrowseViewController newSearchResultsController(Callbacks callbacks, ViewGroup container,
             MediaItemsLiveData mediaItems) {
         return new BrowseViewController(callbacks, container, null, mediaItems, 0, 0, true);
     }

     /**
      * Creates a controller to "display" the children of the root: the children are actually hidden
      * since they are shown as tabs, and the controller is only used to display loading and error
      * messages.
      */
     static BrowseViewController newRootController(Callbacks callbacks, ViewGroup container,
             MediaItemsLiveData mediaItems) {
         return new BrowseViewController(callbacks, container, null, mediaItems, 0, 0, false);
     }


     private BrowseViewController(Callbacks callbacks, ViewGroup container,
             @Nullable MediaItemMetadata parentItem, MediaItemsLiveData mediaItems,
             int rootBrowsableHint, int rootPlayableHint, boolean displayMediaItems) {
         mCallbacks = callbacks;
         mParentItem = parentItem;
         mMediaItems = mediaItems;
         mDisplayMediaItems = displayMediaItems;

         LayoutInflater inflater = LayoutInflater.from(container.getContext());
         mContent = inflater.inflate(R.layout.browse_node, container, false);
         mContent.setAlpha(0f);
         container.addView(mContent);

         mLoadingIndicatorDelay = mContent.getContext().getResources()
                 .getInteger(R.integer.progress_indicator_delay);
         mSetFocusAreaHighlightBottom = mContent.getContext().getResources().getBoolean(
                 R.bool.set_browse_list_focus_area_highlight_above_minimized_control_bar);

         mFocusArea = mContent.findViewById(R.id.focus_area);
         mBrowseList = mContent.findViewById(R.id.browse_list);
         mErrorIcon = mContent.findViewById(R.id.error_icon);
         mMessage = mContent.findViewById(R.id.error_message);
         mFadeDuration = mContent.getContext().getResources().getInteger(
                 R.integer.new_album_art_fade_in_duration);


         FragmentActivity activity = callbacks.getActivity();
         mViewModel = ViewModelProviders.of(activity).get(MediaActivity.ViewModel.class);

         BrowseAdapter browseAdapter = new BrowseAdapter(mBrowseList.getContext());
         mLimitedBrowseAdapter = new LimitedBrowseAdapter(mBrowseList, browseAdapter,
                 mBrowseAdapterObserver);
         mBrowseList.setAdapter(mLimitedBrowseAdapter);

         mUxrContentLimiter = new LifeCycleObserverUxrContentLimiter(
                 new UxrContentLimiterImpl(activity, R.xml.uxr_config));
         mUxrContentLimiter.setAdapter(mLimitedBrowseAdapter);
         activity.getLifecycle().addObserver(mUxrContentLimiter);

         browseAdapter.setRootBrowsableViewType(rootBrowsableHint);
         browseAdapter.setRootPlayableViewType(rootPlayableHint);

         mMediaItems.observe(activity, mItemsObserver);
     }

     public MediaItemMetadata getParentItem() {
         return mParentItem;
     }

     /** Shares the browse adapter with the given view... #local-hack. */
     public void shareBrowseAdapterWith(RecyclerView view) {
         view.setAdapter(mLimitedBrowseAdapter);
     }

     private final Observer<FutureData<List<MediaItemMetadata>>> mItemsObserver =
             this::onItemsUpdate;

     View getContent() {
         return mContent;
     }

     String getDebugInfo() {
         StringBuilder log = new StringBuilder();
         log.append("[");
         log.append((mParentItem != null) ? mParentItem.getTitle() : "Root");
         log.append("]");
         FutureData<List<MediaItemMetadata>> children = mMediaItems.getValue();
         if (children == null) {
             log.append(" null future data");
         } else if (children.isLoading()) {
             log.append(" loading");
         } else if (children.getData() == null) {
             log.append(" null list");
         } else {
             List<MediaItemMetadata> nodes = children.getData();
             log.append(" ");
             log.append(nodes.size());
             log.append(" {");
             if (nodes.size() > 0) {
                 log.append(nodes.get(0).getTitle().toString());
             }
             if (nodes.size() > 1) {
                 log.append(", ");
                 log.append(nodes.get(1).getTitle().toString());
             }
             if (nodes.size() > 2) {
                 log.append(", ...");
             }
             log.append(" }");
         }
         return log.toString();
     }

     void destroy() {
         mCallbacks.getActivity().getLifecycle().removeObserver(mUxrContentLimiter);
         mMediaItems.removeObserver(mItemsObserver);
         removeFromParent(mContent);
     }

     private Runnable mLoadingIndicatorRunnable = new Runnable() {
         @Override
         public void run() {
             mMessage.setText(R.string.browser_loading);
             ViewUtils.showViewAnimated(mMessage, mFadeDuration);
         }
     };

     private void startLoadingIndicator() {
         // Display the indicator after a certain time, to avoid flashing the indicator constantly,
         // even when performance is acceptable.
         mHandler.postDelayed(mLoadingIndicatorRunnable, mLoadingIndicatorDelay);
     }

     private void stopLoadingIndicator() {
         mHandler.removeCallbacks(mLoadingIndicatorRunnable);
         ViewUtils.hideViewAnimated(mMessage, mFadeDuration);
     }

     public void onCarUiInsetsChanged(@NonNull Insets insets) {
         int leftPadding = mBrowseList.getPaddingLeft();
         int rightPadding = mBrowseList.getPaddingRight();
         int bottomPadding = mBrowseList.getPaddingBottom();
         mBrowseList.setPadding(leftPadding, insets.getTop(), rightPadding, bottomPadding);
         if (bottomPadding > mFocusAreaHighlightBottomPadding) {
             mFocusAreaHighlightBottomPadding = bottomPadding;
         }
         mFocusArea.setHighlightPadding(
                 leftPadding, insets.getTop(), rightPadding, mFocusAreaHighlightBottomPadding);
         mFocusArea.setBoundsOffset(leftPadding, insets.getTop(), rightPadding, bottomPadding);
     }

     void onPlaybackControlsChanged(boolean visible) {
         int leftPadding = mBrowseList.getPaddingLeft();
         int topPadding = mBrowseList.getPaddingTop();
         int rightPadding = mBrowseList.getPaddingRight();
         Resources res = getActivity().getResources();
         int bottomPadding = visible
                 ? res.getDimensionPixelOffset(R.dimen.browse_fragment_bottom_padding) : 0;
         mBrowseList.setPadding(leftPadding, topPadding, rightPadding, bottomPadding);
         int highlightBottomPadding = mSetFocusAreaHighlightBottom ? bottomPadding : 0;
         if (highlightBottomPadding > mFocusAreaHighlightBottomPadding) {
             mFocusAreaHighlightBottomPadding = highlightBottomPadding;
         }
         mFocusArea.setHighlightPadding(
                 leftPadding, topPadding, rightPadding, mFocusAreaHighlightBottomPadding);
         // Set the bottom offset to bottomPadding regardless of mSetFocusAreaHighlightBottom so that
         // RotaryService can find the correct target when the user nudges the rotary controller.
         mFocusArea.setBoundsOffset(leftPadding, topPadding, rightPadding, bottomPadding);

         ViewGroup.MarginLayoutParams messageLayout =
                 (ViewGroup.MarginLayoutParams) mMessage.getLayoutParams();
         messageLayout.bottomMargin = bottomPadding;
         mMessage.setLayoutParams(messageLayout);
     }

     private String getErrorMessage() {
         if (/*root*/ !mDisplayMediaItems) {
             MediaSource mediaSource = mViewModel.getMediaSourceValue();
             return getActivity().getString(
                     R.string.cannot_connect_to_app,
                     mediaSource != null
                             ? mediaSource.getDisplayName()
                             : getActivity().getString(
                                     R.string.unknown_media_provider_name));
         } else {
             return getActivity().getString(R.string.unknown_error);
         }
     }

     private void onItemsUpdate(@Nullable FutureData<List<MediaItemMetadata>> futureData) {
         if (futureData == null || futureData.isLoading()) {
             ViewUtils.hideViewAnimated(mErrorIcon, 0);
             ViewUtils.hideViewAnimated(mMessage, 0);

             // TODO(b/139759881) build a jank-free animation of the transition.
             mBrowseList.setAlpha(0f);
             mLimitedBrowseAdapter.submitItems(null, null);

             if (futureData != null) {
                 startLoadingIndicator();
             }
             return;
         }

         stopLoadingIndicator();

         List<MediaItemMetadata> items = MediaBrowserViewModelImpl.filterItems(
                 /*root*/ !mDisplayMediaItems, futureData.getData());
         if (mDisplayMediaItems) {
             mLimitedBrowseAdapter.submitItems(mParentItem, items);

             List<MediaItemMetadata> lastNodes =
                     MediaBrowserViewModelImpl.selectBrowseableItems(futureData.getPastData());
             Collection<MediaItemMetadata> removedNodes =
                     MediaBrowserViewModelImpl.computeRemovedItems(lastNodes, items);
             if (!removedNodes.isEmpty()) {
                 mCallbacks.onChildrenNodesRemoved(this, removedNodes);
             }
         }

         int duration = mFadeDuration;
         if (items == null) {
             mMessage.setText(getErrorMessage());
             ViewUtils.hideViewAnimated(mBrowseList.getView(), duration);
             ViewUtils.showViewAnimated(mMessage, duration);
             ViewUtils.showViewAnimated(mErrorIcon, duration);
         } else if (items.isEmpty()) {
             mMessage.setText(R.string.nothing_to_play);
             ViewUtils.hideViewAnimated(mBrowseList.getView(), duration);
             ViewUtils.hideViewAnimated(mErrorIcon, duration);
             ViewUtils.showViewAnimated(mMessage, duration);
         } else {
             ViewUtils.showViewAnimated(mBrowseList.getView(), duration);
             ViewUtils.hideViewAnimated(mErrorIcon, duration);
             ViewUtils.hideViewAnimated(mMessage, duration);
         }

         if (Log.isLoggable(TAG, Log.VERBOSE)) {
             Log.v(TAG, "onItemsUpdate " + getDebugInfo());
         }
     }
 }
	/*
	* 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;

	import static com.android.car.apps.common.util.ViewUtils.removeFromParent;

	import android.content.res.Resources;
	import android.os.Handler;
	import android.util.Log;
	import android.view.LayoutInflater;
	import android.view.View;
	import android.view.ViewGroup;
	import android.widget.ImageView;
	import android.widget.TextView;

	import androidx.annotation.NonNull;
	import androidx.annotation.Nullable;
	import androidx.fragment.app.FragmentActivity;
	import androidx.lifecycle.Observer;
	import androidx.lifecycle.ViewModelProviders;
	import androidx.recyclerview.widget.RecyclerView;

	import com.android.car.apps.common.util.FutureData;
	import com.android.car.apps.common.util.ViewUtils;
	import com.android.car.media.browse.BrowseAdapter;
	import com.android.car.media.browse.LimitedBrowseAdapter;
	import com.android.car.media.common.MediaItemMetadata;
	import com.android.car.media.common.browse.MediaBrowserViewModelImpl;
	import com.android.car.media.common.browse.MediaItemsRepository.MediaItemsLiveData;
	import com.android.car.media.common.source.MediaSource;
	import com.android.car.ui.FocusArea;
	import com.android.car.ui.baselayout.Insets;
	import com.android.car.ui.recyclerview.CarUiRecyclerView;
	import com.android.car.uxr.LifeCycleObserverUxrContentLimiter;
	import com.android.car.uxr.UxrContentLimiterImpl;

	import java.util.Collection;
	import java.util.List;

	/**
	* A view controller that displays the media item children of a {@link MediaItemMetadata}.
	* The controller manages a recycler view where the items can be displayed as a list or a grid, as
	* well as an error icon and a message used to indicate loading and errors.
	* The content view is initialized with 0 alpha and needs to be animated or set to to full opacity
	* to become visible.
	*/
	public class BrowseViewController {
	private static final String TAG = "BrowseViewController";

	private final Callbacks mCallbacks;
	private final FocusArea mFocusArea;
	private final MediaItemMetadata mParentItem;
	private final MediaItemsLiveData mMediaItems;
	private final boolean mDisplayMediaItems;
	private final LifeCycleObserverUxrContentLimiter mUxrContentLimiter;
	private final View mContent;
	private final CarUiRecyclerView mBrowseList;
	private final ImageView mErrorIcon;
	private final TextView mMessage;
	private final LimitedBrowseAdapter mLimitedBrowseAdapter;

	private final int mFadeDuration;
	private final int mLoadingIndicatorDelay;

	private final boolean mSetFocusAreaHighlightBottom;

	private final Handler mHandler = new Handler();

	private final MediaActivity.ViewModel mViewModel;

	private final BrowseAdapter.Observer mBrowseAdapterObserver = new BrowseAdapter.Observer() {

	@Override
	protected void onPlayableItemClicked(@NonNull MediaItemMetadata item) {
	mCallbacks.onPlayableItemClicked(item);
	}

	@Override
	protected void onBrowsableItemClicked(@NonNull MediaItemMetadata item) {
	mCallbacks.onBrowsableItemClicked(item);
	}
	};

	/**
	* The bottom padding of the FocusArea highlight.
	*/
	private int mFocusAreaHighlightBottomPadding;

	/**
	* Callbacks (implemented by the host)
	*/
	public interface Callbacks {
	/**
	* Method invoked when the user clicks on a playable item
	*
	* @param item item to be played.
	*/
	void onPlayableItemClicked(@NonNull MediaItemMetadata item);

	/** Invoked when the user clicks on a browsable item. */
	void onBrowsableItemClicked(@NonNull MediaItemMetadata item);

	/** Invoked when child nodes have been removed from this controller. */
	void onChildrenNodesRemoved(@NonNull BrowseViewController controller,
	@NonNull Collection<MediaItemMetadata> removedNodes);

	FragmentActivity getActivity();
	}

	private FragmentActivity getActivity() {
	return mCallbacks.getActivity();
	}

	/**
	* Creates a controller to display the children of the given parent {@link MediaItemMetadata}.
	* This parent node can have been obtained from the browse tree, or from browsing the search
	* results.
	*/
	static BrowseViewController newBrowseController(Callbacks callbacks, ViewGroup container,
	@NonNull MediaItemMetadata parentItem, MediaItemsLiveData mediaItems,
	int rootBrowsableHint, int rootPlayableHint) {
	return new BrowseViewController(callbacks, container, parentItem, mediaItems,
	rootBrowsableHint, rootPlayableHint, true);
	}

	/** Creates a controller to display the top results of a search query (in a list). */
	static BrowseViewController newSearchResultsController(Callbacks callbacks, ViewGroup container,
	MediaItemsLiveData mediaItems) {
	return new BrowseViewController(callbacks, container, null, mediaItems, 0, 0, true);
	}

	/**
	* Creates a controller to "display" the children of the root: the children are actually hidden
	* since they are shown as tabs, and the controller is only used to display loading and error
	* messages.
	*/
	static BrowseViewController newRootController(Callbacks callbacks, ViewGroup container,
	MediaItemsLiveData mediaItems) {
	return new BrowseViewController(callbacks, container, null, mediaItems, 0, 0, false);
	}


	private BrowseViewController(Callbacks callbacks, ViewGroup container,
	@Nullable MediaItemMetadata parentItem, MediaItemsLiveData mediaItems,
	int rootBrowsableHint, int rootPlayableHint, boolean displayMediaItems) {
	mCallbacks = callbacks;
	mParentItem = parentItem;
	mMediaItems = mediaItems;
	mDisplayMediaItems = displayMediaItems;

	LayoutInflater inflater = LayoutInflater.from(container.getContext());
	mContent = inflater.inflate(R.layout.browse_node, container, false);
	mContent.setAlpha(0f);
	container.addView(mContent);

	mLoadingIndicatorDelay = mContent.getContext().getResources()
	.getInteger(R.integer.progress_indicator_delay);
	mSetFocusAreaHighlightBottom = mContent.getContext().getResources().getBoolean(
	R.bool.set_browse_list_focus_area_highlight_above_minimized_control_bar);

	mFocusArea = mContent.findViewById(R.id.focus_area);
	mBrowseList = mContent.findViewById(R.id.browse_list);
	mErrorIcon = mContent.findViewById(R.id.error_icon);
	mMessage = mContent.findViewById(R.id.error_message);
	mFadeDuration = mContent.getContext().getResources().getInteger(
	R.integer.new_album_art_fade_in_duration);


	FragmentActivity activity = callbacks.getActivity();
	mViewModel = ViewModelProviders.of(activity).get(MediaActivity.ViewModel.class);

	BrowseAdapter browseAdapter = new BrowseAdapter(mBrowseList.getContext());
	mLimitedBrowseAdapter = new LimitedBrowseAdapter(mBrowseList, browseAdapter,
	mBrowseAdapterObserver);
	mBrowseList.setAdapter(mLimitedBrowseAdapter);

	mUxrContentLimiter = new LifeCycleObserverUxrContentLimiter(
	new UxrContentLimiterImpl(activity, R.xml.uxr_config));
	mUxrContentLimiter.setAdapter(mLimitedBrowseAdapter);
	activity.getLifecycle().addObserver(mUxrContentLimiter);

	browseAdapter.setRootBrowsableViewType(rootBrowsableHint);
	browseAdapter.setRootPlayableViewType(rootPlayableHint);

	mMediaItems.observe(activity, mItemsObserver);
	}

	public MediaItemMetadata getParentItem() {
	return mParentItem;
	}

	/** Shares the browse adapter with the given view... #local-hack. */
	public void shareBrowseAdapterWith(RecyclerView view) {
	view.setAdapter(mLimitedBrowseAdapter);
	}

	private final Observer<FutureData<List<MediaItemMetadata>>> mItemsObserver =
	this::onItemsUpdate;

	View getContent() {
	return mContent;
	}

	String getDebugInfo() {
	StringBuilder log = new StringBuilder();
	log.append("[");
	log.append((mParentItem != null) ? mParentItem.getTitle() : "Root");
	log.append("]");
	FutureData<List<MediaItemMetadata>> children = mMediaItems.getValue();
	if (children == null) {
	log.append(" null future data");
	} else if (children.isLoading()) {
	log.append(" loading");
	} else if (children.getData() == null) {
	log.append(" null list");
	} else {
	List<MediaItemMetadata> nodes = children.getData();
	log.append(" ");
	log.append(nodes.size());
	log.append(" {");
	if (nodes.size() > 0) {
	log.append(nodes.get(0).getTitle().toString());
	}
	if (nodes.size() > 1) {
	log.append(", ");
	log.append(nodes.get(1).getTitle().toString());
	}
	if (nodes.size() > 2) {
	log.append(", ...");
	}
	log.append(" }");
	}
	return log.toString();
	}

	void destroy() {
	mCallbacks.getActivity().getLifecycle().removeObserver(mUxrContentLimiter);
	mMediaItems.removeObserver(mItemsObserver);
	removeFromParent(mContent);
	}

	private Runnable mLoadingIndicatorRunnable = new Runnable() {
	@Override
	public void run() {
	mMessage.setText(R.string.browser_loading);
	ViewUtils.showViewAnimated(mMessage, mFadeDuration);
	}
	};

	private void startLoadingIndicator() {
	// Display the indicator after a certain time, to avoid flashing the indicator constantly,
	// even when performance is acceptable.
	mHandler.postDelayed(mLoadingIndicatorRunnable, mLoadingIndicatorDelay);
	}

	private void stopLoadingIndicator() {
	mHandler.removeCallbacks(mLoadingIndicatorRunnable);
	ViewUtils.hideViewAnimated(mMessage, mFadeDuration);
	}

	public void onCarUiInsetsChanged(@NonNull Insets insets) {
	int leftPadding = mBrowseList.getPaddingLeft();
	int rightPadding = mBrowseList.getPaddingRight();
	int bottomPadding = mBrowseList.getPaddingBottom();
	mBrowseList.setPadding(leftPadding, insets.getTop(), rightPadding, bottomPadding);
	if (bottomPadding > mFocusAreaHighlightBottomPadding) {
	mFocusAreaHighlightBottomPadding = bottomPadding;
	}
	mFocusArea.setHighlightPadding(
	leftPadding, insets.getTop(), rightPadding, mFocusAreaHighlightBottomPadding);
	mFocusArea.setBoundsOffset(leftPadding, insets.getTop(), rightPadding, bottomPadding);
	}

	void onPlaybackControlsChanged(boolean visible) {
	int leftPadding = mBrowseList.getPaddingLeft();
	int topPadding = mBrowseList.getPaddingTop();
	int rightPadding = mBrowseList.getPaddingRight();
	Resources res = getActivity().getResources();
	int bottomPadding = visible
	? res.getDimensionPixelOffset(R.dimen.browse_fragment_bottom_padding) : 0;
	mBrowseList.setPadding(leftPadding, topPadding, rightPadding, bottomPadding);
	int highlightBottomPadding = mSetFocusAreaHighlightBottom ? bottomPadding : 0;
	if (highlightBottomPadding > mFocusAreaHighlightBottomPadding) {
	mFocusAreaHighlightBottomPadding = highlightBottomPadding;
	}
	mFocusArea.setHighlightPadding(
	leftPadding, topPadding, rightPadding, mFocusAreaHighlightBottomPadding);
	// Set the bottom offset to bottomPadding regardless of mSetFocusAreaHighlightBottom so that
	// RotaryService can find the correct target when the user nudges the rotary controller.
	mFocusArea.setBoundsOffset(leftPadding, topPadding, rightPadding, bottomPadding);

	ViewGroup.MarginLayoutParams messageLayout =
	(ViewGroup.MarginLayoutParams) mMessage.getLayoutParams();
	messageLayout.bottomMargin = bottomPadding;
	mMessage.setLayoutParams(messageLayout);
	}

	private String getErrorMessage() {
	if (/root/ !mDisplayMediaItems) {
	MediaSource mediaSource = mViewModel.getMediaSourceValue();
	return getActivity().getString(
	R.string.cannot_connect_to_app,
	mediaSource != null
	? mediaSource.getDisplayName()
	: getActivity().getString(
	R.string.unknown_media_provider_name));
	} else {
	return getActivity().getString(R.string.unknown_error);
	}
	}

	private void onItemsUpdate(@Nullable FutureData<List<MediaItemMetadata>> futureData) {
	if (futureData == null \|\| futureData.isLoading()) {
	ViewUtils.hideViewAnimated(mErrorIcon, 0);
	ViewUtils.hideViewAnimated(mMessage, 0);

	// TODO(b/139759881) build a jank-free animation of the transition.
	mBrowseList.setAlpha(0f);
	mLimitedBrowseAdapter.submitItems(null, null);

	if (futureData != null) {
	startLoadingIndicator();
	}
	return;
	}

	stopLoadingIndicator();

	List<MediaItemMetadata> items = MediaBrowserViewModelImpl.filterItems(
	/root/ !mDisplayMediaItems, futureData.getData());
	if (mDisplayMediaItems) {
	mLimitedBrowseAdapter.submitItems(mParentItem, items);

	List<MediaItemMetadata> lastNodes =
	MediaBrowserViewModelImpl.selectBrowseableItems(futureData.getPastData());
	Collection<MediaItemMetadata> removedNodes =
	MediaBrowserViewModelImpl.computeRemovedItems(lastNodes, items);
	if (!removedNodes.isEmpty()) {
	mCallbacks.onChildrenNodesRemoved(this, removedNodes);
	}
	}

	int duration = mFadeDuration;
	if (items == null) {
	mMessage.setText(getErrorMessage());
	ViewUtils.hideViewAnimated(mBrowseList.getView(), duration);
	ViewUtils.showViewAnimated(mMessage, duration);
	ViewUtils.showViewAnimated(mErrorIcon, duration);
	} else if (items.isEmpty()) {
	mMessage.setText(R.string.nothing_to_play);
	ViewUtils.hideViewAnimated(mBrowseList.getView(), duration);
	ViewUtils.hideViewAnimated(mErrorIcon, duration);
	ViewUtils.showViewAnimated(mMessage, duration);
	} else {
	ViewUtils.showViewAnimated(mBrowseList.getView(), duration);
	ViewUtils.hideViewAnimated(mErrorIcon, duration);
	ViewUtils.hideViewAnimated(mMessage, duration);
	}

	if (Log.isLoggable(TAG, Log.VERBOSE)) {
	Log.v(TAG, "onItemsUpdate " + getDebugInfo());
	}
	}
	}