Java tutorial
/* * Copyright (c) 2016 Google Inc. * * 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.google.samples.apps.iosched.videolibrary; import android.app.Activity; import android.content.Intent; import android.graphics.drawable.ColorDrawable; import android.net.Uri; import android.os.Bundle; import android.support.annotation.NonNull; import android.support.v4.view.ViewCompat; import android.support.v7.widget.RecyclerView; import android.text.TextUtils; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; import com.google.samples.apps.iosched.Config; import com.google.samples.apps.iosched.R; import com.google.samples.apps.iosched.archframework.UpdatableView; import com.google.samples.apps.iosched.ui.widget.VideoThumbnail; import com.google.samples.apps.iosched.ui.widget.recyclerview.UpdatableAdapter; import com.google.samples.apps.iosched.util.AnalyticsHelper; import com.google.samples.apps.iosched.util.ImageLoader; import com.google.samples.apps.iosched.util.UIUtils; import com.google.samples.apps.iosched.videolibrary.data.Video; import java.util.ArrayList; import java.util.List; import java.util.Locale; /** * A {@link RecyclerView.Adapter} for a list of {@link Video}. This adapter runs in two * <i>modes</i>: compact and detail. * <p/> * Compact mode is created via the {@link #createHorizontal(Activity, List, ImageLoader, List)} * factory method & shows a smaller presentation of a video. It is used by {@link * VideoLibraryFragment}. * <p/> * The detail mode is created via the {@link #createVerticalGrid(Activity, List, ImageLoader, List, * int)} factory method and adds headers dividing videos by year and shows a larger presentation of * a video. It is used by {@link VideoLibraryFilteredFragment}. */ public class VideoTrackAdapter extends UpdatableAdapter<List<Video>, RecyclerView.ViewHolder> { // Constants private static final int TYPE_VIDEO = 0; private static final int TYPE_YEAR_HEADER = 1; private static final String VIDEO_LIBRARY_ANALYTICS_CATEGORY = "Video Library"; // Immutable state private final Activity mHost; private final LayoutInflater mInflater; private final ImageLoader mImageLoader; private final List<UpdatableView.UserActionListener> mListeners; private final boolean mCompactMode; private final int mColumns; private final ColorDrawable[] mBackgroundColors; // State private List mItems; // private constructor, see the more meaningful static factory methods private VideoTrackAdapter(@NonNull Activity activity, @NonNull List<Video> videos, @NonNull ImageLoader imageLoader, @NonNull List<UpdatableView.UserActionListener> listeners, boolean compactMode, int columns) { mHost = activity; mInflater = LayoutInflater.from(activity); mImageLoader = imageLoader; mListeners = listeners; mCompactMode = compactMode; mColumns = columns; // load the background colors final int[] colors = mHost.getResources().getIntArray(R.array.session_tile_backgrounds); mBackgroundColors = new ColorDrawable[colors.length]; for (int i = 0; i < colors.length; i++) { mBackgroundColors[i] = new ColorDrawable(colors[i]); } mItems = processData(videos); } public static VideoTrackAdapter createHorizontal(@NonNull Activity activity, @NonNull List<Video> videos, @NonNull ImageLoader imageLoader, @NonNull List<UpdatableView.UserActionListener> listeners) { return new VideoTrackAdapter(activity, videos, imageLoader, listeners, true, -1); } public static VideoTrackAdapter createVerticalGrid(@NonNull Activity activity, @NonNull List<Video> videos, @NonNull ImageLoader imageLoader, @NonNull List<UpdatableView.UserActionListener> listeners, int columns) { return new VideoTrackAdapter(activity, videos, imageLoader, listeners, false, columns); } @Override public void update(@NonNull final List<Video> updatedData) { // Attempt to update data in place i.e. only if it has changed so as not to lose scroll // position etc when an item updates e.g. when a video is marked as watched final List newItems = processData(updatedData); if (newItems.size() != mItems.size()) { mItems = newItems; notifyDataSetChanged(); return; } for (int i = 0; i < newItems.size(); i++) { final Object oldItem = mItems.get(i); final Object newItem = newItems.get(i); // Because we update the Video object directly from the model, we need to check if it // has been updated rather than using equals if (!oldItem.equals(newItem) || (newItem instanceof Video && ((Video) newItem).dataUpdated())) { mItems.set(i, newItem); notifyItemChanged(i); } } } @Override public RecyclerView.ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) { switch (viewType) { case TYPE_VIDEO: return createVideoViewHolder(parent); case TYPE_YEAR_HEADER: return createYearHeaderViewHolder(parent); default: throw new IllegalArgumentException("Unknown view type"); } } @Override public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) { switch (getItemViewType(position)) { case TYPE_VIDEO: bindVideoViewHolder((VideoViewHolder) holder, (Video) mItems.get(position), position); break; case TYPE_YEAR_HEADER: bindYearHeaderViewHolder((HeaderViewHolder) holder, (YearHeader) mItems.get(position)); break; } } @Override public int getItemViewType(final int position) { if (mCompactMode) { return TYPE_VIDEO; } Object item = mItems.get(position); if (item instanceof Video) { return TYPE_VIDEO; } else if (item instanceof YearHeader) { return TYPE_YEAR_HEADER; } throw new IllegalArgumentException("Unknown item type"); } @Override public int getItemCount() { return mItems.size(); } public int getSpanCount(final int position) { if (mCompactMode || getItemViewType(position) == TYPE_VIDEO) { return 1; } else { return mColumns; } } /** * Process the given {@code vidoe} to create the list of items to be displayed by the {@link * RecyclerView}. In detail mode, this means inserting date header objects to separate videos by * year. */ private List processData(final List<Video> videos) { List data = new ArrayList(videos.size()); if (mCompactMode) { data.addAll(videos); } else { int currentYear = Integer.MAX_VALUE; for (final Video video : videos) { if (video.getYear() < currentYear) { currentYear = video.getYear(); data.add(new YearHeader(String.valueOf(currentYear))); } data.add(video); } } return data; } private @NonNull RecyclerView.ViewHolder createVideoViewHolder(final ViewGroup parent) { final VideoViewHolder holder = new VideoViewHolder(mInflater.inflate( mCompactMode ? R.layout.video_item_list_tile : R.layout.video_item_grid_tile, parent, false)); if (mCompactMode) { ViewCompat.setImportantForAccessibility(holder.itemView, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO); ViewCompat.setImportantForAccessibility(holder.title, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO); } return holder; } private @NonNull RecyclerView.ViewHolder createYearHeaderViewHolder(final ViewGroup parent) { return new HeaderViewHolder(mInflater.inflate(R.layout.grid_header_major, parent, false)); } private void bindVideoViewHolder(final VideoViewHolder holder, final Video video, final int position) { holder.itemView.setBackgroundDrawable(mBackgroundColors[position % mBackgroundColors.length]); holder.itemView.setOnClickListener(mVideoClick); mImageLoader.loadImage(video.getThumbnailUrl(), holder.thumbnail); holder.title.setText(video.getTitle()); holder.thumbnail.setPlayed(video.getAlreadyPlayed()); } private final View.OnClickListener mVideoClick = new View.OnClickListener() { @Override public void onClick(final View v) { final ViewGroup.LayoutParams lp = v.getLayoutParams(); if (!(lp instanceof RecyclerView.LayoutParams)) { return; } final int position = ((RecyclerView.LayoutParams) lp).getViewAdapterPosition(); if (position == RecyclerView.NO_POSITION) { return; } final Video video = (Video) mItems.get(position); final String videoId = video.getId(); final String youtubeLink = TextUtils.isEmpty(videoId) ? "" : videoId.contains("://") ? videoId : String.format(Locale.US, Config.VIDEO_LIBRARY_URL_FMT, videoId); if (!TextUtils.isEmpty(youtubeLink)) { // ANALYTICS EVENT: Click on a video on the Video Library screen // Contains: video's YouTube URL, http://www.youtube.com/... AnalyticsHelper.sendEvent(VIDEO_LIBRARY_ANALYTICS_CATEGORY, "selectvideo", youtubeLink); // Start playing the video on Youtube. Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse(youtubeLink)); UIUtils.preferPackageForIntent(mHost, i, UIUtils.YOUTUBE_PACKAGE_NAME); i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET); mHost.startActivity(i); // Mark the video as played. fireVideoPlayedEvent(video); } } }; private void bindYearHeaderViewHolder(final HeaderViewHolder holder, final YearHeader yearHeader) { holder.header.setText(yearHeader.year); } /** * Let all UserActionListener know that the given Video has been played. */ private void fireVideoPlayedEvent(Video video) { for (UpdatableView.UserActionListener h1 : mListeners) { Bundle args = new Bundle(); args.putString(VideoLibraryModel.KEY_VIDEO_ID, video.getId()); h1.onUserAction(VideoLibraryModel.VideoLibraryUserActionEnum.VIDEO_PLAYED, args); } } static class VideoViewHolder extends RecyclerView.ViewHolder { final VideoThumbnail thumbnail; final TextView title; public VideoViewHolder(final View itemView) { super(itemView); thumbnail = (VideoThumbnail) itemView.findViewById(R.id.thumbnail); title = (TextView) itemView.findViewById(R.id.title); } } private static class HeaderViewHolder extends RecyclerView.ViewHolder { final TextView header; public HeaderViewHolder(View itemView) { super(itemView); header = (TextView) itemView; } } private static class YearHeader { private final String year; public YearHeader(String year) { this.year = year; } } }