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.explore; import android.app.Activity; import android.content.Intent; import android.graphics.drawable.ColorDrawable; import android.os.Build; import android.os.Bundle; import android.support.annotation.LayoutRes; import android.support.annotation.NonNull; import android.support.v4.app.ActivityCompat; import android.support.v4.app.ActivityOptionsCompat; import android.support.v4.view.ViewCompat; import android.support.v7.widget.RecyclerView; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.TextView; import com.google.samples.apps.iosched.R; import com.google.samples.apps.iosched.explore.data.SessionData; import com.google.samples.apps.iosched.provider.ScheduleContract; import com.google.samples.apps.iosched.session.SessionDetailActivity; import com.google.samples.apps.iosched.ui.widget.recyclerview.UpdatableAdapter; import com.google.samples.apps.iosched.util.TimeUtils; import java.util.ArrayList; import java.util.Calendar; import java.util.Collections; import java.util.Comparator; import java.util.List; import static com.google.samples.apps.iosched.util.LogUtils.LOGE; import static com.google.samples.apps.iosched.util.LogUtils.makeLogTag; /** * A {@link RecyclerView.Adapter} for a collection of {@link SessionData}. This adapter runs in two * <i>modes</i>: compact and detail. * <p/> * Compact mode is created via the {@link #createHorizontal(Activity, List)} factory method & shows * a smaller representation of a session (title + time). It is used by {@link ExploreIOFragment}. * <p/> * The detail mode is created via the {@link #createVerticalGrid(Activity, List, int)} factory * method and adds headers for day/time blocks and shows a larger representation of a session (title * + description). It is used by {@link ExploreSessionsFragment}. */ public class SessionsAdapter extends UpdatableAdapter<List<SessionData>, RecyclerView.ViewHolder> { // Constants private static final String TAG = makeLogTag(SessionsAdapter.class); private static final int TYPE_SESSION = 0; private static final int TYPE_HEADER_DAY = 1; private static final int TYPE_HEADER_TIME = 2; // Immutable state private final Activity mHost; private final LayoutInflater mInflater; private final ColorDrawable[] mBackgroundColors; private final boolean mCompactMode; private final int mColumns; // State private List mItems; // Private constructor, see the more meaningful static factory methods private SessionsAdapter(@NonNull Activity activity, @NonNull final List<SessionData> sessions, boolean compact, int columns) { mHost = activity; mInflater = LayoutInflater.from(activity); mCompactMode = compact; mColumns = columns; // Load the background colors 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(sessions); } public static SessionsAdapter createHorizontal(@NonNull Activity activity, @NonNull final List<SessionData> sessions) { return new SessionsAdapter(activity, sessions, true, -1); } public static SessionsAdapter createVerticalGrid(@NonNull Activity activity, @NonNull final List<SessionData> sessions, int columns) { return new SessionsAdapter(activity, sessions, false, columns); } @Override public void update(@NonNull final List<SessionData> updatedData) { // Attempt to update data in place i.e. only if it has changed so that we don't lose scroll // position etc when an item updates e.g. adding/removing an item from your schedule 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); if (!oldItem.equals(newItem)) { mItems.set(i, newItem); notifyItemChanged(i); } } } @Override public RecyclerView.ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) { switch (viewType) { case TYPE_SESSION: return createSessionViewHolder(parent); case TYPE_HEADER_DAY: return createHeaderViewHolder(parent, R.layout.grid_header_minor); case TYPE_HEADER_TIME: return createHeaderViewHolder(parent, R.layout.grid_header_major); default: LOGE(TAG, "Unknown view type."); throw new IllegalArgumentException("Unknown view type."); } } @Override public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) { switch (getItemViewType(position)) { case TYPE_SESSION: bindSession((SessionViewHolder) holder, (SessionData) mItems.get(position), position); break; case TYPE_HEADER_DAY: bindDayHeaderHolder((HeaderViewHolder) holder, (DayHeader) mItems.get(position)); break; case TYPE_HEADER_TIME: bindTimeHeaderHolder((HeaderViewHolder) holder, (TimeHeader) mItems.get(position)); break; } } @Override public int getItemViewType(final int position) { if (mCompactMode) { return TYPE_SESSION; } final Object item = mItems.get(position); if (item instanceof SessionData) { return TYPE_SESSION; } else if (item instanceof TimeHeader) { return TYPE_HEADER_TIME; } else if (item instanceof DayHeader) { return TYPE_HEADER_DAY; } throw new IllegalArgumentException("Unknown view type."); } public int getSpanSize(int position) { if (mCompactMode || getItemViewType(position) == TYPE_SESSION) { return 1; } else { return mColumns; } } /** * Process the given list of sessions. If we are in detail mode then insert day/time headers. */ private List processData(final List<SessionData> sessions) { final List data = new ArrayList(sessions.size()); // First sort sessions by start time. // TODO Can we upstream this requirement? Collections.sort(sessions, new Comparator<SessionData>() { @Override public int compare(final SessionData lhs, final SessionData rhs) { return lhs.getStartDate().compareTo(rhs.getStartDate()); } }); if (mCompactMode) { data.addAll(sessions); } else { // loop over the sessions inserting headings at each day, hour boundary int day = -1, time = -1; for (SessionData session : sessions) { if (session.getStartDate().get(Calendar.DAY_OF_YEAR) > day) { day = session.getStartDate().get(Calendar.DAY_OF_YEAR); data.add(new DayHeader(TimeUtils.formatShortDate(mHost, session.getStartDate().getTime()))); time = -1; } if (session.getStartDate().get(Calendar.HOUR_OF_DAY) > time) { time = session.getStartDate().get(Calendar.HOUR_OF_DAY); data.add(new TimeHeader(TimeUtils.formatShortTime(mHost, session.getStartDate().getTime()))); } data.add(session); } } return data; } @NonNull private SessionViewHolder createSessionViewHolder(final ViewGroup parent) { final SessionViewHolder holder = mCompactMode ? new CompactSessionViewHolder( mInflater.inflate(R.layout.explore_io_session_list_tile, parent, false)) : new DetailSessionViewHolder( mInflater.inflate(R.layout.explore_sessions_session_grid_tile, parent, false)); if (mCompactMode) { ViewCompat.setImportantForAccessibility(holder.itemView, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO); ViewCompat.setImportantForAccessibility(holder.title, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO); ViewCompat.setImportantForAccessibility(((CompactSessionViewHolder) holder).footer, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO); } return holder; } private HeaderViewHolder createHeaderViewHolder(ViewGroup parent, @LayoutRes int headerLayoutRedId) { return new HeaderViewHolder(mInflater.inflate(headerLayoutRedId, parent, false)); } private void bindSession(SessionViewHolder holder, final SessionData session, final int position) { holder.itemView.setBackgroundDrawable(mBackgroundColors[position % mBackgroundColors.length]); holder.itemView.setOnClickListener(mSessionClick); holder.title.setText(session.getSessionName()); holder.inSchedule.setVisibility(session.isInSchedule() ? View.VISIBLE : View.INVISIBLE); if (mCompactMode) { bindCompactSession((CompactSessionViewHolder) holder, session); } else { bindDetailSession((DetailSessionViewHolder) holder, session); } } private final View.OnClickListener mSessionClick = 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 SessionData sessionData = (SessionData) mItems.get(position); final Intent intent = new Intent(mHost, SessionDetailActivity.class); intent.setData(ScheduleContract.Sessions.buildSessionUri(sessionData.getSessionId())); final Bundle options; if (Build.VERSION.SDK_INT == 21 || Build.VERSION.SDK_INT == 22) { // Lollipop options = null; } else { options = ActivityOptionsCompat.makeSceneTransitionAnimation(mHost, v, mHost.getString(R.string.transition_session_background)).toBundle(); } ActivityCompat.startActivity(mHost, intent, options); } }; private void bindCompactSession(CompactSessionViewHolder holder, final SessionData session) { holder.footer.setText(TimeUtils.formatShortDateTime(mHost, session.getStartDate().getTime())); } private void bindDetailSession(DetailSessionViewHolder holder, final SessionData session) { holder.description.setText(session.getDetails()); } private void bindTimeHeaderHolder(final HeaderViewHolder holder, final TimeHeader timeHeader) { holder.header.setText(timeHeader.time); } private void bindDayHeaderHolder(final HeaderViewHolder holder, final DayHeader dayHeader) { holder.header.setText(dayHeader.day); } @Override public int getItemCount() { return mItems.size(); } private static abstract class SessionViewHolder extends RecyclerView.ViewHolder { final TextView title; final ImageView inSchedule; public SessionViewHolder(View itemView) { super(itemView); title = (TextView) itemView.findViewById(R.id.title); inSchedule = (ImageView) itemView.findViewById(R.id.indicator_in_schedule); } } private static class CompactSessionViewHolder extends SessionViewHolder { final TextView footer; public CompactSessionViewHolder(View itemView) { super(itemView); footer = (TextView) itemView.findViewById(R.id.footer); } } private static class DetailSessionViewHolder extends SessionViewHolder { final TextView description; public DetailSessionViewHolder(View itemView) { super(itemView); description = (TextView) itemView.findViewById(R.id.description); } } private static class HeaderViewHolder extends RecyclerView.ViewHolder { final TextView header; public HeaderViewHolder(View itemView) { super(itemView); header = (TextView) itemView; } } private static class DayHeader { private final String day; public DayHeader(String day) { this.day = day; } } private static class TimeHeader { private String time; public TimeHeader(String time) { this.time = time; } } }