Java tutorial
/* * Copyright (C) 2012 Christopher Eby <kreed@kreed.org> * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package com.nachiket.titan; import android.content.Intent; import android.content.SharedPreferences; import android.database.ContentObserver; import android.os.Build; import android.os.Bundle; import android.os.Handler; import android.os.Looper; import android.os.Message; import android.os.Parcelable; import android.provider.MediaStore; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.view.ContextMenu; import android.view.ContextMenu.ContextMenuInfo; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.ListView; import android.widget.TextView; import java.util.Arrays; /** * PagerAdapter that manages the library media ListViews. */ public class LibraryPagerAdapter extends PagerAdapter implements Handler.Callback, ViewPager.OnPageChangeListener, View.OnCreateContextMenuListener, AdapterView.OnItemClickListener { /** * The number of unique list types. The number of visible lists may be * smaller. */ public static final int MAX_ADAPTER_COUNT = 6; /** * The human-readable title for each list. The positions correspond to the * MediaUtils ids, so e.g. TITLES[MediaUtils.TYPE_SONG] = R.string.songs */ public static final int[] TITLES = { R.string.artists, R.string.albums, R.string.songs, R.string.playlists, R.string.genres, R.string.files }; /** * Default tab order. */ public static final int[] DEFAULT_ORDER = { MediaUtils.TYPE_ARTIST, MediaUtils.TYPE_ALBUM, MediaUtils.TYPE_SONG, MediaUtils.TYPE_PLAYLIST, MediaUtils.TYPE_GENRE, MediaUtils.TYPE_FILE }; /** * The user-chosen tab order. */ int[] mTabOrder; /** * The number of visible tabs. */ private int mTabCount; /** * The ListView for each adapter. Each index corresponds to that list's * MediaUtils id. */ private final ListView[] mLists = new ListView[MAX_ADAPTER_COUNT]; /** * The adapters. Each index corresponds to that adapter's MediaUtils id. */ public LibraryAdapter[] mAdapters = new LibraryAdapter[MAX_ADAPTER_COUNT]; /** * Whether the adapter corresponding to each index has stale data. */ private final boolean[] mRequeryNeeded = new boolean[MAX_ADAPTER_COUNT]; /** * The artist adapter instance, also stored at mAdapters[MediaUtils.TYPE_ARTIST]. */ private MediaAdapter mArtistAdapter; /** * The album adapter instance, also stored at mAdapters[MediaUtils.TYPE_ALBUM]. */ private MediaAdapter mAlbumAdapter; /** * The song adapter instance, also stored at mAdapters[MediaUtils.TYPE_SONG]. */ private MediaAdapter mSongAdapter; /** * The playlist adapter instance, also stored at mAdapters[MediaUtils.TYPE_PLAYLIST]. */ MediaAdapter mPlaylistAdapter; /** * The genre adapter instance, also stored at mAdapters[MediaUtils.TYPE_GENRE]. */ private MediaAdapter mGenreAdapter; /** * The file adapter instance, also stored at mAdapters[MediaUtils.TYPE_FILE]. */ private FileSystemAdapter mFilesAdapter; /** * The adapter of the currently visible list. */ private LibraryAdapter mCurrentAdapter; /** * The index of the current page. */ private int mCurrentPage; /** * A limiter that should be set when the album adapter is created. */ private Limiter mPendingAlbumLimiter; /** * A limiter that should be set when the song adapter is created. */ private Limiter mPendingSongLimiter; /** * A limiter that should be set when the files adapter is created. */ private Limiter mPendingFileLimiter; /** * List positions stored in the saved state, or null if none were stored. */ private int[] mSavedPositions; /** * The LibraryActivity that owns this adapter. The adapter will be notified * of changes in the current page. */ private final LibraryActivity mActivity; /** * A Handler running on the UI thread. */ private final Handler mUiHandler; /** * A Handler running on a worker thread. */ private final Handler mWorkerHandler; /** * The text to be displayed in the first row of the artist, album, and * song limiters. */ private String mHeaderText; private TextView mArtistHeader; private TextView mAlbumHeader; private TextView mSongHeader; /** * The current filter text, or null if none. */ private String mFilter; /** * The position of the songs page, or -1 if it is hidden. */ public int mSongsPosition = -1; /** * The position of the albums page, or -1 if it is hidden. */ public int mAlbumsPosition = -1; /** * The position of the artists page, or -1 if it is hidden. */ public int mArtistsPosition = -1; /** * The position of the genres page, or -1 if it is hidden. */ public int mGenresPosition = -1; private final ContentObserver mPlaylistObserver = new ContentObserver(null) { @Override public void onChange(boolean selfChange) { if (mPlaylistAdapter != null) { postRequestRequery(mPlaylistAdapter); } } }; /** * Create the LibraryPager. * * @param activity The LibraryActivity that will own this adapter. The activity * will receive callbacks from the ListViews. * @param workerLooper A Looper running on a worker thread. */ public LibraryPagerAdapter(LibraryActivity activity, Looper workerLooper) { mActivity = activity; mUiHandler = new Handler(this); mWorkerHandler = new Handler(workerLooper, this); mCurrentPage = -1; activity.getContentResolver().registerContentObserver(MediaStore.Audio.Playlists.EXTERNAL_CONTENT_URI, true, mPlaylistObserver); } /** * Load the tab order from SharedPreferences. * * @return True if order has changed. */ public boolean loadTabOrder() { String in = PlaybackService.getSettings(mActivity).getString(PrefKeys.TAB_ORDER, null); int[] order; int count; if (in == null || in.length() != MAX_ADAPTER_COUNT) { order = DEFAULT_ORDER; count = MAX_ADAPTER_COUNT; } else { char[] chars = in.toCharArray(); order = new int[MAX_ADAPTER_COUNT]; count = 0; for (int i = 0; i != MAX_ADAPTER_COUNT; ++i) { char v = chars[i]; if (v >= 128) { v -= 128; if (v >= MediaUtils.TYPE_COUNT) { // invalid media type; use default order order = DEFAULT_ORDER; count = MAX_ADAPTER_COUNT; break; } order[count++] = v; } } } if (count != mTabCount || !Arrays.equals(order, mTabOrder)) { mTabOrder = order; mTabCount = count; notifyDataSetChanged(); computeExpansions(); return true; } return false; } /** * Determines whether adapters should be expandable from the visibility of * the adapters each expands to. Also updates mSongsPosition/mAlbumsPositions. */ public void computeExpansions() { int[] order = mTabOrder; int songsPosition = -1; int albumsPosition = -1; int artistsPosition = -1; int genresPosition = -1; for (int i = mTabCount; --i != -1;) { switch (order[i]) { case MediaUtils.TYPE_ALBUM: albumsPosition = i; break; case MediaUtils.TYPE_SONG: songsPosition = i; break; case MediaUtils.TYPE_ARTIST: artistsPosition = i; break; case MediaUtils.TYPE_GENRE: genresPosition = i; break; } } if (mArtistAdapter != null) mArtistAdapter.setExpandable(songsPosition != -1 || albumsPosition != -1); if (mAlbumAdapter != null) mAlbumAdapter.setExpandable(songsPosition != -1); if (mGenreAdapter != null) mGenreAdapter.setExpandable(songsPosition != -1); mSongsPosition = songsPosition; mAlbumsPosition = albumsPosition; mArtistsPosition = artistsPosition; mGenresPosition = genresPosition; } @Override public Object instantiateItem(ViewGroup container, int position) { int type = mTabOrder[position]; ListView view = mLists[type]; if (view == null) { LibraryActivity activity = mActivity; LayoutInflater inflater = activity.getLayoutInflater(); LibraryAdapter adapter; TextView header = null; switch (type) { case MediaUtils.TYPE_ARTIST: adapter = mArtistAdapter = new MediaAdapter(activity, MediaUtils.TYPE_ARTIST, null); mArtistAdapter.setExpandable(mSongsPosition != -1 || mAlbumsPosition != -1); mArtistHeader = header = (TextView) inflater.inflate(R.layout.library_row, null); break; case MediaUtils.TYPE_ALBUM: adapter = mAlbumAdapter = new MediaAdapter(activity, MediaUtils.TYPE_ALBUM, mPendingAlbumLimiter); mAlbumAdapter.setExpandable(mSongsPosition != -1); mPendingAlbumLimiter = null; mAlbumHeader = header = (TextView) inflater.inflate(R.layout.library_row, null); break; case MediaUtils.TYPE_SONG: adapter = mSongAdapter = new MediaAdapter(activity, MediaUtils.TYPE_SONG, mPendingSongLimiter); mPendingSongLimiter = null; mSongHeader = header = (TextView) inflater.inflate(R.layout.library_row, null); break; case MediaUtils.TYPE_PLAYLIST: adapter = mPlaylistAdapter = new MediaAdapter(activity, MediaUtils.TYPE_PLAYLIST, null); break; case MediaUtils.TYPE_GENRE: adapter = mGenreAdapter = new MediaAdapter(activity, MediaUtils.TYPE_GENRE, null); mGenreAdapter.setExpandable(mSongsPosition != -1); break; case MediaUtils.TYPE_FILE: adapter = mFilesAdapter = new FileSystemAdapter(activity, mPendingFileLimiter); mPendingFileLimiter = null; break; default: throw new IllegalArgumentException("Invalid media type: " + type); } view = (ListView) inflater.inflate(R.layout.listview, null); view.setOnCreateContextMenuListener(this); view.setOnItemClickListener(this); view.setTag(type); if (header != null) { header.setText(mHeaderText); header.setTag(type); view.addHeaderView(header); } view.setAdapter(adapter); if (type != MediaUtils.TYPE_FILE) loadSortOrder((MediaAdapter) adapter); enableFastScroll(view); adapter.setFilter(mFilter); mAdapters[type] = adapter; mLists[type] = view; mRequeryNeeded[type] = true; } requeryIfNeeded(type); container.addView(view); return view; } @Override public int getItemPosition(Object item) { int type = (Integer) ((ListView) item).getTag(); int[] order = mTabOrder; for (int i = mTabCount; --i != -1;) { if (order[i] == type) return i; } return POSITION_NONE; } @Override public void destroyItem(ViewGroup container, int position, Object object) { container.removeView((View) object); } @Override public CharSequence getPageTitle(int position) { return mActivity.getResources().getText(TITLES[mTabOrder[position]]); } @Override public int getCount() { return mTabCount; } @Override public boolean isViewFromObject(View view, Object object) { return view == object; } @Override public void setPrimaryItem(ViewGroup container, int position, Object object) { int type = mTabOrder[position]; LibraryAdapter adapter = mAdapters[type]; if (position != mCurrentPage || adapter != mCurrentAdapter) { requeryIfNeeded(type); mCurrentAdapter = adapter; mCurrentPage = position; mActivity.onPageChanged(position, adapter); } } @Override public void restoreState(Parcelable state, ClassLoader loader) { Bundle in = (Bundle) state; mPendingAlbumLimiter = (Limiter) in.getSerializable("limiter_albums"); mPendingSongLimiter = (Limiter) in.getSerializable("limiter_songs"); mPendingFileLimiter = (Limiter) in.getSerializable("limiter_files"); mSavedPositions = in.getIntArray("pos"); } @Override public Parcelable saveState() { Bundle out = new Bundle(10); if (mAlbumAdapter != null) out.putSerializable("limiter_albums", mAlbumAdapter.getLimiter()); if (mSongAdapter != null) out.putSerializable("limiter_songs", mSongAdapter.getLimiter()); if (mFilesAdapter != null) out.putSerializable("limiter_files", mFilesAdapter.getLimiter()); int[] savedPositions = new int[MAX_ADAPTER_COUNT]; ListView[] lists = mLists; for (int i = MAX_ADAPTER_COUNT; --i != -1;) { if (lists[i] != null) { savedPositions[i] = lists[i].getFirstVisiblePosition(); } } out.putIntArray("pos", savedPositions); return out; } /** * Sets the text to be displayed in the first row of the artist, album, and * song lists. */ public void setHeaderText(String text) { if (mArtistHeader != null) mArtistHeader.setText(text); if (mAlbumHeader != null) mAlbumHeader.setText(text); if (mSongHeader != null) mSongHeader.setText(text); mHeaderText = text; } /** * Clear a limiter. * * @param type Which type of limiter to clear. */ public void clearLimiter(int type) { if (type == MediaUtils.TYPE_FILE) { if (mFilesAdapter == null) { mPendingFileLimiter = null; } else { mFilesAdapter.setLimiter(null); requestRequery(mFilesAdapter); } } else { if (mAlbumAdapter == null) { mPendingAlbumLimiter = null; } else { mAlbumAdapter.setLimiter(null); loadSortOrder(mAlbumAdapter); requestRequery(mAlbumAdapter); } if (mSongAdapter == null) { mPendingSongLimiter = null; } else { mSongAdapter.setLimiter(null); loadSortOrder(mSongAdapter); requestRequery(mSongAdapter); } } } /** * Update the adapters with the given limiter. * * @param limiter The limiter to set. * @return The tab type that should be switched to to expand the row. */ public int setLimiter(Limiter limiter) { int tab; switch (limiter.type) { case MediaUtils.TYPE_ALBUM: if (mSongAdapter == null) { mPendingSongLimiter = limiter; } else { mSongAdapter.setLimiter(limiter); loadSortOrder(mSongAdapter); requestRequery(mSongAdapter); } tab = mSongsPosition; break; case MediaUtils.TYPE_ARTIST: if (mAlbumAdapter == null) { mPendingAlbumLimiter = limiter; } else { mAlbumAdapter.setLimiter(limiter); loadSortOrder(mAlbumAdapter); requestRequery(mAlbumAdapter); } if (mSongAdapter == null) { mPendingSongLimiter = limiter; } else { mSongAdapter.setLimiter(limiter); loadSortOrder(mSongAdapter); requestRequery(mSongAdapter); } tab = mAlbumsPosition; if (tab == -1) tab = mSongsPosition; break; case MediaUtils.TYPE_GENRE: if (mAlbumAdapter == null) { mPendingAlbumLimiter = limiter; } else { mAlbumAdapter.setLimiter(limiter); loadSortOrder(mAlbumAdapter); requestRequery(mAlbumAdapter); } if (mSongAdapter == null) { mPendingSongLimiter = null; } else { mSongAdapter.setLimiter(limiter); loadSortOrder(mSongAdapter); requestRequery(mSongAdapter); } tab = mSongsPosition; break; case MediaUtils.TYPE_FILE: if (mFilesAdapter == null) { mPendingFileLimiter = limiter; } else { mFilesAdapter.setLimiter(limiter); requestRequery(mFilesAdapter); } tab = -1; break; default: throw new IllegalArgumentException("Unsupported limiter type: " + limiter.type); } return tab; } /** * Returns the limiter set on the current adapter or null if there is none. */ public Limiter getCurrentLimiter() { LibraryAdapter current = mCurrentAdapter; if (current == null) return null; return current.getLimiter(); } /** * Run on query on the adapter passed in obj. * * Runs on worker thread. */ private static final int MSG_RUN_QUERY = 0; /** * Save the sort mode for the adapter passed in obj. * * Runs on worker thread. */ private static final int MSG_SAVE_SORT = 1; /** * Call {@link LibraryPagerAdapter#requestRequery(LibraryAdapter)} on the adapter * passed in obj. * * Runs on worker thread. */ private static final int MSG_REQUEST_REQUERY = 2; /** * Commit the cursor passed in obj to the adapter at the index passed in * arg1. * * Runs on UI thread. */ private static final int MSG_COMMIT_QUERY = 3; @Override public boolean handleMessage(Message message) { switch (message.what) { case MSG_RUN_QUERY: { LibraryAdapter adapter = (LibraryAdapter) message.obj; int index = adapter.getMediaType(); Handler handler = mUiHandler; handler.sendMessage(handler.obtainMessage(MSG_COMMIT_QUERY, index, 0, adapter.query())); break; } case MSG_COMMIT_QUERY: { int index = message.arg1; mAdapters[index].commitQuery(message.obj); int pos; if (mSavedPositions == null) { pos = 0; } else { pos = mSavedPositions[index]; mSavedPositions[index] = 0; } mLists[index].setSelection(pos); break; } case MSG_SAVE_SORT: { MediaAdapter adapter = (MediaAdapter) message.obj; SharedPreferences.Editor editor = PlaybackService.getSettings(mActivity).edit(); editor.putInt(String.format("sort_%d_%d", adapter.getMediaType(), adapter.getLimiterType()), adapter.getSortMode()); editor.commit(); break; } case MSG_REQUEST_REQUERY: requestRequery((LibraryAdapter) message.obj); break; default: return false; } return true; } /** * Requery the given adapter. If it is the current adapter, requery * immediately. Otherwise, mark the adapter as needing a requery and requery * when its tab is selected. * * Must be called on the UI thread. */ public void requestRequery(LibraryAdapter adapter) { if (adapter == mCurrentAdapter) { postRunQuery(adapter); } else { mRequeryNeeded[adapter.getMediaType()] = true; // Clear the data for non-visible adapters (so we don't show the old // data briefly when we later switch to that adapter) adapter.clear(); } } /** * Call {@link LibraryPagerAdapter#requestRequery(LibraryAdapter)} on the UI * thread. * * @param adapter The adapter, passed to requestRequery. */ public void postRequestRequery(LibraryAdapter adapter) { Handler handler = mUiHandler; handler.sendMessage(handler.obtainMessage(MSG_REQUEST_REQUERY, adapter)); } /** * Schedule a query to be run for the given adapter on the worker thread. * * @param adapter The adapter to run the query for. */ private void postRunQuery(LibraryAdapter adapter) { mRequeryNeeded[adapter.getMediaType()] = false; Handler handler = mWorkerHandler; handler.removeMessages(MSG_RUN_QUERY, adapter); handler.sendMessage(handler.obtainMessage(MSG_RUN_QUERY, adapter)); } /** * Requery the adapter of the given type if it exists and needs a requery. * * @param type One of MediaUtils.TYPE_* */ private void requeryIfNeeded(int type) { LibraryAdapter adapter = mAdapters[type]; if (adapter != null && mRequeryNeeded[type]) { postRunQuery(adapter); } } /** * Invalidate the data for all adapters. */ public void invalidateData() { for (LibraryAdapter adapter : mAdapters) { if (adapter != null) { postRequestRequery(adapter); } } } /** * Set the saved sort mode for the given adapter. The adapter should * be re-queried after calling this. * * @param adapter The adapter to load for. */ public void loadSortOrder(MediaAdapter adapter) { String key = String.format("sort_%d_%d", adapter.getMediaType(), adapter.getLimiterType()); int def = adapter.getDefaultSortMode(); int sort = PlaybackService.getSettings(mActivity).getInt(key, def); adapter.setSortMode(sort); } /** * Set the sort mode for the current adapter. Current adapter must be a * MediaAdapter. Saves this sort mode to preferences and updates the list * associated with the adapter to display the new sort mode. * * @param mode The sort mode. See {@link MediaAdapter#setSortMode(int)} for * details. */ public void setSortMode(int mode) { MediaAdapter adapter = (MediaAdapter) mCurrentAdapter; if (mode == adapter.getSortMode()) return; adapter.setSortMode(mode); requestRequery(adapter); // Force a new FastScroller to be created so the scroll sections // are updated. ListView view = mLists[mTabOrder[mCurrentPage]]; view.setFastScrollEnabled(false); enableFastScroll(view); Handler handler = mWorkerHandler; handler.sendMessage(handler.obtainMessage(MSG_SAVE_SORT, adapter)); } /** * Set a new filter on all the adapters. */ public void setFilter(String text) { if (text.length() == 0) text = null; mFilter = text; for (LibraryAdapter adapter : mAdapters) { if (adapter != null) { adapter.setFilter(text); requestRequery(adapter); } } } @Override public void onPageScrollStateChanged(int state) { } @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { // onPageSelected and setPrimaryItem are called in similar cases, and it // would be nice to use just one of them, but each has caveats: // - onPageSelected isn't called when the ViewPager is first // initialized // - setPrimaryItem isn't called until scrolling is complete, which // makes tab bar and limiter updates look bad // So we use both. setPrimaryItem(null, position, null); } /** * Creates the row data used by LibraryActivity. */ private static Intent createHeaderIntent(View header) { int type = (Integer) header.getTag(); Intent intent = new Intent(); intent.putExtra(LibraryAdapter.DATA_ID, LibraryAdapter.HEADER_ID); intent.putExtra(LibraryAdapter.DATA_TYPE, type); return intent; } @Override public void onCreateContextMenu(ContextMenu menu, View view, ContextMenuInfo menuInfo) { AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) menuInfo; View targetView = info.targetView; Intent intent = info.id == -1 ? createHeaderIntent(targetView) : mCurrentAdapter.createData(targetView); mActivity.onCreateContextMenu(menu, intent); } @Override public void onItemClick(AdapterView<?> list, View view, int position, long id) { Intent intent = id == -1 ? createHeaderIntent(view) : mCurrentAdapter.createData(view); mActivity.onItemClicked(intent); } /** * Enables FastScroller on the given list, ensuring it is always visible * and suppresses the match drag position feature in newer versions of * Android. * * @param list The list to enable. */ private void enableFastScroll(ListView list) { mActivity.mFakeTarget = true; list.setFastScrollEnabled(true); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { CompatHoneycomb.setFastScrollAlwaysVisible(list); } mActivity.mFakeTarget = false; } }