Java tutorial
/* * Copyright 2012 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 net.abcdroid.devfest12.ui.tablet; import net.abcdroid.devfest12.provider.ScheduleContract; import net.abcdroid.devfest12.ui.TracksAdapter; import net.abcdroid.devfest12.util.UIUtils; import net.abcdroid.devfest12.R; import com.actionbarsherlock.app.SherlockFragment; import android.annotation.TargetApi; import android.app.Activity; import android.content.res.Resources; import android.database.Cursor; import android.os.Build; import android.os.Bundle; import android.os.Handler; import android.support.v4.app.LoaderManager; import android.support.v4.content.CursorLoader; import android.support.v4.content.Loader; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.ListPopupWindow; import android.widget.PopupWindow; import android.widget.TextView; /** * A tablet-specific fragment that emulates a giant {@link android.widget.Spinner}-like widget. * When touched, it shows a {@link ListPopupWindow} containing a list of tracks, * using {@link TracksAdapter}. Requires API level 11 or later since {@link ListPopupWindow} is * API level 11+. */ @TargetApi(Build.VERSION_CODES.HONEYCOMB) public class TracksDropdownFragment extends SherlockFragment implements LoaderManager.LoaderCallbacks<Cursor>, AdapterView.OnItemClickListener, PopupWindow.OnDismissListener { public static final String VIEW_TYPE_SESSIONS = "sessions"; public static final String VIEW_TYPE_VENDORS = "vendors"; private static final String STATE_VIEW_TYPE = "viewType"; private static final String STATE_SELECTED_TRACK_ID = "selectedTrackId"; private TracksAdapter mAdapter; private String mViewType; private Handler mHandler = new Handler(); private ListPopupWindow mListPopupWindow; private ViewGroup mRootView; private TextView mTitle; private TextView mAbstract; private String mTrackId; public interface Callbacks { public void onTrackSelected(String trackId); public void onTrackNameAvailable(String trackId, String trackName); } private static Callbacks sDummyCallbacks = new Callbacks() { @Override public void onTrackSelected(String trackId) { } @Override public void onTrackNameAvailable(String trackId, String trackName) { } }; private Callbacks mCallbacks = sDummyCallbacks; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mAdapter = new TracksAdapter(getActivity()); if (savedInstanceState != null) { // Since this fragment doesn't rely on fragment arguments, we must // handle // state restores and saves ourselves. mViewType = savedInstanceState.getString(STATE_VIEW_TYPE); mTrackId = savedInstanceState.getString(STATE_SELECTED_TRACK_ID); } } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putString(STATE_VIEW_TYPE, mViewType); outState.putString(STATE_SELECTED_TRACK_ID, mTrackId); } public String getSelectedTrackId() { return mTrackId; } public void selectTrack(String trackId) { loadTrackList(mViewType, trackId); } public void loadTrackList(String viewType) { loadTrackList(viewType, mTrackId); } public void loadTrackList(String viewType, String selectTrackId) { // Teardown from previous arguments if (mListPopupWindow != null) { mListPopupWindow.setAdapter(null); } mViewType = viewType; mTrackId = selectTrackId; // Start background query to load tracks getLoaderManager().restartLoader(TracksAdapter.TracksQuery._TOKEN, null, this); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { mRootView = (ViewGroup) inflater.inflate(R.layout.fragment_tracks_dropdown, null); mTitle = (TextView) mRootView.findViewById(R.id.track_title); mAbstract = (TextView) mRootView.findViewById(R.id.track_abstract); mRootView.setOnClickListener(new View.OnClickListener() { public void onClick(View view) { mListPopupWindow = new ListPopupWindow(getActivity()); mListPopupWindow.setAdapter(mAdapter); mListPopupWindow.setModal(true); mListPopupWindow .setContentWidth(getResources().getDimensionPixelSize(R.dimen.track_dropdown_width)); mListPopupWindow.setAnchorView(mRootView); mListPopupWindow.setOnItemClickListener(TracksDropdownFragment.this); mListPopupWindow.show(); mListPopupWindow.setOnDismissListener(TracksDropdownFragment.this); } }); return mRootView; } @Override public void onAttach(Activity activity) { super.onAttach(activity); if (!(activity instanceof Callbacks)) { throw new ClassCastException("Activity must implement fragment's callbacks."); } mCallbacks = (Callbacks) activity; } @Override public void onDetach() { super.onDetach(); mCallbacks = sDummyCallbacks; if (mListPopupWindow != null) { mListPopupWindow.dismiss(); } } /** {@inheritDoc} */ public void onItemClick(AdapterView<?> parent, View view, int position, long id) { final Cursor cursor = (Cursor) mAdapter.getItem(position); loadTrack(cursor, true); if (mListPopupWindow != null) { mListPopupWindow.dismiss(); } } public String getTrackName() { return (String) mTitle.getText(); } private void loadTrack(Cursor cursor, boolean triggerCallback) { final int trackColor; final Resources res = getResources(); if (cursor != null) { trackColor = cursor.getInt(TracksAdapter.TracksQuery.TRACK_COLOR); mTrackId = cursor.getString(TracksAdapter.TracksQuery.TRACK_ID); mTitle.setText(cursor.getString(TracksAdapter.TracksQuery.TRACK_NAME)); mAbstract.setText(cursor.getString(TracksAdapter.TracksQuery.TRACK_ABSTRACT)); } else { trackColor = res.getColor(R.color.all_track_color); mTrackId = ScheduleContract.Tracks.ALL_TRACK_ID; mTitle.setText(VIEW_TYPE_SESSIONS.equals(mViewType) ? R.string.all_tracks_sessions : R.string.all_tracks_vendors); mAbstract.setText(VIEW_TYPE_SESSIONS.equals(mViewType) ? R.string.all_tracks_subtitle_sessions : R.string.all_tracks_subtitle_vendors); } boolean isDark = UIUtils.isColorDark(trackColor); mRootView.setBackgroundColor(trackColor); if (isDark) { mTitle.setTextColor(res.getColor(R.color.body_text_1_inverse)); mAbstract.setTextColor(res.getColor(R.color.body_text_2_inverse)); mRootView.findViewById(R.id.track_dropdown_arrow) .setBackgroundResource(R.drawable.track_dropdown_arrow_light); } else { mTitle.setTextColor(res.getColor(R.color.body_text_1)); mAbstract.setTextColor(res.getColor(R.color.body_text_2)); mRootView.findViewById(R.id.track_dropdown_arrow) .setBackgroundResource(R.drawable.track_dropdown_arrow_dark); } mCallbacks.onTrackNameAvailable(mTrackId, mTitle.getText().toString()); if (triggerCallback) { mHandler.post(new Runnable() { @Override public void run() { mCallbacks.onTrackSelected(mTrackId); } }); } } public void onDismiss() { mListPopupWindow = null; } @Override public Loader<Cursor> onCreateLoader(int id, Bundle data) { // Filter our tracks query to only include those with valid results String[] projection = TracksAdapter.TracksQuery.PROJECTION; String selection = null; if (VIEW_TYPE_SESSIONS.equals(mViewType)) { // Only show tracks with at least one session projection = TracksAdapter.TracksQuery.PROJECTION_WITH_SESSIONS_COUNT; selection = ScheduleContract.Tracks.SESSIONS_COUNT + ">0"; } else if (VIEW_TYPE_VENDORS.equals(mViewType)) { // Only show tracks with at least one vendor projection = TracksAdapter.TracksQuery.PROJECTION_WITH_VENDORS_COUNT; selection = ScheduleContract.Tracks.VENDORS_COUNT + ">0"; } return new CursorLoader(getActivity(), ScheduleContract.Tracks.CONTENT_URI, projection, selection, null, ScheduleContract.Tracks.DEFAULT_SORT); } @Override public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) { if (getActivity() == null || cursor == null) { return; } boolean trackLoaded = false; if (mTrackId != null) { cursor.moveToFirst(); while (!cursor.isAfterLast()) { if (mTrackId.equals(cursor.getString(TracksAdapter.TracksQuery.TRACK_ID))) { loadTrack(cursor, false); trackLoaded = true; break; } cursor.moveToNext(); } } if (!trackLoaded) { loadTrack(null, false); } mAdapter.setHasAllItem(true); mAdapter.changeCursor(cursor); } @Override public void onLoaderReset(Loader<Cursor> cursor) { } }