summaryrefslogtreecommitdiff
path: root/app/src/main/java/de/danoeh/antennapod/fragment/AudioPlayerFragment.java
blob: 08c684a15d2eab827b6b9d0205d3c1007334e4a1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
package de.danoeh.antennapod.fragment;

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ProgressBar;
import android.widget.SeekBar;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import com.google.android.material.dialog.MaterialAlertDialogBuilder;
import com.google.android.material.appbar.MaterialToolbar;
import androidx.cardview.widget.CardView;
import androidx.fragment.app.Fragment;
import androidx.interpolator.view.animation.FastOutSlowInInterpolator;
import androidx.viewpager2.adapter.FragmentStateAdapter;
import androidx.viewpager2.widget.ViewPager2;

import com.google.android.material.bottomsheet.BottomSheetBehavior;
import com.google.android.material.elevation.SurfaceColors;
import com.google.android.material.snackbar.Snackbar;

import de.danoeh.antennapod.core.receiver.MediaButtonReceiver;
import de.danoeh.antennapod.core.util.playback.PlaybackController;
import de.danoeh.antennapod.event.playback.BufferUpdateEvent;
import de.danoeh.antennapod.event.playback.PlaybackServiceEvent;
import de.danoeh.antennapod.event.PlayerErrorEvent;
import de.danoeh.antennapod.event.playback.SleepTimerUpdatedEvent;
import de.danoeh.antennapod.event.playback.SpeedChangedEvent;
import de.danoeh.antennapod.playback.cast.CastEnabledActivity;
import org.greenrobot.eventbus.EventBus;
import org.greenrobot.eventbus.Subscribe;
import org.greenrobot.eventbus.ThreadMode;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.List;

import de.danoeh.antennapod.R;
import de.danoeh.antennapod.activity.MainActivity;
import de.danoeh.antennapod.event.FavoritesEvent;
import de.danoeh.antennapod.event.playback.PlaybackPositionEvent;
import de.danoeh.antennapod.model.feed.Chapter;
import de.danoeh.antennapod.event.UnreadItemsUpdateEvent;
import de.danoeh.antennapod.model.feed.FeedItem;
import de.danoeh.antennapod.model.feed.FeedMedia;
import de.danoeh.antennapod.core.feed.util.PlaybackSpeedUtils;
import de.danoeh.antennapod.core.preferences.UserPreferences;
import de.danoeh.antennapod.core.util.ChapterUtils;
import de.danoeh.antennapod.core.util.Converter;
import de.danoeh.antennapod.core.util.TimeSpeedConverter;
import de.danoeh.antennapod.model.playback.Playable;
import de.danoeh.antennapod.dialog.PlaybackControlsDialog;
import de.danoeh.antennapod.dialog.SkipPreferenceDialog;
import de.danoeh.antennapod.dialog.SleepTimerDialog;
import de.danoeh.antennapod.dialog.VariableSpeedDialog;
import de.danoeh.antennapod.menuhandler.FeedItemMenuHandler;
import de.danoeh.antennapod.ui.common.PlaybackSpeedIndicatorView;
import de.danoeh.antennapod.view.ChapterSeekBar;
import de.danoeh.antennapod.view.PlayButton;
import io.reactivex.Maybe;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.disposables.Disposable;
import io.reactivex.schedulers.Schedulers;

/**
 * Shows the audio player.
 */
public class AudioPlayerFragment extends Fragment implements
        ChapterSeekBar.OnSeekBarChangeListener, MaterialToolbar.OnMenuItemClickListener {
    public static final String TAG = "AudioPlayerFragment";
    public static final int POS_COVER = 0;
    public static final int POS_DESCRIPTION = 1;
    private static final int NUM_CONTENT_FRAGMENTS = 2;

    PlaybackSpeedIndicatorView butPlaybackSpeed;
    TextView txtvPlaybackSpeed;
    private ViewPager2 pager;
    private TextView txtvPosition;
    private TextView txtvLength;
    private ChapterSeekBar sbPosition;
    private ImageButton butRev;
    private TextView txtvRev;
    private PlayButton butPlay;
    private ImageButton butFF;
    private TextView txtvFF;
    private ImageButton butSkip;
    private MaterialToolbar toolbar;
    private ProgressBar progressIndicator;
    private CardView cardViewSeek;
    private TextView txtvSeek;

    private PlaybackController controller;
    private Disposable disposable;
    private boolean showTimeLeft;
    private boolean seekedToChapterStart = false;
    private int currentChapterIndex = -1;
    private int duration;

    @Override
    public View onCreateView(@NonNull LayoutInflater inflater,
                             @Nullable ViewGroup container,
                             @Nullable Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);
        View root = inflater.inflate(R.layout.audioplayer_fragment, container, false);
        root.setOnTouchListener((v, event) -> true); // Avoid clicks going through player to fragments below
        toolbar = root.findViewById(R.id.toolbar);
        toolbar.setTitle("");
        toolbar.setNavigationOnClickListener(v ->
                ((MainActivity) getActivity()).getBottomSheet().setState(BottomSheetBehavior.STATE_COLLAPSED));
        toolbar.setOnMenuItemClickListener(this);

        ExternalPlayerFragment externalPlayerFragment = new ExternalPlayerFragment();
        getChildFragmentManager().beginTransaction()
                .replace(R.id.playerFragment, externalPlayerFragment, ExternalPlayerFragment.TAG)
                .commit();
        root.findViewById(R.id.playerFragment).setBackgroundColor(SurfaceColors.getColorForElevation(getContext(), 8));

        butPlaybackSpeed = root.findViewById(R.id.butPlaybackSpeed);
        txtvPlaybackSpeed = root.findViewById(R.id.txtvPlaybackSpeed);
        sbPosition = root.findViewById(R.id.sbPosition);
        txtvPosition = root.findViewById(R.id.txtvPosition);
        txtvLength = root.findViewById(R.id.txtvLength);
        butRev = root.findViewById(R.id.butRev);
        txtvRev = root.findViewById(R.id.txtvRev);
        butPlay = root.findViewById(R.id.butPlay);
        butFF = root.findViewById(R.id.butFF);
        txtvFF = root.findViewById(R.id.txtvFF);
        butSkip = root.findViewById(R.id.butSkip);
        progressIndicator = root.findViewById(R.id.progLoading);
        cardViewSeek = root.findViewById(R.id.cardViewSeek);
        txtvSeek = root.findViewById(R.id.txtvSeek);

        setupLengthTextView();
        setupControlButtons();
        butPlaybackSpeed.setOnClickListener(v -> new VariableSpeedDialog().show(getChildFragmentManager(), null));
        sbPosition.setOnSeekBarChangeListener(this);

        pager = root.findViewById(R.id.pager);
        pager.setAdapter(new AudioPlayerPagerAdapter(this));
        // Required for getChildAt(int) in ViewPagerBottomSheetBehavior to return the correct page
        pager.setOffscreenPageLimit((int) NUM_CONTENT_FRAGMENTS);
        pager.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
            @Override
            public void onPageSelected(int position) {
                pager.post(() -> {
                    if (getActivity() != null) {
                        // By the time this is posted, the activity might be closed again.
                        ((MainActivity) getActivity()).getBottomSheet().updateScrollingChild();
                    }
                });
            }
        });

        return root;
    }

    private void setChapterDividers(Playable media) {

        if (media == null) {
            return;
        }

        float[] dividerPos = null;

        if (media.getChapters() != null && !media.getChapters().isEmpty()) {
            List<Chapter> chapters = media.getChapters();
            dividerPos = new float[chapters.size()];

            for (int i = 0; i < chapters.size(); i++) {
                dividerPos[i] = chapters.get(i).getStart() / (float) duration;
            }
        }

        sbPosition.setDividerPos(dividerPos);
    }

    public View getExternalPlayerHolder() {
        return getView().findViewById(R.id.playerFragment);
    }

    private void setupControlButtons() {
        butRev.setOnClickListener(v -> {
            if (controller != null) {
                int curr = controller.getPosition();
                controller.seekTo(curr - UserPreferences.getRewindSecs() * 1000);
            }
        });
        butRev.setOnLongClickListener(v -> {
            SkipPreferenceDialog.showSkipPreference(getContext(),
                    SkipPreferenceDialog.SkipDirection.SKIP_REWIND, txtvRev);
            return true;
        });
        butPlay.setOnClickListener(v -> {
            if (controller != null) {
                controller.init();
                controller.playPause();
            }
        });
        butFF.setOnClickListener(v -> {
            if (controller != null) {
                int curr = controller.getPosition();
                controller.seekTo(curr + UserPreferences.getFastForwardSecs() * 1000);
            }
        });
        butFF.setOnLongClickListener(v -> {
            SkipPreferenceDialog.showSkipPreference(getContext(),
                    SkipPreferenceDialog.SkipDirection.SKIP_FORWARD, txtvFF);
            return false;
        });
        butSkip.setOnClickListener(v -> getActivity().sendBroadcast(
                MediaButtonReceiver.createIntent(getContext(), KeyEvent.KEYCODE_MEDIA_NEXT)));
    }

    @Subscribe(threadMode = ThreadMode.MAIN)
    public void onUnreadItemsUpdate(UnreadItemsUpdateEvent event) {
        if (controller == null) {
            return;
        }
        updatePosition(new PlaybackPositionEvent(controller.getPosition(),
                controller.getDuration()));
    }

    @Subscribe(threadMode = ThreadMode.MAIN)
    public void onPlaybackServiceChanged(PlaybackServiceEvent event) {
        if (event.action == PlaybackServiceEvent.Action.SERVICE_SHUT_DOWN) {
            ((MainActivity) getActivity()).getBottomSheet().setState(BottomSheetBehavior.STATE_COLLAPSED);
        }
    }

    private void setupLengthTextView() {
        showTimeLeft = UserPreferences.shouldShowRemainingTime();
        txtvLength.setOnClickListener(v -> {
            if (controller == null) {
                return;
            }
            showTimeLeft = !showTimeLeft;
            UserPreferences.setShowRemainTimeSetting(showTimeLeft);
            updatePosition(new PlaybackPositionEvent(controller.getPosition(),
                    controller.getDuration()));
        });
    }

    @Subscribe(threadMode = ThreadMode.MAIN)
    public void updatePlaybackSpeedButton(SpeedChangedEvent event) {
        String speedStr = new DecimalFormat("0.00").format(event.getNewSpeed());
        txtvPlaybackSpeed.setText(speedStr);
        butPlaybackSpeed.setSpeed(event.getNewSpeed());
    }

    private void loadMediaInfo(boolean includingChapters) {
        if (disposable != null) {
            disposable.dispose();
        }
        disposable = Maybe.<Playable>create(emitter -> {
            Playable media = controller.getMedia();
            if (media != null) {
                if (includingChapters) {
                    ChapterUtils.loadChapters(media, getContext());
                }
                emitter.onSuccess(media);
            } else {
                emitter.onComplete();
            }
        })
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(media -> {
            updateUi(media);
            if (media.getChapters() == null && !includingChapters) {
                loadMediaInfo(true);
            }
        }, error -> Log.e(TAG, Log.getStackTraceString(error)),
            () -> updateUi(null));
    }

    private PlaybackController newPlaybackController() {
        return new PlaybackController(getActivity()) {
            @Override
            protected void updatePlayButtonShowsPlay(boolean showPlay) {
                butPlay.setIsShowPlay(showPlay);
            }

            @Override
            public void loadMediaInfo() {
                AudioPlayerFragment.this.loadMediaInfo(false);
            }

            @Override
            public void onPlaybackEnd() {
                ((MainActivity) getActivity()).getBottomSheet().setState(BottomSheetBehavior.STATE_COLLAPSED);
            }
        };
    }

    private void updateUi(Playable media) {
        if (controller == null || media == null) {
            return;
        }
        duration = controller.getDuration();
        updatePosition(new PlaybackPositionEvent(media.getPosition(), media.getDuration()));
        updatePlaybackSpeedButton(new SpeedChangedEvent(PlaybackSpeedUtils.getCurrentPlaybackSpeed(media)));
        setChapterDividers(media);
        setupOptionsMenu(media);
    }

    @Subscribe(threadMode = ThreadMode.MAIN)
    @SuppressWarnings("unused")
    public void sleepTimerUpdate(SleepTimerUpdatedEvent event) {
        if (event.isCancelled() || event.wasJustEnabled()) {
            AudioPlayerFragment.this.loadMediaInfo(false);
        }
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRetainInstance(true);
    }

    @Override
    public void onStart() {
        super.onStart();
        controller = newPlaybackController();
        controller.init();
        loadMediaInfo(false);
        EventBus.getDefault().register(this);
        txtvRev.setText(NumberFormat.getInstance().format(UserPreferences.getRewindSecs()));
        txtvFF.setText(NumberFormat.getInstance().format(UserPreferences.getFastForwardSecs()));
    }

    @Override
    public void onStop() {
        super.onStop();
        controller.release();
        controller = null;
        progressIndicator.setVisibility(View.GONE); // Controller released; we will not receive buffering updates
        EventBus.getDefault().unregister(this);
        if (disposable != null) {
            disposable.dispose();
        }
    }

    @Subscribe(threadMode = ThreadMode.MAIN)
    @SuppressWarnings("unused")
    public void bufferUpdate(BufferUpdateEvent event) {
        if (event.hasStarted()) {
            progressIndicator.setVisibility(View.VISIBLE);
        } else if (event.hasEnded()) {
            progressIndicator.setVisibility(View.GONE);
        } else if (controller != null && controller.isStreaming()) {
            sbPosition.setSecondaryProgress((int) (event.getProgress() * sbPosition.getMax()));
        } else {
            sbPosition.setSecondaryProgress(0);
        }
    }

    @Subscribe(threadMode = ThreadMode.MAIN)
    public void updatePosition(PlaybackPositionEvent event) {
        if (controller == null || txtvPosition == null || txtvLength == null || sbPosition == null) {
            return;
        }

        TimeSpeedConverter converter = new TimeSpeedConverter(controller.getCurrentPlaybackSpeedMultiplier());
        int currentPosition = converter.convert(event.getPosition());
        int duration = converter.convert(event.getDuration());
        int remainingTime = converter.convert(Math.max(event.getDuration() - event.getPosition(), 0));
        currentChapterIndex = ChapterUtils.getCurrentChapterIndex(controller.getMedia(), currentPosition);
        Log.d(TAG, "currentPosition " + Converter.getDurationStringLong(currentPosition));
        if (currentPosition == Playable.INVALID_TIME || duration == Playable.INVALID_TIME) {
            Log.w(TAG, "Could not react to position observer update because of invalid time");
            return;
        }
        txtvPosition.setText(Converter.getDurationStringLong(currentPosition));
        showTimeLeft = UserPreferences.shouldShowRemainingTime();
        if (showTimeLeft) {
            txtvLength.setText(((remainingTime > 0) ? "-" : "") + Converter.getDurationStringLong(remainingTime));
        } else {
            txtvLength.setText(Converter.getDurationStringLong(duration));
        }

        if (!sbPosition.isPressed()) {
            float progress = ((float) event.getPosition()) / event.getDuration();
            sbPosition.setProgress((int) (progress * sbPosition.getMax()));
        }
    }

    @Subscribe(threadMode = ThreadMode.MAIN)
    public void favoritesChanged(FavoritesEvent event) {
        AudioPlayerFragment.this.loadMediaInfo(false);
    }

    @Subscribe(threadMode = ThreadMode.MAIN)
    public void mediaPlayerError(PlayerErrorEvent event) {
        final MaterialAlertDialogBuilder errorDialog = new MaterialAlertDialogBuilder(getContext());
        errorDialog.setTitle(R.string.error_label);
        errorDialog.setMessage(event.getMessage());
        errorDialog.setPositiveButton(android.R.string.ok, (dialog, which) ->
                ((MainActivity) getActivity()).getBottomSheet().setState(BottomSheetBehavior.STATE_COLLAPSED));
        if (!UserPreferences.useExoplayer()) {
            errorDialog.setNeutralButton(R.string.media_player_switch_to_exoplayer, (dialog, which) -> {
                UserPreferences.enableExoplayer();
                ((MainActivity) getActivity()).showSnackbarAbovePlayer(
                        R.string.media_player_switched_to_exoplayer, Snackbar.LENGTH_LONG);
            });
        }
        errorDialog.create().show();
    }

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
        if (controller == null || txtvLength == null) {
            return;
        }

        if (fromUser) {
            float prog = progress / ((float) seekBar.getMax());
            TimeSpeedConverter converter = new TimeSpeedConverter(controller.getCurrentPlaybackSpeedMultiplier());
            int position = converter.convert((int) (prog * controller.getDuration()));
            int newChapterIndex = ChapterUtils.getCurrentChapterIndex(controller.getMedia(), position);
            if (newChapterIndex > -1) {
                if (!sbPosition.isPressed() && currentChapterIndex != newChapterIndex) {
                    currentChapterIndex = newChapterIndex;
                    position = (int) controller.getMedia().getChapters().get(currentChapterIndex).getStart();
                    seekedToChapterStart = true;
                    controller.seekTo(position);
                    updateUi(controller.getMedia());
                    sbPosition.highlightCurrentChapter();
                }
                txtvSeek.setText(controller.getMedia().getChapters().get(newChapterIndex).getTitle()
                                + "\n" + Converter.getDurationStringLong(position));
            } else {
                txtvSeek.setText(Converter.getDurationStringLong(position));
            }
        } else if (duration != controller.getDuration()) {
            updateUi(controller.getMedia());
        }
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        // interrupt position Observer, restart later
        cardViewSeek.setScaleX(.8f);
        cardViewSeek.setScaleY(.8f);
        cardViewSeek.animate()
                .setInterpolator(new FastOutSlowInInterpolator())
                .alpha(1f).scaleX(1f).scaleY(1f)
                .setDuration(200)
                .start();
    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        if (controller != null) {
            if (seekedToChapterStart) {
                seekedToChapterStart = false;
            } else {
                float prog = seekBar.getProgress() / ((float) seekBar.getMax());
                controller.seekTo((int) (prog * controller.getDuration()));
            }
        }
        cardViewSeek.setScaleX(1f);
        cardViewSeek.setScaleY(1f);
        cardViewSeek.animate()
                .setInterpolator(new FastOutSlowInInterpolator())
                .alpha(0f).scaleX(.8f).scaleY(.8f)
                .setDuration(200)
                .start();
    }

    public void setupOptionsMenu(Playable media) {
        if (toolbar.getMenu().size() == 0) {
            toolbar.inflateMenu(R.menu.mediaplayer);
        }
        if (controller == null) {
            return;
        }
        boolean isFeedMedia = media instanceof FeedMedia;
        toolbar.getMenu().findItem(R.id.open_feed_item).setVisible(isFeedMedia);
        if (isFeedMedia) {
            FeedItemMenuHandler.onPrepareMenu(toolbar.getMenu(), ((FeedMedia) media).getItem());
        }

        toolbar.getMenu().findItem(R.id.set_sleeptimer_item).setVisible(!controller.sleepTimerActive());
        toolbar.getMenu().findItem(R.id.disable_sleeptimer_item).setVisible(controller.sleepTimerActive());

        ((CastEnabledActivity) getActivity()).requestCastButton(toolbar.getMenu());
    }

    @Override
    public boolean onMenuItemClick(MenuItem item) {
        if (controller == null) {
            return false;
        }
        Playable media = controller.getMedia();
        if (media == null) {
            return false;
        }

        final @Nullable FeedItem feedItem = (media instanceof FeedMedia) ? ((FeedMedia) media).getItem() : null;
        if (feedItem != null && FeedItemMenuHandler.onMenuItemClicked(this, item.getItemId(), feedItem)) {
            return true;
        }

        final int itemId = item.getItemId();
        if (itemId == R.id.disable_sleeptimer_item || itemId == R.id.set_sleeptimer_item) {
            new SleepTimerDialog().show(getChildFragmentManager(), "SleepTimerDialog");
            return true;
        } else if (itemId == R.id.audio_controls) {
            PlaybackControlsDialog dialog = PlaybackControlsDialog.newInstance();
            dialog.show(getChildFragmentManager(), "playback_controls");
            return true;
        } else if (itemId == R.id.open_feed_item) {
            if (feedItem != null) {
                Intent intent = MainActivity.getIntentToOpenFeed(getContext(), feedItem.getFeedId());
                startActivity(intent);
            }
            return true;
        }
        return false;
    }

    private static class AudioPlayerPagerAdapter extends FragmentStateAdapter {
        private static final String TAG = "AudioPlayerPagerAdapter";

        public AudioPlayerPagerAdapter(@NonNull Fragment fragment) {
            super(fragment);
        }

        @NonNull
        @Override
        public Fragment createFragment(int position) {
            Log.d(TAG, "getItem(" + position + ")");

            switch (position) {
                case POS_COVER:
                    return new CoverFragment();
                default:
                case POS_DESCRIPTION:
                    return new ItemDescriptionFragment();
            }
        }

        @Override
        public int getItemCount() {
            return NUM_CONTENT_FRAGMENTS;
        }
    }

    public void scrollToPage(int page, boolean smoothScroll) {
        if (pager == null) {
            return;
        }

        pager.setCurrentItem(page, smoothScroll);

        Fragment visibleChild = getChildFragmentManager().findFragmentByTag("f" + POS_DESCRIPTION);
        if (visibleChild instanceof ItemDescriptionFragment) {
            ((ItemDescriptionFragment) visibleChild).scrollToTop();
        }
    }

    public void scrollToPage(int page) {
        scrollToPage(page, false);
    }
}