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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package androidx.leanback.widget;
     18 
     19 /**
     20  * Interface to be implemented by UI component to support seeking. PlaybackGlueHost may implement
     21  * the interface to support seeking UI for the PlaybackGlue. There is only one single method
     22  * {@link #setPlaybackSeekUiClient(Client)} in the interface. Client (PlaybackGlue) registers
     23  * itself as a Client to receive events emitted by PlaybackSeekUi and provide data to the
     24  * PlaybackSeekUi.
     25  */
     26 public interface PlaybackSeekUi {
     27 
     28     /**
     29      * Client (e.g. PlaybackGlue) to register on PlaybackSeekUi so that it can interact
     30      * with Seeking UI. For example client(PlaybackGlue) will pause media when PlaybackSeekUi emits
     31      * {@link #onSeekStarted()} event.
     32      */
     33     class Client {
     34 
     35         /**
     36          * Called by PlaybackSeekUi to query client if seek is allowed.
     37          * @return True if allow PlaybackSeekUi to start seek, false otherwise.
     38          */
     39         public boolean isSeekEnabled() {
     40             return false;
     41         }
     42 
     43         /**
     44          * Event for start seeking. Client will typically pause media and save the current position
     45          * in the callback.
     46          */
     47         public void onSeekStarted() {
     48         }
     49 
     50         /**
     51          * Called by PlaybackSeekUi asking for PlaybackSeekDataProvider. This method will be called
     52          * after {@link #isSeekEnabled()} returns true. If client does not provide a
     53          * {@link PlaybackSeekDataProvider}, client may directly seek media in
     54          * {@link #onSeekPositionChanged(long)}.
     55          * @return PlaybackSeekDataProvider or null if no PlaybackSeekDataProvider is available.
     56          */
     57         public PlaybackSeekDataProvider getPlaybackSeekDataProvider() {
     58             return null;
     59         }
     60 
     61         /**
     62          * Called when user seeks to a different location. This callback is called multiple times
     63          * between {@link #onSeekStarted()} and {@link #onSeekFinished(boolean)}.
     64          * @param pos Position that user seeks to.
     65          */
     66         public void onSeekPositionChanged(long pos) {
     67         }
     68 
     69         /**
     70          * Called when cancelled or confirmed. When cancelled, client should restore playing from
     71          * the position before {@link #onSeekStarted()}. When confirmed, client should seek to
     72          * last updated {@link #onSeekPositionChanged(long)}.
     73          * @param cancelled True if cancelled false if confirmed.
     74          */
     75         public void onSeekFinished(boolean cancelled) {
     76         }
     77     }
     78 
     79     /**
     80      * Interface to be implemented by UI widget to support PlaybackSeekUi.
     81      */
     82     void setPlaybackSeekUiClient(Client client);
     83 
     84 }
     85