Google ExoPlayer 指南

Question

我正在努力使用 ExoPlayer 构建基本应用程序。

你好，我对 "getting started" 部分有疑问。不知道需要使用什么才能播放视频或流。如何停止、播放、暂停……另一个问题是我不知道我在提供什么，例如，在 DefaultDataSourceFactory 构造函数中，为什么，我在有和没有一些参数的情况下得到了什么……我很困惑整个用法...请帮助！谢谢！

Answer 1

首先，您需要将此添加到您的 build.gradle
编译'com.google.android.exoplayer:exoplayer:r2.1.1'

1.您的布局文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <com.google.android.exoplayer2.ui.SimpleExoPlayerView
        android:id="@+id/player_view"
        android:focusable="true"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</RelativeLayout>

2。您的 Class 文件

public class ExoPlayerActivity extends AppCompatActivity implements ExoPlayer.EventListener {
        SimpleExoPlayer player;
        String path;        // it can be url of video for online streaming or a url of local video

        @Override
        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_exoplayer);

            // set your path here
            path=<your path>;

            // 1. Create a default TrackSelector
            BandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
            TrackSelection.Factory videoTrackSelectionFactory =
                    new AdaptiveVideoTrackSelection.Factory(bandwidthMeter);
            TrackSelector trackSelector =
                    new DefaultTrackSelector(videoTrackSelectionFactory);

            // 2. Create a default LoadControl
            LoadControl loadControl = new DefaultLoadControl();
            // 3. Create the player
            player = ExoPlayerFactory.newSimpleInstance(this, trackSelector, loadControl);

            SimpleExoPlayerView playerView = (SimpleExoPlayerView) findViewById(R.id.player_view);
            playerView.setPlayer(player);
            playerView.setKeepScreenOn(true);
            // Produces DataSource instances through which media data is loaded.
            DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(this, Util.getUserAgent(this, "ExoPlayer"));

            // Produces Extractor instances for parsing the media data.
            ExtractorsFactory extractorsFactory = new DefaultExtractorsFactory();

            // This is the MediaSource representing the media to be played.
            MediaSource videoSource = new ExtractorMediaSource(Uri.parse(path),
                    dataSourceFactory, extractorsFactory, null, null);
            // Prepare the player with the source.
            player.addListener(this);
            player.prepare(videoSource);
            playerView.requestFocus();
            player.setPlayWhenReady(true);      // to play video when ready. Use false to pause a video
        }


        @Override
        protected void onPause() {
            super.onPause();
            if (player != null) {
                player.setPlayWhenReady(false); //to pause a video because now our video player is not in focus
            }
        }

        @Override
        public void onTimelineChanged(Timeline timeline, Object manifest) {

        }

        @Override
        public void onTracksChanged(TrackGroupArray trackGroups, TrackSelectionArray trackSelections) {

        }

        @Override
        public void onLoadingChanged(boolean isLoading) {

        }

        @Override
        public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
            switch (playbackState) {
                case ExoPlayer.STATE_BUFFERING:
                    //You can use progress dialog to show user that video is preparing or buffering so please wait
                    break;
                case ExoPlayer.STATE_IDLE:
                    //idle state
                    break;
                case ExoPlayer.STATE_READY:
                    // dismiss your dialog here because our video is ready to play now
                    break;
                case ExoPlayer.STATE_ENDED:
                    // do your processing after ending of video
                    break;
            }
        }

        @Override
        public void onPlayerError(ExoPlaybackException error) {
            // show user that something went wrong. I am showing dialog but you can use your way
            AlertDialog.Builder adb = new AlertDialog.Builder(ExoPlayerActivity.this);
            adb.setTitle("Could not able to stream video");
            adb.setMessage("It seems that something is going wrong.\nPlease try again.");
            adb.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();
                    finish(); // take out user from this activity. you can skip this
                }
            });
            AlertDialog ad = adb.create();
            ad.show();
        }

        @Override
        public void onPositionDiscontinuity() {
            //Video is not streaming properly
            Log.d("Mayur", "Discontinuity");
        }

        @Override
        protected void onDestroy() {
            super.onDestroy();
            player.release();   //it is important to release a player
        }
    }

我觉得这对初学者来说已经足够了。还要记住，这个库的标准音频和视频组件依赖于 Android 的 MediaCodec API，它在 Android 4.1（API 级别 16）中发布。因此它不适用于 android 4.0 及以下版本。

Google ExoPlayer 指南

Google ExoPlayer guide

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