ExoPlayer创建的视频播放器不起作用

Question

我正在尝试使用ExoPlayer API创建视频播放器。 我的应用使用的是API 23: Android 6.0 (Marshmallow)和implementation 'com.google.android.exoplayer:exoplayer:2.8.1' 。 我正在通过在线服务器播放.mp4视频文件。 当我尝试在Android Studio模拟器上运行我的应用程序时，该应用程序无法打开。 我的所有代码都在下面，并且我上传了我看到的两个错误的图片。 请帮我。 我无法解决问题，因为为ExoPlayer提供的信息很少。

我的MainActivity.java ：

import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import com.google.android.exoplayer2.ExoPlayerFactory;
import com.google.android.exoplayer2.SimpleExoPlayer;
import com.google.android.exoplayer2.source.ExtractorMediaSource;
import com.google.android.exoplayer2.source.MediaSource;
import com.google.android.exoplayer2.trackselection.AdaptiveTrackSelection;
import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
import com.google.android.exoplayer2.trackselection.TrackSelection;
import com.google.android.exoplayer2.ui.SimpleExoPlayerView;
import com.google.android.exoplayer2.upstream.DataSource;
import com.google.android.exoplayer2.upstream.DefaultBandwidthMeter;
import com.google.android.exoplayer2.upstream.DefaultDataSourceFactory;
import com.google.android.exoplayer2.util.Util;

public class MainActivity extends AppCompatActivity
{
    SimpleExoPlayer player;
    SimpleExoPlayerView simpleExoPlayerView;
    DefaultTrackSelector trackSelector;
    DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
    boolean shouldAutoPlay = true;

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


        simpleExoPlayerView = (SimpleExoPlayerView) findViewById(R.id.player_view);

        simpleExoPlayerView.requestFocus();

        TrackSelection.Factory videoTrackSelectionFactory = new AdaptiveTrackSelection.Factory(bandwidthMeter);

        trackSelector = new DefaultTrackSelector(videoTrackSelectionFactory);

        player = ExoPlayerFactory.newSimpleInstance(this, trackSelector);

        simpleExoPlayerView.setPlayer(player);

        player.setPlayWhenReady(shouldAutoPlay);

        DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(this, Util.getUserAgent(this, "Application Name"), bandwidthMeter);
        MediaSource mediaSource = new ExtractorMediaSource.Factory(dataSourceFactory).createMediaSource(Uri.parse("http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4"));

        player.prepare(mediaSource);
    }
}

我的activity_main.xml ：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <com.google.android.exoplayer2.ui.SimpleExoPlayerView
        android:id="@+id/player_view"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:focusable="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

我的build.gradle依赖项：

dependencies 
{
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
    implementation 'com.google.android.exoplayer:exoplayer:2.8.1'
}

错误（我认为这是问题所在）：

1. There is a crossed line on the SimpleExoPlayerView. I don't know what this means.

2. There is a problem with the dependencies. 

Answer 1

这是我的实现，它对您及其在我的项目中的工作可能会有所帮助。

 public class MainActivity extends AppCompatActivity implements View.OnClickListener, PlaybackPreparer, PlayerControlView.VisibilityListener {

 private PlayerView playerView;
 private ExoPlayer player;
 private PlayerView playerView;
 private Handler mainHandler;
 private DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
 private DataSource.Factory mediaDataSourceFactory;
 protected String userAgent;
 private TrackSelector trackSelector;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);


  playerView = view.findViewById(R.id.player_view);

  mainHandler = new Handler();
  userAgent = Util.getUserAgent(getContext(), "appName");
  mediaDataSourceFactory = buildDataSourceFactory();
  TrackSelection.Factory videoTrackSelectionFactory = new AdaptiveTrackSelection.Factory(new DefaultBandwidthMeter());
  trackSelector = new DefaultTrackSelector(videoTrackSelectionFactory);
  player = ExoPlayerFactory.newSimpleInstance(new DefaultRenderersFactory(getActivity()), trackSelector, new DefaultLoadControl());
  playerView.setPlayer(player);
  playerView.requestFocus();
  playVideoInit();

 }
 private DataSource.Factory buildDataSourceFactory() {
  return buildDataSourceFactory(bandwidthMeter);
 }

 public DataSource.Factory buildDataSourceFactory(TransferListener < ? super DataSource > listener) {
  if (getContext() != null)
   return new DefaultDataSourceFactory(getContext(), listener, buildHttpDataSourceFactory(listener));
  return null;
 }

 public HttpDataSource.Factory buildHttpDataSourceFactory(
  TransferListener < ? super DataSource > listener) {
  return new DefaultHttpDataSourceFactory(userAgent, listener, 60 * 1000,
   60 * 1000, true);
 }

 private MediaSourceEventListener listener = new MediaSourceEventListener() {
  @Override
  public void onLoadStarted(DataSpec dataSpec, int dataType, int trackType,
   Format trackFormat, int trackSelectionReason,
   Object trackSelectionData, long mediaStartTimeMs,
   long mediaEndTimeMs, long elapsedRealtimeMs) {
   Log.e("ExoPlayer", "onLoadStarted");
  }

  @Override
  public void onLoadCompleted(DataSpec dataSpec, int dataType, int trackType,
   Format trackFormat, int trackSelectionReason,
   Object trackSelectionData, long mediaStartTimeMs,
   long mediaEndTimeMs, long elapsedRealtimeMs,
   long loadDurationMs, long bytesLoaded) {
   Log.e("ExoPlayer", "onLoadCompleted Load Duration:  " + loadDurationMs);
  }

  @Override
  public void onLoadCanceled(DataSpec dataSpec, int dataType,
   int trackType, Format trackFormat,
   int trackSelectionReason, Object trackSelectionData,
   long mediaStartTimeMs, long mediaEndTimeMs,
   long elapsedRealtimeMs, long loadDurationMs, long bytesLoaded) {
   Log.e("ExoPlayer", "onLoadCanceled");
  }

  @Override
  public void onLoadError(DataSpec dataSpec, int dataType, int trackType,
   Format trackFormat, int trackSelectionReason,
   Object trackSelectionData, long mediaStartTimeMs,
   long mediaEndTimeMs, long elapsedRealtimeMs,
   long loadDurationMs, long bytesLoaded, IOException error,
   boolean wasCanceled) {
   Log.e("ExoPlayer", "onLoadError");
  }

  @Override
  public void onUpstreamDiscarded(int trackType, long mediaStartTimeMs, long mediaEndTimeMs) {
   Log.e("ExoPlayer", "onUpstreamDiscarded");
  }

  @Override
  public void onDownstreamFormatChanged(int trackType,
   Format trackFormat,
   int trackSelectionReason,
   Object trackSelectionData,
   long mediaTimeMs) {
   Log.e("ExoPlayer", "onDownstreamFormatChanged");
  }
 };
 public void reStartVideoView() {
  if (player != null) {
   player.seekTo(0);
   player.setPlayWhenReady(true);
  } else {
   Log.e("ExoPlayer", "Restart not working....");
  }
 }
 private MediaSource buildMediaSource(Uri uri) {
  int type = Util.inferContentType(uri.getLastPathSegment());
  switch (type) {
   case C.TYPE_DASH:
    return new DashMediaSource.Factory(
      new DefaultDashChunkSource.Factory(mediaDataSourceFactory),
      buildDataSourceFactory())
     .createMediaSource(uri, mainHandler, listener);
   case C.TYPE_SS:
    return new SsMediaSource.Factory(
      new DefaultSsChunkSource.Factory(mediaDataSourceFactory),
      buildDataSourceFactory())
     .createMediaSource(uri, mainHandler, listener);
   case C.TYPE_HLS:
    Log.e("ExoPlayer", "Hls type streaming");
    return new HlsMediaSource.Factory(mediaDataSourceFactory).
    createMediaSource(uri, mainHandler, listener);
   case C.TYPE_OTHER:
    return new ExtractorMediaSource.Factory(mediaDataSourceFactory)
     .createMediaSource(uri, mainHandler, listener);

   default:
    {
     throw new IllegalStateException("Unsupported type: " + type);
    }
  }
 }


 private void playVideoInit() {
  try {
   if (player != null) {
    boolean haveResumePosition = resumeWindow != C.INDEX_UNSET;
    player.prepare(buildMediaSource(Uri.parse(video.getContentUrl())), !haveResumePosition, false);
    player.setPlayWhenReady(true);
    player.seekTo(resumePosition);

   }
  } catch (Exception e) {
   e.printStackTrace();
  }


 }

 private void releasePlayer() {
  if (player != null) {
   player.release();
   player = null;
  }
 }

 @Override
 public void onStart() {
  super.onStart();
  if (Util.SDK_INT > 23) {
   playVideoInit();
  }
 }

 @Override
 public void onResume() {
  super.onResume();
  if ((Util.SDK_INT <= 23 || player == null)) {
   playVideoInit();

  }
 }

 @Override
 public void onPause() {
  super.onPause();
  if (Util.SDK_INT <= 23) {
   releasePlayer();

  }
 }

 @Override
 public void onStop() {
  super.onStop();
  if (Util.SDK_INT > 23) {
   releasePlayer();
  }
 }

 @Override
 public void onClick(View v) {

 }

 @Override
 public void preparePlayback() {
  playVideoInit();
 }

 @Override
 public void onVisibilityChange(int visibility) {

 }
}