在Android studio中使用Google ExoPlayer播放器遇到的问题？

Question

不知道为什么ExoPlayerFactory.newSimpleInstance（）这个地方是错误的，具体内容如下面的图片所示

我编写的代码如下所示

public class MainActivity extends AppCompatActivity {

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

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

    Uri uris = Uri.parse("https://www.apple.com/105/media/us/iphone-x/2017/01df5b43-28e4-4848-bf20-490c34a926a7/films/feature/iphone-x-feature-tpl-cc-us-20170912_1280x720h.mp4");

    SimpleExoPlayer player = ExoPlayerFactory.newSimpleInstance(this);

    DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(this,
            Util.getUserAgent(this, "yourApplicationName"));

    MediaSource videoSource = new ProgressiveMediaSource.Factory(dataSourceFactory)
            .createMediaSource(uris);

    playerView.setPlayer(player);
    player.setPlayWhenReady(true);//是否自动播放
    player.prepare(videoSource);
}

}