YoutubePlayer片段中没有播放视频

Question

我正在制作一款使用Youtube播放器片段的应用。它已加载但视频未播放。这是我的代码：

Youtube.java（片段）

public class Youtube extends YouTubePlayerFragment {


    public Youtube() {
    }

    public static Youtube newInstance(String url) {

        Youtube frag = new Youtube();

        Bundle b = new Bundle();
        b.putString("url", url);

        frag.setArguments(b);
        frag.init();

        return frag;
    }

    private void init() {

        initialize(API_KEY, new YouTubePlayer.OnInitializedListener() {

            @Override
            public void onInitializationFailure(YouTubePlayer.Provider arg0, YouTubeInitializationResult arg1) {
            }

            @Override
            public void onInitializationSuccess(YouTubePlayer.Provider provider, YouTubePlayer player, boolean wasRestored) {
                if (!wasRestored) {
                    player.cueVideo(getArguments().getString("url"));
                   // player.play();
                }
            }
        });
    }
}

活动：

    protected void onCreate(Bundle savedInstanceState) {
        setContentView(R.layout.activity_main);
        Youtube f = Youtube.newInstance("https://www.youtube.com/watch?v=o49aHgzTOGw");
        FragmentManager fragmentManager=getFragmentManager();
        fragmentManager.beginTransaction().add(f,"Fragment").commit();
    }

布局：

<FrameLayout>
    <fragment class="com.google.android.youtube.player.YouTubePlayerFragment"
              android:id="@+id/Fragment"
              android:layout_width="match_parent"
              android:layout_height="wrap_content" />
</FrameLayout>

我哪里出错了。我无法理解。我需要延长YoutubeBaseActivity吗？怎么做到这一点？