cueVideo和null指针展示

Question

这是日志：

  

由于：java.lang.NullPointerException：尝试调用接口   方法“无效”   com.google.android.youtube.player.YouTubePlayer.cueVideo（java.lang.String）'   在空对象引用上

我不知道为什么会有这个错误？

public class StudyActivity extends YouTubeBaseActivity implements YouTubePlayer.OnInitializedListener {

YouTubePlayerView youTubePlayerView;
YouTubePlayer player;

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

    youTubePlayerView.initialize(KEY.YOUTUBE_API_KEY,this);
    player.cueVideo("GyrH6xiFiT0");

}
@Override
public void onInitializationSuccess(YouTubePlayer.Provider provider, YouTubePlayer youTubePlayer, boolean b) {
    player = youTubePlayer;
}

@Override
public void onInitializationFailure(YouTubePlayer.Provider provider, YouTubeInitializationResult youTubeInitializationResult) {
    Toast.makeText(this, "Error!", Toast.LENGTH_SHORT).show();
}
}