在YouTubePlayerFragment的onStart中使用NullPointer

Question

我在扩展YouTubePlayerFragment时收到NullPointerException。

PFB我的代码：

public class VideoFragment extends YouTubePlayerFragment {
private OnFragmentInteractionListener_videoFragment mListener;
YouTubePlayer myPlayer ;

public static VideoFragment newInstance(String url) {
    VideoFragment f = new VideoFragment();
    Bundle b = new Bundle();
    b.putString("url", url);
    f.setArguments(b);
    f.init();
    return f;
}


private void init(){
    initialize(DeveloperKey.DEVELOPER_KEY, new YouTubePlayer.OnInitializedListener() {
        @Override
        public void onInitializationSuccess(YouTubePlayer.Provider provider, YouTubePlayer youTubePlayer, boolean b) {
            myPlayer=youTubePlayer;
            if(!b){
                myPlayer.cueVideo(getArguments().getString("url"));
            }
        }

        @Override
        public void onInitializationFailure(YouTubePlayer.Provider provider, YouTubeInitializationResult youTubeInitializationResult) {
                Log.i("Unable to initialize the player","the result");
            Dialog errorDialog = youTubeInitializationResult.getErrorDialog(getActivity(),0);
            errorDialog.show();
        }
    });
}
public VideoFragment() {
    // Required empty public constructor
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        String url = getArguments().getString("url");

    }
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    return inflater.inflate(R.layout.fragment_video_standard, container, false);
}


public void onButtonPressed(Uri uri) {
    if (mListener != null) {
        mListener.onFragmentInteraction_videoFragment(uri);
    }
}

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    try {
        mListener = (OnFragmentInteractionListener_videoFragment) activity;
    } catch (ClassCastException e) {
        throw new ClassCastException(activity.toString()
                + " must implement OnFragmentInteractionListener");
    }
}

@Override
public void onDetach() {
    super.onDetach();
    mListener = null;
}


public interface OnFragmentInteractionListener_videoFragment {
    // TODO: Update argument type and name
    public void onFragmentInteraction_videoFragment(Uri uri);
}

}

PFB错误：

java.lang.NullPointerException
        at com.google.android.youtube.player.YouTubePlayerFragment.onStart(Unknown Source)
        at android.app.Fragment.performStart(Fragment.java:1719)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:913)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1057)
        at android.app.BackStackRecord.run(BackStackRecord.java:682)
        at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1435)
        at android.app.FragmentManagerImpl$1.run(FragmentManager.java:441)
        at android.os.Handler.handleCallback(Handler.java:730)
        at android.os.Handler.dispatchMessage(Handler.java:92)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:5103)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:525)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
        at dalvik.system.NativeStart.main(Native Method) 

以及我在MainActivity中初始化的方式：

VideoFragment vf =VideoFragment.newInstance(testArray[id]);  getFragmentManager().beginTransaction().replace(R.id.content_frame,vf).commit() ;