尝试调用虚拟方法 [空对象引用]

Question

我在过去 5 天里一直在尝试解决这个问题。我真的不知道如何解决它。我得到Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference。检查我的代码：RecyclerView.javapackage etes.xdda.music;import android.app.Dialog;import android.content.Context;import android.content.Intent;import android.graphics.Color;import android.graphics.drawable.ColorDrawable;import android.media.MediaPlayer;import android.support.v7.widget.RecyclerView;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ImageButton;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.TextView;import java.util.List;public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.MyViewHolder> implements View.OnClickListener{    Context mContext;    List<mList> mData;    Dialog myDialog;    private MediaPlayer mediaPlayer;    private int playbackPosition=0;    private LinearLayout menu_dialog;    public RecyclerViewAdapter(Context mContext, List<mList> mData) {        this.mContext = mContext;        this.mData = mData;    }    }}