无法使用显示适配器从数据库Android填充Listview

Question

我有一个名为“noteName”的列的数据库。我想要的是用mySQLiteDatabase填充listView。我使用显示适配器来帮助这个过程。

但问题是Null Pointer Exception。我必须弄清楚是什么导致NPO，但我仍然没有得到它。

请帮助我，我刚刚被困在这里两天。

NB。这是我的MainActivity.java代码（listview将显示的地方）

public class MainActivity extends ActionBarActivity {
SQLiteDatabase db;
DatabaseHelper dBHelper = new DatabaseHelper(this);
private ListView list;
private ArrayList<String> NoteName = new ArrayList<String>();
private static final String TABLE_NOTES_NAME = "Notes";
private ArrayList<Contact> noteData;



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

    findViewById(R.id.pink_icon).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent registerIntent = new Intent(MainActivity.this, AddNote.class);
            MainActivity.this.startActivity(registerIntent);
        }
    });

    display();

}

public void display() {
    db = dBHelper.getReadableDatabase();
    Cursor mCursor = db.rawQuery("SELECT NoteName FROM " + TABLE_NOTES_NAME  , null);
    ListView list = (ListView)findViewById(android.R.id.list);
    NoteName.clear();

    if (mCursor.moveToFirst()) {
        do {
            NoteName.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.TOL_NOTENAME)));

        } while (mCursor.moveToNext());
    }
    DisplayAdapterTrans disadptr = new DisplayAdapterTrans(MainActivity.this, NoteName);
    list.setAdapter(disadptr);  // Here the console says have a null pointer exception
     mCursor.close();
}

}

这是我的DisplayAdapter

public class DisplayAdapterTrans extends BaseAdapter {
    private Context mContext;
    private ArrayList<String> NoteName;

    public DisplayAdapterTrans(Context c, ArrayList<String> noteName) {
        this.mContext = c;

        this.NoteName = noteName;
    }

    public int getCount() {
        // TODO Auto-generated method stub
        return NoteName.size();
    }

    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return null;
    }

    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }

    public View getView(int pos, View child, ViewGroup parent) {
        Holder mHolder;
        LayoutInflater layoutInflater;
        if (child == null) {
            layoutInflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            child = layoutInflater.inflate(R.layout.notename, null);
            mHolder = new Holder();
            mHolder.noteName= (TextView) child.findViewById(R.id.notenameTxt);

            child.setTag(mHolder);
        } else {
            mHolder = (Holder) child.getTag();
        }

        mHolder.noteName.setText(NoteName.get(pos));

        return child;
    }

    public class Holder {
        TextView noteName;

    }

}