我想请问下，为什么我往数据库插入语句时，总报空指针异常，具体代码如下：
下面代码是我建库和表的，还有插入方法：

public class DBNews {
private static final String DATABASE_NAME = "NewsDB.db";
private static final String DB_TABLE1 = "People";
private static final String DB_TABLE2 = "News";
private static final int DB_VERSON = 1;
public static final String KEY_ID = "id";
public static final String KEY_Name = "name";
public static final String KEY_Password = "password";
public static final String New_Id="id";
public static final String New_Name="name";
public static final String New_Matter="matter";
public static final String New_Data="dataTime";
private SQLiteDatabase db;
private final Context context;
private Dbnewpeople newpeople;

public DBNews(Context _context) {
context = _context;
}

public void open() throws SQLiteException {
newpeople = new Dbnewpeople(context, DATABASE_NAME, null, DB_VERSON);
try {
db = newpeople.getWritableDatabase();
} catch (Exception ex) {
db = newpeople.getReadableDatabase();
}
}

public void close() {
if (db != null) {
db.close();
db = null;
}
}

private static class Dbnewpeople extends SQLiteOpenHelper {

public Dbnewpeople(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
}

private static final String DB_CREATEPEOPLE = "create table " + DB_TABLE1
+ "(" + KEY_ID + " integer primary key autoincrement,"
+ KEY_Name + " text not null," + KEY_Password + " text not null);";
private static final String DB_CREATENEWS= "create table " + DB_TABLE2
+ "(" + New_Id + " integer primary key autoincrement,"
+ New_Name + " text not null," + New_Matter + New_Data + " integer);";

@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DB_CREATEPEOPLE);
db.execSQL(DB_CREATENEWS);

}

@Override
public void onUpgrade(SQLiteDatabase _db, int oldVersion, int newVersion) {
_db.execSQL("DROP TABLE IF EXTSTS" + DB_TABLE1);
_db.equals("DROP TABLE IF EXTSTS"+DB_TABLE2);
onCreate(_db);

}
}
//添加数据
  public long insert(Peoples people){
  Log.i("tag", "aaa");
  //ContentValues类是一个数据承载容器，主要用来向数据库表中添加一条数据
  ContentValues newValues=new ContentValues();
  //newValues.put(KEY_ID, people.nameid);
  newValues.put(KEY_Name, people.name);
  newValues.put(KEY_Password, people.password);
  return db.insert(DB_TABLE1, null, newValues);
 
  }

下面是我插入方法调用的地方，其中运行说的是long a=dbnew.insert(peoples);这句报空指针异常

if(etpassword1.getText().toString().equals(etpassword2.getText().toString())){
peoples.setName(etname1.getText().toString());
peoples.setPassword(etpassword1.getText().toString());
long a=dbnew.insert(peoples);
Toast.makeText(RegisterActivity.this, "添加成功！"+a,Toast.LENGTH_LONG).show();
Log.i("tag", "succsful");
}

------解决方案--------------------
dbnew为null呗，自己看看是什么原因导致dbnew为null的