写了一段多线程访问数据库的代码 有不懂的地方求大神解答

我是着这个个链接下面写的http://www.open-open.com/lib/view/open1421307463625.html 创建了一个DatabaseManager类 然后下面是MainActivity中的代码

public class MainActivity extends AppCompatActivity {
SQLiteDatabase db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DatabaseManager.initializeInstance(getApplicationContext());
db = openOrCreateDatabase("test.db", Context.MODE_PRIVATE, null);
db.execSQL("DROP TABLE IF EXISTS person");
db.execSQL("CREATE TABLE person (_id INTEGER PRIMARY KEY AUTOINCREMENT, name VARCHAR, age SMALLINT)");
Cursor c = db.rawQuery("SELECT * FROM person", null);
while (c.moveToNext()) {
int _id = c.getInt(c.getColumnIndex("_id"));
String name = c.getString(c.getColumnIndex("name"));
int age = c.getInt(c.getColumnIndex("age"));
Log.i("db", "_id=>" + _id + ", name=>" + name + ", age=>" + age);
}
new Thread(new Runnable() {
@Override
public void run() {
db =DatabaseManager.getInstance().openDatabase();
ContentValues cv1 = new ContentValues();
cv1.put("name", "张");
cv1.put("age", 18);
db.insert("person", null, cv1);
DatabaseManager.getInstance().closeDatabase();
}
}).start();
new Thread(new Runnable() {
@Override
public void run() {
db =DatabaseManager.getInstance().openDatabase();
ContentValues cv1 = new ContentValues();
cv1.put("name", "李");
cv1.put("age", 17);
db.insert("person", null, cv1);
DatabaseManager.getInstance().closeDatabase();
}
}).start();

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

}

其中DatabaseManager.initializeInstance(getApplicationContext());这一句已经报错不兼容的类型: Context无法转换为SQLiteOpenHelper
肯定还有其他错误求大神解答啊 不是很理解这一段

应该是和数据源有关，你用的数据源是 sqlite吗？