android - 在android中的1个数据库中创建2个表

Question

在这个例子中，我想要一个包含两个表（SentMessages 和 SavedMessages）的数据库（Databse1.db）。正在创建数据库，但未创建表。我已经在外部创建了数据库和表，并将其复制到 assets 文件夹中。从那里以编程方式将其复制到 data/data/....... 谁能帮我吗？

这是我的 DatabasesActivity.java 类

package com.example.messagingapp2;



import android.os.Bundle;
import android.app.Activity;
import android.database.Cursor;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class DatabasesActivity extends Activity 
{
        EditText text1,text2;
        String str1,str2;
        DBAdapter db;

        @Override
        protected void onCreate(Bundle savedInstanceState) 
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            text1 = (EditText)findViewById(R.id.widget33);
            text2 = (EditText)findViewById(R.id.widget36);
            db = new DBAdapter(this);
            db.createDatabase();
        }

        public void OnClickSend(View v) 
        {
            str1=text1.getText().toString();
            str2=text2.getText().toString();
            db.open();
            long id = db.insertContact1(str1,str2);
            db.close();
        }
        public void OnClickSave(View v) 
        {
            str1=text1.getText().toString();
            str2=text2.getText().toString();
            db.open();
            long id = db.insertContact2(str1,str2);
            db.close();


            }

这是我的 DBAdapter.java 类，它有 DatabaseHelper 作为内部类

package com.example.messagingapp2;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class DBAdapter     
{     
        protected static final String TAG = "DataAdapter";

        private final Context context;
        private SQLiteDatabase db;
            DatabaseHelper DBHelper;    

            public DBAdapter(Context ctx) 
            {
                this.context = ctx;
                DBHelper = new DatabaseHelper(context);
            }

            public DBAdapter createDatabase() throws SQLException 
            {
                try 
                {
                    DBHelper.createDataBase();
                Log.e(TAG, "CreateDatabase Succesful");
                }
                catch (IOException e) 
                {
                    Log.e(TAG, e.toString() + "  UnableToCreateDatabase");
                    throw new Error("UnableToCreateDatabase");
                }
                return this;
            }

            public DBAdapter open() throws SQLException 
            {
                try 
                {
                DBHelper.openDataBase();
                DBHelper.close();
                    db = DBHelper.getReadableDatabase();
                }
                catch (SQLException e) 
                {
                    Log.e(TAG, "open >>"+ e.toString());
                    throw e;
                }
                return this;
            }

            public void close() 
            {
                DBHelper.close(); 
            }

            public long insertContact1(String too, String message) 
            {

                ContentValues initialValues = new ContentValues();        
                initialValues.put("too", too); //Adds a value to the set.
                initialValues.put("message", message);

                return db.insert("SentMessages", null, initialValues); 
            }
            public long insertContact2(String too, String message) 
            {

                ContentValues initialValues = new ContentValues();        
                initialValues.put("too", too); //Adds a value to the set.
                initialValues.put("message", message);

                return db.insert("SavedMessages", null, initialValues); 
            }
}