java - SQlite android中的多个表

Question

我想在 sqlite android 中创建一个数据库，我想在数据库中创建 2 个表，然后我想动态创建表。但是我的类 DBAdapter 只创建一个表，对于其他表会抛出错误“没有这样的表”，所以我应该怎么做呢？请帮助我

    package com.example.asa;


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 {
    public static final String KEY_ROWID_con = "_id";
    public static final String KEY_NAME_con = "name";
    public static final String KEY_NUMBER_con = "number";
    private static final String TAG = "DBAdapter";
    private static final String DATABASE_TABLE_con = "contacts";

    private static final String DATABASE_NAME = "MyDB";
    private static final int DATABASE_VERSION = 2;

    private static final String DATABASE_CREATE_con =
        "create table contacts (_id integer primary key autoincrement, "
        + "name text not null, number text not null);";

    private final Context context;    

    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;

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

    private static class DatabaseHelper extends SQLiteOpenHelper 
    {
        DatabaseHelper(Context context) 
        {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) 
        {
            try {
                db.execSQL(DATABASE_CREATE_con);    
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
        {
            Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                    + newVersion + ", which will destroy all old data");
            db.execSQL("DROP TABLE IF EXISTS chats");
            onCreate(db);
        }
    }    

    //---opens the database---
    public DBAdapter open() throws SQLException 
    {
        db = DBHelper.getWritableDatabase();
        return this;
    }

    //---closes the database---    
    public void close() 
    {
        DBHelper.close();
    }

    //---insert a contact into the database---
    public long insertContact(String name, String number) 
    {
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_NAME_con, name);
        initialValues.put(KEY_NUMBER_con, number);
        return db.insert(DATABASE_TABLE_con, null, initialValues);
    }

    //---deletes a particular contact---
    public boolean deleteContact(long rowId) 
    {
        return db.delete(DATABASE_TABLE_con, KEY_ROWID_con + "=" + rowId, null) > 0;
    }

    //---retrieves all the contacts---
    public Cursor getAllContacts() 
    {
        return db.query(DATABASE_TABLE_con, new String[] {KEY_ROWID_con, KEY_NAME_con,
                KEY_NUMBER_con}, null, null, null, null, null);
    }

    //---retrieves a particular contact---
    public Cursor getContact(long rowId) throws SQLException 
    {
        Cursor mCursor =
                db.query(true, DATABASE_TABLE_con, new String[] {KEY_ROWID_con,
                KEY_NAME_con, KEY_NUMBER_con}, KEY_ROWID_con + "=" + rowId, null,
                null, null, null, null);
        if (mCursor != null) {
            mCursor.moveToFirst();
        }
        return mCursor;
    }

    //---updates a contact---
    public boolean updateContact(long rowId, String name, String number) 
    {
        ContentValues args = new ContentValues();
        args.put(KEY_NAME_con, name);
        args.put(KEY_NUMBER_con, number);
        return db.update(DATABASE_TABLE_con, args, KEY_ROWID_con + "=" + rowId, null) > 0;
    }

    //---Search Contact by String ---//
    public String Search(String str)
    {
        String [] columns = new String[]{ KEY_ROWID_con, KEY_NAME_con, KEY_NUMBER_con};
        return db.query(DATABASE_TABLE_con, columns, KEY_NAME_con + "=?", new String[] { str }, null, null, null).getString(0);
    }

    //---insert a contact into the database---

    }

Answer 1

试试这个。我遇到了同样的问题，这个解决了——

package db;

import java.util.ArrayList;

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

public class DB_Handler_exercise extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "exercise_items";
    private static final int DATABASE_VERSION = 1;
    //table name
    private static final String TABLE_EXERCISE_TOP = "exercise_top";
    private static final String TABLE_EXERCISE_BOTTOM = "exercise_bottom";
    private static final String TABLE_EXERCISE_CARDIO = "exercise_cardio";
    private static final String TABLE_EXERCISE_VARIATIONS= "exercise_variations";

    //column name
    private static final String KEY_EX_ID = "ex_id";
    private static final String KEY_EX_NAME = "ex_name";
    private static final String KEY_EX_NICKNAME = "ex_nickname";
    private static final String KEY_NO_VARIATION = "ex_variation";
    private static final String KEY_MAIN_ID = "main_id";
    private static final String KEY_VARIATION_ID = "v_id";
    private static final String KEY_EX_VARIATION_NAME = "ex_variation_name";
    private static final String KEY_EX_VARIATION_STEPS= "ex_variation_steps";
    private static final String KEY_EX_VARIATION_PHOTOS = "ex_variation_photos";






    public DB_Handler_exercise(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        // TODO Auto-generated constructor stub
    }
    @Override
    public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        super.onDowngrade(db, oldVersion, newVersion);
    }
    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        //create table exercise_top
        String CREATE_TABLE_TOP="CREATE TABLE IF NOT EXISTS "+TABLE_EXERCISE_TOP + "(" + KEY_EX_ID + " INTEGER PRIMARY KEY," + KEY_EX_NAME + " TEXT," + KEY_EX_NICKNAME + " TEXT," + KEY_NO_VARIATION + " INTEGER" + ")";   
        db.execSQL(CREATE_TABLE_TOP);
        //create table exercise_bottom
        String CREATE_TABLE_BOTTOM="CREATE TABLE IF NOT EXISTS " + TABLE_EXERCISE_BOTTOM+ "(" + KEY_EX_ID + " INTEGER PRIMARY KEY," + KEY_EX_NAME + " TEXT," +KEY_EX_NICKNAME + " TEXT," + KEY_NO_VARIATION + " INTEGER" +")";  
        db.execSQL(CREATE_TABLE_BOTTOM);
        //create table exercise_cardio
        String CREATE_TABLE_CARDIO="CREATE TABLE IF NOT EXISTS "+ TABLE_EXERCISE_CARDIO+ "(" + KEY_EX_ID + " INTEGER PRIMARY KEY," + KEY_EX_NAME + " TEXT," +KEY_EX_NICKNAME + " TEXT," + KEY_NO_VARIATION + " INTEGER" +")";   
        db.execSQL(CREATE_TABLE_CARDIO);
        //create table exercise_variations
        String CREATE_TABLE_VARIATION="CREATE TABLE IF NOT EXISTS "+ TABLE_EXERCISE_VARIATIONS+ "(" + KEY_MAIN_ID + " INTEGER ," + KEY_VARIATION_ID + " INTEGER,"+ KEY_EX_NAME+" TEXT,"+ KEY_EX_NICKNAME+" TEXT," + KEY_EX_VARIATION_NAME + " TEXT," +KEY_EX_VARIATION_STEPS + " TEXT," + KEY_EX_VARIATION_PHOTOS + " TEXT" +")";   
        db.execSQL(CREATE_TABLE_VARIATION);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

    }
    //adding data on table_top
    public void addData_top(Table_exercise_top top){
        SQLiteDatabase db=getWritableDatabase();
        ContentValues values=new ContentValues();
        values.put(KEY_EX_ID, top.getEx_id());
        values.put(KEY_EX_NAME, top.getEx_name());
        values.put(KEY_EX_NICKNAME, top.getEx_nickname());
        values.put(KEY_NO_VARIATION, top.getEx_variation());
        db.insert(TABLE_EXERCISE_TOP, null, values);
        db.close();
    }
    //adding data on table_bottom
    public void addData_bottom(Table_exercise_bottom bottom){
        SQLiteDatabase db=getWritableDatabase();
        ContentValues values=new ContentValues();
        values.put(KEY_EX_ID, bottom.getEx_id());
        values.put(KEY_EX_NAME, bottom.getEx_name());
        values.put(KEY_EX_NICKNAME, bottom.getEx_nickname());
        values.put(KEY_NO_VARIATION, bottom.getEx_variation());
        db.insert(TABLE_EXERCISE_BOTTOM, null, values);
        db.close();
    }
    //adding data on table_cardio
    public void addData_cardio(Table_exercise_cardio cardio){
        SQLiteDatabase db=getWritableDatabase();
        ContentValues values=new ContentValues();
        values.put(KEY_EX_ID, cardio.getEx_id());
        values.put(KEY_EX_NAME, cardio.getEx_name());
        values.put(KEY_EX_NICKNAME, cardio.getEx_nickname());
        values.put(KEY_NO_VARIATION, cardio.getEx_variation());
        db.insert(TABLE_EXERCISE_CARDIO, null, values);
        db.close();
    }
    //adding data on table_variation
    public void addData_variation(Table_variation variation){
        SQLiteDatabase db=getWritableDatabase();
        ContentValues values=new ContentValues();
        values.put(KEY_MAIN_ID, variation.getMain_id());
        values.put(KEY_VARIATION_ID, variation.getV_id());
        values.put(KEY_EX_NAME, variation.getEx_name());
        values.put(KEY_EX_NICKNAME, variation.getEx_nickname());
        values.put(KEY_EX_VARIATION_NAME, variation.getVariation_name());
        values.put(KEY_EX_VARIATION_STEPS, variation.getVariation_steps());
        values.put(KEY_EX_VARIATION_PHOTOS, variation.getVariation_photos());
        db.insert(TABLE_EXERCISE_VARIATIONS, null, values);
        db.close();
    }

}