我将在我使用Unity创建的Android游戏中使用预先填充的SQLite数据库。
由于the simple way无法在Android上运行（它在Windows上完美运行），因此我跟随this tutorial在Android应用中使用我的数据库。< / p>
public void OpenDB(string p) //p is the database name
{
// check if file exists in Application.persistentDataPath
string filepath = Application.persistentDataPath + "/" + p;
if(!File.Exists(filepath))
{
// if it doesn't ->
// open StreamingAssets directory and load the db ->
WWW loadDB = new WWW("jar:file://" + Application.dataPath + "!/assets/" + p); // this is the path to your StreamingAssets in android
while(!loadDB.isDone) {} // CAREFUL here, for safety reasons you shouldn't let this while loop unattended, place a timer and error check
// then save to Application.persistentDataPath
File.WriteAllBytes(filepath, loadDB.bytes);
}
//open db connection
connection = "URI=file:" + filepath;
dbcon = new SqliteConnection(connection);
dbcon.Open();
}
当我运行此代码时，出现以下错误：
SqliteSyntaxException：文件已加密或不是数据库
这是完整的错误：
SqliteSyntaxException：文件已加密或不是数据库 Mono.Data.SqliteClient.SqliteCommand.GetNextStatement（IntPtr pzStart， System.IntPtr＆安培; pzTail，System.IntPtr＆amp;数PreparedStatement pstmt） Mono.Data.SqliteClient.SqliteCommand.ExecuteReader（CommandBehavior 行为，布尔值want_results，System.Int32＆amp; rows_affected） Mono.Data.SqliteClient.SqliteCommand.ExecuteReader（CommandBehavior 行为）Mono.Data.SqliteClient.SqliteCommand.ExecuteDbDataReader （CommandBehavior行为）System.Data.Common.DbCommand.ExecuteReader （）System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader （）dbAccess.SingleSelectWhere（System.String tableName，System.String itemToSelect，System.String wCol，System.String wPar，System.String wValue）（在Assets / dbAccess.cs：152）
我已从该帖子下载了该示例，并得到了同样的错误。
我对这一行感到怀疑：
File.WriteAllBytes(filepath, loadDB.bytes);
我的想法是出于某种原因，它无法将数据库数据写入文件。
有谁知道如何解决这个问题？
答案 0 :(得分：3)
由于this blog，我解决了这个问题。
由于 if 语句将根据应用程序运行的平台执行不同的行为，因此此代码在每个平台上都运行良好。
这是执行重要部分的DataService.cs（或者我更好地说整个部分）
using SQLite4Unity3d;
using UnityEngine;
#if !UNITY_EDITOR
using System.Collections;
using System.IO;
#endif
using System.Collections.Generic;
public class DataService {
private SQLiteConnection _connection;
public DataService(string DatabaseName){
#if UNITY_EDITOR
var dbPath = string.Format(@"Assets/StreamingAssets/{0}", DatabaseName);
#else
// check if file exists in Application.persistentDataPath
var filepath = string.Format("{0}/{1}", Application.persistentDataPath, DatabaseName);
if (!File.Exists(filepath))
{
Debug.Log("Database not in Persistent path");
// if it doesn't ->
// open StreamingAssets directory and load the db ->
#if UNITY_ANDROID
var loadDb = new WWW("jar:file://" + Application.dataPath + "!/assets/" + DatabaseName); // this is the path to your StreamingAssets in android
while (!loadDb.isDone) { } // CAREFUL here, for safety reasons you shouldn't let this while loop unattended, place a timer and error check
// then save to Application.persistentDataPath
File.WriteAllBytes(filepath, loadDb.bytes);
#elif UNITY_IOS
var loadDb = Application.dataPath + "/Raw/" + DatabaseName; // this is the path to your StreamingAssets in iOS
// then save to Application.persistentDataPath
File.Copy(loadDb, filepath);
#elif UNITY_WP8
var loadDb = Application.dataPath + "/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS
// then save to Application.persistentDataPath
File.Copy(loadDb, filepath);
#elif UNITY_WINRT
var loadDb = Application.dataPath + "/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS
// then save to Application.persistentDataPath
File.Copy(loadDb, filepath);
#else
var loadDb = Application.dataPath + "/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS
// then save to Application.persistentDataPath
File.Copy(loadDb, filepath);
#endif
Debug.Log("Database written");
}
var dbPath = filepath;
#endif
_connection = new SQLiteConnection(dbPath, SQLiteOpenFlags.ReadWrite | SQLiteOpenFlags.Create);
Debug.Log("Final PATH: " + dbPath);
}
public void CreateDB(){
_connection.DropTable<Person> ();
_connection.CreateTable<Person> ();
_connection.InsertAll (new[]{
new Person{
Id = 1,
Name = "Tom",
Surname = "Perez",
Age = 56
},
new Person{
Id = 2,
Name = "Fred",
Surname = "Arthurson",
Age = 16
},
new Person{
Id = 3,
Name = "John",
Surname = "Doe",
Age = 25
},
new Person{
Id = 4,
Name = "Roberto",
Surname = "Huertas",
Age = 37
}
});
}
public IEnumerable<Person> GetPersons(){
return _connection.Table<Person>();
}
public IEnumerable<Person> GetPersonsNamedRoberto(){
return _connection.Table<Person>().Where(x => x.Name == "Roberto");
}
public Person GetJohnny(){
return _connection.Table<Person>().Where(x => x.Name == "Johnny").FirstOrDefault();
}
public Person CreatePerson(){
var p = new Person{
Name = "Johnny",
Surname = "Mnemonic",
Age = 21
};
_connection.Insert (p);
return p;
}
}
它由另外两个脚本来创建或使用现有数据库。
<强> ExistingDBScript.cs
using UnityEngine;
using System.Collections.Generic;
using UnityEngine.UI;
public class ExistingDBScript : MonoBehaviour {
public Text DebugText;
// Use this for initialization
void Start () {
var ds = new DataService ("existing.db");
//ds.CreateDB ();
var people = ds.GetPersons ();
ToConsole (people);
people = ds.GetPersonsNamedRoberto ();
ToConsole("Searching for Roberto ...");
ToConsole (people);
ds.CreatePerson ();
ToConsole("New person has been created");
var p = ds.GetJohnny ();
ToConsole(p.ToString());
}
private void ToConsole(IEnumerable<Person> people){
foreach (var person in people) {
ToConsole(person.ToString());
}
}
private void ToConsole(string msg){
DebugText.text += System.Environment.NewLine + msg;
Debug.Log (msg);
}
}
<强> CreateDBScript.cs
using UnityEngine;
using System.Collections.Generic;
using UnityEngine.UI;
public class CreateDBScript : MonoBehaviour {
public Text DebugText;
// Use this for initialization
void Start () {
StartSync();
}
private void StartSync()
{
var ds = new DataService("tempDatabase.db");
ds.CreateDB();
var people = ds.GetPersons ();
ToConsole (people);
people = ds.GetPersonsNamedRoberto ();
ToConsole("Searching for Roberto ...");
ToConsole (people);
}
private void ToConsole(IEnumerable<Person> people){
foreach (var person in people) {
ToConsole(person.ToString());
}
}
private void ToConsole(string msg){
DebugText.text += System.Environment.NewLine + msg;
Debug.Log (msg);
}
}
person脚本演示了数据库中的人员表
using SQLite4Unity3d;
public class Person {
[PrimaryKey, AutoIncrement]
public int Id { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
public int Age { get; set; }
public override string ToString ()
{
return string.Format ("[Person: Id={0}, Name={1}, Surname={2}, Age={3}]", Id, Name, Surname, Age);
}
}
您还需要在项目中添加插件和Sqlite.cs，您可以在git repository
它帮助我克服了这个问题，希望它能帮助其他人。