我在Libgdx新的，我对我的游戏使用一个数据库中获取的麻烦。
我搜索了如何使使用Libgdx Android和桌面应用程序的SQLite工作的教程，但我没有找到一个简单的一个。
我在Android中使用的数据库的最后一次，我创建了从扩展一个类SQLiteOpenHelper 。
有一个简单的方式做使用Libgdx一样吗？ 或者至少，任何人都可以点我一步一步的教程或类似的东西？
编辑
我忘了说，我在寻找，让我管理的版本一样东西SQLiteOpenHelper 。 换句话说，我希望我重新在Android的数据库APK安装，当我改变我的数据库版本的代码。
解
继@42n4的答案，我设法如何连接到使用SQLite数据库SQLiteOpenHelper在Android应用程序和JDBC的桌面应用程序。
首先，我创建了桌面和Android应用程序“共同类”：
//General class that needs to be implemented on Android and Desktop Applications
public abstract class DataBase {
protected static String database_name="recycling_separation";
protected static DataBase instance = null;
protected static int version=1;
//Runs a sql query like "create".
public abstract void execute(String sql);
//Identical to execute but returns the number of rows affected (useful for updates)
public abstract int executeUpdate(String sql);
//Runs a query and returns an Object with all the results of the query. [Result Interface is defined below]
public abstract Result query(String sql);
public void onCreate(){
//Example of Highscore table code (You should change this for your own DB code creation)
execute("CREATE TABLE 'highscores' ('_id' INTEGER PRIMARY KEY NOT NULL , 'name' VARCHAR NOT NULL , 'score' INTEGER NOT NULL );");
execute("INSERT INTO 'highscores'(name,score) values ('Cris',1234)");
//Example of query to get DB data of Highscore table
Result q=query("SELECT * FROM 'highscores'");
if (!q.isEmpty()){
q.moveToNext();
System.out.println("Highscore of "+q.getString(q.getColumnIndex("name"))+": "+q.getString(q.getColumnIndex("score")));
}
}
public void onUpgrade(){
//Example code (You should change this for your own DB code)
execute("DROP TABLE IF EXISTS 'highscores';");
onCreate();
System.out.println("DB Upgrade maded because I changed DataBase.version on code");
}
//Interface to be implemented on both Android and Desktop Applications
public interface Result{
public boolean isEmpty();
public boolean moveToNext();
public int getColumnIndex(String name);
public float getFloat(int columnIndex);
[...]
}
}
然后，我创建了一个DatabaseDesktop类的桌面应用程序：
public class DatabaseDesktop extends DataBase{
protected Connection db_connection;
protected Statement stmt;
protected boolean nodatabase=false;
public DatabaseDesktop() {
loadDatabase();
if (isNewDatabase()){
onCreate();
upgradeVersion();
} else if (isVersionDifferent()){
onUpgrade();
upgradeVersion();
}
}
public void execute(String sql){
try {
stmt.execute(sql);
} catch (SQLException e) {
e.printStackTrace();
}
}
public int executeUpdate(String sql){
try {
return stmt.executeUpdate(sql);
} catch (SQLException e) {
e.printStackTrace();
}
return 0;
}
public Result query(String sql) {
try {
return new ResultDesktop(stmt.executeQuery(sql));
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
private void loadDatabase(){
File file = new File (database_name+".db");
if(!file.exists())
nodatabase=true;
try {
Class.forName("org.sqlite.JDBC");
db_connection = DriverManager.getConnection("jdbc:sqlite:"+database_name+".db");
stmt = db_connection.createStatement();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
private void upgradeVersion() {
execute("PRAGMA user_version="+version);
}
private boolean isNewDatabase() {
return nodatabase;
}
private boolean isVersionDifferent(){
Result q=query("PRAGMA user_version");
if (!q.isEmpty())
return (q.getInt(1)!=version);
else
return true;
}
public class ResultDesktop implements Result{
ResultSet res;
boolean called_is_empty=false;
public ResultDesktop(ResultSet res) {
this.res = res;
}
public boolean isEmpty() {
try {
if (res.getRow()==0){
called_is_empty=true;
return !res.next();
}
return res.getRow()==0;
} catch (SQLException e) {
e.printStackTrace();
}
return false;
}
public boolean moveToNext() {
try {
if (called_is_empty){
called_is_empty=false;
return true;
} else
return res.next();
} catch (SQLException e) {
e.printStackTrace();
}
return false;
}
public int getColumnIndex(String name) {
try {
return res.findColumn(name);
} catch (SQLException e) {
e.printStackTrace();
}
return 0;
}
public float getFloat(int columnIndex) {
try {
return res.getFloat(columnIndex);
} catch (SQLException e) {
e.printStackTrace();
}
return 0;
}
[...]
}
}
和DatabaseAndroid为Android应用
public class DatabaseAndroid extends DataBase{
protected SQLiteOpenHelper db_connection;
protected SQLiteDatabase stmt;
public DatabaseAndroid(Context context) {
db_connection = new AndroidDB(context, database_name, null, version);
stmt=db_connection.getWritableDatabase();
}
public void execute(String sql){
stmt.execSQL(sql);
}
public int executeUpdate(String sql){
stmt.execSQL(sql);
SQLiteStatement tmp = stmt.compileStatement("SELECT CHANGES()");
return (int) tmp.simpleQueryForLong();
}
public Result query(String sql) {
ResultAndroid result=new ResultAndroid(stmt.rawQuery(sql,null));
return result;
}
class AndroidDB extends SQLiteOpenHelper {
public AndroidDB(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
}
public void onCreate(SQLiteDatabase db) {
stmt=db;
DatabaseAndroid.this.onCreate();
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
stmt=db;
DatabaseAndroid.this.onUpgrade();
}
}
public class ResultAndroid implements Result{
Cursor cursor;
public ResultAndroid(Cursor cursor) {
this.cursor=cursor;
}
public boolean isEmpty() {
return cursor.getCount()==0;
}
public int getColumnIndex(String name) {
return cursor.getColumnIndex(name);
}
public String[] getColumnNames() {
return cursor.getColumnNames();
}
public float getFloat(int columnIndex) {
return cursor.getFloat(columnIndex);
}
[...]
}
}
最后，我改变了Android和桌面应用程序的主要类：
public class Main extends AndroidApplication {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
initialize(new MyGame(new DatabaseAndroid(this.getBaseContext())), false);
}
}
public class Main {
public static void main(String[] args) {
new LwjglApplication(new MyGame(new DatabaseDesktop()), "Example", MyGame.SCREEN_WIDTH, MyGame.SCREEN_HEIGHT,false);
}
}
注意：
我做了一个版本管理一样，在发生在一个SQLiteOpenHelper使用PRAGMA user_version 。 这样一来，我只是改变了的版本DataBase类，当我需要升级。
我没有把所有我所取得的方法Result ，但是，我把我认为更important.that是更重要的。
