以下に示すコードを使用して、アセット フォルダーからアプリケーションに外部データベースを追加したいと考えています。エミュレーターで Android の古いバージョン (Android 2.3.3 など) でアプリケーションを実行すると、次のエラーが表示されます:
android.database.sqlite.SQLiteException: no such table: android_metadata
しかし、コードは新しいバージョンで正常に動作します。
これはコードです：
public class MainDataBase extends SQLiteOpenHelper{
private static String DB_PATH = "/data/data/com.nony.dictionary/databases/";
private static String DB_NAME = "allwords.db";
private String TABLE_NAME ="ENGLISH";
private SQLiteDatabase myDataBase;
private final Context myContext;
public MainDataBase(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
}
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist){
//do nothing - database already exist
}else{
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
SQLiteDatabase db = this.getReadableDatabase();
if (db.isOpen()){
db.close();
}
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database does't exist yet.
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
private void copyDataBase() throws IOException{
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException{
//Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
@Override
public synchronized void close() {
if(myDataBase != null)
myDataBase.close();
super.close();
}
public ArrayList<HashMap<String,String>> getalldatas()
{
String select=null;
ArrayList<HashMap<String,String>> allContacts = new ArrayList<HashMap<String,String>> ();
select ="SELECT * FROM "+TABLE_NAME +" ORDER BY ENGWORD" ;
SQLiteDatabase data = this.getReadableDatabase();
Cursor thecusor = data.rawQuery(select, null);
if(thecusor.moveToFirst())
{
do{
HashMap<String, String> createtheMap = new HashMap<String, String> ();
createtheMap.put("_ID", thecusor.getString(0));
createtheMap.put("ENGWORD", thecusor.getString(1));
// Log.d("gggg", thecusor.getString(0)+thecusor.getString(1)+thecusor.getString(2));
allContacts.add(createtheMap);
}while(thecusor.moveToNext());
}
return allContacts;
}
@Override
public void onCreate(SQLiteDatabase arg0) {
// TODO Auto-generated method stub
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}