Skopiuj moją własną bazę danych SQLite z folderu zasobów do

Question

Nie rozumiem, dlaczego nie mogę skopiować pliku db (abic_) do katalogu aplikacji ("/ data/data /" + context.getPackageName() + "/ bazy danych")

to moja klasa DataBaseHelper:

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

import android.content.Context; 
import android.database.SQLException; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteException; 
import android.database.sqlite.SQLiteOpenHelper; 


public class DataBaseHelper extends SQLiteOpenHelper{ 

    //The Android's default system path of your application database. 
    private String DB_PATH; 

    private static String DB_NAME = "abic_"; 
    private static final Integer DB_VERSION = 1; 

    private SQLiteDatabase mydb; 

    private final Context myContext; 

    /** 
    * Constructor 
    * Takes and keeps a reference of the passed context in order to access to the application assets and resources. 
    * @param context 
    */ 
    public DataBaseHelper(Context context) { 

     super(context, DB_NAME, null, DB_VERSION); 
     this.myContext = context; 
     DB_PATH = "/data/data/" + context.getPackageName() + "/databases"; 
    } 

    @Override 
    public void onCreate(SQLiteDatabase db) {; 
    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    } 

public void apriDatabase() throws SQLException { 
    try { 
      String percorso = DB_PATH + DB_NAME; 
      mydb = SQLiteDatabase.openDatabase(percorso, null, SQLiteDatabase.OPEN_READONLY); 
    } catch (Exception e) { 
      e.printStackTrace(); 
    } 
} 

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. 
      this.getReadableDatabase(); 
      try { 
        copyDataBase(); 
      } catch (IOException e) { 
        e.printStackTrace(); 
      } 
    } 
} 

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; 

    // if the path doesn't exist first, create it 
    File f = new File(outFileName); 
    if (!f.exists()){ 
      f.mkdir(); 
      f.createNewFile(); 
    } 

    //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(); 

} 

private boolean checkDataBase(){ 

    SQLiteDatabase checkDB = null; 

    try{ 
      String myPath = DB_PATH + DB_NAME; 
      checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE); 

    }catch(SQLiteException e){ 

      //database does't exist yet. 

    } 

    if(checkDB != null){ 

      checkDB.close(); 

    } 

    return checkDB != null ? true : false; 
} 

@Override 
    public synchronized void close() { 
     if(mydb != null) 
      mydb.close(); 
     super.close(); 
    } 

}

to ListView, który wykorzystuje tę klasę:

import android.app.ListActivity; 
import android.content.Intent; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.EditText; 
import android.widget.ListAdapter; 
import android.widget.ListView; 
import android.widget.SimpleCursorAdapter; 

public class abicabList extends ListActivity { 

     protected EditText searchText; 
     protected SQLiteDatabase mydb; 
     protected Cursor cursor; 
     protected ListAdapter adapter; 

    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 
     mydb = (new DataBaseHelper(this)).getWritableDatabase(); 
     searchText = (EditText) findViewById (R.id.searchText); 
    } 

    public void search(View view) { 

    String text = searchText.getText().toString(); 
    String cap = "CAP"; 
    // || is the concatenation operation in SQLite 
     if (text.length()14) {  
cursor = mydb.rawQuery("SELECT _id, ABI, BANCA, CAB, CAP, Filiale, City FROM abicab WHERE ABI || CAB LIKE ? LIMIT 30", 
      new String[]{"%" + searchText.getText().toString().substring(6,10) + "%" + searchText.getText().toString().substring(11,15) + "%"});  
    adapter = new SimpleCursorAdapter( 
           this, 
           R.layout.abicab_list_item, 
           cursor, 
           new String[] {"BANCA", "Filiale", "City", "CAP"}, 
       new int[] {R.id.BANCA, R.id.Filiale, R.id.City ,R.id.CAP}); 
     setListAdapter(adapter); 
    } 

    }

Więc kiedy uruchomić aplikację db jest tworzony w folder, ale nie zawiera tabeli tha t znajduje się w katalogu db Mam w folderze aktywów (patrz zdjęcie [1]: http://i.stack.imgur.com/AaFj8.jpg). Z góry dziękuję za pomoc.

Answer 1

Rozwiązałem problem.

1) Użyłem klasy AlmanacSQLiteDatabaseAdapter.java używanej w Almanac 0.0.17 (projekt open source), który można znaleźć tutaj: link. Możesz dopasować się do swoich potrzeb (w moim przypadku zmieniłem nazwę na DatabaseHelper);

2) To jest klasa, która korzysta z Pomocnika (jest to listview, który wykonuje sql czytania ciągów tekstowych w EditText - jest to układ tego samouczka "coenraets.org/blog/android-samples/androidtutorial/" :

public class MiaList extends Activity { 

     protected EditText searchText; 
     protected SQLiteDatabase db; 
     protected Cursor cursor; 
     protected ListAdapter ladapter; 
     protected ListView miaList; 
     private static final String DATABASE_NAME = "miodb.jpg"; 
/* 
L'ESTENSIONE JPG (o mp3, mov) questo perchè android ha il limite di 1 mb per i file di testo 
o simili nella asset, mentre NON HA limiti per i file multimediali! Nel mio caso si tratta di 4mb 
*/ 

    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 

//qui sotto richiamo la classe DatabaseHelper 

     DatabaseHelper dbAdapter = DatabaseHelper.getInstance(this, DATABASE_NAME); 
     /*note di Vytek*/ 
     // OK Dovrei usare aSQLiteDatabaseAdapter.getDatabase(); ma questo crea 
     // problemi nella fase di OnPause quando premo Back cosi' invece non 
     // ottengo errori 
     // e viene fatta la normale copia del DB (13/8/2010 23.18) 
     // db = aSQLiteDatabaseAdapter.getWritableDatabase(); 
     // Per ovviare a questo problema controllo se e' la prima volta che 
     // chiamo applicazione 
     if (getFirstRun()) { 
       db = dbAdapter.getDatabase(); 
       setRunned(); 
     } else { 
       db = dbAdapter.getWritableDatabase(); 
     } 

     searchText = (EditText) findViewById (R.id.searchText); 
     miaList = (ListView) findViewById (R.id.list); 
    } 


    private void setRunned() { 
       // TODO Auto-generated method stub 

     } 

     private boolean getFirstRun() { 
       // TODO Auto-generated method stub 
       return false; 
     } 

     public void search(View view) { 

     String text = searchText.getText().toString(); 
     // || è l'operatore "concatena" in SQLite 
     if (text.length()<15){ 
        cursor = db.rawQuery("SELECT *FROM miatable WHERE AAA || ' ' || BBB || ' ' || CCC LIKE ? LIMIT 30", 
          new String[]{"%" + searchText.getText().toString() + "%"}); 
           ladapter = new SimpleCursorAdapter( 
               this, 
               R.layout.mialist_list_item, 
               cursor, 
               new String[] {"_id", "AAA", "BBB", "CCC"}, 
               new int[] {R.id._id, R.id.AAA, R.id.BBB, R.id.CCC}); 
           miaList.setAdapter(ladapter); 
           //istruzione da eseguire 
       } 
     else {   
        cursor = db.rawQuery("SELECT * FROM miatable WHERE AAA || BBB LIKE ? LIMIT 30", 
          new String[]{"%" + searchText.getText().toString().substring(6,10) + "%" + searchText.getText().toString().substring(11,15) + "%"});   
           ladapter = new SimpleCursorAdapter( 
               this, 
               R.layout.mialist_list_item, 
               cursor, 
               new String[] {"_id", "AAA", "BBB", "CCC"}, 
               new int[] {R.id._id, R.id.AAA, R.id.BBB, R.id.CCC}); 
           miaList.setAdapter(ladapter); 
           //istruzione da eseguire 
        } 


     } 

} 

oczywiście "miodb.jpg" SQLite dB musi być w folderze aktywów roboczej zaćmienia

PS Użyłem rozszerzenie jpg na db beacause folder atutem ma. limit 1 MB dla rozszerzenia db lub txt lub xml

Answer 2

Czy używasz emulatora lub urządzenia?

Wykonuję tę samą procedurę, ale kopiuję bazę danych na kartę SD, ponieważ emulator ma ograniczony rozmiar przestrzeni, jaka jest wielkość bazy danych?

---

Wymień metodę kopiowania na tę i daj mi znać, ponieważ nie mogłem znaleźć niczego dziwnego poza metodą kopiowania, Powodzenia.

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(); 

} 

Answer 3

Oto prosty i wygodny kod, który używam:

public class DataBaseImportHelper { 
    private DataBaseImportHelper() {}; // Avoid instantiation 

/** 
* Creates a empty database on the system and rewrites it with your own database. 
*/ 
public static boolean importDataBase(Context context) { 
    InputStream myInput = null; 
    OutputStream myOutput = null; 
    try { 
     // Open local db from assets as the input stream 
     myInput = context.getAssets().open(DATABASE_NAME); 
     createEmptyDatabase(context); // See this method below 
     // Open the empty db as the output stream 
     myOutput = new FileOutputStream(getDatabaseFile(context)); 

     // 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(); 
     myInput.close(); 
     myOutput.close(); 
     return true; 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    return false; 
} 

/** 
* Check if the database already exists. 
* @return true if it exists, false if it doesn't 
*/ 
public static boolean isDatabaseExists(Context context) { 
    return getDatabaseFile(context).exists(); 
} 

private static File getDatabaseFile(Context context) { 
    return context.getDatabasePath(DatabaseHelper.DATABASE_NAME); 
} 

/** 
* Create an empty database into the default application database 
* folder.So we are gonna be able to overwrite that database with our database 
*/ 
private static void createEmptyDatabase(Context context) { 
      // use anonimous helper to create empty database 
    new SQLiteOpenHelper(context, DatabaseHelper.DATABASE_NAME, null, 1) { 
        // Methods are empty. We don`t need to override them 
     @Override 
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
     } 

     @Override 
     public void onCreate(SQLiteDatabase db) { 
     } 
    }.getReadableDatabase().close(); 
} 

}

i używanie w postaci kodu:

if(!DataBaseImportHelper.isDatabaseExists(this)){ 
    if (!DataBaseImportHelper.importDataBase(this)){ 
      throw new IllegalStateException("Database doesn`t exist and hasn`t been copied!"); 
    } 
} 

Answer 4

przede wszystkim upewnij się dodać android.permission .WRITE_EXTERNAL_STORAGE uprawnienia do pliku manifestu. W jednym z moich aplikacji użyłem klasy poniżej i działa idealnie. Spróbuj tego i daj mi znać, jeśli to działa.

public class ImpotDatabaseFileTask extends AsyncTask<String, Void, Boolean> { 
ProgressDialog dialog; 
private Context con; 
boolean success = false; 

public ImpotDatabaseFileTask(Context con) { 
    this.con = con; 
    dialog = new ProgressDialog(con); 
    this.dialog.setMessage("Importing database..."); 
    execute(null); 
} 

@Override 
protected Boolean doInBackground(String... params) { 
    try { 
     OutputStream myOutput; 
     File destination = new File(Environment.getDataDirectory() 
       + "//data//<package name>//databases//database_name.db"); 

     // Set the folder on the SDcard 
     File dbFile = new File(Environment.getExternalStorageDirectory(), 
       "//<custom folder>//<database_name>.db"); 
     if (dbFile.exists()) { 
      copyFile(dbFile, destination); 
      success = true; 
     } 

    } catch (FileNotFoundException e) { 
     // Toast.makeText(Settings.this, 
     // "Restore unsuccessful! File not found! Directory does not exist?", 
     // Toast.LENGTH_LONG).show(); 

     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } catch (IOException e) { 
     Toast.makeText(con, "Restore unsuccessful!", Toast.LENGTH_SHORT) 
       .show(); 

     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 
    return null; 
} 

void copyFile(File src, File dst) throws IOException { 
    FileChannel inChannel = new FileInputStream(src).getChannel(); 
    FileChannel outChannel = new FileOutputStream(dst).getChannel(); 
    try { 
     inChannel.transferTo(0, inChannel.size(), outChannel); 
    } finally { 
     if (inChannel != null) 
      inChannel.close(); 
     if (outChannel != null) 
      outChannel.close(); 
    } 
} 

@Override 
protected void onPostExecute(Boolean result) { 
    if (this.dialog.isShowing()) { 
     this.dialog.dismiss(); 
    } 
    if (success) { 
     Toast.makeText(con, "Restore successful!", Toast.LENGTH_SHORT) 
       .show(); 
    } else { 
     Toast.makeText(con, "Restore failed", Toast.LENGTH_SHORT).show(); 
    } 
    super.onPostExecute(result); 
} 

}