androidの/ data/data/package-name/app_database /にデータベースを作成する方法

Question

/data/data/package-nameの代わりに/ data/data/package-name/app_database /にdbを作成する必要があります/データベース/ ...それを行う方法？

Answer 1

を拡張し、次のコードをDBHelper.javaを作成し、追加し、このHow to make a database for my android appリンクからアクセスしてください私のansを見てください。ちょうどあなたはデータベースのパスを変更する必要があります...それが動作することを願って

Answer 2

最初のコピー、あなたの資産へのデータベースとは

パブリッククラスDBHelperはSQLiteOpenHelper {

private static final String DATABASE_NAME = "database_name.sqlite"; 
private static final int DATABASE_VERSION = 1; 
private static final String DB_PATH = "/data/data/package_name/databases/"; 
private Context myContext; 
private SQLiteDatabase myDataBase; 

public DBHelper(Context context) { 

    super(context, DATABASE_NAME, null, DATABASE_VERSION); 
    this.myContext = context; 
} 

/** 
* Creates a empty database on the system and rewrites it with your own database. 
* */ 
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(); 
      throw new Error("Error copying database"); 

     } 
    } 

} 

/** 
* Check if the database already exist to avoid re-copying the file each time you open the application. 
* @return true if it exists, false if it doesn't 
*/ 
public boolean checkDataBase(){ 

    SQLiteDatabase checkDB = null; 

    try{ 
     String myPath = DB_PATH + DATABASE_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; 
} 

/** 
* Copies your database from your local assets-folder to the just created empty database in the 
* system folder, from where it can be accessed and handled. 
* This is done by transfering bytestream. 
* */ 
public void copyDataBase() throws IOException{ 

    //Open your local db as the input stream 
    InputStream myInput = myContext.getAssets().open(DATABASE_NAME); 

    // Path to the just created empty db 
    String outFileName = DB_PATH + DATABASE_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 + DATABASE_NAME; 
    myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE); 

} 

@Override 
public synchronized void close() { 


    if(myDataBase != null) 
     myDataBase.close(); 



} 


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

} 

@Override 
public void onCreate(SQLiteDatabase db) { 
    // TODO Auto-generated method stub 

} 

}