复制现有数据库sqlite并在设备上运行-android

Question

I want to check the database if it's exists or not. If did not exist, i will copy the file to the specific path. Here the code as below:

Main.java

   UserDbAdapter objChatMessageDbAdapter = new UserDbAdapter();
   objChatMessageDbAdapter.context = context;
   User objChatMessage = objChatMessageDbAdapter.getUser();

   if(objChatMessage.getID()<1){

        //call register intent
   }else{
        // call the first intent
   }

UserDbAdapter.java

    private SQLiteDatabase db;
    private static String TABLE_USER = "User";
    private boolean isDbClosed =true;
    public Context context;
    String TAG = "UserDbAdapter";

    public UserDbAdapter() { }

    public void init(Context context) {

      if(isDbClosed){
        DatabaseAdapter dbAdapter = DatabaseAdapter.getInstance(context);
        isDbClosed =false;
        db = dbAdapter.getWritableDatabase();
      }     

      this.context = context;
    }

    private void processConnection()
    {
      Log.i(TAG, "isDbClosed==="+isDbClosed);
      if(isDbClosed){
        DatabaseAdapter dbAdapter = new DatabaseAdapter(context);
        dbAdapter = DatabaseAdapter.getInstance(context);
        isDbClosed =false;
        db = dbAdapter.getWritableDatabase();
        Log.i(TAG, "processConnection db===="+db.toString());
       }     
   }

   public boolean isDatabaseClosed(){
     return isDbClosed;
   }

   public User getUser()
   {

            processConnection();
            User objChatMessageEntity = new User();
            String selectQuery = "Select UserId, Name, Password FROM "+TABLE_USER;  
            Cursor cursor = db.rawQuery(selectQuery, null);
            // looping through all rows and adding to list 
            if (cursor.moveToFirst()) {                              
            objChatMessageEntity = fieldMappingForGetRecord(cursor);

             }
             cursor.close();
             db.close();
             isDbClosed =true;
             return objChatMessageEntity;
   }
}

DatabaseAdapter.java

private static String dbPath;
private static String dbName = "ownexpensesdb"; 
private SQLiteDatabase applicationDatabase;  
public final Context applicationContext;
private static DatabaseAdapter mInstance = null;
private static final int DATABASE_VERSION = 1;


public static DatabaseAdapter getInstance(Context ctx) { 

    if (mInstance == null) { 
        dbPath = "/data/data/" + ctx.getPackageName() + "/databases/";
        mInstance = new DatabaseAdapter(ctx.getApplicationContext()); 
    } 
    return mInstance; 
}

public DatabaseAdapter(Context context) {    
    super(context,  dbName , null, DATABASE_VERSION);
    this.applicationContext  = context;

    boolean  dbExist = checkDataBase();
    //SQLiteDatabase db_Read = null;
    if (dbExist){
       Log.w("Database","file found ");
       openDataBase();
    }
    else
    {
        Log.w("Database","file not found ");
        this.getReadableDatabase(); 
        try 
        {
            copyDatabase();
        } 
        catch (IOException e) 
        {
            Log.e("Error",""+e.getMessage());
            e.printStackTrace();
        } 
   }
}


private boolean checkDataBase(){  
   File dbFile = new File( dbPath +  dbName);  
   return dbFile.exists();
}

private void copyDatabase() throws IOException
{  
    InputStream input =  applicationContext.getAssets().open(dbName);
     String outPutFileName=  dbPath  +  dbName ;
     OutputStream output = new FileOutputStream( outPutFileName); 
    byte[] buffer = new byte[1024];
    int length;
    while ((length = input.read(buffer))>0){
     output.write(buffer, 0, length);
    }
    output.flush();
    output.close();
    input.close();
}


   public void openDataBase() throws SQLException
   {
        String fullDbPath= dbPath + dbName;
        Log.w("Database","open DB");
        try
        {
            applicationDatabase = SQLiteDatabase.openDatabase( fullDbPath, null,SQLiteDatabase.OPEN_READONLY);
        }
        catch (Exception e) {
            Log.e("error",e.toString());
        }
   }

  @Override
    public synchronized void close() {
         if( applicationDatabase != null)
           applicationDatabase .close();
               super.close();
  }
  @Override
  public void onCreate(SQLiteDatabase db) {
  }

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

when I run the code, I get error as below and the application is crash: 08-28 11:01:10.785: W/Database(9975): file not found 08-28 11:01:10.875: E/Error(9975): /nullownexpensesdb: open failed: EROFS (Read-only file system) 08-28 11:01:10.875: W/System.err(9975): java.io.FileNotFoundException: /nullownexpensesdb: open failed: EROFS (Read-only file system) 08-28 11:01:10.875: W/System.err(9975): at libcore.io.IoBridge.open(IoBridge.java:416) 08-28 11:01:10.880: W/System.err(9975): at java.io.FileOutputStream.(FileOutputStream.java:88) 08-28 11:01:10.880: W/System.err(9975): at java.io.FileOutputStream.(FileOutputStream.java:128) 08-28 11:01:10.880: W/System.err(9975): at java.io.FileOutputStream.(FileOutputStream.java:117) 08-28 11:01:10.880: W/System.err(9975): at com.canmmy.expensesmanager.data.DatabaseAdapter.copyDatabase(DatabaseAdapter.java:70) 08-28 11:01:10.880: W/System.err(9975): at com.canmmy.expensesmanager.data.DatabaseAdapter.(DatabaseAdapter.java:50) 08-28 11:01:10.880: W/S ystem.err(9975): at com.canmmy.expensesmanager.data.UserDbAdapter.processConnection(UserDbAdapter.java:35) 08-28 11:01:10.880: W/System.err(9975): at com.canmmy.expensesmanager.data.UserDbAdapter.getUser(UserDbAdapter.java:77) 08-28 11:01:10.880: W/System.err(9975): at com.canmmy.expensesmanager.SplashActivity.initMain(SplashActivity.java:34) 08-28 11:01:10.880: W/System.err(9975): at com.canmmy.expensesmanager.SplashActivity.access$0(SplashActivity.java:32) 08-28 11:01:10.880: W/System.err(9975): at com.canmmy.expensesmanager.SplashActivity$1.run(SplashActivity.java:27) 08-28 11:01:10.880: W/System.err(9975): at android.os.Handler.handleCallback(Handler.java:615) 08-28 11:01:10.880: W/System.err(9975): at android.os.Handler.dispatchMessage(Handler.java:92) 08-28 11:01:10.880: W/System.err(9975): at android.os.Looper.loop(Looper.java:137) 08-28 11:01:10.880: W/System.err(9975): at android.app.ActivityThread.main(ActivityThread.java:4898) 08-28 11:01:10.880: W/System.err(9975): at java. lang.reflect.Method.invokeNative(Native Method) 08-28 11:01:10.880: W/System.err(9975): at java.lang.reflect.Method.invoke(Method.java:511) 08-28 11:01:10.880: W/System.err(9975): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008) 08-28 11:01:10.880: W/System.err(9975): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775) 08-28 11:01:10.880: W/System.err(9975): at dalvik.system.NativeStart.main(Native Method) 08-28 11:01:10.880: W/System.err(9975): Caused by: libcore.io.ErrnoException: open failed: EROFS (Read-only file system) 08-28 11:01:10.885: W/System.err(9975): at libcore.io.Posix.open(Native Method) 08-28 11:01:10.885: W/System.err(9975): at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110) 08-28 11:01:10.885: W/System.err(9975): at libcore.io.IoBridge.open(IoBridge.java:400) 08-28 11:01:10.885: W/System.err(9975): ... 19 more 08-28 11:01:10.885: W/Database(9975): file found 08-28 11:01:10.885: W/Database(9975): open DB 08-28 11:01:1 0.895: I/UserDbAdapter(9975): processConnection db====SQLiteDatabase: /data/data/com.canmmy.expensesmanager/databases/ownexpensesdb 08-28 11:01:10.895: I/sqlite-select query(9975): Select UserId, Name, Password FROM User; 08-28 11:01:10.895: E/SQLiteLog(9975): (1) no such table: User 08-28 11:01:10.895: D/AndroidRuntime(9975): Shutting down VM 08-28 11:01:10.895: W/dalvikvm(9975): threadid=1: thread exiting with uncaught exception (group=0x410502a0) 08-28 11:01:10.900: E/AndroidRuntime(9975): FATAL EXCEPTION: main 08-28 11:01:10.900: E/AndroidRuntime(9975): android.database.sqlite.SQLiteException: no such table: User (code 1): , while compiling: Select UserId, Name, Password FROM User; 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:1011) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:622) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.database.sqlite.SQLiteProgram.(SQLiteProgram.java:58) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.database.sqlite.SQLiteQuery.(SQLiteQuery.java:37) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314) 08-28 11:01 :10.900: E/AndroidRuntime(9975): at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1253) 08-28 11:01:10.900: E/AndroidRuntime(9975): at com.canmmy.expensesmanager.data.UserDbAdapter.getUser(UserDbAdapter.java:81) 08-28 11:01:10.900: E/AndroidRuntime(9975): at com.canmmy.expensesmanager.SplashActivity.initMain(SplashActivity.java:34) 08-28 11:01:10.900: E/AndroidRuntime(9975): at com.canmmy.expensesmanager.SplashActivity.access$0(SplashActivity.java:32) 08-28 11:01:10.900: E/AndroidRuntime(9975): at com.canmmy.expensesmanager.SplashActivity$1.run(SplashActivity.java:27) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.os.Handler.handleCallback(Handler.java:615) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.os.Handler.dispatchMessage(Handler.java:92) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.os.Looper.loop(Looper.java:137) 08-28 11:01:10.900: E/AndroidRuntime(9975): at android.app.ActivityThread.main(ActivityThread.java:4898) 08-28 11:01:1 0.900: E/AndroidRuntime(9975): at java.lang.reflect.Method.invokeNative(Native Method) 08-28 11:01:10.900: E/AndroidRuntime(9975): at java.lang.reflect.Method.invoke(Method.java:511) 08-28 11:01:10.900: E/AndroidRuntime(9975): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008) 08-28 11:01:10.900: E/AndroidRuntime(9975): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775) 08-28 11:01:10.900: E/AndroidRuntime(9975): at dalvik.system.NativeStart.main(Native Method)

Answer 1

The following code works for me. I put the database in the assets folder.

The only thing that you have to be aware of, if you change the database in the asset folder, you have to first uninstall the application with adb uninstall yourpackagename, otherwise the app will be updated but the database will not. It took me a little bit to figure this out. Hope this helps.

Note: TDAdb is a method that defines the variables used with the database. The TDAdb.onCreate and TDAdb.onUpdate don't have to do anything in this case.

    public class TDAdbHelper extends SQLiteOpenHelper {

public static String DATABASE_PATH;
public static final String DATABASE_NAME = "tda.db";
private static final int DATABASE_VERSION = 1;
private Context context;
private SQLiteDatabase db;

public TDAdbHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
    this.context = context;
    String packageName = context.getPackageName();
    DATABASE_PATH = String.format(context.getString(R.string.str_databasepath),
            packageName);
    openDataBase();
}

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

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

// Performing a database existence check
private boolean checkDataBase() {
    SQLiteDatabase checkDb = null;
    try {
        String path = DATABASE_PATH + DATABASE_NAME;
        checkDb = SQLiteDatabase.openDatabase(path, null,
                SQLiteDatabase.OPEN_READONLY);
    } catch (SQLException e) {
        Log.e(this.getClass().toString(), context.getString(R.string.str_error_while_checking_db));
    }

    if (checkDb != null) {
        checkDb.close();
    }
    return checkDb != null;
}

// Method for copying the database
private void copyDataBase() throws IOException {
    //Log.i(this.getClass().toString(), "... in copyDataBase ");
    InputStream externalDbStream = context.getAssets().open(DATABASE_NAME);

    String outFileName = DATABASE_PATH + DATABASE_NAME;

    OutputStream localDbStream = new FileOutputStream(outFileName);

    byte[] buffer = new byte[1024];
    int bytesRead;
    while ((bytesRead = externalDbStream.read(buffer)) > 0) {
        localDbStream.write(buffer, 0, bytesRead);
    }

    localDbStream.close();
    externalDbStream.close();
}

public void createDataBase() {
    //Log.i(this.getClass().toString(), "... in createDataBase ");
    boolean dbExist = checkDataBase();
    if (!dbExist) {
        this.getReadableDatabase();
        try {
            copyDataBase();
        } catch (IOException e) {
            Log.e(this.getClass().toString(), context.getString(R.string.str_copying_error));
            throw new Error(context.getString(R.string.str_error_copying_database_exclamation));
        }
    } else {
        //Log.i(this.getClass().toString(), "Database already exists");
    }
}

public SQLiteDatabase openDataBase() throws SQLException {
    String path = DATABASE_PATH + DATABASE_NAME;
    // Log.i(this.getClass().toString(), "Starting openDatabase " + path);
    if (db == null) {
        createDataBase();
        db = SQLiteDatabase.openDatabase(path, null,
                SQLiteDatabase.OPEN_READWRITE);
    }

    return db;
}

}

Have a great day.