android - 是否可以将 iOS db 文件用于 Android 项目？

Question

我正在为 Android 实现一个与数据库相关的应用程序。同样的项目也在 iOS 中实现。我可以将此 iOS 数据库文件用于我的 Android 项目吗？

编辑

以下是我的代码和日志，我在日志中收到错误，但我的应用程序没有崩溃。我唯一关心的是我哪里做错了。

我的代码是:

public class DataBaseHelper extends SQLiteOpenHelper{

//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.example.test/databases/";

private static String DB_NAME = "testdb.sql";

private SQLiteDatabase myDataBase;

private final Context myContext;
public DataBaseHelper(Context context) {

    super(context, DB_NAME, null, 1);
    this.myContext = context;
    } 
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();

}

@Override
public void onCreate(SQLiteDatabase db)
{

}

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

}
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) 
        {

            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;
}

}

错误日志:

02-14 04:42:01.358: E/SQLiteLog(1552): (14) cannot open file at line 30176 of  [00bb9c9ce4]
02-14 04:42:01.378: E/SQLiteLog(1552): (14) os_unix.c:30176: (2) open(/data/data/com.example.test/databases/testdb.sql) - 
02-14 04:42:01.508: E/SQLiteDatabase(1552): Failed to open database '/data/data/com.example.test/databases/testdb.sql'.
02-14 04:42:01.508: E/SQLiteDatabase(1552): android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:804)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:789)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:669)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at com.example.test.DataBaseHelper.checkDataBase(DataBaseHelper.java:126)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at com.example.test.DataBaseHelper.createDataBase(DataBaseHelper.java:90)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at com.example.test.LoginActivity.onCreate(LoginActivity.java:59)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.app.Activity.performCreate(Activity.java:5104)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.os.Looper.loop(Looper.java:137)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at android.app.ActivityThread.main(ActivityThread.java:5039)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at java.lang.reflect.Method.invokeNative(Native Method)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at java.lang.reflect.Method.invoke(Method.java:511)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
02-14 04:42:01.508: E/SQLiteDatabase(1552):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

简短的回答是:是的。但是有一些注意事项。

1. 如果 iOS 项目使用 Core Data，生成的 db 文件的架构将很难理解。另请参阅下一点。

2. 如果 iOS 项目使用没有 Core Data 的 sqlite 数据库，您可以直接使用它，但您需要确保:

   • 您的表的 id 字段被命名为 _id
   • 有一个名为 android_metada 的表，它是使用 CREATE TABLE "android_metadata"("locale"TEXT DEFAULT 'en_US') 创建的，其中有一行是使用 INSERT INTO "android_metadata"VALUES 创建的('en_US')

(来源:reigndesign: Using your own SQLite database in Android applications)