Question

我正在开发一个Android应用程序，在应用程序启动时，我将数据库从RES文件夹复制到本地数据库，为应用程序创建一个SQLite数据库。除了HTC Google Nexus One设备外，它在所有其他设备和所有操作系统版本中均可正常工作。我第二次问这个问题，因为我试图以不同的方式发现解决方案。我使用以下代码将数据库复制到本地数据库。

public class ECatalogueDatabase {

    private static final String DB_PATH = "/data/data/com.weg.ecatalogue/databases/";
    public static final String DATABASE_NAME = "ECatalogue";
    public static final String DATABASE_TABLE = "T_Electrical";
    public static final int DATABASE_VERSION = 1;

    public static final String KEY_ROWID="id";
    public static final String KEY_PRODUCT_LINE="productline";

    public static final String KEY_VOLTAGE="voltage";
    public static final String KEY_OUTPUTHP="outputhp";

    public static final String KEY_FRAME="frame";
    public static final String KEY_RPM="rpm";

    private Context context=null;
    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;

    private static final String CREAT_DATABASE="Create Table if not exists "+ DATABASE_TABLE+"("+ KEY_ROWID +" INTEGER PRIMARY KEY NOT NULL,"
    +KEY_PRODUCT_LINE +" nvarchar ,"+ KEY_OUTPUTHP+" numeric ,"+ KEY_RPM +" nvarchar ,"+KEY_VOLTAGE +" nvarchar ," +KEY_FRAME +" nvarchar"+")";

    /**
     * Constructor - takes the context to allow the database to be
     * opened/created
     *
     * @param ctx the Context within which to work
     */
    public ECatalogueDatabase(Context ctx) {
        this.context = ctx;
        DBHelper = new DatabaseHelper(context);
    }
    //Helper class
    private static class DatabaseHelper extends SQLiteOpenHelper
    {
        public DatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

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

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            db.execSQL("DROP TABLE IF EXISTS titles");
            onCreate(db);
        }

    }

    public ECatalogueDatabase open() //throws SQLException
    {
        try
        {
            db=DBHelper.getWritableDatabase();

        }catch(Exception exception)
        {
            exception.printStackTrace();
        }
        return null;
    }


    public void close()
    {
        DBHelper.close();
    }

    /**
     * Creates a empty database on the system and rewrites it with your own database.
     * */
    public void createDataBase() throws IOException{

        @SuppressWarnings("unused")
        boolean dbExist = checkDataBase();

        /**
        * CHANGES DONE BY SHAILESH SHARMA TO SOLVE THE PROBLEM OF 2.2 HTC DESIRE IN CLIENT'S WIFE DEVICE :(
        */
        SQLiteDatabase db_Read = null;
        if(dbExist){
        //DO NOTHING IN THIS CASE
        }else{

        db_Read = DBHelper.getReadableDatabase();
        db_Read.close();
        }
        //=================================

        try {

            copyDataBase();

        } catch (IOException e) {

            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
     */
    private boolean checkDataBase(){
        try{
            String myPath = DB_PATH + DATABASE_NAME;
            //db = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
            db = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS | SQLiteDatabase.OPEN_READONLY);

        }catch(SQLiteException e){

        }

        if(db != null){

            db.close();

        }

        return db != 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.
     * */
    private void copyDataBase() throws IOException{


        InputStream myInput = context.getAssets().open(DATABASE_NAME);

        // Path to the just created empty db
        String outFileName = DB_PATH + DATABASE_NAME;


        OutputStream myOutput = new FileOutputStream(outFileName);


        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer))>0){
            myOutput.write(buffer, 0, length);
        }
        myOutput.flush();
        myOutput.close();
        myInput.close();

    }

    public int getDatabaseCount(){
        int count = 0;
        Cursor cursor = db.rawQuery("Select * from " + DATABASE_TABLE, null);
        if(cursor!=null){
            count = cursor.getCount();
        }
        cursor.deactivate();
        cursor.close();
        return count;
    }
}

Answer 1

我已经找到了解决这个问题的方法，而且我想在这一刻与大家分享这个问题。我得到的例外

CREATE TABLE android_metadata failed
Failed to setLocale() when constructing, closing the database
android.database.sqlite.SQLiteDatabaseCorruptException: database disk image is malformed

这是完全不同的问题，我只在少数设备如HTC Nexus ONE设备中得到它并且它适用于所有操作系统和所有其他设备。

当我们创建数据库时，我们会自动生成一个名为“ android_table ”的表，我删除了该表并在我的SQLite管理器中手动重新创建了该表。通过以下两个查询步骤：

CREATE TABLE "android_metadata" ("locale" TEXT DEFAULT 'en_US')

和

INSERT INTO "android_metadata" VALUES ('en_US')

在我运行代码的这一步之后，我在圣诞节前得到了惊喜。我的申请工作正常。

所有功劳归功于我的长期R＆amp; D和经过这么多努力后得到的这个链接：

http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/

将数据库从RES文件夹复制到Android中的Google Nexus One中的本地数据库？

1 个答案: