Question

我正在尝试创建一个应用程序，它将使用我已经创建的SQLite数据库并能够读取/写入该数据库。我跟随this site.when我尝试运行我的应用程序并插入或读取数据库中的数据。 LogCat一直告诉我，没有名为User的表，这是我知道我创建的数据库中的一个表，并放入项目中的assets资源文件夹中

11-28 08:15:06.469: E/SQLiteLog(1945): (1) no such table: User

我创建了一个也包含SQLiteHelper嵌套类的Adapter。任何人都可以帮我解决这个错误吗？我怎么处理它？的 EDIT2

public class DatabaseAdapter {

private final String TAG = "DatabaseAdapter";
private DatabaseOpenHelper openHelper;

public DatabaseAdapter(Context context) {
    openHelper = new DatabaseOpenHelper(context, "DietDatabase.db",
            null, 1);
}
public DatabaseAdapter createDatabase() throws SQLException 
{
    try 
    {
        openHelper.createDataBase();
    } 
    catch (IOException mIOException) 
    {
        Log.e(TAG, mIOException.toString() + "  UnableToCreateDatabase");
        throw new Error("UnableToCreateDatabase");
    }
    return this;
}

public DatabaseAdapter open() throws SQLException 
{
    try 
    {
        openHelper.openDataBase();
        openHelper.close();
        mDb = openHelper.getReadableDatabase();
    } 
    catch (SQLException mSQLException) 
    {
        Log.e(TAG, "open >>"+ mSQLException.toString());
        throw mSQLException;
    }
    return this;
}

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


// for User table ==================================================

public static final String TABLE_USER = "User";
public static final String TABLE_USER_ID = "_id";
public static final String TABLE_USER_HEIGHT = "_height";
public static final String TABLE_USER_WEIGHT = "_weight";
public static final String TABLE_USER_AGE = "_age";
public static final String TABLE_USER_GENDER = "_gender";
public static final String TABLE_USER_PA = "_pa";
public static final String TABLE_USER_BMIVALUE = "_bmivalue";
public static final String TABLE_USER_BMIINTERPRETATION = "_bmiInterpretation";
public static final String TABLE_USER_IDEALWEIGHT = "_idealweight";
public static final String TABLE_USER_DAILYCALORIES = "_dailycalories";

public int getuserid(){
int id;
SQLiteDatabase myDataBase = null;
 myDataBase = openHelper.getWritableDatabase();
Cursor cur = myDataBase.query(TABLE_USER, 
        null, null, null, null, null, null);
    cur.moveToFirst();
id=cur.getInt(0);
    cur.close();

return id;}

// insert into user table======================================================
public Long insertUser(User user) {
SQLiteDatabase myDataBase = null;
Long id = -1L;
try {
    ContentValues values = new ContentValues();
    values.put(TABLE_USER_HEIGHT, user.getHeight());
    values.put(TABLE_USER_WEIGHT, user.getWeight());
    values.put(TABLE_USER_AGE, user.getAge());
    values.put(TABLE_USER_GENDER, user.getGender());
    values.put(TABLE_USER_PA, user.getPa());
    values.put(TABLE_USER_BMIVALUE, user.getBmivalue());
    values.put(TABLE_USER_BMIINTERPRETATION,
            user.getBmiInterpretation());
    values.put(TABLE_USER_IDEALWEIGHT, user.getIdealweight());
    values.put(TABLE_USER_DAILYCALORIES, user.getDailycalories());

    myDataBase = openHelper.getWritableDatabase();
    id = myDataBase.insert(TABLE_USER, null, values);

} catch (Exception e) {
    Log.e(TAG, "Exception: " + e.getMessage());
} finally {
    if (myDataBase != null && myDataBase.isOpen())
        myDataBase.close();
}
return id;
}

//databaseOpenHelper=========================================================

static class DatabaseOpenHelper extends SQLiteOpenHelper {

        private static String TAG1 = "DatabaseOpenHelper";

        public static File DB_PATH ;

        private static String DB_NAME = "DietDatabase.db";

        private SQLiteDatabase myDataBase;

        private final Context myContext;



        public DatabaseOpenHelper(Context context, String name,
                CursorFactory factory, int version) {
            super(context, DB_NAME, null, 1);
            DB_PATH=context.getDatabasePath(DB_NAME);
            this.myContext = context;
        }

        public void createDataBase() throws IOException {

            boolean dbExist = checkDataBase();
            if (dbExist) {

            } else {

                this.getReadableDatabase();
                this.close();

                try {

                    copyDataBase();
                    Log.e(TAG1, "createDatabase database created");


                } catch (IOException e) {

                    throw new Error("Error copying database");

                }
            }

        }
        private boolean checkDataBase() {

             File dbFile = new File(DB_PATH + DB_NAME);
                //Log.v("dbFile", dbFile + "   "+ dbFile.exists());
                return dbFile.exists();
        }

        private void copyDataBase() throws IOException {

            // Open 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.CREATE_IF_NECESSARY);
        }
        @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) {
        }
    }
   }

我在哪里使用数据库

DatabaseAdapter dbAdapter = new DatabaseAdapter(BmiCalculaterPage.this);
            dbAdapter.createDatabase();      
            dbAdapter.open();
            dbAdapter.insertUser(user);
            int x=dbAdapter.getuserid();
            dbAdapter.close();

当我跟踪它时，我发现应用程序在尝试返回x的值时停止了但我无法找到为什么会产生这种情况？

Answer 1

你只是在写

super(context, DB_NAME, null, 1);

{p}在DatabaseOpenHelper的构造函数中。

此处不是DB_NAME，您需要提供如下所示的路径+ DB_NAME，

super(context, EXTERNAL_PATH + "\" + DB_NAME, null, 1);

现在它将指向外部存储中的数据库。以前，代码在本地应用程序路径中搜索DB。

没有这样的表格和＃39;加载外部数据库时出错

1 个答案: