Question

DBAdapter.java

        public void onCreate(SQLiteDatabase db) {

                    db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME
                            + " TEXT NOT NULL, " + KEY_MIDDLENAME + " TEXT NOT NULL, "
                            + KEY_LASTNAME + " TEXT NOT NULL, " + KEY_USERNAME + " TEXT NOT NULL, " + KEY_MAIL_ID + " TEXT NOT NULL, "
                            + KEY_PASSWORD + " TEXT NOT NULL, " + KEY_CONFIRM
                            + " TEXT NOT NULL, " + KEY_DATE_OF_BIRTH
                            + " INTEGER NOT NULL "
                            + ");");

        public long insertRecord(String firstname, String middlename,
                    String lastname, String username, String mail_id, String pass_word,
                    String re_password, String d_o_b) {

                ContentValues cv = new ContentValues();
                cv.put(KEY_FIRSTNAME, firstname);
                cv.put(KEY_MIDDLENAME, middlename);
                cv.put(KEY_LASTNAME, lastname);
                cv.put(KEY_USERNAME, username);
                cv.put(KEY_MAIL_ID, mail_id);
                cv.put(KEY_PASSWORD, pass_word);
                cv.put(KEY_CONFIRM, re_password);
                cv.put(KEY_DATE_OF_BIRTH, d_o_b);
                //cv.put(KEY_COUNTRY, country);
                return mDB.insert(DATABASE_TABLE, null, cv);

            }

        public String getSinlgeEntry(String userName) {
        Cursor cursor = mDB.query(DATABASE_TABLE,null,KEY_USERNAME+" =?",new String[]{userName},null,null,null);
        if (cursor.getCount() < 1) // UserName Not Exist
            return "NOT EXIST";
        cursor.moveToFirst();
        String password = cursor.getString(cursor
                .getColumnIndex(KEY_PASSWORD));
        return password;

    }

MainActivity.java：

            dbadapter = new DBAdapter(MainActivity.this);
                            dbadapter.open();
                            String stored_password = dbadapter.getSinlgeEntry(username);
                            Log.i("MainActivity", "The stored password is" + stored_password);
                            if(password.equals(stored_password))
                            {
                                Toast.makeText(MainActivity.this,"It is logging in",Toast.LENGTH_SHORT).show();
                                Intent intent = new Intent(MainActivity.this,Profile_view.class);
                                startActivity(intent);
            }
            else
            {
                                Toast.makeText(MainActivity.this,"Either username or password in invalid",Toast.LENGTH_LONG).show();
        }

Logcat：

        12-06 16:58:14.981: I/RegistrationPage(4527): It has reached onclick
        12-06 16:58:14.981: I/RegistrationPage(4527): It has reached the database
        12-06 16:58:15.582: I/RegistrationPage(4527): The records are inserted and it is past insertRecord
        12-06 16:58:15.594: I/RegistrationPage(4527): Database is closed
        12-06 16:58:31.571: I/MainActivity(4527): The stored password isNOT EXIST
        12-06 16:58:31.671: I/MainActivity(4527): Database is opened
        12-06 17:09:31.023: W/IInputConnectionWrapper(4527): showStatusIcon on inactive InputConnection
        12-06 17:09:39.931: D/dalvikvm(4527): GC_EXPLICIT freed 1693K, 9% free 20048K/21959K, paused 13ms+20ms

编辑：我无法匹配用户名和密码。方法getSingleentry应该返回密码但它总是返回NOT EXIST，尽管数据库中有条目，游标总是返回NOT EXIST，好像数据库中没有数据一样。

有人可以帮我这个吗？提前致谢。

Answer 1

您可以使用POJO对象这样使用：

public List<UserPojo> getNameList() {
        List<UserPojo> contactList = new ArrayList<UserPojo>();
        // Select All Query
        String selectQuery = "SELECT  * FROM Class_Levels";

        open();
        Cursor cursor = database.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                UserPojo names = new UserPojo();
                names.setC_Id(cursor.getString(0));
                names.setC_Name(cursor.getString(1));

                // Adding contact to list
                contactList.add(names);
            } while (cursor.moveToNext());
        }
        cursor.close();
        close();
        // return contact list
        return contactList;
    }

这只是一个示例您只需尝试就可以达到您的要求。

Answer 2

试试这个方法，

public String getSinlgeEntry(String userName) {
        Cursor cursor = mDB.query(DATABASE_TABLE,null,KEY_USERNAME+"='" + username +"'",null,null,null);
        cursor.moveToFirst();
        String password = "";
        if (cursor.getCount() > 0)
        { 
             password = cursor.getString(cursor.getColumnIndex(KEY_PASSWORD));
        } 
       return password;
    }

即使数据库中有数据，光标也会返回零

2 个答案:

您可以使用POJO对象这样使用：