Android 根据Firstname从SQLite数据库检索数据_Android_Database_Sqlite

Android 根据Firstname从SQLite数据库检索数据

android database sqlite

Android 根据Firstname从SQLite数据库检索数据,android,database,sqlite,Android,Database,Sqlite,我能够存储数据并从数据库中检索数据，但在检索数据时显示以前存储的所有数据，但应仅显示我就插进去了。基本上，如果用户使用其用户名登录，则应仅显示该用户名他的个人资料很详细，但它显示了数据库中的所有条目。我该怎么做根据名字或任何特定条目（我相信是主键）将其分开。对不起感谢你提出这样一个愚蠢的问题，但我对编程和数据库一无所知。任何非常感谢您的帮助。快速建议将id作为主键列添加到用户表中。然后在插入新记录后获取该id，并将该id保存在SharedReferences中，然后在需要时可以使用W

我能够存储数据并从数据库中检索数据，但在检索数据时

显示以前存储的所有数据，但应仅显示

我就插进去了。基本上，如果用户使用其用户名登录，则应仅显示该用户名

他的个人资料很详细，但它显示了数据库中的所有条目。我该怎么做

根据名字或任何特定条目（我相信是主键）将其分开。对不起

感谢你提出这样一个愚蠢的问题，但我对编程和数据库一无所知。任何

非常感谢您的帮助。

快速建议将id作为主键列添加到用户表中。然后在插入新记录后获取该id，并将该id保存在SharedReferences中，然后在需要时可以使用WHERE

id

=my\u id\u save从用户表中提取该记录。

下面是示例

快速建议将id添加为用户表的主键列。然后在插入新记录后获取该id，并将该id保存在SharedReferences中，然后在需要时可以使用WHERE

id

=my\u id\u save从用户表中提取该记录。

以下是示例

您正在检索在

列

数组中指定的三列的所有行，因为您在对

查询（）的调用中为WHERE
子句传递了null

您正在检索在

列

数组中指定的三列的所有行，因为在调用

query（）

的过程中，为

WHERE

子句传递了

null

，然后可以过滤要检索的结果

我建议您看看，它将使您的代码更具可读性，并使整个数据库的使用更简单

使用WHERE子句，然后可以筛选要检索的结果

我建议您看看，它将使您的代码更具可读性，并使整个数据库的使用更简单

在Profile\u view.java中，您可以调用传递要匹配的字符串的方法：

    **DBAdapter.java :**

    public void onCreate(SQLiteDatabase db) {

                db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME
                        + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try);
            return mDB.insert(DATABASE_TABLE, null, cv);

        }

    public String getName() {


            String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME,
                    KEY_LASTNAME };
            Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null,
                    null);
            String name = "";
            int iFirst = c.getColumnIndex(KEY_FIRSTNAME);
            int iMiddle = c.getColumnIndex(KEY_MIDDLENAME);
            int iLast = c.getColumnIndex(KEY_LASTNAME);
            for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
                name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle)
                        + "\t" + c.getString(iLast) + "\t";
            }
            c.close();
            return name;

        }



----------


    **Profile_view.java :**

    DBAdapter dbAdapter = new DBAdapter(Profile_view.this);
            dbAdapter.open();
            String name = dbAdapter.getName();
            full_name.setText(name);
            username_display.setText(dbAdapter.getUserName());
            mail_display.setText(dbAdapter.getMail_id());
            date_of_birth_display.setText(dbAdapter.get_date_of_birth());


----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?";
Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);

调整后的getName方法应该如下所示：

    **DBAdapter.java :**

    public void onCreate(SQLiteDatabase db) {

                db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME
                        + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try);
            return mDB.insert(DATABASE_TABLE, null, cv);

        }

    public String getName() {


            String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME,
                    KEY_LASTNAME };
            Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null,
                    null);
            String name = "";
            int iFirst = c.getColumnIndex(KEY_FIRSTNAME);
            int iMiddle = c.getColumnIndex(KEY_MIDDLENAME);
            int iLast = c.getColumnIndex(KEY_LASTNAME);
            for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
                name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle)
                        + "\t" + c.getString(iLast) + "\t";
            }
            c.close();
            return name;

        }



----------


    **Profile_view.java :**

    DBAdapter dbAdapter = new DBAdapter(Profile_view.this);
            dbAdapter.open();
            String name = dbAdapter.getName();
            full_name.setText(name);
            username_display.setText(dbAdapter.getUserName());
            mail_display.setText(dbAdapter.getMail_id());
            date_of_birth_display.setText(dbAdapter.get_date_of_birth());


----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?";
Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);

最后，您正在调用的SQLiteDatabase类的查询方法定义如下：

    **DBAdapter.java :**

    public void onCreate(SQLiteDatabase db) {

                db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME
                        + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try);
            return mDB.insert(DATABASE_TABLE, null, cv);

        }

    public String getName() {


            String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME,
                    KEY_LASTNAME };
            Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null,
                    null);
            String name = "";
            int iFirst = c.getColumnIndex(KEY_FIRSTNAME);
            int iMiddle = c.getColumnIndex(KEY_MIDDLENAME);
            int iLast = c.getColumnIndex(KEY_LASTNAME);
            for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
                name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle)
                        + "\t" + c.getString(iLast) + "\t";
            }
            c.close();
            return name;

        }



----------


    **Profile_view.java :**

    DBAdapter dbAdapter = new DBAdapter(Profile_view.this);
            dbAdapter.open();
            String name = dbAdapter.getName();
            full_name.setText(name);
            username_display.setText(dbAdapter.getUserName());
            mail_display.setText(dbAdapter.getMail_id());
            date_of_birth_display.setText(dbAdapter.get_date_of_birth());


----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?";
Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);

查询（字符串表、字符串[]列、字符串选择、字符串[]选择项、字符串分组依据、字符串拥有、字符串排序依据）
因此，将查询调用调整为如下所示：

**DBAdapter.java :** public void onCreate(SQLiteDatabase db) { db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try); return mDB.insert(DATABASE_TABLE, null, cv); } public String getName() { String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME, KEY_LASTNAME }; Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null, null); String name = ""; int iFirst = c.getColumnIndex(KEY_FIRSTNAME); int iMiddle = c.getColumnIndex(KEY_MIDDLENAME); int iLast = c.getColumnIndex(KEY_LASTNAME); for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle) + "\t" + c.getString(iLast) + "\t"; } c.close(); return name; } ---------- **Profile_view.java :** DBAdapter dbAdapter = new DBAdapter(Profile_view.this); dbAdapter.open(); String name = dbAdapter.getName(); full_name.setText(name); username_display.setText(dbAdapter.getUserName()); mail_display.setText(dbAdapter.getMail_id()); date_of_birth_display.setText(dbAdapter.get_date_of_birth()); ----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?"; Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);
让事情变得更有活力：

**DBAdapter.java :** public void onCreate(SQLiteDatabase db) { db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try); return mDB.insert(DATABASE_TABLE, null, cv); } public String getName() { String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME, KEY_LASTNAME }; Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null, null); String name = ""; int iFirst = c.getColumnIndex(KEY_FIRSTNAME); int iMiddle = c.getColumnIndex(KEY_MIDDLENAME); int iLast = c.getColumnIndex(KEY_LASTNAME); for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle) + "\t" + c.getString(iLast) + "\t"; } c.close(); return name; } ---------- **Profile_view.java :** DBAdapter dbAdapter = new DBAdapter(Profile_view.this); dbAdapter.open(); String name = dbAdapter.getName(); full_name.setText(name); username_display.setText(dbAdapter.getUserName()); mail_display.setText(dbAdapter.getMail_id()); date_of_birth_display.setText(dbAdapter.get_date_of_birth()); ----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?"; Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);
这样，您就可以调用query（），返回您想要的任何内容新的get方法可以是：

**DBAdapter.java :** public void onCreate(SQLiteDatabase db) { db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try); return mDB.insert(DATABASE_TABLE, null, cv); } public String getName() { String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME, KEY_LASTNAME }; Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null, null); String name = ""; int iFirst = c.getColumnIndex(KEY_FIRSTNAME); int iMiddle = c.getColumnIndex(KEY_MIDDLENAME); int iLast = c.getColumnIndex(KEY_LASTNAME); for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle) + "\t" + c.getString(iLast) + "\t"; } c.close(); return name; } ---------- **Profile_view.java :** DBAdapter dbAdapter = new DBAdapter(Profile_view.this); dbAdapter.open(); String name = dbAdapter.getName(); full_name.setText(name); username_display.setText(dbAdapter.getUserName()); mail_display.setText(dbAdapter.getMail_id()); date_of_birth_display.setText(dbAdapter.get_date_of_birth()); ----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?"; Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);

在Profile\u view.java中，您可以调用传递要匹配的字符串的方法：

**DBAdapter.java :** public void onCreate(SQLiteDatabase db) { db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try); return mDB.insert(DATABASE_TABLE, null, cv); } public String getName() { String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME, KEY_LASTNAME }; Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null, null); String name = ""; int iFirst = c.getColumnIndex(KEY_FIRSTNAME); int iMiddle = c.getColumnIndex(KEY_MIDDLENAME); int iLast = c.getColumnIndex(KEY_LASTNAME); for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle) + "\t" + c.getString(iLast) + "\t"; } c.close(); return name; } ---------- **Profile_view.java :** DBAdapter dbAdapter = new DBAdapter(Profile_view.this); dbAdapter.open(); String name = dbAdapter.getName(); full_name.setText(name); username_display.setText(dbAdapter.getUserName()); mail_display.setText(dbAdapter.getMail_id()); date_of_birth_display.setText(dbAdapter.get_date_of_birth()); ----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?"; Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);
调整后的getName方法应该如下所示：

**DBAdapter.java :** public void onCreate(SQLiteDatabase db) { db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try); return mDB.insert(DATABASE_TABLE, null, cv); } public String getName() { String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME, KEY_LASTNAME }; Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null, null); String name = ""; int iFirst = c.getColumnIndex(KEY_FIRSTNAME); int iMiddle = c.getColumnIndex(KEY_MIDDLENAME); int iLast = c.getColumnIndex(KEY_LASTNAME); for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle) + "\t" + c.getString(iLast) + "\t"; } c.close(); return name; } ---------- **Profile_view.java :** DBAdapter dbAdapter = new DBAdapter(Profile_view.this); dbAdapter.open(); String name = dbAdapter.getName(); full_name.setText(name); username_display.setText(dbAdapter.getUserName()); mail_display.setText(dbAdapter.getMail_id()); date_of_birth_display.setText(dbAdapter.get_date_of_birth()); ----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?"; Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);
最后，您正在调用的SQLiteDatabase类的查询方法定义如下：

**DBAdapter.java :** public void onCreate(SQLiteDatabase db) { db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try); return mDB.insert(DATABASE_TABLE, null, cv); } public String getName() { String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME, KEY_LASTNAME }; Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null, null); String name = ""; int iFirst = c.getColumnIndex(KEY_FIRSTNAME); int iMiddle = c.getColumnIndex(KEY_MIDDLENAME); int iLast = c.getColumnIndex(KEY_LASTNAME); for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle) + "\t" + c.getString(iLast) + "\t"; } c.close(); return name; } ---------- **Profile_view.java :** DBAdapter dbAdapter = new DBAdapter(Profile_view.this); dbAdapter.open(); String name = dbAdapter.getName(); full_name.setText(name); username_display.setText(dbAdapter.getUserName()); mail_display.setText(dbAdapter.getMail_id()); date_of_birth_display.setText(dbAdapter.get_date_of_birth()); ----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?"; Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);
查询（字符串表、字符串[]列、字符串选择、字符串[]选择项、字符串分组依据、字符串拥有、字符串排序依据）
因此，将查询调用调整为如下所示：

**DBAdapter.java :** public void onCreate(SQLiteDatabase db) { db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try); return mDB.insert(DATABASE_TABLE, null, cv); } public String getName() { String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME, KEY_LASTNAME }; Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null, null); String name = ""; int iFirst = c.getColumnIndex(KEY_FIRSTNAME); int iMiddle = c.getColumnIndex(KEY_MIDDLENAME); int iLast = c.getColumnIndex(KEY_LASTNAME); for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle) + "\t" + c.getString(iLast) + "\t"; } c.close(); return name; } ---------- **Profile_view.java :** DBAdapter dbAdapter = new DBAdapter(Profile_view.this); dbAdapter.open(); String name = dbAdapter.getName(); full_name.setText(name); username_display.setText(dbAdapter.getUserName()); mail_display.setText(dbAdapter.getMail_id()); date_of_birth_display.setText(dbAdapter.get_date_of_birth()); ----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?"; Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);
让事情变得更有活力：

**DBAdapter.java :** public void onCreate(SQLiteDatabase db) { db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try); return mDB.insert(DATABASE_TABLE, null, cv); } public String getName() { String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME, KEY_LASTNAME }; Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null, null); String name = ""; int iFirst = c.getColumnIndex(KEY_FIRSTNAME); int iMiddle = c.getColumnIndex(KEY_MIDDLENAME); int iLast = c.getColumnIndex(KEY_LASTNAME); for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle) + "\t" + c.getString(iLast) + "\t"; } c.close(); return name; } ---------- **Profile_view.java :** DBAdapter dbAdapter = new DBAdapter(Profile_view.this); dbAdapter.open(); String name = dbAdapter.getName(); full_name.setText(name); username_display.setText(dbAdapter.getUserName()); mail_display.setText(dbAdapter.getMail_id()); date_of_birth_display.setText(dbAdapter.get_date_of_birth()); ----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?"; Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);
这样，您就可以调用query（），返回您想要的任何内容新的get方法可以是：

**DBAdapter.java :** public void onCreate(SQLiteDatabase db) { db.execSQL(" CREATE TABLE " + DATABASE_TABLE + " (" + KEY_FIRSTNAME + " TEXT NOT NULL PRIMARY KEY, " + 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, coun_try); return mDB.insert(DATABASE_TABLE, null, cv); } public String getName() { String column[] = new String[] { KEY_FIRSTNAME, KEY_MIDDLENAME, KEY_LASTNAME }; Cursor c = mDB.query(DATABASE_TABLE, column, null, null, null, null, null); String name = ""; int iFirst = c.getColumnIndex(KEY_FIRSTNAME); int iMiddle = c.getColumnIndex(KEY_MIDDLENAME); int iLast = c.getColumnIndex(KEY_LASTNAME); for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { name = name + c.getString(iFirst) + "\t" + c.getString(iMiddle) + "\t" + c.getString(iLast) + "\t"; } c.close(); return name; } ---------- **Profile_view.java :** DBAdapter dbAdapter = new DBAdapter(Profile_view.this); dbAdapter.open(); String name = dbAdapter.getName(); full_name.setText(name); username_display.setText(dbAdapter.getUserName()); mail_display.setText(dbAdapter.getMail_id()); date_of_birth_display.setText(dbAdapter.get_date_of_birth()); ----------

String name = dbAdapter.getName(currentUser);

public String getName(String currentUser);

Cursor c = mDB.query(DATABASE_TABLE, column, null, "where firstname = ?", new String[]{"" + currentUser + ""}, null, null);

String where = "where " + columnToMatch + " = ?"; Cursor c = mDB.query(DATABASE_TABLE, column, null, where, new String[]{"" + stringToMatch + ""}, null, null);

@博比·迪伦：谢谢你，朋友。我刚开始编程，这段代码对我小小的大脑来说似乎太难了，但无论如何，感谢你的努力。酷…@bobby.dhillon谢谢，朋友。因为我刚开始编程，这段代码对我小小的大脑来说似乎太难了，但无论如何，感谢你的努力。酷..那么你建议我在查询方法中替换null？是的，你应该替换
null
，这是
WHERE
子句的参数。您应该检索其密码和用户名与用户输入的密码和用户名匹配的用户。因此，您建议我在查询方法中替换null？是的，您应该替换
null
，这是
WHERE
子句的参数。您应该检索其密码和用户名与用户输入的密码和用户名匹配的用户。但是Bennet先生，该方法只是我在类中实现的几种方法的一个示例。我还有getmailid（）、getusername（）、getdob（）等等。谢谢B先生，我会试试看，然后再给你回复。非常感谢。这将返回与您定义的currentUser变量的任何匹配项（可能为空）。因此，在返回之前测试游标是否为null是明智的。我的游标希望重新排列参数，如游标c=mDB.query（DATABASE_TABLE，column，null，new String[]{”“+currentUser+”“}，其中，null，null）；可以吗？在这里查看SQLiteDatabase的类定义：-光标不应该想重新排列任何内容。它有结果，希望能有所帮助。但是Bennet先生，这个方法只是我在我的课堂上实现的几个方法中的一个例子。我还有getmailid（）、getusername（）、getdob（）等等。谢谢B先生，我会试试看，然后再给你回复。非常感谢。这将返回与您定义的currentUser变量的任何匹配项（可能为空）。因此，在返回之前测试游标是否为null是明智的。我的游标希望重新排列参数，如游标c=mDB.query（DATABASE_TABLE，column，null，new String[]{”“+currentUser+”“}，其中，null，null）；可以吗？在这里查看SQLiteDatabase的类定义：-光标不应该想重新排列任何内容。它有结果，希望有帮助。