Question

Android Studio新手，所以一些帮助会有很长的路要走！

尝试在用户输入电子邮件的位置进行搜索，如果是在数据库中，则会在文本视图中显示。

我认为我的选择是正确的，但这是我的数据库处理程序类中的方法：

public String searchEmail(String email)
    {
        SQLiteDatabase db = this.getWritableDatabase();


        String fName;
        String sName;
        String selectQuery = "SELECT FIRSTNAME, SURNAME FROM friends_table WHERE EMAIL=? ";
        Cursor c = db.rawQuery(selectQuery, new String[] { email });
        if (c.moveToFirst()) {
            fName = c.getString(c.getColumnIndex("FIRSTNAME"));
            sName = c.getString(c.getColumnIndex("SURNAME"));
        }
        c.close();

        return email;
    }

然后我的搜索：

public void searchFriend(View v) {
        EditText emailSearch = (EditText) findViewById(R.id.emailSearch);

        String emailSearchString = emailSearch.getText().toString();
        myDB.searchEmail(emailSearchString);

    //I need to get the first name and surname from the db handler class
        TextView firstName = (TextView)findViewById(R.id.firstname);
        TextView surname = (TextView)findViewById(R.id.surname);

        firstName.setText("");
        surname.setText("");




    }

我发现很难理解，如果电子邮件匹配，我将如何显示名字和姓氏。

谢谢你们，我爱你

Answer 1

创建一个新类User（带有getter，setter）并尝试这个：

public User searchEmail(String email) {
    SQLiteDatabase db = this.getWritableDatabase();

    User u = null;
    String selectQuery = "SELECT FIRSTNAME, SURNAME FROM friends_table WHERE EMAIL=? ";
    Cursor c = db.rawQuery(selectQuery, new String[] { email });
    if (c.moveToFirst()) {
        u = new User();
        u.setfName(c.getString(c.getColumnIndex("FIRSTNAME")));
        u.setsName(c.getString(c.getColumnIndex("SURNAME")));
    }
    c.close();

    return u;
}

在活动中显示结果：

public void searchFriend(View v) {
    EditText emailSearch = (EditText) findViewById(R.id.emailSearch);
    TextView firstName = (TextView)findViewById(R.id.firstname);
    TextView surname = (TextView)findViewById(R.id.surname);

    String emailSearchString = emailSearch.getText().toString();
    User user = myDB.searchEmail(emailSearchString);

    firstName.setText(user.getfName());
    surname.setText(user.getsName());

}

Answer 2

创建一个新类用户并尝试此操作：

public User searchEmail(String email)
    {
        SQLiteDatabase db = this.getWritableDatabase();

        User u = null;
        String selectQuery = "SELECT FIRSTNAME, SURNAME FROM friends_table WHERE EMAIL=? ";
        Cursor c = db.rawQuery(selectQuery, new String[] { email });
        if (c.moveToFirst()) {
            u = new User();
            u.setfName(c.getString(c.getColumnIndex("FIRSTNAME")));
            u.setsName(c.getString(c.getColumnIndex("SURNAME")));
        }
        c.close();

        return u;
    }

从我的数据库处理程序中获取数据到我的活动中的文本视图

2 个答案: