i have problem to validate data after insert data. and i don't know about insert data is the code is working or not.
i have try using Cursor, but i don't know where is error.
this is my DatabaseHelper.java
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "user_db";
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
// create notes table
db.execSQL(User.CREATE_TABLE);
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + User.TABLE_NAME);
// Create tables again
onCreate(db);
}
public long insertUser(String email,String password,String dob, String sex) {
// get writable database as we want to write data
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
// `id` and `timestamp` will be inserted automatically.
// no need to add them
values.put(User.COLUMN_Email, email);
values.put(User.COLUMN_Password, password);
values.put(User.COLUMN_DOB, dob);
values.put(User.COLUMN_Sex, sex);
// insert row
long id = db.insert(User.TABLE_NAME, null, values);
// close db connection
db.close();
// return newly inserted row id
return id;
}
public User getUser(String email, String password) {
// get readable database as we are not inserting anything
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(User.TABLE_NAME,
new String[]{User.COLUMN_ID, User.COLUMN_Email,User.COLUMN_Password, User.COLUMN_TIMESTAMP},
User.COLUMN_Email + "=?" + " AND " + User.COLUMN_Password + "=?",
new String[]{email, password}, null, null, null, null);
User note = null;
if (cursor != null) {
if (cursor.moveToFirst()) {
note = new User(
cursor.getInt(cursor.getColumnIndex(User.COLUMN_ID)),
cursor.getString(cursor.getColumnIndex(User.COLUMN_Email)),
cursor.getString(cursor.getColumnIndex(User.COLUMN_Password)),
cursor.getString(cursor.getColumnIndex(User.COLUMN_DOB)),
cursor.getString(cursor.getColumnIndex(User.COLUMN_Sex)),
cursor.getString(cursor.getColumnIndex(User.COLUMN_TIMESTAMP)));
}
}
// close the db connection
cursor.close();
return note;
}
public List<User> getAllUsers() {
List<User> notes = new ArrayList<>();
// Select All Query
String selectQuery = "SELECT * FROM " + User.TABLE_NAME + " ORDER BY " +
User.COLUMN_TIMESTAMP + " DESC";
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
User note = new User();
note.setId(cursor.getInt(cursor.getColumnIndex(User.COLUMN_ID)));
note.setEmail(cursor.getString(cursor.getColumnIndex(User.COLUMN_Email)));
note.setPassword(cursor.getString(cursor.getColumnIndex(User.COLUMN_Password)));
note.setDOB(cursor.getString(cursor.getColumnIndex(User.COLUMN_DOB)));
note.setSex(cursor.getString(cursor.getColumnIndex(User.COLUMN_Sex)));
note.setTimestamp(cursor.getString(cursor.getColumnIndex(User.COLUMN_TIMESTAMP)));
notes.add(note);
} while (cursor.moveToNext());
}
// close db connection
db.close();
// return notes list
return notes;
}
This is code for check user
private void cekUser(String username,String password) {
User n = db.getUser(username,password);
if (n != null) {
Login();
}
else{
Toast.makeText(Login.this,"Register First",Toast.LENGTH_SHORT).show();
}
}
And this is my model for my DB
public static final String TABLE_NAME = "user";
public static final String COLUMN_ID = "id";
public static final String COLUMN_Email = "email";
public static final String COLUMN_Password = "password";
public static final String COLUMN_DOB = "dob";
public static final String COLUMN_Sex = "sex";
public static final String COLUMN_TIMESTAMP = "timestamp";
private int id;
private String email;
private String password;
private String dob;
private String sex;
private String timestamp;
// Create table SQL query
public static final String CREATE_TABLE =
"CREATE TABLE " + TABLE_NAME + "("
+ COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ COLUMN_Email + " TEXT,"
+ COLUMN_Password + " TEXT,"
+ COLUMN_DOB + " TEXT,"
+ COLUMN_Sex + " TEXT,"
+ COLUMN_TIMESTAMP + " DATETIME DEFAULT CURRENT_TIMESTAMP"
+ ")";
public User() {
}
public User(int id, String email,String password, String dob, String sex ,String timestamp) {
this.id = id;
this.email = email;
this.password = password;
this.dob = dob;
this.sex = sex;
this.timestamp = timestamp;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getDOB() {
return dob;
}
public void setDOB(String dob) {
this.dob = dob;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getTimestamp() {
return timestamp;
}
public void setTimestamp(String timestamp) {
this.timestamp = timestamp;
}
I expected i can move to another activity, but i get error is on a null object reference
First, you must place AND between the 2 conditions inside the WHERE argument:
Cursor cursor = db.query(User.TABLE_NAME,
new String[]{User.COLUMN_ID, User.COLUMN_Email,User.COLUMN_Password, User.COLUMN_TIMESTAMP},
User.COLUMN_Email + "=?" + " AND " + User.COLUMN_Password + "=?",
new String[]{email, password}, null, null, null, null);
Also email and password are strings so there is no need for String.valueOf().
Then, you should not instantiate the User object, if the user is not found in the table, so that you return null in that case:
User note = null;
if (cursor != null) {
if (cursor.moveToFirst()) {
note = new User(
cursor.getInt(cursor.getColumnIndex(User.COLUMN_ID)),
cursor.getString(cursor.getColumnIndex(User.COLUMN_Email)),
cursor.getString(cursor.getColumnIndex(User.COLUMN_Password)),
cursor.getString(cursor.getColumnIndex(User.COLUMN_DOB)),
cursor.getString(cursor.getColumnIndex(User.COLUMN_Sex)),
cursor.getString(cursor.getColumnIndex(User.COLUMN_TIMESTAMP)));
}
}