Using database in android
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The document describes how to create an Android app that allows users to create an account and log in using a SQLite database. The app includes activities for sign up and login. The sign up activity allows creating a new user account by inserting data into a database table. The login activity authenticates users by querying the database and checking the password. The database is implemented using a DatabaseHelper class to manage creating and upgrading the database, and a LoginDatabaseAdapter class for performing CRUD operations.
![// Context of the application using the database.
private final Context context;
// Database open/upgrade helper
private DataBaseHelper dbHelper;
public LoginDataBaseAdapter(Context _context)
{
context = _context;
dbHelper = new DataBaseHelper(context, DATABASE_NAME, null,
DATABASE_VERSION);
}
// Method to openthe Database
public LoginDataBaseAdapter open() throws SQLException
{
db = dbHelper.getWritableDatabase();
return this;
}
// Method to close the Database
public void close()
{
db.close();
}
// method returns an Instance of the Database
public SQLiteDatabase getDatabaseInstance()
{
return db;
}
// method to insert a record in Table
public void insertEntry(String userName,String password)
{
ContentValues newValues = new ContentValues();
// Assign values for each column.
newValues.put("USERNAME", userName);
newValues.put("PASSWORD",password);
// Insert the row into your table
db.insert("LOGIN", null, newValues);
Toast.makeText(context, "User Info Saved", Toast.LENGTH_LONG).show();
}
// method to delete a Record of UserName
public int deleteEntry(String UserName)
{
String where="USERNAME=?";
int numberOFEntriesDeleted= db.delete("LOGIN", where, new String[]{UserName}) ;](https://image.slidesharecdn.com/usingdatabaseinandroid-160808180432/85/Using-database-in-android-10-320.jpg)
![Toast.makeText(context, "Number fo Entry Deleted Successfully :
"+numberOFEntriesDeleted, Toast.LENGTH_LONG).show();
return numberOFEntriesDeleted;
}
// method to get the password of userName
public String getSinlgeEntry(String userName)
{
Cursor cursor=db.query("LOGIN", null, " 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("PASSWORD"));
return password;
}
// Method to Update an Existing Record
public void updateEntry(String userName,String password)
{
// create object of ContentValues
ContentValues updatedValues = new ContentValues();
// Assign values for each Column.
updatedValues.put("USERNAME", userName);
updatedValues.put("PASSWORD",password);
String where="USERNAME = ?";
db.update("LOGIN",updatedValues, where, new String[]{userName});
}
}](https://image.slidesharecdn.com/usingdatabaseinandroid-160808180432/85/Using-database-in-android-11-320.jpg)
Using database in android
- 1. Md.Delwar Hossain Made for Open IT Using Database In Android In this post we will develop an app in which a user can perform following task 1: User Can Create Account 2: User Can log in we will use and learn following this in this Post Customized Dialog: Here we have used Customized Dialog for User Login. Creating DataBase: Here we have created database for Storing UserName and Password. Writing functions for Inserting, Deleting, Updating and querying a Datbase we have create a Table with following Fields : USERNAME : to store the user name. PASSWORD: to store the password of User Table Name is LOGIN List of XMLs Used. main.xml : main screen signup.xml : to create a new account login.xml : to login main.xml
- 2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:gravity="center_vertical" > <Button android:id="@+id/buttonSignIN" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Sign IN" android:onClick="signIn"/> <Button android:id="@+id/buttonSignUP" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Sign UP" /> </LinearLayout> signup.xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
- 3. android:layout_height="match_parent" android:orientation="vertical" android:gravity="center_vertical" > <EditText android:id="@+id/editTextUserName" android:hint="User Name" android:layout_width="match_parent" android:layout_height="wrap_content" > <requestFocus /> </EditText> <EditText android:id="@+id/editTextPassword" android:layout_width="fill_parent" android:layout_height="wrap_content" android:hint="Password" android:inputType="textPassword" /> <EditText android:id="@+id/editTextConfirmPassword" android:layout_width="fill_parent" android:layout_height="wrap_content" android:hint="Confirm Password" android:inputType="textPassword" /> <Button android:id="@+id/buttonCreateAccount" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Create Account" android:layout_marginBottom="60dp" /> </LinearLayout> login.xml
- 4. <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <EditText android:id="@+id/editTextUserNameToLogin" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="User Name" android:ems="10" > <requestFocus /> </EditText> <EditText android:id="@+id/editTextPasswordToLogin" android:layout_width="match_parent" android:layout_height="wrap_content" android:ems="10" android:inputType="textPassword" android:hint="Password" /> <Button
- 5. android:id="@+id/buttonSignIn" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Sign In" /> </LinearLayout> Activities: 1: HomeActivity.java public class HomeActivity extends Activity { Button btnSignIn,btnSignUp; LoginDataBaseAdapter loginDataBaseAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // create the instance of Database loginDataBaseAdapter=new LoginDataBaseAdapter(this); loginDataBaseAdapter=loginDataBaseAdapter.open(); // Get The Reference OfButtons btnSignIn=(Button)findViewById(R.id.buttonSignIN); btnSignUp=(Button)findViewById(R.id.buttonSignUP); // Set OnClick Listener on SignUp button btnSignUp.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { // TODO Auto-generated method stub /// Create Intent for SignUpActivity abd Start The Activity Intent intentSignUP=new Intent(getApplicationContext(),SignUPActivity.class); startActivity(intentSignUP); } }); }
- 6. //Methods to handle Click Event of Sign In Button public void signIn(View V) { final Dialog dialog = new Dialog(HomeActivity.this); dialog.setContentView(R.layout.login); dialog.setTitle("Login"); // get the Refferences of views final EditText editTextUserName=(EditText)dialog.findViewById(R.id.editTextUserNameToLogin); final EditText editTextPassword=(EditText)dialog.findViewById(R.id.editTextPasswordToLogin); Button btnSignIn=(Button)dialog.findViewById(R.id.buttonSignIn); // Set On ClickListener btnSignIn.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { // TODO Auto-generated method stub // get The User name and Password String userName=editTextUserName.getText().toString(); String password=editTextPassword.getText().toString(); // fetch the Password form database for respective user name String storedPassword=loginDataBaseAdapter.getSinlgeEntry(userName); // check if the Stored password matches with Password entered by user if(password.equals(storedPassword)) { Toast.makeText(HomeActivity.this, "Login Successfull", Toast.LENGTH_LONG).show(); dialog.dismiss(); } else { Toast.makeText(HomeActivity.this, "User Name and Does Not Matches", Toast.LENGTH_LONG).show(); } } }); dialog.show();
- 7. } @Override protected void onDestroy() { // TODO Auto-generated method stub super.onDestroy(); // Close The Database loginDataBaseAdapter.close(); } } 2: SignUpActivity.java public class SignUPActivity extends Activity { EditText editTextUserName,editTextPassword,editTextConfirmPassword; Button btnCreateAccount; LoginDataBaseAdapter loginDataBaseAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.signup); // get Instance of Database Adapter loginDataBaseAdapter=new LoginDataBaseAdapter(this); loginDataBaseAdapter=loginDataBaseAdapter.open(); // Get Refferences of Views editTextUserName=(EditText)findViewById(R.id.editTextUserName); editTextPassword=(EditText)findViewById(R.id.editTextPassword); editTextConfirmPassword=(EditText)findViewById(R.id.editTextConfirmPassword); btnCreateAccount=(Button)findViewById(R.id.buttonCreateAccount); btnCreateAccount.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { // TODO Auto-generated method stub String userName=editTextUserName.getText().toString(); String password=editTextPassword.getText().toString(); String confirmPassword=editTextConfirmPassword.getText().toString();
- 8. // check if any of the fields are vaccant if(userName.equals("")||password.equals("")||confirmPassword.equals("")) { Toast.makeText(getApplicationContext(), "Field Vaccant", Toast.LENGTH_LONG).show(); return; } // check if both password matches if(!password.equals(confirmPassword)) { Toast.makeText(getApplicationContext(), "Password Does Not Matches", Toast.LENGTH_LONG).show(); return; } else { // Save the Data in Database loginDataBaseAdapter.insertEntry(userName, password); Toast.makeText(getApplicationContext(), "Account Successfully Created ", Toast.LENGTH_LONG).show(); } } }); } @Override protected void onDestroy() { // TODO Auto-generated method stub super.onDestroy(); loginDataBaseAdapter.close(); } } 3: DataBaseHelper.java package com.example.login; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper; import android.util.Log;
- 9. public class DataBaseHelper extends SQLiteOpenHelper { public DataBaseHelper(Context context, String name,CursorFactory factory, int version) { super(context, name, factory, version); } // Called when no database exists in disk and the helper class needs // to create a new one. @Override public void onCreate(SQLiteDatabase _db) { _db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE); } // Called when there is a database version mismatch meaning that the version // of the database on disk needs to be upgraded to the current version. @Override public void onUpgrade(SQLiteDatabase _db, int _oldVersion, int _newVersion) { // Log the version upgrade. Log.w("TaskDBAdapter", "Upgrading from version " +_oldVersion + " to " +_newVersion + ", which will destroy all old data"); // Upgrade the existing database to conform to the new version. Multiple // previous versions can be handled by comparing _oldVersion and _newVersion // values. // The simplest case is to drop the old table and create a new one. _db.execSQL("DROP TABLE IF EXISTS " + "TEMPLATE"); // Create a new one. onCreate(_db); } } 4: LoginDataBaseAdapter.java public class LoginDataBaseAdapter { static final String DATABASE_NAME = "login.db"; static final int DATABASE_VERSION = 1; public static final int NAME_COLUMN = 1; // TODO: Create public field for each column in your table. // SQL Statement to create a new database. static final String DATABASE_CREATE = "create table "+"LOGIN"+ "( " +"ID"+" integer primary key autoincrement,"+ "USERNAME text,PASSWORD text); "; // Variable to hold the database instance public SQLiteDatabase db;
- 10. // Context of the application using the database. private final Context context; // Database open/upgrade helper private DataBaseHelper dbHelper; public LoginDataBaseAdapter(Context _context) { context = _context; dbHelper = new DataBaseHelper(context, DATABASE_NAME, null, DATABASE_VERSION); } // Method to openthe Database public LoginDataBaseAdapter open() throws SQLException { db = dbHelper.getWritableDatabase(); return this; } // Method to close the Database public void close() { db.close(); } // method returns an Instance of the Database public SQLiteDatabase getDatabaseInstance() { return db; } // method to insert a record in Table public void insertEntry(String userName,String password) { ContentValues newValues = new ContentValues(); // Assign values for each column. newValues.put("USERNAME", userName); newValues.put("PASSWORD",password); // Insert the row into your table db.insert("LOGIN", null, newValues); Toast.makeText(context, "User Info Saved", Toast.LENGTH_LONG).show(); } // method to delete a Record of UserName public int deleteEntry(String UserName) { String where="USERNAME=?"; int numberOFEntriesDeleted= db.delete("LOGIN", where, new String[]{UserName}) ;
- 11. Toast.makeText(context, "Number fo Entry Deleted Successfully : "+numberOFEntriesDeleted, Toast.LENGTH_LONG).show(); return numberOFEntriesDeleted; } // method to get the password of userName public String getSinlgeEntry(String userName) { Cursor cursor=db.query("LOGIN", null, " 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("PASSWORD")); return password; } // Method to Update an Existing Record public void updateEntry(String userName,String password) { // create object of ContentValues ContentValues updatedValues = new ContentValues(); // Assign values for each Column. updatedValues.put("USERNAME", userName); updatedValues.put("PASSWORD",password); String where="USERNAME = ?"; db.update("LOGIN",updatedValues, where, new String[]{userName}); } }