Learning Objective: Do you want to store data locally? You can use SQLite Database to store data on a mobile device. Here is a sample code for the same.
You need the following files/class while using SQLite:
- getter setter Class
- Database Handler
- Fragment from where you will add/fetch data.
Getter Setter Class (People.java)
package com.at.mytestapplication.myapplication;
public class People {
int _id;
String _name;
String _phone_number;
public People(){ }
public People(int id, String name, String _phone_number){
this._id = id;
this._name = name;
this._phone_number = _phone_number;
}
public People(String name, String _phone_number){
this._name = name;
this._phone_number = _phone_number;
}
public int getID(){
return this._id;
}
public void setID(int id){
this._id = id;
}
public String getName(){
return this._name;
}
public void setName(String name){
this._name = name;
}
public String getPhoneNumber(){
return this._phone_number;
}
public void setPhoneNumber(String phone_number){
this._phone_number = phone_number;
}
}
Database handler class (DatabaseHandler.java)
package com.at.mytestapplication.myapplication;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import java.util.ArrayList;
import java.util.List;
public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "contactsManager";
private static final String TABLE_CONTACTS = "contacts";
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_PH_NO = "phone_number";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
//3rd argument to be passed is CursorFactory instance
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
+ KEY_PH_NO + " TEXT" + ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
// Create tables again
onCreate(db);
}
// code to add the new contact
void addContact(People contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName()); // Contact Name
values.put(KEY_PH_NO, contact.getPhoneNumber()); // Contact Phone
// Inserting Row
db.insert(TABLE_CONTACTS, null, values);
//2nd argument is String containing nullColumnHack
db.close(); // Closing database connection
}
// code to get the single contact
People getContact(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
KEY_NAME, KEY_PH_NO }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
People contact = new People(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2));
// return contact
return contact;
}
// code to get all contacts in a list view
public List<People> getAllContacts() {
List<People> contactList = new ArrayList<People>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
People contact = new People();
contact.setID(Integer.parseInt(cursor.getString(0)));
contact.setName(cursor.getString(1));
contact.setPhoneNumber(cursor.getString(2));
// Adding contact to list
contactList.add(contact);
} while (cursor.moveToNext());
}
// return contact list
return contactList;
}
// code to update the single contact
public int updateContact(People contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName());
values.put(KEY_PH_NO, contact.getPhoneNumber());
// updating row
return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",
new String[] { String.valueOf(contact.getID()) });
}
// Deleting single contact
public void deleteContact(People contact) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_CONTACTS, KEY_ID + " = ?",
new String[] { String.valueOf(contact.getID()) });
db.close();
}
// Getting contacts Count
public int getContactsCount() {
String countQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
}Add Data to SQLite Method
db = new DatabaseHandler(getContext());
db.addContact(new People(etname.getText().toString(),etnumber.getText().toString() ));Fetch Data from SQLite
List<People> contacts = db.getAllContacts();
String log = "";
for (People cn : contacts) {
log += "Id: " + cn.getID() + " ,Name: " + cn.getName() + " ,Phone: " +
cn.getPhoneNumber() + "\n";
tvoutput.setText(log);
}Implementation of Add and Fetch Data from/to SQLite (FifthFragment.java)
package com.at.mytestapplication.myapplication;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.util.List;
/**
* A simple {@link Fragment} subclass.
* Use the {@link FifthFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class FifthFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
TextView tvoutput;
DatabaseHandler db;// = new DatabaseHandler(getContext());
public FifthFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment FifthFragment.
*/
// TODO: Rename and change types and number of parameters
public static FifthFragment newInstance(String param1, String param2) {
FifthFragment fragment = new FifthFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_fifth, container, false);
db = new DatabaseHandler(getContext());
EditText etname = (EditText) view.findViewById(R.id.etname);
EditText etnumber = (EditText) view.findViewById(R.id.etnumber);
Button btnadd = (Button) view.findViewById(R.id.btnadd);
tvoutput = (TextView) view.findViewById(R.id.tvoutput);
btnadd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
db.addContact(new People(etname.getText().toString(),etnumber.getText().toString() ));
FetchfromSQLiteandDisplaytoTextView();
}
});
FetchfromSQLiteandDisplaytoTextView();
// Inflate the layout for this fragment
return view;
}
void FetchfromSQLiteandDisplaytoTextView()
{
List<People> contacts = db.getAllContacts();
String log = "";
for (People cn : contacts) {
log += "Id: " + cn.getID() + " ,Name: " + cn.getName() + " ,Phone: " +
cn.getPhoneNumber() + "\n";
tvoutput.setText(log);
}
}
}