Q12

<resources>
    <string name="app_name">Q12_Database_App</string>
    <string name="name">Name</string>
    <string name="surname">Surname</string>
    <string name="marks">Marks</string>
    <string name="reset">Reset</string>
    <string name="id">ID</string>
    <string name="AppHeading">Database Application</string>
    <string name="add_data">Add data</string>
    <string name="view_all">View All</string>
    <string name="update">Update</string>
    <string name="delete">Delete</string>
    <string 
    name="for_update_delete_enter_id_first">
    For Update/delete, Enter ID first</string>


</resources>

package com.example.q12_database_app;

import android.app.AlertDialog;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;


public class MainActivity extends AppCompatActivity {
    dbhelper myDb;
    EditText editName,editSurname,editMarks ,editTextId;
    Button btnAddData;
    Button btnviewAll;
    Button btnDelete;

    Button btnviewUpdate;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myDb = new dbhelper(this);

        editName = findViewById(R.id.editText_name);
        editSurname = findViewById(R.id.editText_surname);
        editMarks = findViewById(R.id.editText_Marks);
        editTextId = findViewById(R.id.editText_id);
        btnAddData = findViewById(R.id.button_add);
        btnviewAll = findViewById(R.id.button_viewAll);
        btnviewUpdate= findViewById(R.id.button_update);
        btnDelete= findViewById(R.id.button_delete);
        AddData();
        viewAll();
        UpdateData();
        DeleteData();
    }
    public void DeleteData() {
        btnDelete.setOnClickListener(
                v -> {
                    Integer deletedRows = 
                    myDb.deleteData(
                    editTextId.getText().toString()
                    );
                    if(deletedRows > 0)
                        Toast.makeText(
                        MainActivity.this,
                        "Data Deleted",
                        Toast.LENGTH_LONG
                        ).show();
                    else
                        Toast.makeText(
                        MainActivity.this,
                        "Data not Deleted",
                        Toast.LENGTH_LONG
                        ).show();
                }
        );
    }
    public void UpdateData() {
        btnviewUpdate.setOnClickListener(
                v -> {
                    boolean isUpdate = 
                    myDb.updateData(
                    editTextId.getText().toString(),
                            editName.getText().toString(),
                            editSurname.getText().toString(),
                            editMarks.getText().toString());
                    if(isUpdate)
                        Toast.makeText(
                        MainActivity.this,
                        "Data Update",
                        Toast.LENGTH_LONG
                        ).show();
                    else
                        Toast.makeText(
                        MainActivity.this,
                        "Data not Updated",
                        Toast.LENGTH_LONG
                        ).show();
                }
        );
    }
    public  void AddData() {
        btnAddData.setOnClickListener(
                v -> {
                    boolean isInserted = 
                    myDb.insertData(
                    editName.getText().toString(),
                            editSurname.getText().toString(),
                            editMarks.getText().toString());
                    if(isInserted)
                        Toast.makeText(
                        MainActivity.this,
                        "Data Inserted",
                        Toast.LENGTH_LONG
                        ).show();
                    else
                        Toast.makeText(
                        MainActivity.this,
                        "Data not Inserted",
                        Toast.LENGTH_LONG
                        ).show();
                }
        );
    }

    public void viewAll() {
        btnviewAll.setOnClickListener(
                v -> {
                    Cursor res = myDb.getAllData();
                    if(res.getCount() == 0) {
                        // show message
                        showMessage("Error","Nothing found");
                        return;
                    }

                    StringBuilder buffer = 
                    new StringBuilder();
                    while (res.moveToNext()) {
                        buffer.append("Id :").append(
                        res.getString(0)).append("\n");
                        buffer.append("Name :").append(
                        res.getString(1)).append("\n");
                        buffer.append("Surname :").append(
                        res.getString(2)).append("\n");
                        buffer.append("Marks :").append(
                        res.getString(3)).append("\n\n");
                    }

                    // Show all data
                    showMessage("Data",buffer.toString());
                }
        );
    }

    public void showMessage(String title,String Message){
        AlertDialog.Builder builder = 
        new AlertDialog.Builder(this);
        builder.setCancelable(true);
        builder.setTitle(title);
        builder.setMessage(Message);
        builder.show();
    }
    public void clear(View v) {
        editName.setText("");
        editSurname.setText("");
        editMarks.setText("");
        editTextId.setText("");
    }
}

package com.example.q12_database_app;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class dbhelper extends SQLiteOpenHelper {
    public static final String DATABASE_NAME = "Student.db";
    public static final String TABLE_NAME = "student_table";
    public static final String COL_1 = "ID";
    public static final String COL_2 = "NAME";
    public static final String COL_3 = "SURNAME";
    public static final String COL_4 = "MARKS";

    public dbhelper(Context context) {
        super(context, DATABASE_NAME, null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table " 
        + TABLE_NAME 
        + " (ID INTEGER PRIMARY KEY AUTOINCREMENT " 
        + ",NAME TEXT,SURNAME TEXT,MARKS INTEGER)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, 
    int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS "+TABLE_NAME);
        onCreate(db);
    }

    public boolean insertData(String name,
    String surname,String marks) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_2,name);
        contentValues.put(COL_3,surname);
        contentValues.put(COL_4,marks);
        long result = db.insert(TABLE_NAME,null, 
        contentValues);
        return result != -1;
    }

    public Cursor getAllData() {
        SQLiteDatabase db = this.getWritableDatabase();
        return db.rawQuery("select * from " 
        + TABLE_NAME, null);
    }

    public boolean updateData(String id,
    String name,String surname,String marks) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_1,id);
        contentValues.put(COL_2,name);
        contentValues.put(COL_3,surname);
        contentValues.put(COL_4,marks);
        db.update(TABLE_NAME, contentValues,
         "ID = ?",new String[] { id });
        return true;
    }

    public Integer deleteData (String id) {
        SQLiteDatabase db = this.getWritableDatabase();
        return db.delete(TABLE_NAME,
         "ID = ?",new String[] {id});
    }
}