SQLite Delete

MainActivity.java

import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
 public class MainActivity extends AppCompatActivity {
 DataBaseHelper myDb;
  EditText txtId;
  Button btnClick;
  @Override 
   protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);
   myDb = new DataBaseHelper(this);
   txtId = (EditText) findViewById(R.id.idID);
   btnClick = (Button) findViewById(R.id.idBtn);
   btnClick.setOnClickListener(new View.OnClickListener() {
   @Override 
    public void onClick(View v) {
     ClickMe();
   }
  });
 }
  private void ClickMe() {
   String id = txtId.getText().toString();
   int result = myDb.deleteData(id);
   Toast.makeText(this, result + " :Rows Affected", Toast.LENGTH_SHORT).show();
 }
}

DBHelper.java

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

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

activity_main.xml

<?xml version="1.0" encoding="utf-8"?> 
<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:paddingBottom="@dimen/activity_vertical_margin"
     android:paddingLeft="@dimen/activity_horizontal_margin"
     android:paddingRight="@dimen/activity_horizontal_margin"
     android:paddingTop="@dimen/activity_vertical_margin" 
     tools:context="anu.com.sqlite.MainActivity" 
     android:orientation="vertical"> 
    
    <EditText
     android:id="@+id/idID" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:hint="ID" /> 
    
    <Button 
     android:id="@+id/idBtn" 
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:background="#FFCC65" 
     android:text="UPDATE" />  
</LinearLayout>  ​