AndroidのSQLiteデータベース：コンストラクタを解決できません

Question

私はアンドロイドで簡単なSQLiteデータベースを作成しようとしています。私はthis tutorialに従っています。しかし、コードはこのエラーを返します"コンストラクタのContact（）を解決できません"。以下はDatabaseHandler.javaのコードです。エラーが発生した行を指摘して分かりやすくしています。

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; 

/** 
* Created by Usama on 10/7/2017. 
*/ 

public class DatabaseHandler extends SQLiteOpenHelper { 

    // Database Version 
    private static final int DATABASE_VERSION = 1; 

    // Database Name 
    private static final String DATABASE_NAME = "favouritesmanager"; 

    // Contacts table name 
    private static final String TABLE_CONTACTS = "favourites"; 

    // Contacts Table Columns names 
    private static final String KEY_ID = "id"; 
    private static final String KEY_NAME = "name"; 
    private static final String KEY_PH_NO = "phone_number"; 
    private static final String KEY_ADRESS = "adress"; 


    public DatabaseHandler(Context context) { 
     super(context, DATABASE_NAME, null, DATABASE_VERSION); 
    } 

    // 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" + KEY_ADRESS + " 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); 
    } 

    // Adding new contact 
    public void addContact(Contact 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 Number 
     values.put(KEY_ADRESS, contact.getAdress()); //address 

     // Inserting Row 
     db.insert(TABLE_CONTACTS, null, values); 
     db.close(); // Closing database connection 
    } 


    // Getting All Contacts 
    public List<Contact> getAllContacts() { 
     List<Contact> contactList = new ArrayList<Contact>(); 
     // 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 { 
       Contact contact = new Contact(); <<<< HERE IS THE ERROR 
       contact.setID(Integer.parseInt(cursor.getString(0))); 
       contact.setName(cursor.getString(1)); 
       contact.setPhoneNumber(cursor.getString(2)); 
       contact.setAdress(cursor.getString(3)); 

       // Adding contact to list 
       contactList.add(contact); 
      } while (cursor.moveToNext()); 
     } 

     // return contact list 
     return contactList; 
    } 

} 

、ここではcontact.javaクラスは

ある

public class Contact { 

    int _id; 
    String _name; 
    String _phone_number; 
    String _adress; 

    // constructor 
    public Contact(int id, String name, String _phone_number, String adress){ 
     this._id = id; 
     this._name = name; 
     this._phone_number = _phone_number; 
     this._adress = adress; 
    } 

    // constructor 
    public Contact(String name, String _phone_number, String adress){ 
     this._name = name; 
     this._phone_number = _phone_number; 
     this._adress = adress; 
    } 

    // getting ID 
    public int getID(){ 
     return this._id; 
    } 

    // setting id 
    public void setID(int id){ 
     this._id = id; 
    } 

    // getting name 
    public String getName(){ 
     return this._name; 
    } 

    // setting name 
    public void setName(String name){ 
     this._name = name; 
    } 

    // getting phone number 
    public String getPhoneNumber(){ 
     return this._phone_number; 
    } 

    // setting phone number 
    public void setPhoneNumber(String phone_number){ 
     this._phone_number = phone_number; 
    } 

    //getting adress 
    public String getAdress(){ 

     return this._adress; 
    } 

    //setting adress 
    public void setAdress(String adresstowrite){ 
     this._adress = adresstowrite; 
    } 
} 

このエラーのどれ修正してください？

Answer 1

空のコンストラクタを作成します。

// Empty constructor 
public Contact(){ 

}