I have 2 subclasses and one superclass. I try to run test file but don't work. Any suggest?
Error: https://i.imgur.com/ciG9EPF.png
First file, the superclass (persoana= person)
package proj;
public class persoana {
private String name, address, phone, email;
public persoana(){
}
public persoana(String name, String address, String phone, String email) {
this.name = name;
this.address = address;
this.phone = phone;
this.email = email;
}
public String getName(){
return name;
}
public void setName(String name){
this.name = name;
}
public String getAddress(){
return address;
}
public void setAddress(String address){
this.address = address;
}
public String getPhone(){
return phone;
}
public void setPhone(String phone){
this.phone = phone;
}
public String getEmail(){
return phone;
}
public void setEmail(String email){
this.email = email;
}
}
File 2 is employee, subclass for persoana:
package proj;
public class employee extends persoana{
private String office, salary;
public employee(){
}
public employee(String office, String salary){
this.office = office;
this.salary = salary;
}
public String office(){
return office;
}
public void setOffice(String office){
this.office = office;
}
public String getSalary(){
return salary;
}
public void setSalary(String salary){
this.salary = salary;
}
}
File 3, subclass of class persoana:
package proj;
public class student extends persoana{
private String bac, adm;
public student(){
}
public student(String bac, String adm){
this.bac = bac;
this.adm = adm;
}
public String bac(){
return bac;
}
public void setBac(String bac){
this.bac = bac;
}
public String getAdm(){
return adm;
}
public void setAdm(String adm){
this.adm = adm;
}
}
And the test file where appears 2 errors at line 6 and 7
package proj;
public class test {
public static void main(String[] args) {
persoana persoana= new persoana ("John", "Somewhere", "415",
"john#somewhere.com");
persoana student= new student("Jane", "School Street", "650", "mj#abc.com");
persoana employee= new employee ("Tom ", "Street", "408", "asd");
System.out.println(persoana.toString() + "\n");
System.out.println(student.toString() + "\n");
System.out.println(employee.toString() + "\n");
}
}
Your student class don't provide that constructor (and constructor are not inherited like methods).
You need to provide it.
public student(String name, String address, String phone, String email){
super(name, adress, phone, email);
}
Note that class shoud start with a uppercase.
Related
I am getting this error when I am trying to compile. This used to work when I was using sdk 23 but now that I have upgraded to 26 I cant get it to compile.
Error:(41, 13) error: cannot find symbol class SimpleAdapter
This is my code that goes and gets a list of contacts off a website and displays them in a list view.
public class ContactsActivity extends Activity {
private SimpleAdapter adpt;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_contacts);
adpt = new SimpleAdapter(new ArrayList<Contact>(), this);
adpt.setStyle(R.layout.contact_list_item);
ListView lView = (ListView) findViewById(R.id.listview_contacts);
The contact class is as follows this is what I cast the returned xml into once it gets returned.
public class Contact implements Serializable {
private String Name;
private String Phone;
private String Cell;
private String Email;
private String Address;
private String Work;
public Contact() {
super();
}
public Contact(String name, String phone, String cell, String email, String address,String work) {
super();
this.Name = name;
this.Phone = phone;
this.Cell = cell;
this.Email = email;
this.Address = address;
this.Work = work;
}
public String getName() {
return Name;
}
public void setName(String name) {
this.Name = name;
}
public String getPhone() {
return Phone;
}
public void setPhone(String phone) {
this.Phone = phone;
}
public String getCell() {
return Cell;
}
public void setCell(String cell) {
this.Cell = cell;
}
public String getEmail() {
return Email;
}
public void setEmail(String email) {
this.Email = email;
}
public String getAddress() {
return Address;
}
public void setAddress(String address) {
this.Address = address;
}
public String getWork() {
return Work;
}
public void setWork(String work) {
this.Work = work;
}
}
Please let me know where I am going wrong.
You need create a SimpleAdapter, can extend from ArrayAdapter, BaseAdapter,...
I want to create a programm that creates a list that looks like this
ID: 1
Name: Example
Surname: Example
email: example
//New list
ID: 2
Name: Example
Surname: Example
email: example
and then when i want to change something (like Name: ) i'd like to change it by id, so it can only be changed inside the list with ID: 2
You should use a HashMap.
Create a class (let's class it YourClass) that contains ID, name, surname and email instance variables.
Then create a HashMap where the key is the identifier and the value is YourClass:
Map<Integer,YourClass> map = new HashMap<>();
map.put(objectOfYourClassWithID1.getID(),objectOfYourClassWithID1);
map.put(objectOfYourClassWithID2.getID(),objectOfYourClassWithID2);
if (map.containsKey(2)) {
map.get(2).setSomeProperty(newValue); // this will only change the object whose ID is 2
}
you can create class like this
public class Record{
private int id;
private String name;
private String Surname;
private String email;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSurname() {
return Surname;
}
public void setSurname(String surname) {
Surname = surname;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
and then use it like this:
Record record1 = new Record();
record1.setId(1);
record1.setName("example");
record1.setSurname("example");
record1.setEmail("example");
Record record2 = new Record();
record2.setId(2);
record2.setName("example");
record2.setSurname("example");
record2.setEmail("example");
Map<Integer,Record> recordMap = new HashMap<Integer, Record>();
recordMap.put(record1.getId(),record1);
recordMap.put(record2.getId(),record2);]
recordMap.get(2).getName();//example
recordMap.get(2).setName("ebi");
recordMap.get(2).getName();//ebi
import java.util.ArrayList;
import java.util.List;
public class Person {
private int id;
private String name;
private String Surname;
private String email;
public Person(int id, String name, String surname, String email) {
super();
this.id = id;
this.name = name;
Surname = surname;
this.email = email;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSurname() {
return Surname;
}
public void setSurname(String surname) {
Surname = surname;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public static void main(String[] args) {
List<Person> list = new ArrayList<Person>();
list.add(new Person(1, "example", "example", "example"));
list.add(new Person(2, "example", "example", "example"));
}
}
There is a compliation error stating that class name is already define i can't find the way to resolve it
further the class name are declared only once and can't find the place where the things are going wrong
package practo;
import java.io.*;
import java.lang.*;
import java.util.*;
#SuppressWarnings("unused")
class Customer /* compilation error occurs here */
{
private int id;
private String name;
private String email;
private String address;
void setid(int id)
{
this.id=id;
}
int getid()
{
return id;
}
void setname(String name)
{
this.name=name;
}
String getname()
{
return name;
}
void setemail(String email)
{
this.email=email;
}
String getemail()
{
return email;
}
void setaddress(String address)
{
this.address=address;
}
String getaddress()
{
return address;
}
class PhoneNumber
{
private String phoneNumber;
private String heldFromDate;
private String heldToDate;
void setphoneNumber(String phoneNumber)
{
this.phoneNumber=phoneNumber;
}
String getphoneNumber()
{
return phoneNumber;
}
void setheldToDate(String heldToDate)
{
this.heldToDate=heldToDate;
}
String getheldToDate()
{
return heldToDate;
}
public String getHeldFromDate() {
return heldFromDate;
}
public void setHeldFromDate(String heldFromDate) {
this.heldFromDate = heldFromDate;
}
class NumberType
{
private String code;
private String description;
void setcode(String code)
{
this.code=code;
}
void setdescription(String description)
{
this.description=description;
}
String getcode()
{
return code;
}
String getdescription()
{
return description;
}
}
}
}
class x1
{
public void main(String args[])
{
#SuppressWarnings("resource")
Scanner s=new Scanner(System.in);
Customer c=new Customer();
Customer.PhoneNumber p=c.new PhoneNumber();
Customer.PhoneNumber.NumberType n=p.new NumberType();
System.out.println("Enter the customer details");
System.out.println("Enter the id :");
int id=s.nextInt();
c.setid(id);
System.out.println(c.getid());
System.out.println("Enter the name :");
String name=s.nextLine();
c.setname(name);
System.out.println(c.getname());
System.out.println("Enter the email :");
String email=s.nextLine();
c.setemail(email);
System.out.println(c.getemail());
System.out.println("Enter the address :");
String address=s.nextLine();
c.setaddress(address);
System.out.println(c.getaddress());
System.out.println("Enter the customer contact details");
System.out.println("Enter the phone number :");
String phoneNumber=s.nextLine();
p.setphoneNumber(phoneNumber);
System.out.println(p.getphoneNumber());
System.out.println("Enter the held from date (dd/MM/yyyy) :");
String heldFromDate=s.next();
p.setHeldFromDate(heldFromDate);
System.out.println(p.getHeldFromDate());
System.out.println("Enter the held to date (dd/MM/yyyy) :");
String heldToDate=s.next();
p.setheldToDate(heldToDate);
System.out.println(p.getheldToDate());
System.out.println("Enter number type code :");
String code=s.next();
n.setcode(code);
System.out.println(n.getcode());
System.out.println("Enter number type description");
String description=s.next();
n.setdescription(description);
System.out.println(n.getdescription());
}
}
Your class does not give me any compilation error. You might try making the class public i.e. public class Customer and file name having the name Customer.java. It may happen that the package practo already contains a class named Customer.
Can you please verify Customer class is not duplicate ? If it is not there, can you choose Clean from the Project menu, it might fix these errors.
Sometime eclipse trouble us.
Lots of recommendations for improvement:
Open public class per file, and a file for each class. Your arrangement is confusing.
Learn and follow the Java coding standards.
Using a Date for a date instead of a String is a better design, especially with JDK 8 and the java.time package.
Learn JUnit instead of that x1.main.
These are examples of how your classes should look.
Customer.java
package practo;
/**
* Created by Michael
* Creation date 5/29/2016.
* #link https://stackoverflow.com/questions/37511168/it-show-the-error-that-customer-is-already-defined-please-let-me-know-whats-wron
*/
public class Customer {
private int id;
private String name;
private String email;
private String address;
public Customer() {
this(0, "", "", "");
}
public Customer(int id, String name, String email, String address) {
this.id = id;
this.name = name;
this.email = email;
this.address = address;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
PhoneNumber.java:
package practo;
/**
* Created by Michael
* Creation date 5/29/2016.
* #link https://stackoverflow.com/questions/37511168/it-show-the-error-that-customer-is-already-defined-please-let-me-know-whats-wron
*/
public class PhoneNumber {
private String phoneNumber;
private String heldFromDate; // Bad design. This ought to be a Date, not a String
private String heldToDate; // Bad design. This ought to be a Date, not a String
public PhoneNumber() {
this("", "", "");
}
public PhoneNumber(String phoneNumber, String heldFromDate, String heldToDate) {
this.phoneNumber = phoneNumber;
this.heldFromDate = heldFromDate;
this.heldToDate = heldToDate;
}
public String getPhoneNumber() {
return phoneNumber;
}
public void setPhoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}
public String getHeldFromDate() {
return heldFromDate;
}
public void setHeldFromDate(String heldFromDate) {
this.heldFromDate = heldFromDate;
}
public String getHeldToDate() {
return heldToDate;
}
public void setHeldToDate(String heldToDate) {
this.heldToDate = heldToDate;
}
}
Check if you have another class called Customer in the package practo. That would cause a name conflict.
Recently I am doing a coding exercises I need to make my project , and so far I am practicing it with the code below what I want to ask is that, is this a has a relationship? am I doing the right practice? look at my code, sorry for my bad english
public class Personal {
private String firstName;
private String middleInitial;
private String lastName;
private int age;
public Personal(String firstName,String middleInitial , String lastName , int age){
setFirstName(firstName);
setMiddleInitial(middleInitial);
setLastName(lastName);
setAge(age);
}
public void setFirstName(String firstName){
this.firstName = firstName;
}
public String getFirstName(){
return firstName;
}
public void setMiddleInitial(String middleInitial){
this.middleInitial = middleInitial;
}
public String getMiddleInitial(){
return middleInitial;
}
public void setLastName(String lastName){
this.lastName = lastName;
}
public String getLastName(){
return lastName;
}
public void setAge(int age){
this.age = age;
}
public int getAge(){
return age;
}
public String toString(){
return String.format("First Name: "+getFirstName()+"\nMiddle Initial: "+getMiddleInitial()+
"\nLast Name: "+getLastName()+"\nAge: "+getAge());
}
}
Contact Class
public class Contact {
private String address;
private String email;
private String contactNumber;
public Contact(String address,String contactNumber, String email){
setAddress(address);
setContactNumber(contactNumber);
setEmail(email);
}
public void setAddress(String address){
this.address = address;
}
public String getAddress(){
return address;
}
public void setEmail(String email){
this.email = email;
}
public String getEmail(){
return email;
}
public void setContactNumber(String contactNumber){
this.contactNumber = contactNumber;
}
public String getContactNumber(){
return contactNumber;
}
public String toString(){
return String.format("Address: "+getAddress()+"\nContact Number: "+getContactNumber()+
"\nEmail Address: "+getEmail());
}
}
Employee Class
public class Employee {
private Personal personal;
private Contact contact;
public Employee(Personal personal, Contact contact){
this.personal = personal;
this.contact = contact;
}
public void setFirstName(String firstName){
this.personal.setFirstName(firstName);
}
public String toString(){
return String.format(personal.toString()+contact.toString());
}
}
And the Test class
public class TestClass {
public static void main(String[] args){
Personal personalHerp = new Personal("John","M","Doe",18);
Contact contactHerp = new Contact("88 Herp Derp St U mad New york","724-15-70","fido.com");
Employee employeeHerp = new Employee(personalHerp,contactHerp);
System.out.println(employeeHerp);
}
}
Well, since Employee doesn't extend Personal it has a Personal and a Contact.
I guess you'd rather like Employee to be a Personal and thus it should look like this:
public class Employee extends Personal {
private Contact contact;
...
}
So to summarize:
is-a means a class/object extends another class or implements an interface, i.e. A is-a B if A extends B or A implements B
has-a means that a class/object has a variable of that type, like Contact contact in your Employee class, which means Employee has-a contact.
Yes, this is a "has-a" relationship (exactly as we discussed in your other question).
I need to delete certain lines from a file, the file is a list of contacts that I read in from a file into my GUI. When I get to the contact I want to delete, my program should delete the contact from the file. I've tried to do this, but it is not working.
Here is the code I'm currently using:
String temp=txtname.getText();
for (Contact Contact:contacts)
{
if (temp.equals(Contact.getname()));
{
txtname.setText("");
txtsurname.setText("");
txtphone.setText("");
txtmobile.setText("");
txtaddress.setText("");
txtpostcode.setText("");
contacts.remove(Contact);
contacts.remove(Contact);
contacts.remove(Contact);
contacts.remove(Contact);
contacts.remove(Contact);
contacts.remove(Contact);
}
}
My contact class is:
public class Contact {
static void add(String text) {
}
public String name;
public String surname;
public String phone;
public String mobile;
public String address;
public String postcode;
public Contact(){}
public Contact(String name, String surname, String phone,
String mobile, String address, String postcode)
{
this.name = name;
this.surname = surname;
this.phone = phone;
this.mobile = mobile;
this.address = address;
this.postcode = postcode;
}
public String getname()
{
return this.name;
}
public String getsurname()
{
return this.surname;
}
public String getphone()
{
return this.phone;
}
public String getmobile()
{
return this.mobile;
}
public String getaddress()
{
return this.address;
}
public String getpostcode()
{
return this.postcode;
}
public void setname(String name)
{
this.name = name;
}
public void setsurname(String surname)
{
this.surname = surname;
}
public void setphone(String phone)
{
this.phone = phone;
}
public void setmobile(String mobile)
{
this.mobile = mobile;
}
public void setaddress(String address)
{
this.address = address;
}
public void setpostcode(String postcode)
{
this.postcode = postcode;
}
}
I'm guessing it deletes it from the arraylist, but I'm not sure how the program knows what to delete from the file.
Thanks.
Modifying the internal list doesn't change the file. There is no automatic way to synchronize the two. You have to save the array back to the file to update it.
There is no way to delete anything from the middle of the file.
The only way is to rewrite the file every time something should be changed.
you can use a random access file but it seems like an over kill for this task.
the best way to do it is to have the remove function write the whole file back to the disk.
If you have no specific format for the file, then I suggest you to use the default serialization and serialize the contacts list. Like this,
//To serialize
ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(new File("D:/newfile.txt")));
out.writeObject(contacts);
//To deserialize
ObjectInputStream in = new ObjectInputStream(new FileInputStream(new File("d:/newFile.txt")));
contacts = (ArrayList<Contact>)in.readObject();
You first have to implement the Serializable interface in your Contact class.
Or if you need more control over the file format use the standard XML classes or JSON libraries.
Files can be rewrited, or appended to. In you case you'll have to rewrite it. There are other ways, but they would be an overkill here.
String temp = txtname.getText();
for (Contact contact : contacts) {
if (temp.equals(contact.getname())) {
contacts.remove(contact);
break;
}
}
Fixed a lot of general problems with your code
public class Contact {
private String name;
private String surname;
private String phone;
private String mobile;
private String address;
private String postcode;
public Contact(String name, String surname, String phone, String mobile, String address, String postcode) {
this.name = name;
this.surname = surname;
this.phone = phone;
this.mobile = mobile;
this.address = address;
this.postcode = postcode;
}
public String getName() {
return this.name;
}
public String getSurname() {
return this.surname;
}
public String getPhone() {
return this.phone;
}
public String getMobile() {
return this.mobile;
}
public String getAddress() {
return this.address;
}
public String getPostcode() {
return this.postcode;
}
}