at Zad21.Cennik.getCenna(Cennik.java)
at Zad21.KwiaciarniaView$1.actionPerformed(Kwiaciarni aView.java)
at javax.swing.AbstractButton.fireActionPerformed(Unk nown Source)
at javax.swing.AbstractButton$Handler.actionPerformed (Unknown Source)
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- package Zad21;
- import java.util.HashMap;
- import java.util.Map;
- public class Cennik {
- private static Cennik instance = null;
- Map<String,Double> cennik = new HashMap<String,Double> ();
- private Cennik() { // prywatny konstruktor
- }
- public static Cennik getInstance() {
- if(instance == null) {
- instance = new Cennik();
- }
- return instance;
- }
- public void setCennik(String nazwaKwiat,double cena){
- cennik.put(nazwaKwiat,cena);
- }
- public Map<String,Double> getCennik(){ return cennik;}
- public double getCenna(String nazwaKwiata){ return cennik.get(nazwaKwiata);}
- }
in some other class
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- m_add.addActionListener( new ActionListener() {
- public void actionPerformed(ActionEvent e) {
- Cennik c= Cennik.getInstance();
- int a=Integer.parseInt(m_amount.getText());
- table.addRow((String)kwiatyList.getSelectedItem(),a,c.getCenna((String)kwiatyList.getSelectedItem()));
- }
- });
String)kwiatyList.getSelectedItem(), and when a user enters some input into JTextField then take the both values when a button is clicked and add the entries to a table
i get the nullpointerexception in c.getCenna((String)kwiatyList.getSelectedItem()));
thank u