从另一个JPanel中的数组获取信息

Question

I am storing some info in an ArrayList that is in a JPanel. I want to access this info from a JFrame so that I can print the contents of the ArrayList .

How do I do this?

This is what i have tried so far:

    package projektarbete;

import java.awt.*;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;
import java.util.ArrayList;

public class Spelet extends javax.swing.JPanel {
ArrayList<String> Resultat = new ArrayList<>();


.....

        if(gameOver == true || vinst == true){
        btnTillbakaTillMeny.setVisible(true);
        int klick = antalKlick;
        String namn = txfNamn.getText();
        //Integer.toString(klick);
        String klickString = klick+"";
        String score = namn+"\t"+klickString;
        Resultat.add(score);

That was the JPanel and the info is stored in the ArrayList called Restultat.

This is how I am trying to retrieve the info from the JFrame:

    package projektarbete;

import javax.swing.JFrame;

public class Instruktioner extends javax.swing.JFrame {
//private final Meny Meny = new projektarbete.Meny();
    private static void close() {
      //  throw new UnsupportedOperationException("Not supported yet."); 
    }


    public Instruktioner() {
        initComponents();

    Spelet Resultat = new Spelet(); 
        jTextArea1.setText(Resultat);
    }

The thing is that NetBeans is underlining Resultat in jTextArea1.setText(Resultat);

Any ideas?

Answer 1

You cannot put a Resultat object as a parameter to setText(), because that method does not Accept a parameter of that type. If you look at the javadoc for the method, you will see what type(s) it takes (there may be more than one 'signature' for the method, each signature taking a different combination of types).

I think what you want to do is have a class and then an object that holds the data for your program. It will have the necessary methods for setting and obtaining data, and for calculating things that need calculation. Then, any object that is going to present information to the user (panel, frame, whatever) will need to have a reference to the class holding the data, and can call methods to get what it needs.

This is the very fundamental idea behind "model-view-controller" -- a *separation of concerns", where the logic for handling data is separated from the logic for displaying that data. It helps in the common cases where you need to change the presentation but the data handling itself is ok.

Answer 2

setText（）正在等待字符串，但是您给了它一个ArrayList