如何在AWT中添加ArrayList的打印？

Question

我正在尝试使用for循环在AWT中打印出我的ArrayList的内容。但是，当我尝试编译代码并运行它时，没有显示任何内容。我对Java很新，所以我不确定是什么导致了这一点。

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.time.*;
import javax.swing.*;
import java.util.ArrayList;

public class TimeDisplay extends Applet {
    private City WashingtonDC, Beijing, London, Tokyo, Moscow, TimeRetrieval;
    String temp;
    String []cities = {"WashingtonDC", "Beijing", "London", "Tokyo", "Moscow"};
    String [] GMT = {"-4", "+8", "+1", "+9", "+3"};
    ArrayList DisplayStrings;
    Boolean displaytype;

public void init() {
    WashingtonDC = new City("-4", "Washington D.C.");
    Beijing = new City("+8", "Beijing");
    London = new City("+1", "London");
    Tokyo = new City("+9", "Tokyo");
    Moscow = new City("+3", "Moscow");
    displaytype = false;
    DisplayStrings = new ArrayList();

    //timer
    int delay = 1000; //milliseconds
    ActionListener taskPerformer = new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                if (displaytype = true) {
                    for (int i=0; i<GMT.length; i++) {
                        DisplayStrings.add(TimeRetrieval.GetCurrentTime12(GMT[i]).toString());
                    }
                }
                else {
                    for (int i=0; i<GMT.length; i++) {
                        DisplayStrings.add(i, TimeRetrieval.GetCurrentTime(GMT[i]).toString());
                    }
                }
                repaint();
            }
        };

    new Timer(delay, taskPerformer).start();
}

public void paint (Graphics g) {
    for (int i=0; i<cities.length; i++) {
        g.drawString(Arrays.deepToString(DisplayStrings.get(i))(), 25, (i+1)*50+25);
    }
    for (int i=0; i<cities.length; i++) {
        g.drawString(cities[i], 25, (i+1)*50);
    }
}
}