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我是新來的java，我正在尋求一些幫助。我遇到的問題是，我無法在主類中更改不同類中的速度變量。從ChangeListener方法更改ArrayList中所有項目的速度
我有setter/getter方法，但我遇到的問題是決定哪個「對象」來解決setter/getter方法。
此滑塊用於更改ArrayList中所有龜的速度。如果我可以得到一些幫助，那會很棒。除了速度變化之外，ChangeListener方法的其餘部分也適用。
主類：
import javax.swing.*;
import java.awt.*;
import java.util.ArrayList;
import java.awt.event.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
class TurtleProgram
{
\t private JFrame frame;
\t private Canvas canvas;
\t private JPanel lowerPanel;
\t private JButton addTurtleButton;
\t private ArrayList<DynamicTurtle> turtles;
\t private JSlider turtleSpeed;
\t private int oldSliderState = 100;
\t
\t public static void main(String[] args)
\t {
\t \t new TurtleProgram();
\t }
\t public TurtleProgram()
\t {
\t \t frame = new JFrame();
\t \t canvas = new Canvas();
\t \t lowerPanel = new JPanel();
\t \t lowerPanel.setLayout(new FlowLayout());
\t \t DynamicTurtle referenceTurtle = new DynamicTurtle(canvas , new CartesianCoordinate(400,300));
\t \t
\t \t turtles = new ArrayList<DynamicTurtle>();
\t \t turtles.add(new RandomTurtleB(canvas, 400, 300)); \t \t
\t \t addTurtleButton = new JButton("Add A Turtle?");
\t \t lowerPanel.add(addTurtleButton);
\t \t turtleSpeed = new JSlider(0, 100, 100);
\t \t lowerPanel.add(turtleSpeed);
\t \t frame.setTitle("Welcome to Button Simulator!");
\t \t frame.setSize(800, 600);
\t \t frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); \t \t
\t \t frame.setVisible(true); \t \t
\t \t frame.add(lowerPanel, BorderLayout.PAGE_END);
\t \t frame.add(canvas);
\t \t addTurtleButton.addActionListener(new ActionListener()
\t \t {
\t \t \t public void actionPerformed(ActionEvent event)
\t \t \t {
\t \t \t \t turtles.add(new RandomTurtleB(canvas, 400, 300));
\t \t \t }
\t \t });
\t \t turtleSpeed.addChangeListener(new ChangeListener()
\t \t {
\t \t \t public void stateChanged(ChangeEvent event)
\t \t \t {
\t \t \t \t int currentSliderState = turtleSpeed.getValue();
\t \t \t \t int currentSpeed = (turtles.get(i)).getSpeed(); //HERE I CANNOT USE THE TURTLES IN THE ARRAYLIST TO SET SPEED
\t \t \t \t if(currentSliderState < oldSliderState)
\t \t \t \t {
\t \t \t \t \t System.out.println("is less");
\t \t \t \t \t (turtles.get(i)).setSpeed(currentSpeed - 100); //DECREASES ALL TURTLES SPEED
\t \t \t \t }
\t \t \t \t else if(currentSliderState > oldSliderState)
\t \t \t \t {
\t \t \t \t \t System.out.println("is more");
\t \t \t \t \t (turtles.get(i)).setSpeed(currentSpeed + 100); //INCREASES ALL TURTLES SPEED
\t \t \t \t }
\t \t \t \t oldSliderState = (turtles.get(i)).getValue(); \t \t \t \t
\t \t \t }
\t \t }); \t \t
\t \t gameLoop();
\t }
\t private void gameLoop()
\t {
\t \t int deltaTime = 20;
\t \t
\t \t while(true)
\t \t {
\t \t \t for (int i = 0; i < turtles.size(); i++)
\t \t \t {
\t \t \t \t (turtles.get(i)).unDrawTurtle(); \t \t \t \t
\t \t \t \t (turtles.get(i)).wrapPosition((turtles.get(i)).getPositionX(), (turtles.get(i)).getPositionY());
\t \t \t }
\t \t \t for (int i = 0; i < turtles.size(); i++)
\t \t \t {
\t \t \t \t (turtles.get(i)).update(1000); \t
\t \t \t }
\t \t \t for (int i = 0; i < turtles.size(); i++)
\t \t \t {
\t \t \t \t (turtles.get(i)).drawTurtle(); \t \t \t \t
\t \t \t }
\t \t
\t \t Utils.pause(deltaTime/2);
\t \t } \t
\t } \t
}含有的setter/getter方法的類：
class DynamicTurtle extends Turtle
{
\t private int speed = 100;
\t private int time;
\t private double xPos, yPos;
\t private CartesianCoordinate myLocation;
\t private int Angle = 0;
\t DynamicTurtle(Canvas canvas, CartesianCoordinate initLocation)
\t {
\t \t super(canvas, initLocation); \t \t
\t }
\t DynamicTurtle(Canvas canvas, double xPosition, double yPosition) //THE PROBLEM CONSTRUCTOR
\t {
\t \t super(canvas, new CartesianCoordinate(xPosition, yPosition)); \t \t
\t }
\t public int getSpeed()
\t {
\t \t return this.speed;
\t }
\t public void setSpeed(int speed)
\t {
\t \t this.speed = speed;
\t }
\t public void update(int time)
\t {
\t \t this.move((speed*100/time)); \t
\t \t canvas.removeMostRecentLine();
\t }
}謝謝你們提前幫忙，我還沒有從Main中刪除代碼（我知道它很長），所以你可以看到我在處理主ArrayLists的過程中的邏輯。我知道我不能使用這個「get（i）」。乾杯。
是否所有的龜都有相同的速度？ –
@SaviourSelf你好，是的。在DynamicTurtle類中，所有的龜具有相同的速度，速度變量僅用於update（）方法。 –
如果所有的海龜總是以相同的速度移動，你可以使速度變爲「靜態」。 –