Click事件-从另一个类访问布尔变量 [英] Click Event - Accessing a boolean variable from another class

问题描述

停留在一个需要从另一个类中获取一个boolean变量的问题上.

Stuck on a problem that requires grabbing a boolean variable from another class.

我有以下for-loop，boolea n和if-else语句

import java.awt.*;
import javax.swing.*;
import java.awt.Color.*;
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;
import java.util.Random;

public class Checkers extends JFrame 
{
    Random random = new Random();
    private final int ROWS = 2;
    private final int COLS = 5;
    private final int GAP = 2;
    private final int NUM = ROWS * COLS;
    private int i;
    private int score;
    private JPanel pane = new JPanel(new GridLayout(ROWS,COLS, GAP,GAP));
    private JPanel pane2 = new JPanel();
    private JPanel pane3 = new JPanel();

    private JButton btn1 = new JButton("Play A Game");
    private JButton btn2 = new JButton("Exit");

    private JButton btn3 = new JButton("Easy");
    private JButton btn4 = new JButton("Intermediate");
    private JButton btn5 = new JButton("Difficult");
    private JLabel lbl1 = new JLabel ("score: " + score);
    private JLabel gameLost = new JLabel("You lose! You got: " + score + " points");

    private JButton btnRestart = new JButton("Restart");

    private MyPanel [] panel = new MyPanel[NUM];
    private Color col1 = Color.RED;
    private Color col2 = Color.WHITE;
    private Color col3 = Color.GREEN;
    private Color tempColor;
    private boolean isPanelDisabled;

    //Starts the checkers GUI, calling the constructor below this.

    public static void main(String[] args){
        new Checkers();
    }

    //Sets the dimensions of the GUI, visibility, background color and 
    //contents via the setBoard(); 

    public Checkers()
    {
        super("Checkers");
        setSize(600,600);
        setVisible(true);
        setBackground(Color.BLACK);
        setBoard();
    }

    //Makes the grid, contains a conditional boolean, adds the panels to grid based on i value.
    //sets Colours accordingly

    public void setBoard()


    {

        boolean isPanelDisabled = false;
        for (int i = 0; i < panel.length; i++) {
            panel[i] = new MyPanel(this);
            pane.add(panel[i]);

            if (i % COLS == 0) {
                tempColor = col1;
            }
            if (i == 9 || i <8) {
                panel[i].setBackground(col1);

            }
            if(i == 8){
                isPanelDisabled = true;
                panel[i].setBackground(col3);
            }

        }

        //pane background colour and the size of this pane.

        pane.setBackground(Color.BLACK);
        pane.setPreferredSize(new Dimension(300,300));

        //pane background colour and size of this pane.

        pane2.setBackground(Color.white);
        pane2.setPreferredSize(new Dimension(300,300));

        //directions on the board where these panes appear.

        add(pane, BorderLayout.WEST);
        add(pane2, BorderLayout.EAST);
        pane2.add(lbl1);
        pane2.add(btnRestart);
        btnRestart.addActionListener( e -> restartBoard());
        pane2.setLayout(new BoxLayout(pane2, BoxLayout.PAGE_AXIS));

    }

    //increments the score for the user based on current points.

    public void incrementScore(){
        if (score != 5){

            score++;
            lbl1.setText("Score: " + Integer.toString(score));
        }
        else if(score == 5){

            lbl1.setText("Congratulations!, you've won!, your score is:" + score);
        }

    }
}

和此mouseClicked事件

 import java.awt.Color;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.*;  
import java.awt.event.*;  
import javax.swing.JPanel;


public class MyPanel extends JPanel implements MouseListener, ActionListener {
    private final Checkers checkers;
    private boolean isPanelDisabled;

    //MyPanel Constructor that initiates a instance of checkers.

    public MyPanel(Checkers checkers) {
        this.checkers = checkers;
        addMouseListener(this);

    }

    @Override
    public void actionPerformed(ActionEvent e){

    }
    // Sets the panel colours according to their int number and the boolean condiiton.
    @Override
    public void mouseClicked(MouseEvent e) {
        if (isPanelDisabled == true){ 

            setBackground(Color.CYAN);
        }
        else{
            setBackground(Color.BLACK);
            checkers.incrementScore();
        }

    }

我的预期结果应该是，如果用户单击该网格中的第8个面板，则该面板的颜色在被按下时将是青色而不是黑色，但是它无法访问布尔变量?我在哪里错了?

My Expected result of this should be that if the user clicks the 8th panel in that grid, then the color of that panel will be cyan when pressed and not black, but it cant access the boolean variable? where am i going wrong here?

推荐答案

您的问题涉及不同类的对象之间的通信，有几种方法可以实现，但是最基本的方法是在一个类中调用对象的方法到另一个.

Your question involves communication between objects of different classes, and there are several ways to do this, but most basic is to call a method of an object in one class to the other.

首先让我们设置问题，...我创建了名为MyPanel2和Checkers2的类，以区别于您的类.

First lets set up the problem,... I've created classes called MyPanel2 and Checkers2, to distinguish them from yours.

在MyPanel2中说，我们有一个Checkers2字段和一个名为selected的布尔值字段，设置为false:

Say in MyPanel2 we have a Checkers2 field and a boolean field called selected that is set to false:

private Checkers2 checkers;
private boolean selected = false;

以及适当的布尔型getter和setter:

along with appropriate boolean getter and setter:

public void setSelected(boolean selected) {
    this.selected = selected;
}

public boolean isSelected() {
    return selected;
}

并说在Checkers2类中，数组中包含10个MyPanel2实例，并且希望用户能够选择"该类的实例，但只允许选择其中的7个，并假设要使用当前正在使用的设置，可以给主类一个方法public boolean isPanelDisabled()，并让MyPanel2类调用此方法来确定是否允许选择.因此，在MyPanel2中，您可以拥有一个类似以下内容的MouseListener:

And say within the Checkers2 class you have a 10 instances of MyPanel2 held within an array, and you want the user to be able to "select" instances of the class, but only allow 7 of them to be selected, and assume that you want to user the set up that you're currently using, you could give the main class, a method, public boolean isPanelDisabled(), and have the MyPanel2 class call this method to determine if selection is allowed. So within MyPanel2 you could have a MouseListener with something like:

@Override
public void mousePressed(MouseEvent e) {
    if (selected) {
        return;
    }

    // call the Checkers2 boolean method to check
    if (checkers.isPanelDisabled()) {
        setBackground(DISABLED_COLOR);
    } else {
        setBackground(SELECTED_COLOR);
        setSelected(true);
    }
}

在Checkers2 .isPanelDisabled()方法中，您将遍历MyPanel2实例数组以查看已选择了多少实例，这样可以起作用:

Within Checkers2 .isPanelDisabled() method you'd iterate through the array of MyPanel2 instances to see how many have been selected, something like this could work:

public boolean isPanelDisabled() {
    int count = 0;
    for (MyPanel2 panel2 : myPanels) {
        if (panel2.isSelected()) {
            count++;
        }
    }
    return count >= MAX_COUNT;
}

整个MCVE可测试代码如下:

The whole MCVE testable code could look like:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Checkers2 extends JFrame {
    private static final int MAX_COUNT = 7;
    private final int ROWS = 2;
    private final int COLS = 5;
    private final int GAP = 2;
    private final int NUM = ROWS * COLS;
    private MyPanel2[] myPanels = new MyPanel2[NUM];

    public Checkers2() {
        super("Checkers");
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        JPanel gridPanel = new JPanel(new GridLayout(ROWS, COLS, 1, 1));
        gridPanel.setBackground(Color.BLACK);
        gridPanel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
        for (int i = 0; i < myPanels.length; i++) {
            MyPanel2 myPanel = new MyPanel2(this);
            gridPanel.add(myPanel);
            myPanels[i] = myPanel;
        }

        JButton resetButton = new JButton("Reset");
        resetButton.setMnemonic(KeyEvent.VK_R);
        resetButton.addActionListener(evt -> {
            for (MyPanel2 myPanel2 : myPanels) {
                myPanel2.reset();
            }
        });
        JButton exitButton = new JButton("Exit");
        exitButton.setMnemonic(KeyEvent.VK_X);
        exitButton.addActionListener(evt -> System.exit(0));

        JPanel buttonPanel = new JPanel();
        buttonPanel.add(resetButton);

        add(gridPanel);
        add(buttonPanel, BorderLayout.PAGE_END);

        pack();
        setLocationRelativeTo(null);
    }

    public boolean isPanelDisabled() {
        int count = 0;
        for (MyPanel2 panel2 : myPanels) {
            if (panel2.isSelected()) {
                count++;
            }
        }
        return count >= MAX_COUNT;
    }


    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            new Checkers2().setVisible(true);
        });
    }

}

class MyPanel2 extends JPanel {
    private static final int PREF_W = 200;
    private static final int PREF_H = PREF_W;
    private static final int GR = 240;
    public static final Color BASE_COLOR = new Color(GR, GR, GR);
    public static final Color DISABLED_COLOR = Color.CYAN;
    public static final Color SELECTED_COLOR = Color.BLACK;
    private Checkers2 checkers;
    private boolean selected = false;

    public MyPanel2(Checkers2 checkers) {
        setBackground(BASE_COLOR);
        this.checkers = checkers;
        setPreferredSize(new Dimension(PREF_W, PREF_H));
        addMouseListener(new MyMouse());
    }

    public void setSelected(boolean selected) {
        this.selected = selected;
    }

    public boolean isSelected() {
        return selected;
    }

    public void reset() {
        setBackground(BASE_COLOR);
        setSelected(false);
    }

    private class MyMouse extends MouseAdapter {
        @Override
        public void mousePressed(MouseEvent e) {
            if (selected) {
                return;
            }
            if (checkers.isPanelDisabled()) {
                setBackground(DISABLED_COLOR);
            } else {
                setBackground(SELECTED_COLOR);
                setSelected(true);
            }
        }
    }
}

---

另一个选项是提取MyPanel的所有逻辑 ，并将其放入主程序中，例如:

---

Another Option is to take all the logic out of MyPanel and put it into the main program, something like:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

@SuppressWarnings("serial")
public class Checkers3 extends JPanel {
    private static final int MAX_COUNT = 7;
    private final int ROWS = 2;
    private final int COLS = 5;
    private final int GAP = 2;
    private final int NUM = ROWS * COLS;
    private MyPanel3[] myPanels = new MyPanel3[NUM];

    public Checkers3() {
        JPanel gridPanel = new JPanel(new GridLayout(ROWS, COLS, 1, 1));
        gridPanel.setBackground(Color.BLACK);
        gridPanel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
        MyMouse myMouse = new MyMouse();
        for (int i = 0; i < myPanels.length; i++) {
            MyPanel3 myPanel = new MyPanel3();
            myPanel.addMouseListener(myMouse);
            gridPanel.add(myPanel);
            myPanels[i] = myPanel;
        }

        JButton resetButton = new JButton("Reset");
        resetButton.setMnemonic(KeyEvent.VK_R);
        resetButton.addActionListener(evt -> {
            for (MyPanel3 myPanel : myPanels) {
                myPanel.reset();
            }
        });
        JButton exitButton = new JButton("Exit");
        exitButton.setMnemonic(KeyEvent.VK_X);
        exitButton.addActionListener(evt -> System.exit(0));

        JPanel buttonPanel = new JPanel();
        buttonPanel.add(resetButton);

        setLayout(new BorderLayout());
        add(gridPanel);
        add(buttonPanel, BorderLayout.PAGE_END);
    }

    public boolean isPanelDisabled() {
        int count = 0;
        for (MyPanel3 panel : myPanels) {
            if (panel.isSelected()) {
                count++;
            }
        }
        return count >= MAX_COUNT;
    }

    private class MyMouse extends MouseAdapter {
        @Override
        public void mousePressed(MouseEvent e) {
            MyPanel3 myPanel = (MyPanel3) e.getSource();
            if (myPanel.isSelected()) {
                return; // it's already selected
            } else if (isPanelDisabled()) {
                myPanel.setSelected(false);
            } else {
                myPanel.setSelected(true);
            }
        }
    }

    private static void createAndShowGui() {
        Checkers3 mainPanel = new Checkers3();

        JFrame frame = new JFrame("Checkers");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(mainPanel);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGui());
    }
}

@SuppressWarnings("serial")
class MyPanel3 extends JPanel {
    private static final int PREF_W = 200;
    private static final int PREF_H = PREF_W;
    private static final int GR = 240;
    public static final Color BASE_COLOR = new Color(GR, GR, GR);
    public static final Color DISABLED_COLOR = Color.CYAN;
    public static final Color SELECTED_COLOR = Color.BLACK;
    private boolean selected = false;

    public MyPanel3() {
        setBackground(BASE_COLOR);
        setPreferredSize(new Dimension(PREF_W, PREF_H));
    }

    public void setSelected(boolean selected) {
        this.selected = selected;
        Color background = selected ? SELECTED_COLOR : DISABLED_COLOR;
        setBackground(background);
    }

    public boolean isSelected() {
        return selected;
    }

    public void reset() {
        setSelected(false);
        setBackground(BASE_COLOR);
    }
}

但是 BEST 选项是将所有逻辑放在一个或多个单独的模型类中，并使GUI尽可能哑.

But the BEST option is to put all logic within a separate model class (or classes) and make the GUI's as dumb as possible.

这篇关于Click事件-从另一个类访问布尔变量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！