java - 从组件更改 JLabel ICON

Question

所以我有一个 JLabels 网格，随机分配背景颜色和图标来匹配(Bubble Breaker 游戏的气泡)，当我使用 findComponentAt(getX(), getY()) 来获取组件我点击....这是因为我想找出我被点击的标签并将其图标更改为不同的图标，但是组件API似乎没有 setIcon() 方法，关于如何操作的任何建议我可以更改图标吗？

下面给出了我的一个文件的代码，但很困惑，因为我显然仍在开发中，所以很抱歉。

代码粘贴得很奇怪......:

import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.util.Random;
import java.awt.Color.*;
import java.awt.Cursor.*;
import javax.swing.border.*;
import java.awt.event.*;

public class GridForGame extends JPanel {
JTextField myNumberArray[] = new JTextField[16];
MouseHandling handler = new MouseHandling();

JLabel statusbar = new JLabel("default");
JLabel tempLabel = new JLabel();

JPanel squareContainer = new JPanel();
Boolean handlerOn = false;
boolean colourChanged = false;

ImageIcon redBubble;
ImageIcon blueBubble;
ImageIcon yellowBubble;
ImageIcon orangeBubble;
ImageIcon greenBubble;
ImageIcon pinkBubble;
ImageIcon purpleBubble;


public void smallIcons(){
    redBubble = new ImageIcon("images/redSmall.jpg");
    blueBubble = new ImageIcon("images/blueSmall.jpg");
    yellowBubble = new ImageIcon("images/yellowSmall.jpg");
    orangeBubble = new ImageIcon("images/orangeSmall.jpg");
    greenBubble = new ImageIcon("images/greenSmall.jpg");
    pinkBubble = new ImageIcon("images/pinkSmall.jpg");
    purpleBubble = new ImageIcon("images/purpleSmall.jpg");
}

public void mediumIcons(){
    redBubble = new ImageIcon("images/redMedium.jpg");
    blueBubble = new ImageIcon("images/blueMedium.jpg");
    yellowBubble = new ImageIcon("images/yellowMedium.jpg");
    orangeBubble = new ImageIcon("images/orangeMedium.jpg");
    greenBubble = new ImageIcon("images/greenMedium.jpg");
    pinkBubble = new ImageIcon("images/pinkMedium.jpg");
}

public void largeIcons(){
    redBubble = new ImageIcon("images/redLarge.jpg");
    blueBubble = new ImageIcon("images/blueLarge.jpg");
    yellowBubble = new ImageIcon("images/yellowLarge.jpg");
    orangeBubble = new ImageIcon("images/orangeLarge.jpg");
    greenBubble = new ImageIcon("images/greenLarge.jpg");
    pinkBubble = new ImageIcon("images/pinkLarge.jpg");
}

public GridForGame(){
    setLayout(new BorderLayout());
    setBackground(Color.gray);  
    setBorder(new EtchedBorder(4, Color.blue, Color.blue));
    setPreferredSize(new Dimension(600,600));
}

public void small(){

    smallIcons();
    /*
     * Below empties the main game view so that
     * more can be 'painted' on it.
     */
    squareContainer.removeAll();
    revalidate();

    // Set the grid for 8 x 8
    squareContainer.setLayout(new GridLayout(8,8));
    squareContainer.setPreferredSize(new Dimension(500,500));
    squareContainer.setMaximumSize(new Dimension(500,500));

    /*
     * Checks if a Mouse handler has already been
     * assigned to game view, if not, Add one!
     */
    if(!handlerOn){
        squareContainer.addMouseListener(handler);
        handlerOn = true;
    }

    statusbar.setText("default");
    add(statusbar, BorderLayout.NORTH);

    for(int i=0; i<8; i++){

        for(int j=0; j<8; j++){
            JLabel number = new JLabel();

            number.setEnabled(true);
            number.setOpaque(true);
            number.setBorder(new MatteBorder(1, 1, 1, 1, Color.black));

            for(int k=0; k<8; k++){
                int n = new Random().nextInt(7);
                    switch(n){
                        case 0: number.setBackground(Color.red);
                                number.setIcon(redBubble); break;
                        case 1: number.setBackground(Color.cyan);
                                number.setIcon(orangeBubble); break;
                        case 2: number.setBackground(Color.blue);
                                number.setIcon(blueBubble); break;
                        case 3: number.setBackground(Color.green);
                                number.setIcon(greenBubble); break;
                        case 4: number.setBackground(Color.yellow);
                                number.setIcon(yellowBubble); break;
                        case 5: number.setBackground(Color.magenta);
                                number.setIcon(pinkBubble); break;
                        default:
                    }   
                }

                 squareContainer.add(number);
            }

            //squareContainer.add(squares);
        }
    add(squareContainer);
    revalidate();
}

public void medium(){

    mediumIcons();

    /*
     * Below empties the main game view so that
     * more can be 'painted' on it.
     */
    squareContainer.removeAll();
    revalidate();

    // Set the grid for 12 x 12
    squareContainer.setLayout(new GridLayout(12,12));
    squareContainer.setPreferredSize(new Dimension(500,500));
    squareContainer.setMaximumSize(new Dimension(500,500));

    /*
     * Checks if a Mouse handler has already been
     * assigned to game view, if not, Add one!
     */
    if(!handlerOn){
        squareContainer.addMouseListener(handler);
        handlerOn = true;
    }

    statusbar.setText("default");
    add(statusbar, BorderLayout.NORTH);

    for(int i=0; i<12; i++){
        JPanel squares = new JPanel();
        squares.setLayout(new GridLayout(1,1));
        for(int j=0; j<12; j++){
            JLabel number = new JLabel();
            number.setEnabled(true);
            number.setOpaque(true);
            number.setBorder(new MatteBorder(1, 1, 1, 1, Color.black));

            squares.add(number);
            for(int k=0; k<12; k++){
                int n = new Random().nextInt(7);
                    switch(n){
                        case 0: number.setBackground(Color.red);
                                number.setIcon(redBubble); break;
                        case 1: number.setBackground(Color.cyan);
                                number.setIcon(orangeBubble); break;
                        case 2: number.setBackground(Color.blue);
                                number.setIcon(blueBubble); break;
                        case 3: number.setBackground(Color.green);
                                number.setIcon(greenBubble); break;
                        case 4: number.setBackground(Color.yellow);
                                number.setIcon(yellowBubble); break;
                        case 5: number.setBackground(Color.magenta);
                                number.setIcon(pinkBubble); break;
                        default:
                    }   
                }
            }

            squareContainer.add(squares);
        }
    add(squareContainer);
    revalidate();
}

public void large(){

    largeIcons();

    /*
     * Below empties the main game view so that
     * more can be 'painted' on it.
     */
    squareContainer.removeAll();
    revalidate();

    // Set the grid for 16 x 16
    squareContainer.setLayout(new GridLayout(16,16));
    squareContainer.setPreferredSize(new Dimension(500,500));
    squareContainer.setMaximumSize(new Dimension(500,500));

    /*
     * Checks if a Mouse handler has already been
     * assigned to game view, if not, Add one!
     */
    if(!handlerOn){
        squareContainer.addMouseListener(handler);
        handlerOn = true;
    }

    statusbar.setText("default");
    add(statusbar, BorderLayout.NORTH);

    for(int i=0; i<16; i++){
        JPanel squares = new JPanel();
        squares.setLayout(new GridLayout(1,1));
        for(int j=0; j<16; j++){
            JLabel number = new JLabel();
            number.setEnabled(true);
            number.setOpaque(true);
            number.setBorder(new MatteBorder(1, 1, 1, 1, Color.black));

            squares.add(number);
            for(int k=0; k<16; k++){
                int n = new Random().nextInt(7);
                    switch(n){
                        case 0: number.setBackground(Color.red);
                                number.setIcon(redBubble); break;
                        case 1: number.setBackground(Color.cyan);
                                number.setIcon(orangeBubble); break;
                        case 2: number.setBackground(Color.blue);
                                number.setIcon(blueBubble); break;
                        case 3: number.setBackground(Color.green);
                                number.setIcon(greenBubble); break;
                        case 4: number.setBackground(Color.yellow);
                                number.setIcon(yellowBubble); break;
                        case 5: number.setBackground(Color.magenta);
                                number.setIcon(pinkBubble); break;
                        default:
                    }   
                }
            }

            squareContainer.add(squares);
        }
    add(squareContainer);
    revalidate();
}

private class MouseHandling implements MouseListener{
    public void mouseClicked(MouseEvent event){
        statusbar.setText(String.format("Clicked at %d,%d", event.getX(), event.getY()));
        System.out.println(String.format("Component clicked was " + findComponentAt(event.getX(), event.getY()).getBackground()));

        /*JLabel temp = new JLabel();

        temp = findComponentAt(event.getX(), event.getY());*/

        if(colourChanged == true){
            findComponentAt(event.getX(), event.getY()).setBackground(Color.white);
            System.out.println("selected label now set to white");
        }

        if(colourChanged == false){
            findComponentAt(event.getX(), event.getY()).setBackground(Color.black);
            System.out.println("selected label now set to black");
            colourChanged = true;
        }
    }   

    public void mousePressed(MouseEvent event){
        statusbar.setText("anything");
    }

    public void mouseReleased(MouseEvent event){
        statusbar.setText(String.format("Released at %d,%d", event.getX(), event.getY()));
    }

    public void mouseEntered(MouseEvent event){
        statusbar.setText("Entered");
    }

    public void mouseExited(MouseEvent event){
        statusbar.setText("Exited");
    }
}

}

Answer 1

通过instanceof运算符检查组件是否是JLabel，如果为假，则退出鼠标监听器方法，否则如果为真，则转换为JLabel并设置其图标。例如:

public void mouseClicked(MouseEvent event){
    statusbar.setText(String.format("Clicked at %d,%d", event.getX(), event.getY()));
    System.out.println(String.format("Component clicked was " + findComponentAt(event.getX(), event.getY()).getBackground()));

    Component comp =  findComponentAt(event.getX(), event.getY());
    if (!(comp instanceof JLabel)) {
       return;   // if it's not a JLabel get out of this method
    }

    // it is a JLabel so cast it.

    JLabel temp = (JLabel) comp;

    // now you can use the JLabel