如何使用单个按钮在不同的面板上执行不同的操作？答案

【问题标题】：How to use single button to carry out different actions on different panels?如何使用单个按钮在不同的面板上执行不同的操作？
【发布时间】：2021-06-28 13:57:53
【问题描述】：

我正在制作一个面板来显示底部有“购买”和“收藏”按钮的房产广告。我没有多次制作相同的面板，而是创建了一个为我生成广告面板的方法，我只需使用不同的坐标多次调用该方法。

public JPanel createAdvertisement(int price, String owner, String location, int bedrooms, int bathrooms,
        int stories, int area) {
    JPanel adPanel = new JPanel();
    adPanel.setBackground(Color.WHITE);
    adPanel.setBorder(new LineBorder(new Color(0, 0, 0), 1, true));
    adPanel.setBounds(50, 138, 500, 230);
    this.add(adPanel);
    adPanel.setLayout(null);

    JLabel housePicture = new JLabel("");
    housePicture.setIcon(new ImageIcon(BrowseAds.class.getResource("/images/stock house.jpg")));
    housePicture.setBounds(10, 0, 194, 200);
    adPanel.add(housePicture);

    JLabel priceLabel = new JLabel(String.valueOf(price));
    priceLabel.setFont(new Font("SansSerif", Font.BOLD, 18));
    priceLabel.setIcon(new ImageIcon(BrowseAds.class.getResource("/images/price.png")));
    priceLabel.setBounds(214, 11, 276, 32);
    adPanel.add(priceLabel);

    JLabel ownerLabel = new JLabel(owner);
    ownerLabel.setIcon(new ImageIcon(BrowseAds.class.getResource("/images/owner.png")));
    ownerLabel.setFont(new Font("SansSerif", Font.PLAIN, 16));
    ownerLabel.setBounds(218, 50, 270, 21);
    adPanel.add(ownerLabel);

    JLabel locationLabel = new JLabel("<html>" + location + "</html>");
    locationLabel.setIcon(new ImageIcon(BrowseAds.class.getResource("/images/location.png")));
    locationLabel.setFont(new Font("SansSerif", Font.PLAIN, 12));
    locationLabel.setBounds(220, 75, 270, 30);
    adPanel.add(locationLabel);

    JLabel bedroomLabel = new JLabel(String.valueOf(bedrooms) + " Rooms");
    bedroomLabel.setIcon(new ImageIcon(BrowseAds.class.getResource("/images/bedroom.png")));
    bedroomLabel.setFont(new Font("SansSerif", Font.PLAIN, 12));
    bedroomLabel.setBounds(224, 118, 100, 21);
    adPanel.add(bedroomLabel);

    JLabel bathroomLabel = new JLabel(String.valueOf(bathrooms) + " Baths");
    bathroomLabel.setIcon(new ImageIcon(BrowseAds.class.getResource("/images/bathroom.png")));
    bathroomLabel.setFont(new Font("SansSerif", Font.PLAIN, 12));
    bathroomLabel.setBounds(350, 118, 100, 21);
    adPanel.add(bathroomLabel);

    JLabel storiesLabel = new JLabel(String.valueOf(stories) + " Stories");
    storiesLabel.setIcon(new ImageIcon(BrowseAds.class.getResource("/images/floors.png")));
    storiesLabel.setFont(new Font("SansSerif", Font.PLAIN, 12));
    storiesLabel.setBounds(224, 150, 100, 21);
    adPanel.add(storiesLabel);

    JLabel areaLabel = new JLabel(String.valueOf(area) + " Marla");
    areaLabel.setIcon(new ImageIcon(BrowseAds.class.getResource("/images/area.png")));
    areaLabel.setFont(new Font("SansSerif", Font.PLAIN, 12));
    areaLabel.setBounds(350, 150, 100, 21);
    adPanel.add(areaLabel);

    buyButton = new JButton("Buy");
    buyButton.addActionListener(this);
    buyButton.setFont(new Font("SansSerif", Font.PLAIN, 10));
    buyButton.setBounds(214, 196, 120, 23);
    adPanel.add(buyButton);

    JButton btnAddToFavorite = new JButton("Add to Favorite");
    btnAddToFavorite.setFont(new Font("SansSerif", Font.PLAIN, 10));
    btnAddToFavorite.setBounds(360, 196, 120, 23);
    adPanel.add(btnAddToFavorite);

    return adPanel;
}

我想根据其位置在同一个按钮上调用不同的方法。例如。如果用户点击屏幕上的第三个“购买”按钮，我想将该广告的数据发送到后端。你能建议我一种使用同一个按钮执行不同操作的方法吗？

制作广告的代码：

public void viewAds() {
    for (int i = 0; i < 4; i++) {
        int index = ((pageNumber - 1) * 4) + i;
        if (index < totalCount) {
            Ad curr = array.get(i);
            JPanel panel = createAdvertisement(curr.price, curr.owner, curr.location, curr.bedrooms, curr.bathrooms,
                    curr.stories, curr.area);
            if (index % 4 == 0) {
                panel.setBounds(70, 138, 500, 230);
            }
            if (index % 4 == 1) {
                panel.setBounds(700, 138, 500, 230);
            }
            if (index % 4 == 2) {
                panel.setBounds(70, 380, 500, 230);
            } else if (index % 4 == 3) {
                panel.setBounds(700, 380, 500, 230);
            }
        } else {
            break;
        }
    }
}

【问题讨论】：

1) 为了尽快获得更好的帮助，edit 添加minimal reproducible example 或Short, Self Contained, Correct Example。首先使用一两个按钮解决问题，并忽略图标，除非这会影响问题。 2) Java GUI 必须在不同的语言环境中使用不同的 PLAF 在不同的操作系统、屏幕尺寸、屏幕分辨率等上工作。因此，它们不利于像素完美布局。而是使用布局管理器，或 combinations of them 以及 white space 的布局填充和边框。

标签： java swing button actionlistener

【解决方案1】：

SExtend JButton 以包含一个私有字段或其他记录它的字段。所需要的只是一个ID。比这更进一步的是一种缓存形式，或者拥有一个保存信息的组件/容器可能会更好，例如屏幕上的坐标。

class SButton extends JButton {

    int myID;

    // Code that accepts an ActionListener and applies it to this button.
    // Or use super classes' methods and constructors.

    // Constructor has to set the button's command to include the ID
    // The ID can be generated statically in sequence or provide by
    // outside code.  This is because the command is passed through
    // the ActionEvent generated by the thread.  So a simple way
    // is to append the ID at the end of the command.  This can
    // be easy because the SButtons will all have the same label
    // or you can provide a single base for their command for all.

}


class Ad {

    Point myLocation;

    // Ad code creates panel that uses an SButton, maybe providing ID.

}

class AdManager implements ActionListener {

    Ad [] myAds = new Ad []; // use lists, hashmaps, etc. as appropriate.

    void initAds () {
        for (some kind of loop) {
            make some kind of Ad;
            set its ActionListener to this AdManager;
            put it in myAds;
        }
    }

    public void actionPerformed (ActionEvent e) {
        String cmd = e.getActionCommand ();
        int anID = cmd.subString (some index at the end);
        theOneMethodThatSyedWroteThatHandlesAllTheSButtons (anID);
    }
}

【讨论】：

class SButton extends JButton { 如果没有更好的方法来实现这一点，我会感到惊讶..
我会同样感到惊讶并渴望知道它。但有时，特别是对于有问题的新学习者，复杂但优雅的方法可能会令人困惑。因此需要定义“更好”；其他一些因素可能是效率、代码空间、数据存储、可维护性、可重用性、可扩展性以及您能想到的其他因素。
@Syed，Andrew 正在调用一个很好的指导原则来避免扩展 Swing 组件，除非真的要添加功能。在这种情况下，ID 将是额外的功能。可以使用对每个 Button 的实际引用作为 ID 作为一种避免扩展 JButton 的方法，但这可能会涉及更多内容，并且如果重新创建 Button 或 Ads 时更改引用会变得脆弱，因此我不会推荐它。
我是初学者，不具备扩展 GUI 组件的知识，所以我将采用不同的方法。也许创建 4 个不同的按钮对我来说是一个标准。无论如何感谢您的帮助。感谢您的帮助。