按名稱搜索JPanel

我正在按照如何使用 CardLayout Java Swing 教程進行操作，然后將面板添加到布局中：

JPanel cards;
final static String BUTTONPANEL = "Card with JButtons";

//Create the "cards".
JPanel card1 = new JPanel();

//Create the panel that contains the "cards".
cards = new JPanel(new CardLayout());
cards.add(card1, BUTTONPANEL);

他們還說：

要將組件添加到 CardLayout 物件管理的容器中，請指定一個標識要添加的組件的字串。例如，在這個演示中，第一個面板有字串“Card with JButtons”

因此，如果該字串用于標識要添加的組件，我想知道是否有辦法從 AssertJ SwingFrameFixture或直接從JFrame物件獲取布局中的特定面板，并傳遞字串。

我看到該add方法是繼承自java.awt.Container. 我期待找到一種方法可以讓我做類似的事情，frame.getComponent(BUTTONPANEL)但該方法需要一個索引作為引數。我忽略了什么嗎？

我也知道我可以這樣做card1.setName(BUTTONPANEL)，然后在我的測驗中檢索它：

window = new FrameFixture(view);
window.panel(BUTTONPANEL);

add但是，如果沒有用，那么在方法中設定該字串有什么意義。謝謝。

編輯：

我錯過了一個事實，當然BUTTONPANEL它用于從卡片布局更改面板的字串，如下所示：

cardLayout.show(getContentPane(), BUTTONPANEL);

很明顯，那個字串是有用的。

但是，我正在尋找一種能夠通過在or物件JPanel上呼叫方法并傳遞字串來獲取物件的方法。像這樣的東西：JFrameFrameFixture

JPanel buttonPanelPanel = frame.getPanelFromName(BUTTONPANEL);

這是因為在測驗中我無法直接訪問面板，而只能訪問框架。為了在特定面板上做出斷言，我希望能夠使用add. 但也許這是不可能的。

uj5u.com熱心網友回復：

我在類中添加了一個方法以在您傳遞 a 時MainPanel回傳a 。我不使用該方法，但它就在那里。JPanelString

我將所有額外的類都做成了內部類，這樣我就可以將代碼作為一個塊發布。

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

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

public class CardPanelExample implements Runnable {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new CardPanelExample());
    }
    
    private final MainPanel mainPanel;
    
    public CardPanelExample() {
        this.mainPanel = new MainPanel(this);
    }

    @Override
    public void run() {
        JFrame frame = new JFrame("CardPanel Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        frame.add(mainPanel.getPanel(), BorderLayout.CENTER);
        
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }
    
    public void setNextPanel() {
        mainPanel.setNextPanel();
    }
    
    public JPanel getPanelFromName(String name) {
        return mainPanel.getPanelFromName(name);
    }
    
    public class MainPanel {
        
        private final CardLayout cardLayout;
        
        private final JPanel panel;
        private JPanel yellowPanel, orangePanel, whitePanel;
        
        private final String[] panelStrings;
        private String currentPanelString;
        
        public MainPanel(CardPanelExample view) {
            this.cardLayout = new CardLayout();
            this.panelStrings = new String[] { "alpha", "beta", "gamma" };
            this.currentPanelString = panelStrings[0];
            this.panel = createMainPanel(view, cardLayout, panelStrings);
        }
        
        private JPanel createMainPanel(CardPanelExample view, 
                CardLayout cardLayout, String[] panelStrings) {
            this.yellowPanel = new ColorPanel(view, Color.YELLOW).getPanel();
            this.orangePanel = new ColorPanel(view, Color.ORANGE).getPanel();
            this.whitePanel = new ColorPanel(view, Color.WHITE).getPanel();
            
            JPanel panel = new JPanel(cardLayout);
            panel.add(yellowPanel, panelStrings[0]);
            panel.add(orangePanel, panelStrings[1]);
            panel.add(whitePanel, panelStrings[2]);
            
            return panel;
        }
        
        public JPanel getPanelFromName(String name) {
            if (name.equals(panelStrings[0])) {
                return yellowPanel;
            } else if (name.equals(panelStrings[1])) {
                return orangePanel;
            } else if (name.equals(panelStrings[2])) {
                return whitePanel;
            } else {
                return null;
            }
        }
        
        
        public void setNextPanel() {
            for (int index = 0; index < panelStrings.length; index  ) {
                if (currentPanelString.equals(panelStrings[index])) {
                    index =   index % panelStrings.length;
                    currentPanelString = panelStrings[index];
                    cardLayout.show(panel, currentPanelString);
                    return;
                }
            }
        }

        public JPanel getPanel() {
            return panel;
        }
        
    }
    
    public class ColorPanel {
        
        private final JPanel panel;
        
        public ColorPanel(CardPanelExample view, Color backgroundColor) {
            this.panel = createMainPanel(view, backgroundColor);
        }
        
        private JPanel createMainPanel(CardPanelExample view, Color backgroundColor) {
            JPanel panel  = new JPanel(new FlowLayout());
            panel.setBackground(backgroundColor);
            panel.setBorder(BorderFactory.createEmptyBorder(25, 150, 25, 150));
            
            JButton button = new JButton("Next Panel");
            button.addActionListener(new ButtonListener(view));
            panel.add(button);
            
            return panel;
        }

        public JPanel getPanel() {
            return panel;
        }
        
    }
    
    public class ButtonListener implements ActionListener {
        
        private final CardPanelExample view;

        public ButtonListener(CardPanelExample view) {
            this.view = view;
        }

        @Override
        public void actionPerformed(ActionEvent event) {
            view.setNextPanel();
        }
        
    }

}

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