java - 从 JPanel 获取选定的组件

Question

我通过ArrayList<Items>动态地将项目添加到我的JPanel中。基本上 items 对象看起来像这样:

public class Item {

    private JComponent component;
    private String functionality;

    public Item(JComponent component, String functionality) {
        super();
        this.component = component;
        this.functionality = functionality;
    }

    public JComponent getComponent() {
        return component;
    }

    public void setComponent(JComponent component) {
        this.component = component;
    }

    public String getFunctionality() {
        return functionality;
    }

    public void setFunctionality(String functionality) {
        this.functionality = functionality;
    }
}

在这里，我动态添加按钮:(如果需要，请尝试该示例)

public class minimumExample extends JFrame {

    private JButton addItem;

    private JComboBox itemBox;

    private String[] itemSelect = { "test1", "test2" };

    private JPanel addUpperPane;

    private JPanel addLowerPane;

    private ArrayList<Item> displayedItems = new ArrayList<Item>();

    private JButton upButton;

    private JButton downButton;

    private JButton deleteButton;

    public void createControlPane() {

        addUpperPane = new JPanel();
        addLowerPane = new JPanel(new GridLayout(0, 1));

        addItem = new JButton("Add item");
        upButton = new JButton("Up");
        downButton = new JButton("Down");
        deleteButton = new JButton("Delete");

        itemBox = new JComboBox(itemSelect);

        addItem.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {

                if(itemBox.getSelectedItem().toString().equals("test1")) {
                    displayedItems.add(new Item( new ButtonComp().butt(), "test1"));                
                    validate();
                    repaint();
                }

                if(itemBox.getSelectedItem().toString().equals("test2")) {
                    displayedItems.add(new Item( new LabelComp().label(), "test2"));    
                    validate();
                    repaint();
                }


                for (int i = 0; i < displayedItems.size(); i++) {
                    addLowerPane.add(displayedItems.get(i).getComponent());
                    validate();
                    repaint();
                }
            }
        });



        addUpperPane.add(itemBox, BorderLayout.EAST);
        addUpperPane.add(addItem, BorderLayout.WEST);
        addUpperPane.add(new JLabel(" | "), BorderLayout.WEST);
        addUpperPane.add(upButton, BorderLayout.WEST);
        addUpperPane.add(downButton, BorderLayout.WEST);
        addUpperPane.add(deleteButton, BorderLayout.WEST);
        addUpperPane.add(new JSeparator(JSeparator.HORIZONTAL));

        //put everything together

        add(addUpperPane, BorderLayout.NORTH);
        add(addLowerPane, BorderLayout.SOUTH);

        repaint();

    }

    private void makeLayout() {

        setTitle("Test App");
        setLayout(new BorderLayout());
        setPreferredSize(new Dimension(1000, 500));

        createControlPane();
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
        setVisible(true);

    }


    /**
     * starts the GUI
     */
    public void start() {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                makeLayout();   
            }
        });
    }

    public static void main(String[] args) throws IOException {
        minimumExample ex = new minimumExample();
        ex.start();
    }



    public class ButtonComp extends Component {

        public JPanel butt() {
            JPanel panel = new JPanel();

            JButton button = new JButton("Test1");
            JCheckBox check = new JCheckBox();

            panel.add(button);
            panel.add(check);

            return panel;
        }
    }

    public class LabelComp extends Component {

        public JPanel label() {
            JPanel panel = new JPanel();

            JLabel label = new JLabel("Test2");
            JCheckBox check = new JCheckBox();

            panel.add(label);
            panel.add(check);

            return panel;
        }
    }
}

该程序基本上如下所示:

我的问题是按钮 Up, Down and Delete不起作用，因为我不知道如何从 Pane 中获取选定的元素，以将其从所有组件所在的列表中删除。有关如何使其工作的任何建议？

非常感谢您的回答!

更新

我更改了我的代码，您的规范@cghislai，但它不起作用。自己尝试一下:

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSeparator;

public class minimumExample extends JFrame {

    private JButton addItem;

    private JComboBox itemBox;

    private String[] itemSelect = { "test1", "test2" };

    private JPanel addUpperPane;

    private JPanel addLowerPane;

    private List<CheckableItem> displayedItems = new ArrayList<CheckableItem>();

    private JButton upButton;

    private JButton downButton;

    private JButton deleteButton;

    public void createControlPane() {

        addUpperPane = new JPanel();
        addLowerPane = new JPanel(new GridLayout(0, 1));

        addItem = new JButton("Add item");
        upButton = new JButton("Up");
        downButton = new JButton("Down");
        deleteButton = new JButton("Delete");

        itemBox = new JComboBox(itemSelect);

        addItem.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {

                if(itemBox.getSelectedItem().toString().equals("test1")) {
                    ButtonComp butt = new ButtonComp();
                    butt.init();
                    displayedItems.add(butt);
                    validate();
                    repaint();
                }

                if(itemBox.getSelectedItem().toString().equals("test2")) {
                    //                  displayedItems.add(new CopyOfItem( new LabelComp(), "test2"));  
                    validate();
                    repaint();
                }


                for (int i = 0; i < displayedItems.size(); i++) {
                    addLowerPane.add(displayedItems.get(i).getComponent());
                    validate();
                    repaint();
                }
            }
        });


        deleteButton.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent arg0) {

                Iterator<CheckableItem> it = displayedItems.iterator();
                while (it.hasNext()) {
                    CheckableItem next = it.next();
                    if (next.isSelected()) {
                        addLowerPane.remove(next.getComponent());
                        it.remove();
                        continue;
                    }
                }

            }
        });

        addUpperPane.add(itemBox, BorderLayout.EAST);
        addUpperPane.add(addItem, BorderLayout.WEST);
        addUpperPane.add(new JLabel(" | "), BorderLayout.WEST);
        addUpperPane.add(upButton, BorderLayout.WEST);
        addUpperPane.add(downButton, BorderLayout.WEST);
        addUpperPane.add(deleteButton, BorderLayout.WEST);
        addUpperPane.add(new JSeparator(JSeparator.HORIZONTAL));

        //put everything together

        add(addUpperPane, BorderLayout.NORTH);
        add(addLowerPane, BorderLayout.SOUTH);

        repaint();

    }

    private void makeLayout() {

        setTitle("Test App");
        setLayout(new BorderLayout());
        setPreferredSize(new Dimension(1000, 500));

        createControlPane();
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
        setVisible(true);

    }


    /**
     * starts the GUI
     */
    public void start() {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                makeLayout();   
            }
        });
    }

    public static void main(String[] args) throws IOException {
        minimumExample ex = new minimumExample();
        ex.start();
    }




    public abstract class CheckableItem {

        protected JCheckBox check;

        public boolean isSelected() {
            return check.isSelected();
        }

        public abstract Component getComponent();

    }

    public class ButtonComp extends CheckableItem {
        JPanel panel = new JPanel();

        public void init() {
            JButton button = new JButton("Test1");
            check = new JCheckBox();
            panel.add(button);
            panel.add(check);
        }

        @Override
        public Component getComponent() {
            return panel;
        }

    }

    public class LabelComp extends JPanel {

        public void label() {
            //          JPanel panel = new JPanel();

            JLabel label = new JLabel("Test2");
            JCheckBox check = new JCheckBox();

            add(label);
            add(check);

        }
    }
}

Answer 1

您需要遍历您的所有项目，检查项目复选框是否被选中，如果是这种情况，请从面板中删除您的项目。我将创建一个抽象的 CheckableItem 类，其中包含 JCheckbox 和组件的 getter。然后，对于每个项目，如果选中该复选框，则从父级中删除该组件。

public abstract class CheckableItem {
    protected JCheckbox checkbox;
    public boolean isSelected() {
        return checkbox.isSelected();
    }
    public abstract Component getComponent();
}
public class ButtonComp extends CheckableItem {
    private Panel panel;
    public void init() {
        checkbox = new JCheckbox;
        panel = new JPanel();
        panel.add(new JButton());
        panel.add(checkbox);
    }
    public Component getComponent() {
        return panel;
    }
}

然后跟踪您的元素:

 private List<CheckableItem> items = new ArrayList<>();
    // ...
    ButtonComp comp = new ButtonComp();
    comp.init();  
    items.add(comp);

然后删除所有选中的:

Iterator<CheckbleItem> it = items.iterator();
while (it.hasNext()) {
    CheckableItem next = it.next();
    if (next.isSelected()) {
        mainPanel.remove(next.getComponent());
        it.remove();
        continue;
    }
}