如何在此示例中添加第三个JList

Question

我正在开始编程，学习一点Swing。我正在使用Netbeans的Visual IDE进行实践;这很容易。我只需单击要添加到表单的组件。我在互联网上发现example有两个JList。我需要添加第三个，但我不知道因为没有图形界面;它是在代码中完成的。你可以帮我在Form结尾添加第三个吗？

这是修改后的代码和原始应用程序运行的照片：

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.SortedSet;
import java.util.TreeSet;

import javax.swing.AbstractListModel;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.ListCellRenderer;
import javax.swing.ListModel;

import br.com.project.receita.dao.IngredienteDao;
import br.com.project.receita.vo.IngredienteVo;

public class DualListBox extends JPanel {

  private static final Insets EMPTY_INSETS = new Insets(0, 0, 0, 0);

  private static final String ADD_BUTTON_LABEL = "Adicionar >>";

  private static final String REMOVE_BUTTON_LABEL = "<< Remover";

  private static final String INGREDIENTES_DISPONIVEIS = "Ingredientes Disponíveis";

  private static final String INGREDIENTES_SELECIONADOS = "Ingredientes Selecionados";

  private static final String RECEITAS_DISPONIVEIS = "Receitas Disponíveis";

  private JLabel sourceLabel;

  private JList sourceList;

  private SortedListModel sourceListModel;

  private JList destList;

  private SortedListModel destListModel;

  private JLabel destLabel;

  private JButton addButton;

  private JButton removeButton;


  public DualListBox() {
    initScreen();
  }

  public String getSourceChoicesTitle() {
    return sourceLabel.getText();
  }

  public void setSourceChoicesTitle(String newValue) {
    sourceLabel.setText(newValue);
  }

  public String getDestinationChoicesTitle() {
    return destLabel.getText();
  }

  public void setDestinationChoicesTitle(String newValue) {
    destLabel.setText(newValue);
  }

  public void clearSourceListModel() {
    sourceListModel.clear();
  }

  public void clearDestinationListModel() {
    destListModel.clear();
  }

  public void addSourceElements(ListModel newValue) {
    fillListModel(sourceListModel, newValue);
  }

  public void setSourceElements(ListModel newValue) {
    clearSourceListModel();
    addSourceElements(newValue);
  }

  public void addDestinationElements(ListModel newValue) {
    fillListModel(destListModel, newValue);
  }

  private void fillListModel(SortedListModel model, ListModel newValues) {
    int size = newValues.getSize();
    for (int i = 0; i < size; i++) {
      model.add(newValues.getElementAt(i));
    }
  }

  public void addSourceElements(Object newValue[]) {
    fillListModel(sourceListModel, newValue);
  }

  public void setSourceElements(Object newValue[]) {
    clearSourceListModel();
    addSourceElements(newValue);
  }

  public void addDestinationElements(Object newValue[]) {
    fillListModel(destListModel, newValue);
  }

  private void fillListModel(SortedListModel model, Object newValues[]) {
    model.addAll(newValues);
  }

  public Iterator sourceIterator() {
    return sourceListModel.iterator();
  }

  public Iterator destinationIterator() {
    return destListModel.iterator();
  }

  public void setSourceCellRenderer(ListCellRenderer newValue) {
    sourceList.setCellRenderer(newValue);
  }

  public ListCellRenderer getSourceCellRenderer() {
    return sourceList.getCellRenderer();
  }

  public void setDestinationCellRenderer(ListCellRenderer newValue) {
    destList.setCellRenderer(newValue);
  }

  public ListCellRenderer getDestinationCellRenderer() {
    return destList.getCellRenderer();
  }

  public void setVisibleRowCount(int newValue) {
    sourceList.setVisibleRowCount(newValue);
    destList.setVisibleRowCount(newValue);
  }

  public int getVisibleRowCount() {
    return sourceList.getVisibleRowCount();
  }

  public void setSelectionBackground(Color newValue) {
    sourceList.setSelectionBackground(newValue);
    destList.setSelectionBackground(newValue);
  }

  public Color getSelectionBackground() {
    return sourceList.getSelectionBackground();
  }

  public void setSelectionForeground(Color newValue) {
    sourceList.setSelectionForeground(newValue);
    destList.setSelectionForeground(newValue);
  }

  public Color getSelectionForeground() {
    return sourceList.getSelectionForeground();
  }

  private void clearSourceSelected() {
    Object selected[] = sourceList.getSelectedValues();
    for (int i = selected.length - 1; i >= 0; --i) {
      sourceListModel.removeElement(selected[i]);
    }
    sourceList.getSelectionModel().clearSelection();
  }

  private void clearDestinationSelected() {
    Object selected[] = destList.getSelectedValues();
    for (int i = selected.length - 1; i >= 0; --i) {
      destListModel.removeElement(selected[i]);
    }
    destList.getSelectionModel().clearSelection();
  }

  private void initScreen() {
    setBorder(BorderFactory.createEtchedBorder());
    setLayout(new GridBagLayout());
    sourceLabel = new JLabel(INGREDIENTES_DISPONIVEIS);
    JButton button = new JButton("Buscar");
    add(button, new GridBagConstraints(1, 3, 1, 2, 0, .25,
        GridBagConstraints.CENTER, GridBagConstraints.NONE,
        EMPTY_INSETS, 0, 0));
    button.addActionListener(new PrintListener());

    sourceListModel = new SortedListModel();
    sourceList = new JList(sourceListModel);
    add(sourceLabel, new GridBagConstraints(0, 0, 1, 1, 0, 0,
        GridBagConstraints.CENTER, GridBagConstraints.NONE,
        EMPTY_INSETS, 0, 0));
    add(new JScrollPane(sourceList), new GridBagConstraints(0, 1, 1, 5, .5,
        1, GridBagConstraints.CENTER, GridBagConstraints.BOTH,
        EMPTY_INSETS, 0, 0));

    addButton = new JButton(ADD_BUTTON_LABEL);
    add(addButton, new GridBagConstraints(1, 2, 1, 2, 0, .25,
        GridBagConstraints.CENTER, GridBagConstraints.NONE,
        EMPTY_INSETS, 0, 0));
    addButton.addActionListener(new AddListener());
    removeButton = new JButton(REMOVE_BUTTON_LABEL);
    add(removeButton, new GridBagConstraints(1, 4, 1, 2, 0, .25,
        GridBagConstraints.CENTER, GridBagConstraints.NONE, new Insets(
            0, 5, 0, 5), 0, 0));
    removeButton.addActionListener(new RemoveListener());

    destLabel = new JLabel(INGREDIENTES_SELECIONADOS);
    destListModel = new SortedListModel();
    destList = new JList(destListModel);
    add(destLabel, new GridBagConstraints(2, 0, 1, 1, 0, 0,
        GridBagConstraints.CENTER, GridBagConstraints.NONE,
        EMPTY_INSETS, 0, 0));
    add(new JScrollPane(destList), new GridBagConstraints(2, 1, 1, 5, .5,
        1.0, GridBagConstraints.CENTER, GridBagConstraints.BOTH,
        EMPTY_INSETS, 0, 0));
  }

  public static void main(String args[]) {
    JFrame f = new JFrame("Dual List Box Tester");
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    List<IngredienteVo> listaIngredientes = new ArrayList<IngredienteVo>();
    DualListBox dual = new DualListBox();
    Map<String, IngredienteVo> mapCodigoIngredientes = new HashMap();
    int i = 0;
    IngredienteDao ingredienteDao = new IngredienteDao();

    listaIngredientes = ingredienteDao.getIngredientesList();

    String[] myArray = new String[listaIngredientes.size()];

    for (IngredienteVo IngredienteVo : listaIngredientes) {
        myArray[i] = IngredienteVo.getNome();
        i++;

        mapCodigoIngredientes.put(IngredienteVo.getNome(), IngredienteVo);
    }

    dual.addSourceElements(myArray);

    f.getContentPane().add(dual, BorderLayout.CENTER);
    f.setSize(400, 300);
    f.setVisible(true);
  }

  private class AddListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      Object selected[] = sourceList.getSelectedValues();
      addDestinationElements(selected);
      clearSourceSelected();
    }
  }

  private class RemoveListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      Object selected[] = destList.getSelectedValues();
      addSourceElements(selected);
      clearDestinationSelected();
    }
  }

    class PrintListener implements ActionListener {
    @Override
    public void actionPerformed(ActionEvent e) {
      int selected[] = destList.getSelectedIndices();
      System.out.println("Selected Elements:  ");

      for (int i = 0; i < destList.getModel().getSize(); i++) {
        Object element = destList.getModel().getElementAt(i);
        System.out.println("Item - " + element);
      }
    }
  }
}

class SortedListModel extends AbstractListModel {

  SortedSet model;

  public SortedListModel() {
    model = new TreeSet();
  }

  public int getSize() {
    return model.size();
  }

  public Object getElementAt(int index) {
    return model.toArray()[index];
  }

  public void add(Object element) {
    if (model.add(element)) {
      fireContentsChanged(this, 0, getSize());
    }
  }

  public void addAll(Object elements[]) {
    Collection c = Arrays.asList(elements);
    model.addAll(c);
    fireContentsChanged(this, 0, getSize());
  }

  public void clear() {
    model.clear();
    fireContentsChanged(this, 0, getSize());
  }

  public boolean contains(Object element) {
    return model.contains(element);
  }

  public Object firstElement() {
    return model.first();
  }

  public Iterator iterator() {
    return model.iterator();
  }

  public Object lastElement() {
    return model.last();
  }

  public boolean removeElement(Object element) {
    boolean removed = model.remove(element);
    if (removed) {
      fireContentsChanged(this, 0, getSize());
    }
    return removed;
  }

}

Answer 1

从example引用的here和之前的question开始，关注此主题，并专注于布局，添加相关的字段和组件，如下所示。请注意GridBagConstraints与上一列的相同之处，但gridx现在是3，代表新的第四列。

private JList newList;
private SortedListModel newListModel;
…
private void initScreen() {
    …
    JLabel newLabel = new JLabel("More Choices");
    newListModel = new SortedListModel<>();
    newList = new JList(newListModel);
    add(newLabel, new GridBagConstraints(3, 0, 1, 1, 0, 0,
        GridBagConstraints.CENTER, GridBagConstraints.NONE,
        EMPTY_INSETS, 0, 0));
    add(new JScrollPane(newList), new GridBagConstraints(3, 1, 1, 5, .5,
        1.0, GridBagConstraints.CENTER, GridBagConstraints.BOTH,
        EMPTY_INSETS, 0, 0));
}

稍后在main()，我会将f.setsize()替换为f.pack()，原因是here。

public static void main(String args[]) {
    …
    f.add(dual, BorderLayout.CENTER);
    // f.setSize(400, 300);
    f.pack();
    f.setLocationRelativeTo(null);
    f.setVisible(true);
}

还要考虑嵌套布局，见here。