Question

我正在使用带有GUI的HashMap做家庭作业。用户将输入Country和该国家的Capital，然后按Add，这会将这两个字符串添加到地图中，并且应该将Capital添加到右侧的列表中。接下来是搜索功能。用户将能够键入国家/地区的名称，并且将突出显示在添加的其他大写的右侧蓝色的国家。这是它应该是什么样子。

enter image description here

如何将hashMap的内容复制到JList中？我只需要显示首都，这样我就可以搜索它们。

感谢任何帮助，谢谢。

P.S。对于生成的代码，很抱歉，变量声明位于底部，因为它。

import java.util.ArrayList;
import java.util.HashMap;

public class MapPanel extends javax.swing.JPanel {

HashMap<String, String> hashMap=new HashMap<String,String>();
ArrayList<String> array = new ArrayList<String>();

/**
 * Creates new form MapPanel
 */
public MapPanel() {
    initComponents();
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    searchPanel = new javax.swing.JPanel();
    countrySearch = new javax.swing.JTextField();
    jLabel3 = new javax.swing.JLabel();
    jButton2 = new javax.swing.JButton();
    inputPanel = new javax.swing.JPanel();
    countryInput = new javax.swing.JTextField();
    capitalInput = new javax.swing.JTextField();
    jLabel1 = new javax.swing.JLabel();
    jLabel2 = new javax.swing.JLabel();
    jButton1 = new javax.swing.JButton();
    listPanel = new javax.swing.JPanel();
    jScrollPane1 = new javax.swing.JScrollPane();
    capitalList = new javax.swing.JList();

    searchPanel.setBorder(javax.swing.BorderFactory.createEtchedBorder());

    jLabel3.setText("Search Country");

    jButton2.setText("Search");
    jButton2.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton2ActionPerformed(evt);
        }
    });

    javax.swing.GroupLayout searchPanelLayout = new javax.swing.GroupLayout(searchPanel);
    searchPanel.setLayout(searchPanelLayout);
    searchPanelLayout.setHorizontalGroup(
        searchPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(searchPanelLayout.createSequentialGroup()
            .addGroup(searchPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(searchPanelLayout.createSequentialGroup()
                    .addGroup(searchPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addGroup(searchPanelLayout.createSequentialGroup()
                            .addGap(14, 14, 14)
                            .addComponent(jLabel3))
                        .addGroup(searchPanelLayout.createSequentialGroup()
                            .addContainerGap()
                            .addComponent(countrySearch, javax.swing.GroupLayout.PREFERRED_SIZE, 236, javax.swing.GroupLayout.PREFERRED_SIZE)))
                    .addGap(0, 0, Short.MAX_VALUE))
                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, searchPanelLayout.createSequentialGroup()
                    .addGap(0, 0, Short.MAX_VALUE)
                    .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 65, javax.swing.GroupLayout.PREFERRED_SIZE)))
            .addContainerGap())
    );
    searchPanelLayout.setVerticalGroup(
        searchPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(searchPanelLayout.createSequentialGroup()
            .addGap(10, 10, 10)
            .addComponent(jLabel3)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(countrySearch, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
    );

    countryInput.setToolTipText("");
    countryInput.addFocusListener(new java.awt.event.FocusAdapter() {
        public void focusGained(java.awt.event.FocusEvent evt) {
            countryInputFocusGained(evt);
        }
    });

    jLabel1.setText("Country");

    jLabel2.setText("Capital");

    jButton1.setText("Add");
    jButton1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton1ActionPerformed(evt);
        }
    });

    javax.swing.GroupLayout inputPanelLayout = new javax.swing.GroupLayout(inputPanel);
    inputPanel.setLayout(inputPanelLayout);
    inputPanelLayout.setHorizontalGroup(
        inputPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(inputPanelLayout.createSequentialGroup()
            .addGap(15, 15, 15)
            .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 84, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        .addGroup(inputPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addGroup(inputPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(countryInput)
                .addComponent(capitalInput)
                .addGroup(inputPanelLayout.createSequentialGroup()
                    .addGap(8, 8, 8)
                    .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 84, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(0, 0, Short.MAX_VALUE))
                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, inputPanelLayout.createSequentialGroup()
                    .addGap(0, 0, Short.MAX_VALUE)
                    .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 65, javax.swing.GroupLayout.PREFERRED_SIZE)))
            .addContainerGap())
    );
    inputPanelLayout.setVerticalGroup(
        inputPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(inputPanelLayout.createSequentialGroup()
            .addGap(19, 19, 19)
            .addComponent(jLabel1)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(countryInput, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(23, 23, 23)
            .addComponent(jLabel2)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(capitalInput, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
            .addComponent(jButton1, javax.swing.GroupLayout.DEFAULT_SIZE, 40, Short.MAX_VALUE)
            .addContainerGap())
    );

    jScrollPane1.setViewportView(capitalList);

    javax.swing.GroupLayout listPanelLayout = new javax.swing.GroupLayout(listPanel);
    listPanel.setLayout(listPanelLayout);
    listPanelLayout.setHorizontalGroup(
        listPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(listPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 226, Short.MAX_VALUE)
            .addContainerGap())
    );
    listPanelLayout.setVerticalGroup(
        listPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, listPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jScrollPane1)
            .addContainerGap())
    );

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
    this.setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                .addComponent(inputPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(searchPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
            .addComponent(listPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(listPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
            .addComponent(inputPanel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(searchPanel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
    );
}// </editor-fold>                        

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    String text = countryInput.getText();
    String text2 = capitalInput.getText();
    hashMap.put(text,text2);

}                                        

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
hashMap.get(countrySearch.getText());
}                                        

private void countryInputFocusGained(java.awt.event.FocusEvent evt) {                                         
    countryInput.requestFocusInWindow();
}                                        


// Variables declaration - do not modify                     
private javax.swing.JTextField capitalInput;
private javax.swing.JList capitalList;
private javax.swing.JTextField countryInput;
private javax.swing.JTextField countrySearch;
private javax.swing.JPanel inputPanel;
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JPanel listPanel;
private javax.swing.JPanel searchPanel;
// End of variables declaration                   
}

Answer 1

查看documentation of JList，这是很多示例用例。

您可以使用setListData()方法修改添加值事件来执行此类操作：

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt)
{                                         
    String text = countryInput.getText();
    String text2 = capitalInput.getText();
    hashMap.put(text,text2);
    capitalList.setListData(hashMap.values().toArray());
}

我已经成功测试了它：

MapPanel mp = new MapPanel();
JFrame frame = new JFrame("Countries and capitals");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(mp);
frame.pack();
frame.setVisible(true);

添加国家/地区后，其资本会显示在右侧列表中。问题解决了; - ）

需要一些帮助将我的地图复制到此列表中

1 个答案: