从 Jcombo 抓取选定的数据

Question

正在尝试将用户的选择保存到字符串中以便在代码中进一步使用。但我未能成功检索用户选择的数据。不确定我做错了还是做对了，或者老实说该怎么做，因为我觉得我做错了。该代码在脚本底部附近被注释掉了。并且是

 //String stationS = (String)station.getSelectedItem();

其余代码只是为了参考我如何创建 jcombobox

import javax.swing.*;

import java.awt.Dialog.ModalityType;
import java.awt.event.*;
import java.awt.*;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;

public class TouchOn extends JDialog {
private JPanel mainPanel;

public ArrayList Reader(String Txtfile) {
    try {

    ArrayList<String> Trains = new ArrayList<String>();
    int count = 0;
    String testing = "";
    File file = new File(Txtfile);
    FileReader fileReader = new FileReader(file);
    BufferedReader bufferedReader = new BufferedReader(fileReader);
    StringBuffer stringBuffer = new StringBuffer();
    String line;
    while ((line = bufferedReader.readLine()) != null) 
    {
        stringBuffer.append(line);
        count += count;
        if(!line.contains("*")){
            Trains.add(line + "\n");
        }
        stringBuffer.append("\n");



    }
    fileReader.close();
    //Arrays.asList(Trains).stream().forEach(s -> System.out.println(s));
    return Trains;
} catch (IOException e) {
    e.printStackTrace();
}
//return toString();
return null;




 }


public TouchOn()
{
    setPanels();

    setModalityType(ModalityType.APPLICATION_MODAL);
    setSize(400, 300);
    setVisible(true);
}
public void setPanels()
{
    mainPanel = new JPanel(new GridLayout(0, 2));
    JPanel containerPanel = new JPanel(new GridLayout(0, 1));
    JLabel startDay = new JLabel("Day:");
    JTextField sDay = new JTextField();

    JLabel startMonth = new JLabel("Month:");
    JTextField sMonth = new JTextField();

    JLabel startYear = new JLabel("Year:");
    JTextField sYear = new JTextField("2015");
    String trainline;
    String checked = "";

    JLabel touchOnTimehr = new JLabel("Time Hour: ");
    JLabel touchOnTimem = new JLabel("Time Minute:");
    JLabel station = new JLabel("Station: ");


    JTextField touchOnTimeFieldhour = new JTextField();
    JTextField touchOnTimeFieldminute = new JTextField();

    JPanel lowerPanel = new JPanel(new FlowLayout());
    ArrayList<String> stations = Reader("TrainLines.txt");
    JComboBox<String> cb = new JComboBox<>(stations.toArray(new String[stations.size()]));
    JRadioButton belgrave = new JRadioButton("Belgrave Line");      
    JRadioButton glenwaverly = new JRadioButton("Glen Waverly Line");
    ButtonGroup bG = new ButtonGroup();
    JButton apply = new JButton("Touch on");
    JButton cancel = new JButton("Cancel");
    cancel.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            dispose();
        }
    });
    apply.addActionListener(new ActionListener()
    {
        @SuppressWarnings("unused")
        public void actionPerformed(ActionEvent e)
        {

            String timestamp = new java.text.SimpleDateFormat("dd/MM/yyyy").format(new Date());
            String day = sDay.getText();
            String month = sMonth.getText();
            String year = sYear.getText();
            String trainline = "";
            String hour = touchOnTimeFieldhour.getText();
            String minute = touchOnTimeFieldminute.getText();
            if(belgrave.isSelected()){
                trainline = belgrave.getText();
            }
            if(glenwaverly.isSelected()){
                trainline = glenwaverly.getText();
            }


            //String stationS = (String)station.getSelectedItem();

            // The code above is the one that doesnt im not to sure how it works 
            System.out.println(trainline);
        }
    });



    cb.setVisible(true);
    bG.add(belgrave);
    bG.add(glenwaverly);
    mainPanel.add(startDay);
    mainPanel.add(sDay);
    mainPanel.add(startMonth);
    mainPanel.add(sMonth);
    mainPanel.add(startYear);
    mainPanel.add(sYear);
    mainPanel.add(touchOnTimehr);
    mainPanel.add(touchOnTimeFieldhour);
    mainPanel.add(touchOnTimem);
    mainPanel.add(touchOnTimeFieldminute);
    mainPanel.add(belgrave);
    mainPanel.add(glenwaverly);
    mainPanel.add(station);
    mainPanel.add(new JLabel());
    mainPanel.add(cb);
    lowerPanel.add(apply);
    lowerPanel.add(cancel);
    touchOnTimeFieldhour.setSize(10,10);
    containerPanel.add(mainPanel);
    containerPanel.add(lowerPanel);

    add(containerPanel);
}



  }

Answer 1

IMO 的问题是，您从内部 class 访问局部变量。您应该在 TouchOn 中实现 ActionListener 并覆盖 actionPerformed()，而不是向按钮添加 actionListeners。

@override
public void actionPerformed(ActionEvent ex){
    Object source = ex.getSource();
    if (source == apply){
        //your code here
    }
    if (source == cancel){
        //your code here
    }

在

//your code here

您可以使用对 JRadioButtons 的引用

从 Jcombo 抓取选定的数据

grabbing the selected data from the Jcombo

java

swing

jcombobox