How can I fill the Jtable with a complex json

Question

I have this api: https://api.openweathermap.org/data/2.5/weather?q=paris&appid=460b3f2acf469e5a496d8c019a2b364a&units=metric I need to fill the JTable with the data in this API. So I created the class (one of the classes im json in my api on the link: package dataWeather;

public class Main {
    private float temp;
     private float pressure;
     private float humidity;
     private float temp_min;
     private float temp_max;


     // Getter Methods 

     public float getTemp() {
      return temp;
     }

     public float getPressure() {
      return pressure;
     }

     public float getHumidity() {
      return humidity;
     }

     public float getTemp_min() {
      return temp_min;
     }

     public float getTemp_max() {
      return temp_max;
     }

     // Setter Methods 

     public void setTemp(float temp) {
      this.temp = temp;
     }

     public void setPressure(float pressure) {
      this.pressure = pressure;
     }

     public void setHumidity(float humidity) {
      this.humidity = humidity;
     }

     public void setTemp_min(float temp_min) {
      this.temp_min = temp_min;
     }

     public void setTemp_max(float temp_max) {
      this.temp_max = temp_max;
     }
}

And a table model:

package dataWeather;
import java.util.ArrayList;
import java.util.List;

import javax.swing.table.AbstractTableModel;

public class MainWeatherTableModel extends AbstractTableModel{

    private List<Main> mainWeatherData = new ArrayList<Main>();
    private String[] columnNames = {"temp", "pressure", "humidiry", "temp_min", "temp_max"};

    public MainWeatherTableModel(List<Main> mainWeatherData)
    {
        this.mainWeatherData = mainWeatherData;
    }

    @Override
public String getColumnName(int column)
{
    return columnNames[column];
}
@Override
public int getRowCount() {
    return mainWeatherData.size();
}

@Override
public int getColumnCount() {
    return columnNames.length;
}

@Override
public Object getValueAt(int rowIndex, int columnIndex) {
    Object mainElementAttribute = null;
    Main mainObject = mainWeatherData.get(rowIndex);

    switch(columnIndex)
    {
    case 0: mainElementAttribute = mainObject.getTemp();break;
    case 1: mainElementAttribute = mainObject.getPressure(); break;
    case 2: mainElementAttribute = mainObject.getHumidity(); break;
    case 3: mainElementAttribute = mainObject.getTemp_min(); break;
    case 5: mainElementAttribute = mainObject.getTemp_max(); break;
    default: break;
    }
    return mainElementAttribute;
}


}

And this is my MainFrame code:

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.image.BufferedImage;
import java.beans.PropertyChangeListener;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import javax.imageio.ImageIO;
import javax.net.ssl.HttpsURLConnection;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.BorderFactory;
import javax.swing.DefaultListModel;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTable;
import javax.swing.JTextArea;
import javax.swing.KeyStroke;
import javax.swing.border.Border;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

import dataWeather.Main;
import dataWeather.MainWeatherTableModel;

public class MainFrame extends JFrame{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    private JPanel leftPanel = new JPanel(); 
    private JPanel rightPanel = new JPanel();
    private JPanel downPanel = new JPanel();
    private JPanel centralPanel = new JPanel();
    private JPanel weatherPanel = new JPanel();

    private JMenuBar menuBar;
    private JFileChooser fileChooser;

    JScrollPane scrollPane = new JScrollPane();

    private JTabbedPane tabbedPane = new JTabbedPane(); 

    private JLabel imageBox = new JLabel();
    private JLabel imageBox2 = new JLabel();
    private JList<AppImage> imageList;

    private MainWeatherTableModel mainModel;
    private ObjectMapper objectMapper = new ObjectMapper();
    private JTable mainTable;

    private JButton buttonGo = new JButton("GO!");
    private JTextArea downTextArea = new JTextArea();


    public MainFrame () {
        super("AppTask");

        setLayout(new BorderLayout());
        setMinimumSize(new Dimension(500, 400));
        setSize(600, 500);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);

        addLeftPanel();
        addRightPanel();
        addDownPanel();
        addCentralPanel();
        addWeatherPanel();

        menuBar = createMenuBar();
        setJMenuBar(menuBar);


        tabbedPane.addTab("Image", centralPanel);
        tabbedPane.addTab("Weather", weatherPanel);
        add(tabbedPane);

        buttonGo.setAction(new AbstractAction() {

            @Override
            public void actionPerformed(ActionEvent e) {
                OnGoButtonClick(e);
            }
        });
        buttonGo.setText("GOO");



        downPanel.add(buttonGo);
        downPanel.add(downTextArea);


    }

    void OnGoButtonClick(ActionEvent e) {
        try
        {
        URL chosenUrl = new URL(imageList.getSelectedValue().getUrl());
        HttpURLConnection connection = (HttpURLConnection)chosenUrl.openConnection();
        connection.setRequestMethod("GET");
        Integer responseCode = connection.getResponseCode();
        downTextArea.append("Response: " + responseCode.toString());
        String chosenUrlString = imageList.getSelectedValue().getUrl();
        setImageUrl(chosenUrlString, imageBox);
        }
     catch (MalformedURLException ex) {
        System.out.println("Malformed URL");
    } catch (IOException iox) {
        System.out.println("Can not load file");
    }
    }
    public void addLeftPanel()
    {
        Dimension dim = getPreferredSize();
        dim.width = 300;
        leftPanel.setPreferredSize(dim);

        Border innerBorder = BorderFactory.createTitledBorder("Choose an Image");
        Border outerBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
        leftPanel.setBorder(BorderFactory.createCompoundBorder(outerBorder, innerBorder));
        add(leftPanel, BorderLayout.WEST);

        imageList = new JList<>();
        ArrayList<AppImage> images = new DataModel().getImages();
        DefaultListModel<AppImage> imageListModel = new DefaultListModel<>();

        for( AppImage item: images) {
            imageListModel.addElement(item);
        }

        imageList.setModel(imageListModel);
        imageList.setPreferredSize(new Dimension(110, 74));
        imageList.setBorder(BorderFactory.createEtchedBorder());
        imageList.setSelectedIndex(0);


        leftPanel.setLayout(new BorderLayout());

        leftPanel.add(imageList, BorderLayout.CENTER);

    }

    public void addRightPanel()
    {
        Dimension dim = getPreferredSize();
        dim.width = 300;
        rightPanel.setPreferredSize(dim);

        Border innerBorder = BorderFactory.createTitledBorder("");
        Border outerBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
        rightPanel.setBorder(BorderFactory.createCompoundBorder(outerBorder, innerBorder));
        add(rightPanel, BorderLayout.EAST);
    }

    public void addDownPanel() {
        Dimension dim = getPreferredSize();
        dim.height = 100;
        downPanel.setPreferredSize(dim);

        Border innerBorder = BorderFactory.createEtchedBorder();
        Border outerBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
        downPanel.setBorder(BorderFactory.createCompoundBorder(outerBorder, innerBorder));
        downPanel.setLayout(new GridLayout(1, 4, 40, 0));

        add(downPanel, BorderLayout.SOUTH);
    }

    public void addMainTable() {
        URL url = null;
        Main mainWeather = null;
        try {
            url = new URL("https://api.openweathermap.org/data/2.5/weather?q=paris&appid=460b3f2acf469e5a496d8c019a2b364a&units=metric");
        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        try {
            mainWeather = objectMapper.readValue(url, Main.class);
            System.out.println(mainWeather.getHumidity());
        } catch (JsonParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JsonMappingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        List<Main> listMainWeather = new ArrayList<>();

        listMainWeather.add(mainWeather);
        mainModel = new MainWeatherTableModel(listMainWeather);
        mainTable = new JTable(mainModel);

        weatherPanel.add(mainTable);

    }

    public void addWeatherPanel()
    {
            weatherPanel.setLayout(new FlowLayout());
            addMainTable();

    }

    public void addCentralPanel()
    {
        String imageUrl = "https://thumbs.dreamstime.com/z/welcome-to-summer-concept-written-sand-47585464.jpg";
            setImageUrl(imageUrl, imageBox);
            centralPanel.add(imageBox, BorderLayout.CENTER);

            getContentPane().add(centralPanel, BorderLayout.CENTER);
            pack();
    }

    private void setImageUrl(String imageUrl, JLabel imageBox) {
        BufferedImage image = null;
        URL url = null;
        try {
            url = new URL(imageUrl);
            image = ImageIO.read(url);
        } catch (MalformedURLException ex) {
            System.out.println("Malformed URL");
        } catch (IOException iox) {
            System.out.println("Can not load file");
        }

        imageBox.setIcon(new ImageIcon(image));
    }

private JMenuBar createMenuBar() {

        JMenuBar menuBar = new JMenuBar();

        JMenu windowMenu = new JMenu("Window");

        JMenu fileMenu = new JMenu("File");
        JMenuItem exportDataItem = new JMenuItem("Export Data...");
        JMenuItem importDataItem = new JMenuItem("Import Data...");

        JMenuItem exitItem = new JMenuItem("Exit");

        menuBar.add(fileMenu);
        menuBar.add(windowMenu);

        fileMenu.add(importDataItem);
        fileMenu.add(exportDataItem);
        fileMenu.addSeparator();
        fileMenu.add(exitItem);

        JMenu showMenu = new JMenu("Show");

        fileMenu.setMnemonic(KeyEvent.VK_F);  //Alt+F opens the fileMenu
        exitItem.setMnemonic(KeyEvent.VK_X);
        exitItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_X, ActionEvent.CTRL_MASK));

        exitItem.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {

                int action = JOptionPane.showConfirmDialog(MainFrame.this, "Do you really want to exit from application?", 
                        "Confirm Exit", JOptionPane.OK_CANCEL_OPTION);

                if (action == JOptionPane.OK_OPTION) 
                {
                    System.exit(0);
                }
            }
        });

        exportDataItem.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                if(fileChooser.showSaveDialog(MainFrame.this) == JFileChooser.APPROVE_OPTION)  //MainFrame.this its a parent component
                {
                    System.out.println(fileChooser.getSelectedFile());
                }
            }
        });

        importDataItem.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                if(fileChooser.showOpenDialog(MainFrame.this) == JFileChooser.APPROVE_OPTION)  //MainFrame.this its a parent component
                {
                    System.out.println(fileChooser.getSelectedFile());
                }
            }
        });
        return menuBar;
    }
}

I cant see what I'm doing wrong... Please help, dealing with it hours and can't make it work... I'm very newbie in swing java, trying to understand what I have to do.

Answer 1

By default Swing components don't have a size/location.

It is the job of the layout manger to give components a size/location based on the rules of the layout manager.

The layout manager is invoked whenever you pack() a frame of use setVisible(true) on the frame.

You are making your frame visible BEFORE you add components to the frame, so I'm guessing your components still have a size of (0, 0) so there is nothing to paint.

Typically your would use:

panel.revalidate();
panel.repaint();

after you add components to a visible panel.

But in your case you appear to be creating all the panels after you make the frame visible so I think you just need to add

revalidate();
repaint();

at the end of your constructor.

weatherPanel.add(mainTable);

Also you need to display a JTable in a JScrollPane in order to see the table headers so the code should be:

//weatherPanel.add(mainTable);
JScrollPane scrollPane = new JScrollPane(mainTable);
weatherPanel.add( scrollPane );

I also question why you need the panel. You can add any component directly to a tabbed pane.