JTable 已填充但未显示。使用默认表模型

Question

我不明白为什么我的 JTable 没有更新。

下面是我的代码：

package it.franpic.chat.client.prestazioni.view;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.EventQueue;
import java.util.List;

import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTable;
import javax.swing.SwingConstants;
import javax.swing.border.LineBorder;
import javax.swing.border.TitledBorder;
import javax.swing.table.DefaultTableModel;

import it.franpic.chat.client.prestazioni.model.RecordBean;

public class FinestraPrincipale {

    private JFrame frame;
    private JTable tabellaDati;
    private JScrollPane scrollPaneTabella;
    private JSplitPane splitPaneContenuti;

    /**
     * Launch the application.
     */
    public void avvia() {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    FinestraPrincipale window = new FinestraPrincipale();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public FinestraPrincipale() {
        initialize();
    }

    /**
     * Initialize the contents of the frame.
     */
    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 450, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel pnlOpzioni = new JPanel();
        frame.getContentPane().add(pnlOpzioni, BorderLayout.NORTH);
        pnlOpzioni.setBorder(new TitledBorder(new LineBorder(new Color(0, 0, 0)), "Opzioni", TitledBorder.LEADING, TitledBorder.TOP, null, new Color(0, 0, 0)));
        pnlOpzioni.setLayout(new BorderLayout(0, 0));

        JCheckBox chckbxAggiornaAutomaticamente = new JCheckBox("Aggiorna Automaticamente");
        chckbxAggiornaAutomaticamente.setEnabled(false);
        pnlOpzioni.add(chckbxAggiornaAutomaticamente);
        chckbxAggiornaAutomaticamente.setVerticalAlignment(SwingConstants.TOP);

        splitPaneContenuti = new JSplitPane();
        splitPaneContenuti.setOneTouchExpandable(true);
        splitPaneContenuti.setOrientation(JSplitPane.VERTICAL_SPLIT);
        frame.getContentPane().add(splitPaneContenuti, BorderLayout.CENTER);

        JScrollPane scrollPaneGrafico = new JScrollPane();
        splitPaneContenuti.setLeftComponent(scrollPaneGrafico);

        scrollPaneTabella = new JScrollPane();
        splitPaneContenuti.setRightComponent(scrollPaneTabella);

        tabellaDati = new JTable();
        tabellaDati.setModel(new DefaultTableModel(
            new Object[][] {
            },
            new String[] {
                "ISTANTE", "GESTITE", "DISTRIBUITE", "PIANIFICATO", "SOSTENIBILE", "LOGGATI", "LOGGATI_PIANIFICATO"
            }
        ) {
            Class[] columnTypes = new Class[] {
                String.class, Integer.class, Integer.class, Integer.class, Integer.class, Integer.class, Integer.class
            };
            public Class getColumnClass(int columnIndex) {
                return columnTypes[columnIndex];
            }
        });
        tabellaDati.getColumnModel().getColumn(3).setPreferredWidth(76);
        tabellaDati.getColumnModel().getColumn(6).setPreferredWidth(127);
        tabellaDati.setColumnSelectionAllowed(true);
        tabellaDati.setCellSelectionEnabled(true);
        scrollPaneTabella.setViewportView(tabellaDati);
    }

    public void aggiornaTabella(List<RecordBean> lista) {
        DefaultTableModel model = (DefaultTableModel) tabellaDati.getModel();
        model.setRowCount(0);
        System.out.println("tabellaDati.getRowCount() = " + tabellaDati.getRowCount());

        for (RecordBean record : lista) {
            model.addRow(new Object[]{record.getMomento(), record.getGestite(), record.getDistribuite(), record.getSostenibile(), record.getPianificato(), record.getLoggati(), record.getLoggatiPianificato()});
        }

        System.out.println("tabellaDati.getRowCount() = " + tabellaDati.getRowCount());
    }   

}

这是调用这些方法的主要 class 代码：

package it.franpic.chat.client.prestazioni.control;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.List;

import it.franpic.chat.client.prestazioni.model.RecordBean;
import it.franpic.chat.client.prestazioni.view.FinestraPrincipale;

public class Client {
    public static void main(String[] args) {
        FinestraPrincipale finestraPrincipale = new FinestraPrincipale();
        GestoreDb gestoreDb = new GestoreDb();


        String adessoFormatoMySql = LocalDateTime.now().format(DateTimeFormatter.ofPattern("YYYY-MM-dd HH:mm:ss"));

        List<RecordBean> lista = gestoreDb.getRecordsDaDate("2019-01-26 18:00:00", adessoFormatoMySql);

        finestraPrincipale.avvia();
        finestraPrincipale.aggiornaTabella(lista);
    }
}

从其他讨论和文档来看，我认为我的代码很好，但显然不是。

table 在构造时正确显示，但未通过 aggiornaTabella(List<RecordBean> lista) 方法更新。我不明白为什么。

我在 aggiornaTabella(List<RecordBean> lista) 中尝试过 addRow 周期后：

tabellaDati.setModel(model);
.invalidate() 方法在 GUI 的每个组件上（即使不推荐）
.repaint() GUI 的每个组件上的方法
model.fire....() 方法（即使不推荐）

从 aggiornaTabella(List<RecordBean> lista) 方法中的 2 println 我可以看到 JTable 的行已填充但未显示。

Answer 1

这个...

public class Client {
    public static void main(String[] args) {
        FinestraPrincipale finestraPrincipale = new FinestraPrincipale();
        GestoreDb gestoreDb = new GestoreDb();


        String adessoFormatoMySql = LocalDateTime.now().format(DateTimeFormatter.ofPattern("YYYY-MM-dd HH:mm:ss"));

        List<RecordBean> lista = gestoreDb.getRecordsDaDate("2019-01-26 18:00:00", adessoFormatoMySql);

        finestraPrincipale.avvia();
        finestraPrincipale.aggiornaTabella(lista);
    }
}

解释了很多。

首先，您创建 FinestraPrincipale 的实例，加载一些数据并调用 finestraPrincipale.avvia，但是 avvia 正在创建 FinestraPrincipale[=18= 的新实例]

public void avvia() {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                // Hello new instance...
                FinestraPrincipale window = new FinestraPrincipale();
                window.frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

显示在屏幕上，与您最初创建（正在更新）的实例无关

avvia 不应该创建一个新实例，它应该简单地使用它自己和之前在构造时初始化的状态...

public void avvia() {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

仅此一项就可以解决您的问题

JTable 已填充但未显示。使用默认表模型

JTable populated but not shown. Using DefaultTableModel

java

swing

jtable

defaulttablemodel