为什么JTable不能正确调整大小？

Question

你好，谢谢你花时间处理我的问题。首先让我向你介绍我的虚拟/培训项目。下面列出的类应该代表MVC模型（模型、视图、控制器）之后的程序。运行主类时，会打开FileChooser，从中可以选择. csv-File，其中包含保存为String[][]的信息。这个String[][]然后在视图类中可视化为JTable。这个JTable是带有BorderLayout的JFrame中的JPanel的一部分。中心。现在的问题，为什么不会我的JTable调整大小正确，如果我重新调整JFrame？我在网上搜索，甚至this.table.setAutoResizeMode（JTable.AUTO_RESIZE_ALL_COLUMNS）；根本不会影响调整大小。我希望你能以某种方式帮助我。谢谢！

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Scanner;

/**
 * This class is responsible for the actual data being "processed".
 * It saves the Strings out of a File into a String[][] and further more updates its content,
 * if changed by the View-Class.
 * 
 * @author CodeScrub
 * @version 2022-01-13
 */

public class Model {

    private File selectedFile;
    
    private String[][] dataSetTotal;
    private ArrayList<String> dataSetList;
    
    private ArrayList<String> tableDatasetList;
    
    public Model() {
        dataSetList = new ArrayList<String>();
        tableDatasetList = new ArrayList<String>();
    }
    
    public void evaluateData() {
        try {
            Scanner scanner = new Scanner(this.selectedFile);
            while(scanner.hasNextLine()) {
                String data = scanner.nextLine();
                dataSetList.add(data);
            }
            scanner.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        
        this.dataSetTotal = new String[dataSetList.size()][3];
        
        for(String info : dataSetList) {
            String[] dataSetSeperate = info.split(";");
            for(int i = 0; i < dataSetSeperate.length; i++) {
                dataSetTotal[dataSetList.indexOf(info)][i] = dataSetSeperate[i];
            }
        }
    }
    
    public void setSelectedFile(File selectedFile) {
        this.selectedFile = selectedFile;
    }
    
    public File getSelectedFile() {
        return this.selectedFile;
    }
    
    public String[][] getDataSetTotal(){
        return this.dataSetTotal;
    }
    
    public void updateData(String[][] tableContent) {
        for(int i = 0; i < tableContent.length; i++) {
            String dataSetSeperate = "";
            for(int j = 0; j < tableContent[i].length; j++) {
                if(j < 2) {
                    dataSetSeperate = dataSetSeperate + tableContent[i][j] + ";";
                }else {
                    dataSetSeperate = dataSetSeperate + tableContent[i][j];
                }
            }
            this.tableDatasetList.add(dataSetSeperate);
        }
        
        try {
            BufferedWriter writer = new BufferedWriter(new FileWriter(this.selectedFile));
            for(String info : this.tableDatasetList){
                writer.write(info + "\n");
            }
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        this.tableDatasetList = new ArrayList<String>();
    }
}

import java.awt.Dimension;
import javax.swing.*;
import javax.swing.filechooser.FileNameExtensionFilter;

/**
 * This class visualizes the processed data inside a JFrame.
 * The data sets are visualized as a JTable.
 * 
 * @author CodeScrub
 * @version 2022-01-13
 */

public class View extends JFrame{
    
    private static final long serialVersionUID = 1L;
    
    private JFileChooser chooser;
    private FileNameExtensionFilter filter;
    
    private JLabel firstName;
    private JLabel lastName;
    private JLabel socialSecurityNumber;
    
    private JButton buttonSafeChanges;
    
    private JScrollPane scrollPane;
    
    private JTable table;
    
    private JPanel centerPanel;
    
    private Controller controller;
    
    public View(Controller controller) {
        this.controller = controller;
        init();
    }
    
    private void init() {
        this.chooser = new JFileChooser();
        this.filter = new FileNameExtensionFilter(
                "CSV Files", "csv");
        this.chooser.setFileFilter(filter);
        this.chooser.setPreferredSize(new Dimension(800,500));
        int returnVal = chooser.showOpenDialog(this);
        if(returnVal == JFileChooser.APPROVE_OPTION) {
            this.controller.updateData(chooser.getSelectedFile());
            this.controller.evaluateData();
            
            this.firstName = new JLabel("First Name");
            this.lastName = new JLabel("Last Name");
            this.socialSecurityNumber = new JLabel("Social Security Number");
            
            this.centerPanel = new JPanel(new BorderLayout());
            
            String[] title = {firstName.getText() , lastName.getText() , socialSecurityNumber.getText()}; 
            this.table = new JTable(this.controller.getDataSetTotal(), title);
            this.table.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS);
            this.centerPanel.add(table, BorderLayout.CENTER);
            
            this.scrollPane = new JScrollPane(this.table);
            this.centerPanel.add(scrollPane, BorderLayout.EAST);
            
            this.buttonSafeChanges = new JButton("Safe Changes");
            this.buttonSafeChanges.addActionListener(controller);
            
            this.centerPanel.add(table.getTableHeader(), BorderLayout.NORTH);
            this.add(centerPanel,BorderLayout.CENTER);
            this.add(buttonSafeChanges, BorderLayout.SOUTH);
            this.setTitle("MVC");
            this.setSize(475,350);
            this.setMinimumSize(new Dimension(475,350));
            this.setLocationRelativeTo(null);
            this.setDefaultCloseOperation(EXIT_ON_CLOSE);
            this.setVisible(true);
            getTableContent();
        }else {
            System.exit(0);
        }
    }
    
    public JButton getButtonSafeChanges() {
        return this.buttonSafeChanges;
    }
    
    public String[][] getTableContent() {
        String[][] tableContent;
        tableContent = new String[this.table.getRowCount()][this.table.getColumnCount()];
        for(int i = 0; i < table.getRowCount(); i++) {
            for(int j = 0; j < table.getColumnCount(); j++) {
                tableContent[i][j] = table.getValueAt(i,j).toString();
            }
        }
        return tableContent;
    }
}

import java.io.File;

/**
 * This class works as an interface between the view- and model-class 
 * and also handles the action performed after the button press "Safe Changes".
 * 
 * @author CodeScrub
 * @version 2022-01-13
 */

public class Controller implements ActionListener{

    private View view;
    private Model model;
    
    public Controller() {
        this.model = new Model();
        this.view = new View(this);
    }
    
    @Override
    public void actionPerformed(ActionEvent e) {
        if(e.getSource() == this.view.getButtonSafeChanges()) {
            this.model.updateData(this.view.getTableContent());
        }
    }
    
    public void updateData(File selectedFile) {
        this.model.setSelectedFile(selectedFile);
    }
    
    public File getSelectedFile() {
        return this.model.getSelectedFile();
    }
    
    public void evaluateData() {
        this.model.evaluateData();
    }
    
    public String[][] getDataSetTotal(){
        return this.model.getDataSetTotal();
    }
}

public class MVC_Testclass {

    public static void main(String[] args) {
        Controller controller = new Controller();
    }
}

Answer 1

基本上，当您为JTable使用JScrollPane容器时，只需在中心面板中添加滚动窗格，并确保将其添加到中心。下面解决了代码中的问题。

this.table.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS);
//this.centerPanel.add(table, BorderLayout.CENTER);

this.scrollPane = new JScrollPane(this.table);
this.centerPanel.add(scrollPane, BorderLayout.CENTER);