如何自动将JTable的所有列调整为相同大小? [英] How to auto-resize all columns of a JTable to the same size?

问题描述

我在项目上使用JTable. 我希望表格将所有列自动调整为相同大小，并同时填充包含JScrollPane的宽度.

I'm using a JTable on a project. I want the table to auto-resize all columns to the same size, and at the same time, to fill the width of the containing JScrollPane.

我不能只是将首选宽度设置为固定值，因为当用户调整框架大小时，我希望将所有列调整为相同的大小，但是要约束它仍然必须填充100％的宽度. JScrollPane.

I can't just set a preferred width to a fixed value, because when the user will resize the frame, I want all the columns being resized to the same size, but with the constraint that it must still fill 100% of the JScrollPane.

例如，如果JScrollPane的宽度为1000，而我有10列，我希望这些列的大小都为100. 如果随后将JScrollPane缩小到500，我希望将这些列的大小分别调整为50.

For instance, if the JScrollPane has a width of 1000, and I've got 10 columns, I'd like the columns to each have a size of 100. If the JScrollPane is then shrinked to 500, I'd like the columns to resize to 50 each.

现在，我只设置JTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF)，结果如下:

For now, I just set JTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF) and here's the result :

我怎么能简单地做到这一点?

How can I simply achieve that ?

谢谢.

推荐答案

当表更改大小时，您需要一些方法来更新列模型.

You need some way to update the column model when the table changes size.

此基本示例使用invaldiate方法更新其列模型.还将列设置为不可调整大小".

This basic example uses the invaldiate method to update it's column model. It also sets the columns as "not" resizable.

这还将覆盖表格getScrollableTracksViewportWidth方法，以确保表格自动填充水平空间.这确实意味着它永远不会显示水平滚动条.

This also overrides the tables getScrollableTracksViewportWidth method to ensure that the table automatically fills the horizontal space. This does mean that it will never display a horizontal scroll bar though.

public class SpringTable extends JTable {

    public SpringTable(TableModel dm) {
        super(dm);
        setAutoResizeMode(AUTO_RESIZE_OFF);
    }

    public SpringTable() {
        setAutoResizeMode(AUTO_RESIZE_OFF);
    }

    @Override
    public void doLayout() {
        int width = getWidth();
        int columnCount = getColumnCount();
        int columnSize = width / columnCount;
        for (int index = 0; index < columnCount; index++) {
            TableColumn column = getColumnModel().getColumn(index);
            column.setResizable(false);
            column.setPreferredWidth(width);
        }
        super.doLayout();
    }

    @Override
    public boolean getScrollableTracksViewportWidth() {
        return true;
    }

}

最好在invalidate上使用doLayout，但是您应该玩一下，看看能满足您的需求

It may be better to use doLayout instead on invalidate, but you should have a play and see what meets your needs

运行示例

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.KeyStroke;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableColumn;
import javax.swing.table.TableModel;

public class TestJTable {

    public static void main(String[] args) {
        new TestJTable();
    }

    public TestJTable() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                List<Pet> pets = new ArrayList<>(25);
                pets.add(new Pet("Tyrannosauridae", "TYRANNOSAURUS", 20, 35));
                pets.add(new Pet("Dromaeosauridae", "VELOCIRAPTOR", 45, 90));
                pets.add(new Pet("Ceratopsidae", "TRICERATOPS", 15, 30));
                pets.add(new Pet("Stegosauridae", "STEGOSAURUS", 22, 25));
                pets.add(new Pet("Titanosauridae", "MALAWISAURUS", 22, 25));
                pets.add(new Pet("Compsognathidae", "COMPSOGNATHUS", 8, 25));
                pets.add(new Pet("Brachiosauridae", "BRACHIOSAURUS", 8, 25));
                pets.add(new Pet("Diplodocidae", "DIPLODOCUS", 8, 25));

                final PetTableModel model = new PetTableModel(pets);
                final JTable table = new SpringTable(model);

                InputMap im = table.getInputMap(JTable.WHEN_FOCUSED);
                ActionMap am = table.getActionMap();
                im.put(KeyStroke.getKeyStroke(KeyEvent.VK_DELETE, 0), "delete");
                am.put("delete", new AbstractAction() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        int[] indicies = table.getSelectedRows();
                        int[] mapped = new int[indicies.length];
                        for (int index = 0; index < indicies.length; index++) {
                            mapped[index] = table.convertRowIndexToModel(indicies[index]);
                        }
                        model.removePets(mapped);
                    }
                });

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new JScrollPane(table));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class SpringTable extends JTable {

        public SpringTable(TableModel dm) {
            super(dm);
            setAutoResizeMode(AUTO_RESIZE_OFF);
        }

        public SpringTable() {
            setAutoResizeMode(AUTO_RESIZE_OFF);
        }

        @Override
        public void doLayout() {
            int width = getWidth();
            int columnCount = getColumnCount();
            int columnSize = width / columnCount;
            for (int index = 0; index < columnCount; index++) {
                TableColumn column = getColumnModel().getColumn(index);
                column.setResizable(false);
                column.setPreferredWidth(width);
            }
            super.doLayout();
        }

        @Override
        public boolean getScrollableTracksViewportWidth() {
            return true;
        }

    }

    public class PetTableModel extends AbstractTableModel {

        private List<Pet> pets;

        public PetTableModel() {
            pets = new ArrayList<>(25);
        }

        public PetTableModel(List<Pet> pets) {
            this.pets = pets;
        }

        @Override
        public int getRowCount() {
            return pets.size();
        }

        public void removePets(int... indicies) {
            List<Pet> old = new ArrayList<>(indicies.length);
            for (int index : indicies) {
                old.add(pets.get(index));
            }

            for (Pet pet : old) {
                int index = pets.indexOf(pet);
                pets.remove(pet);
                fireTableRowsDeleted(index, index);
            }
        }

        @Override
        public Class<?> getColumnClass(int columnIndex) {
            Class clazz = String.class;
            switch (columnIndex) {
                case 2:
                case 3:
                    clazz = Float.class;
            }
            return clazz;
        }

        @Override
        public String getColumnName(int column) {
            String name = "??";
            switch (column) {
                case 0:
                    name = "Breed";
                    break;
                case 1:
                    name = "Category";
                    break;
                case 2:
                    name = "Buy Price";
                    break;
                case 3:
                    name = "Sell Price";
                    break;
            }
            return name;
        }

        @Override
        public int getColumnCount() {
            return 4;
        }

        @Override
        public Object getValueAt(int rowIndex, int columnIndex) {
            Pet pet = pets.get(rowIndex);
            Object value = null;
            switch (columnIndex) {
                case 0:
                    value = pet.getBreed();
                    break;
                case 1:
                    value = pet.getCategory();
                    break;
                case 2:
                    value = pet.getBuyPrice();
                    break;
                case 3:
                    value = pet.getSellPrice();
                    break;
            }
            return value;
        }

        public void add(Pet pet) {
            pets.add(pet);
            fireTableRowsInserted(getRowCount() - 1, getRowCount() - 1);
        }

    }

    public class Pet {

        private String breed;
        private String category; 
        private float buyPrice; 
        private float sellPrice; 

        public Pet(String breed, String category, float buyPrice, float sellPrice) {
            this.breed = breed;
            this.category = category;
            this.buyPrice = buyPrice;
            this.sellPrice = sellPrice;
        }

        public String getBreed() {
            return breed;
        }

        public float getBuyPrice() {
            return buyPrice;
        }

        public String getCategory() {
            return category;
        }

        public float getSellPrice() {
            return sellPrice;
        }

    }

}

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