Comment le retour à la ligne dans une jtable cellule?

Le problème est que la hauteur des lignes dans JTable est fixe, il n'est donc pas juste une question d'avoir un moteur de rendu qui enveloppe; je ne sais pas pourquoi ça ne marche pas, mais si il l'a fait, le texte enveloppé pourrait être recadrée ou peut-être que c'est exactement ce que vous voyez. Pour ajuster la hauteur des lignes, vous devez définir individuellement.

En plus de cette question, je voudrais partager avec vous une solution pour multiligne cellule de l'éditeur. C'est un peu hacky (magasins de référence édité ligne), mais fait le travail.

import javax.swing.*;
import javax.swing.table.TableCellEditor;
import java.awt.*;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
class MultilineTableCellEditor extends AbstractCellEditor implements TableCellEditor {
JComponent component = new JTextArea();
JTable table;
int lastRowIndex;
public MultilineTableCellEditor() {
JTextArea textArea = ((JTextArea) component);
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
textArea.addComponentListener(new ComponentAdapter() {
@Override
public void componentResized(ComponentEvent e) {
super.componentResized(e);
table.setRowHeight(lastRowIndex, (int) (textArea.getPreferredSize().getHeight()));
}
});
textArea.addKeyListener(new KeyAdapter() {
@Override
public void keyTyped(KeyEvent e) {
super.keyTyped(e);
table.setRowHeight(lastRowIndex, (int) (textArea.getPreferredSize().getHeight()));
}
});
}
public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected,
int rowIndex, int vColIndex) {
this.table = table;
lastRowIndex = rowIndex;
((JTextArea) component).setText((String) value);
component.setFont(table.getFont());
return component;
}
public Object getCellEditorValue() {
return ((JTextArea) component).getText();
}
}

Utilisé de la manière suivante:

    JTable table = new JTable(tableModel) {
//Cell renderer by Alessandro Rossi (posted as solution to this question)
MultilineTableCell renderer = new MultilineTableCell();
MultilineTableCellEditor editor = new MultilineTableCellEditor();
@Override
public TableCellRenderer getCellRenderer(int row, int column) {
if (column == multilineColumn) {
return renderer;
}
return super.getCellRenderer(row, column);
}
@Override
public TableCellEditor getCellEditor(int row, int column) {
if ( column == multilineColumn ) {
return editor;
}
return super.getCellEditor(row, column);
}
};

Je suis tombé dans ce même problème, et j'ai dû modifier un peu le code qu'il a été écrit ici, j'ai donc brancher mon propre version:

import java.awt.Component;
import javax.swing.JTable;
import javax.swing.JTextArea;
import javax.swing.table.TableCellRenderer;
public class LineWrapCellRenderer extends JTextArea implements TableCellRenderer {
@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus,
int row, int column) {
this.setText((String) value);
this.setWrapStyleWord(true);
this.setLineWrap(true);
int fontHeight = this.getFontMetrics(this.getFont()).getHeight();
int textLength = this.getText().length();
int lines = textLength / this.getColumnWidth();
if (lines == 0) {
lines = 1;
}
int height = fontHeight * lines;
table.setRowHeight(row, height);
return this;
}
}

utilisation setBounds sur le moteur de rendu composant (voir ci-dessous)

import java.awt.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;
public class MultiWrapColDemo {
public static void main(String[] args) throws FileNotFoundException {
EventQueue.invokeLater(new ShowIt());
}
}
class ShowIt implements Runnable {
@Override
public void run() {
JTable table = new JTable();
table.getColumnModel().addColumnModelListener( new WrapColListener( table ) );
table.setDefaultRenderer( Object.class, new JTPRenderer() );
//examples:
//   table.setIntercellSpacing( new Dimension( 40, 20 ));
//   table.setIntercellSpacing( new Dimension( 4, 2 ));
Vector<Vector<String>> dataVector = new Vector<Vector<String>>();
String lorem1 = "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore";
String lorem2 = "et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum";
for (int i = 0; i < 12; i++) {
Vector<String> row = null;
if (i % 4 == 0) {
row = new Vector<String>(Arrays.asList(new String[] { "iggle", lorem1, "poggle", "poke" }));
} else if (i % 4 == 1) {
row = new Vector<String>(Arrays.asList(new String[] { lorem2, "piggle", "poggle", lorem1 }));
} else if (i % 4 == 2) {
row = new Vector<String>(Arrays.asList(new String[] { lorem1, "piggle", lorem2, "poke" }));
} else
row = new Vector<String>(Arrays.asList(new String[] { "iggle", lorem2, "poggle", lorem2 }));
dataVector.add(row);
}
Vector<String> columnIdentifiers = new Vector<String>(Arrays.asList(new String[] { "iggle", "piggle", "poggle",
"poke" }));
table.getTableHeader().setFont(table.getTableHeader().getFont().deriveFont(20f).deriveFont(Font.BOLD));
((DefaultTableModel) table.getModel()).setDataVector(dataVector, columnIdentifiers);
JFrame frame = new JFrame("MultiWrapColTable");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane jsp = new JScrollPane(table);
frame.getContentPane().add(jsp);
frame.pack();
frame.setBounds(50, 50, 800, 500);
frame.setVisible(true);
}
}
//if the renderer on a column (or the whole table) is not a JTextComponent calculating its preferredSize will not do 
//any wrapping ... but it won't do any harm....
class JTPRenderer extends JTextPane implements TableCellRenderer {
@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus,
int row, int column) {
setText(value.toString());
return this;
}
}
class WrapColListener implements TableColumnModelListener {
JTable m_table;
WrapColListener( JTable table ){
m_table = table;
}
void refresh_row_heights() {
int n_rows = m_table.getRowCount();
int n_cols = m_table.getColumnCount();
int intercell_width = m_table.getIntercellSpacing().width;
int intercell_height = m_table.getIntercellSpacing().height;
TableColumnModel col_model = m_table.getColumnModel();
//these null checks are due to concurrency considerations... much can change between the col margin change
//event and the call to refresh_row_heights (although not in this SSCCE...)
if( col_model == null ) return;
//go through ALL rows, calculating row heights
for (int row = 0; row < n_rows; row++) {
int pref_row_height = 1;
//calculate row heights from cell, setting width constraint by means of setBounds...
for (int col = 0; col < n_cols; col++) {
Object value = m_table.getValueAt(row, col);
TableCellRenderer renderer = m_table.getCellRenderer(row, col);
if( renderer == null ) return;
Component comp = renderer.getTableCellRendererComponent( m_table, value, false, false,
row, col);
if( comp == null ) return;
int col_width = col_model.getColumn(col).getWidth();
//constrain width of component
comp.setBounds(new Rectangle(0, 0, col_width - intercell_width, Integer.MAX_VALUE ));
//getPreferredSize then returns "true" height as a function of attributes (e.g. font) and word-wrapping
int pref_cell_height = comp.getPreferredSize().height  + intercell_height;
if (pref_cell_height > pref_row_height) {
pref_row_height = pref_cell_height;
}
}
if (pref_row_height != m_table.getRowHeight(row)) {
m_table.setRowHeight(row, pref_row_height);
}
}
}
@Override
public void columnAdded(TableColumnModelEvent e) {
refresh_row_heights();
}
@Override
public void columnRemoved(TableColumnModelEvent e) {
//probably no need to call refresh_row_heights
}
@Override
public void columnMoved(TableColumnModelEvent e) {
//probably no need to call refresh_row_heights
}
@Override
public void columnMarginChanged(ChangeEvent e) {
refresh_row_heights();
}
@Override
public void columnSelectionChanged(ListSelectionEvent e) {
//probably no need to call refresh_row_heights
}
}

Ci-dessus fonctionne très bien dans ce SSCCE... mais dans le monde réel, avec des polices plus complexes, plus de texte et les plus grandes tables vous commencez à rencontrer des problèmes. Je vous propose donc ci-dessous une nouvelle version de l'Auditeur classe avec une nouvelle version du moteur de rendu (juste pour introduire l'utilisation d'un complexe de police...). Remplacer dans le ci-dessus SSCCE si intéressé...

/*
* This class reflects the fact that 1) when you drag a column boundary using the mouse a very large number of
* ChangeEvents are generated and 2) with more complex fonts, more text and larger tables ("real world") the amount
* of computation in calculating the row heights becomes significant and leads to an unresponsive GUI, or worse.
* This "first" strategy to address this involves setting a pause between the detection of a change event and the
* refreshing of the rows.  Naturally this involves a Timer, the run() method of which is not the EDT, so it
* must then submit to EventQueue.invokeLater...
* The larger the table, the more text involved, and the more complex the fonts... the more ingenuity will have to 
* be used in coping with the potentially vast amount of computation involved in getting the ideal row heights.  This
* is in the nature of the beast.  Ideas might involve: 
* 1) adjusting the row heights immediately only for rows which are visible or likely to be visible (Viewport), and 
* then making successive calls to EventQueue.invokeLater to deal with all the other rows
* 2) giving cells a "memory" of their heights as a function of the allowed width.  Unfortunately it will not allow
* the possibility of interpolating intermediate values because the question of whether a line wraps may hinge on a 
* single pixel difference, although an imperfect solution to this would be err on the side of caution, i.e. pretend
* that a column is a little thinner than it is to cause wrapping before it is strictly necessary... particularly when 
* cells are out of view...
* ... other ideas...(?)  
*/
class FirstRealWorldWrapColListener implements TableColumnModelListener {
JTable m_table;
final static long PAUSE_TIME = 50L;
java.util.Timer m_pause_timer = new java.util.Timer( "pause timer", true );
TimerTask m_pause_task;
class PauseTask extends TimerTask{
@Override
public void run() {
EventQueue.invokeLater( new Runnable(){
@Override
public void run() {
refresh_row_heights();
System.out.println( "=== setting m_pause_task to null..." );
m_pause_task = null;
}});
}
}
FirstRealWorldWrapColListener( JTable table ){
m_table = table;
}
void queue_refresh(){
if( m_pause_task != null ){
return;
}
System.out.println( "=== scheduling..." );
m_pause_task = new PauseTask();
m_pause_timer.schedule( m_pause_task, PAUSE_TIME ); 
}
void refresh_row_heights() {
int n_rows = m_table.getRowCount();
int n_cols = m_table.getColumnCount();
int intercell_width = m_table.getIntercellSpacing().width;
int intercell_height = m_table.getIntercellSpacing().height;
TableColumnModel col_model = m_table.getColumnModel();
//these null checks are due to concurrency considerations... much can change between the col margin change
//event and the call to refresh_row_heights (although not in this SSCCE...)
if( col_model == null ) return;
//go through ALL rows, calculating row heights
for (int row = 0; row < n_rows; row++) {
int pref_row_height = 1;
//calculate row heights from cell, setting width constraint by means of setBounds...
for (int col = 0; col < n_cols; col++) {
Object value = m_table.getValueAt(row, col);
TableCellRenderer renderer = m_table.getCellRenderer(row, col);
if( renderer == null ) return;
Component comp = renderer.getTableCellRendererComponent( m_table, value, false, false,
row, col);
if( comp == null ) return;
int col_width = col_model.getColumn(col).getWidth();
//constrain width of component
comp.setBounds(new Rectangle(0, 0, col_width - intercell_width, Integer.MAX_VALUE ));
//getPreferredSize then returns "true" height as a function of attributes (e.g. font) and word-wrapping
int pref_cell_height = comp.getPreferredSize().height  + intercell_height;
if (pref_cell_height > pref_row_height) {
pref_row_height = pref_cell_height;
}
}
if (pref_row_height != m_table.getRowHeight(row)) {
m_table.setRowHeight(row, pref_row_height);
}
}
}
@Override
public void columnAdded(TableColumnModelEvent e) {
//   refresh_row_heights();
queue_refresh();
}
@Override
public void columnRemoved(TableColumnModelEvent e) {
//probably no need to call refresh_row_heights
}
@Override
public void columnMoved(TableColumnModelEvent e) {
//probably no need to call refresh_row_heights
}
@Override
public void columnMarginChanged(ChangeEvent e) {
//   refresh_row_heights();
queue_refresh();
}
@Override
public void columnSelectionChanged(ListSelectionEvent e) {
//probably no need to call refresh_row_heights
}
}
//if the renderer on a column (or the whole table) is not a JTextComponent calculating its preferredSize will not do 
//any wrapping ... but it won't do any harm....
class JTPRenderer extends JTextPane implements TableCellRenderer {
Font m_default_font, m_big_font, m_default_alternate_font, m_big_alternate_font;
HashMap<AttributedCharacterIterator.Attribute, Object>  m_red_serif_attr_map;
//
JTPRenderer() {
m_default_font = getFont();
m_big_font = m_default_font.deriveFont(m_default_font.getSize() * 1.5f);
m_red_serif_attr_map = new HashMap<AttributedCharacterIterator.Attribute, Object >();
m_red_serif_attr_map.put( TextAttribute.FAMILY, Font.SERIF );
m_red_serif_attr_map.put( TextAttribute.FOREGROUND, Color.RED );
m_red_serif_attr_map.put( TextAttribute.WIDTH, TextAttribute.WIDTH_EXTENDED );
m_default_alternate_font = m_default_font.deriveFont( m_red_serif_attr_map );
m_big_alternate_font = m_big_font.deriveFont( m_red_serif_attr_map );
//simpler alternate font:
//   m_default_alternate_font = m_default_font.deriveFont( Font.BOLD | Font.ITALIC );
//   m_big_alternate_font = m_big_font.deriveFont( Font.BOLD | Font.ITALIC );
}
@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus,
int row, int column) {
int rc = row + column;
if( rc % 4 == 2 )
setFont( rc % 5 == 1 ?  m_big_alternate_font : m_default_alternate_font );
else 
setFont( rc % 5 == 1 ?  m_big_font : m_default_font );
setText(value.toString());
return this;
}
}