使用TextAreaRenderer在JTable單元格中居文本對齊

Question

我正在使用TextAreaRenderer在我的JTable單元格中自動換行文本。 但是，我的項目規范要求能夠使文本居中（水平和垂直）。 我無法弄清楚如何做到這一點。

因為我已經在使用extends JTextArea的TextAreaRenderer ，所以我無法擴展DefaultTableCellRenderer ，這是訪問setHorizontalAlignment()和setVerticalAlignment()方法所必需的（請參閱此問題和答案： 如何在JTable單元格中居中一個值？ ）。 我無法實現DefaultTableCellRenderer因為它不是一個接口。

我正在使用的TextAreaRenderer SSCCE：

import java.awt.Component;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextArea;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;

public class Test {

    public static void main(String args[]) {
        JFrame frame = new JFrame();
        JTable table = new JTable();
        JScrollPane jsp = new JScrollPane(table);
        Object[][] data = new Object[2][2];
        data[0][0] = 1;
        data[0][1] = "Super long text just to illustrate word wrap. Super long text just to illustrate word wrap. Super long text just to illustrate word wrap. Super long text just to illustrate word wrap. Super long text just to illustrate word wrap. Super long text just to illustrate word wrap. Super long text just to illustrate word wrap. Super long text just to illustrate word wrap. ";
        data[1][0] = 2;
        data[1][1] = "Two Lines / Two Lines";
        String[] headers = new String[]{"Digit", "Text"};
        table.setModel(new DefaultTableModel(data, headers) {

            @Override
            public Class<?> getColumnClass(int columnIndex) {
                switch(columnIndex){
                    case 1: return Integer.class;
                    case 2: return String.class;
                    default: return Object.class;
                }
            }
        });
        table.getColumnModel().getColumn(1).setCellRenderer(new TextAreaRenderer());
        frame.add(jsp);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }



    static class TextAreaRenderer extends JTextArea implements TableCellRenderer {

        private final DefaultTableCellRenderer adaptee = new DefaultTableCellRenderer();
        /** map from table to map of rows to map of column heights */
        private final Map cellSizes = new HashMap();


        public TextAreaRenderer() {
            setLineWrap(true);
            setWrapStyleWord(true);
        }

        public Component getTableCellRendererComponent(
                JTable table, Object obj, boolean isSelected,
                boolean hasFocus, int row, int column) {

            // set the colours, etc. using the standard for that platform
            adaptee.getTableCellRendererComponent(table, obj,
                    isSelected, hasFocus, row, column);
            setForeground(adaptee.getForeground());
            setBackground(adaptee.getBackground());
            setBorder(adaptee.getBorder());
            setFont(adaptee.getFont());
            setText(adaptee.getText());


            // This line was very important to get it working with JDK1.4
            TableColumnModel columnModel = table.getColumnModel();
            setSize(columnModel.getColumn(column).getWidth(), 100000);
            int height_wanted = (int) getPreferredSize().getHeight();
            addSize(table, row, column, height_wanted);
            height_wanted = findTotalMaximumRowSize(table, row);
            if (height_wanted != table.getRowHeight(row)) {
                table.setRowHeight(row, height_wanted);
            }
            return this;
        }

        @SuppressWarnings("unchecked")
        private void addSize(JTable table, int row, int column, int height) {
            Map rows = (Map) cellSizes.get(table);
            if (rows == null) {
                cellSizes.put(table, rows = new HashMap());
            }
            Map rowheights = (Map) rows.get(new Integer(row));
            if (rowheights == null) {
                rows.put(new Integer(row), rowheights = new HashMap());
            }
            rowheights.put(new Integer(column), new Integer(height));
        }

        /**
         * Look through all columns and get the renderer.  If it is
         * also a TextAreaRenderer, we look at the maximum height in
         * its hash table for this row.
         */
        private int findTotalMaximumRowSize(JTable table, int row) {
            int maximum_height = 0;
            Enumeration columns = table.getColumnModel().getColumns();
            while (columns.hasMoreElements()) {
                TableColumn tc = (TableColumn) columns.nextElement();
                TableCellRenderer cellRenderer = tc.getCellRenderer();
                if (cellRenderer instanceof TextAreaRenderer) {
                    TextAreaRenderer tar = (TextAreaRenderer) cellRenderer;
                    maximum_height = Math.max(maximum_height,
                            tar.findMaximumRowSize(table, row));
                }
            }
            return maximum_height;
        }

        private int findMaximumRowSize(JTable table, int row) {
            Map rows = (Map) cellSizes.get(table);
            if (rows == null) {
                return 0;
            }
            Map rowheights = (Map) rows.get(new Integer(row));
            if (rowheights == null) {
                return 0;
            }
            int maximum_height = 0;
            for (Iterator it = rowheights.entrySet().iterator();
                    it.hasNext();) {
                Map.Entry entry = (Map.Entry) it.next();
                int cellHeight = ((Integer) entry.getValue()).intValue();
                maximum_height = Math.max(maximum_height, cellHeight);
            }
            return maximum_height;
        }
    }
}

Answer 1

您需要一個使用JTextPane而不是JTextArea的渲染器，然后設置Document的樣式屬性。

即

static class TextAreaRenderer extends JTextPane implements TableCellRenderer {

  private final DefaultTableCellRenderer adaptee = new DefaultTableCellRenderer();
  /** map from table to map of rows to map of column heights */
  private final Map cellSizes = new HashMap();

  public TextAreaRenderer() {
     // !! setLineWrap(true);
     // setWrapStyleWord(true);

     StyledDocument doc = getStyledDocument();
     SimpleAttributeSet center = new SimpleAttributeSet();
     StyleConstants.setAlignment(center, StyleConstants.ALIGN_CENTER);
     doc.setParagraphAttributes(0, doc.getLength(), center, false);
  }

如需更多信息，請參閱（和贊成票）camickr的答案在這里 。