Question

我在TextAreaRenderer单元格中使用JTable自动换行文字。但是，我的项目规范要求能够使文本居中（水平和垂直）。我无法弄清楚如何做到这一点。

由于我已使用TextAreaRenderer extends JTextArea，因此无法扩展DefaultTableCellRenderer，这是访问setHorizontalAlignment()和setVerticalAlignment()方法所必需的（{1}}看到这个问题和答案：How to center in JTable cell a value?）。我无法实现DefaultTableCellRenderer因为它不是接口。

我正在使用TextAreaRenderer的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

您需要一个使用JTextPane而不是JTextArea的渲染器，然后设置Document的样式属性。

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);
  }

有关更多信息，请参阅（及投票）camickr的回答here。

使用TextAreaRenderer在JTable单元格中居文本对齐

1 个答案: