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解决JTable排序问题的方法详解

  • 时间:2021-12-14 00:53 编辑: 来源: 阅读:
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摘要:解决JTable排序问题的方法详解
JTable的排序是一个让人头疼的问题,Sun没有为排序这个最常用的功能提供类。 但是近日翻看Sun官方java的tutorial,却发现其在文档中提供了这个类的实现,使用非常简单! [b]使用方法示例: [/b]
[u]复制代码[/u] 代码如下:
TableSorter sorter = new TableSorter(new MyTableModel()); //ADDED THIS //JTable table = new JTable(new MyTableModel()); //OLD JTable table = new JTable(sorter); //NEW sorter.setTableHeader(table.getTableHeader()); //ADDED THIS
我把TableSorter类贴出来,自己编译就可以使用了
[u]复制代码[/u] 代码如下:
import java.awt.*; import java.awt.event.*; import java.util.*; import java.util.List; import javax.swing.*; import javax.swing.event.TableModelEvent; import javax.swing.event.TableModelListener; import javax.swing.table.*; /**  * TableSorter is a decorator for TableModels; adding sorting  * functionality to a supplied TableModel. TableSorter does  * not store or copy the data in its TableModel; instead it maintains  * a map from the row indexes of the view to the row indexes of the  * model. As requests are made of the sorter (like getValueAt(row, col))  * they are passed to the underlying model after the row numbers  * have been translated via the internal mapping array. This way,  * the TableSorter appears to hold another copy of the table  * with the rows in a different order.  * <p/>  * TableSorter registers itself as a listener to the underlying model,  * just as the JTable itself would. Events recieved from the model  * are examined, sometimes manipulated (typically widened), and then  * passed on to the TableSorter's listeners (typically the JTable).  * If a change to the model has invalidated the order of TableSorter's  * rows, a note of this is made and the sorter will resort the  * rows the next time a value is requested.  * <p/>  * When the tableHeader property is set, either by using the  * setTableHeader() method or the two argument constructor, the  * table header may be used as a complete UI for TableSorter.  * The default renderer of the tableHeader is decorated with a renderer  * that indicates the sorting status of each column. In addition,  * a mouse listener is installed with the following behavior:  * <ul>  * <li>  * Mouse-click: Clears the sorting status of all other columns  * and advances the sorting status of that column through three  * values: {NOT_SORTED, ASCENDING, DESCENDING} (then back to  * NOT_SORTED again).  * <li>  * SHIFT-mouse-click: Clears the sorting status of all other columns  * and cycles the sorting status of the column through the same  * three values, in the opposite order: {NOT_SORTED, DESCENDING, ASCENDING}.  * <li>  * CONTROL-mouse-click and CONTROL-SHIFT-mouse-click: as above except  * that the changes to the column do not cancel the statuses of columns  * that are already sorting - giving a way to initiate a compound  * sort.  * </ul>  * <p/>  * This is a long overdue rewrite of a class of the same name that  * first appeared in the swing table demos in 1997.  *  * @author Philip Milne  * @author Brendon McLean  * @author Dan van Enckevort  * @author Parwinder Sekhon  * @version 2.0 02/27/04  */ public class TableSorter extends AbstractTableModel {     protected TableModel tableModel;     public static final int DESCENDING = -1;     public static final int NOT_SORTED = 0;     public static final int ASCENDING = 1;     private static Directive EMPTY_DIRECTIVE = new Directive(-1, NOT_SORTED);     public static final Comparator COMPARABLE_COMAPRATOR = new Comparator() {         public int compare(Object o1, Object o2) {             return ((Comparable) o1).compareTo(o2);         }     };     public static final Comparator LEXICAL_COMPARATOR = new Comparator() {         public int compare(Object o1, Object o2) {             return o1.toString().compareTo(o2.toString());         }     };     private Row[] viewToModel;     private int[] modelToView;     private JTableHeader tableHeader;     private MouseListener mouseListener;     private TableModelListener tableModelListener;     private Map columnComparators = new HashMap();     private List sortingColumns = new ArrayList();     public TableSorter() {         this.mouseListener = new MouseHandler();         this.tableModelListener = new TableModelHandler();     }     public TableSorter(TableModel tableModel) {         this();         setTableModel(tableModel);     }     public TableSorter(TableModel tableModel, JTableHeader tableHeader) {         this();         setTableHeader(tableHeader);         setTableModel(tableModel);     }     private void clearSortingState() {         viewToModel = null;         modelToView = null;     }     public TableModel getTableModel() {         return tableModel;     }     public void setTableModel(TableModel tableModel) {         if (this.tableModel != null) {             this.tableModel.removeTableModelListener(tableModelListener);         }         this.tableModel = tableModel;         if (this.tableModel != null) {             this.tableModel.addTableModelListener(tableModelListener);         }         clearSortingState();         fireTableStructureChanged();     }     public JTableHeader getTableHeader() {         return tableHeader;     }     public void setTableHeader(JTableHeader tableHeader) {         if (this.tableHeader != null) {             this.tableHeader.removeMouseListener(mouseListener);             TableCellRenderer defaultRenderer = this.tableHeader.getDefaultRenderer();             if (defaultRenderer instanceof SortableHeaderRenderer) {                 this.tableHeader.setDefaultRenderer(((SortableHeaderRenderer) defaultRenderer).tableCellRenderer);             }         }         this.tableHeader = tableHeader;         if (this.tableHeader != null) {             this.tableHeader.addMouseListener(mouseListener);             this.tableHeader.setDefaultRenderer(                     new SortableHeaderRenderer(this.tableHeader.getDefaultRenderer()));         }     }     public boolean isSorting() {         return sortingColumns.size() != 0;     }     private Directive getDirective(int column) {         for (int i = 0; i < sortingColumns.size(); i++) {             Directive directive = (Directive)sortingColumns.get(i);             if (directive.column == column) {                 return directive;             }         }         return EMPTY_DIRECTIVE;     }     public int getSortingStatus(int column) {         return getDirective(column).direction;     }     private void sortingStatusChanged() {         clearSortingState();         fireTableDataChanged();         if (tableHeader != null) {             tableHeader.repaint();         }     }     public void setSortingStatus(int column, int status) {         Directive directive = getDirective(column);         if (directive != EMPTY_DIRECTIVE) {             sortingColumns.remove(directive);         }         if (status != NOT_SORTED) {             sortingColumns.add(new Directive(column, status));         }         sortingStatusChanged();     }     protected Icon getHeaderRendererIcon(int column, int size) {         Directive directive = getDirective(column);         if (directive == EMPTY_DIRECTIVE) {             return null;         }         return new Arrow(directive.direction == DESCENDING, size, sortingColumns.indexOf(directive));     }     private void cancelSorting() {         sortingColumns.clear();         sortingStatusChanged();     }     public void setColumnComparator(Class type, Comparator comparator) {         if (comparator == null) {             columnComparators.remove(type);         } else {             columnComparators.put(type, comparator);         }     }     protected Comparator getComparator(int column) {         Class columnType = tableModel.getColumnClass(column);         Comparator comparator = (Comparator) columnComparators.get(columnType);         if (comparator != null) {             return comparator;         }         if (Comparable.class.isAssignableFrom(columnType)) {             return COMPARABLE_COMAPRATOR;         }         return LEXICAL_COMPARATOR;     }     private Row[] getViewToModel() {         if (viewToModel == null) {             int tableModelRowCount = tableModel.getRowCount();             viewToModel = new Row[tableModelRowCount];             for (int row = 0; row < tableModelRowCount; row++) {                 viewToModel[row] = new Row(row);             }             if (isSorting()) {                 Arrays.sort(viewToModel);             }         }         return viewToModel;     }     public int modelIndex(int viewIndex) {         return getViewToModel()[viewIndex].modelIndex;     }     private int[] getModelToView() {         if (modelToView == null) {             int n = getViewToModel().length;             modelToView = new int[n];             for (int i = 0; i < n; i++) {                 modelToView[modelIndex(i)] = i;             }         }         return modelToView;     }     // TableModel interface methods     public int getRowCount() {         return (tableModel == null) ? 0 : tableModel.getRowCount();     }     public int getColumnCount() {         return (tableModel == null) ? 0 : tableModel.getColumnCount();     }     public String getColumnName(int column) {         return tableModel.getColumnName(column);     }     public Class getColumnClass(int column) {         return tableModel.getColumnClass(column);     }     public boolean isCellEditable(int row, int column) {         return tableModel.isCellEditable(modelIndex(row), column);     }     public Object getValueAt(int row, int column) {         return tableModel.getValueAt(modelIndex(row), column);     }     public void setValueAt(Object aValue, int row, int column) {         tableModel.setValueAt(aValue, modelIndex(row), column);     }     // Helper classes     private class Row implements Comparable {         private int modelIndex;         public Row(int index) {             this.modelIndex = index;         }         public int compareTo(Object o) {             int row1 = modelIndex;             int row2 = ((Row) o).modelIndex;             for (Iterator it = sortingColumns.iterator(); it.hasNext();) {                 Directive directive = (Directive) it.next();                 int column = directive.column;                 Object o1 = tableModel.getValueAt(row1, column);                 Object o2 = tableModel.getValueAt(row2, column);                 int comparison = 0;                 // Define null less than everything, except null.                 if (o1 == null && o2 == null) {                     comparison = 0;                 } else if (o1 == null) {                     comparison = -1;                 } else if (o2 == null) {                     comparison = 1;                 } else {                     comparison = getComparator(column).compare(o1, o2);                 }                 if (comparison != 0) {                     return directive.direction == DESCENDING ? -comparison : comparison;                 }             }             return 0;         }     }     private class TableModelHandler implements TableModelListener {         public void tableChanged(TableModelEvent e) {             // If we're not sorting by anything, just pass the event along.                         if (!isSorting()) {                 clearSortingState();                 fireTableChanged(e);                 return;             }             // If the table structure has changed, cancel the sorting; the                         // sorting columns may have been either moved or deleted from                         // the model.             if (e.getFirstRow() == TableModelEvent.HEADER_ROW) {                 cancelSorting();                 fireTableChanged(e);                 return;             }             // We can map a cell event through to the view without widening                         // when the following conditions apply:             //             // a) all the changes are on one row (e.getFirstRow() == e.getLastRow()) and,             // b) all the changes are in one column (column != TableModelEvent.ALL_COLUMNS) and,             // c) we are not sorting on that column (getSortingStatus(column) == NOT_SORTED) and,             // d) a reverse lookup will not trigger a sort (modelToView != null)             //             // Note: INSERT and DELETE events fail this test as they have column == ALL_COLUMNS.             //             // The last check, for (modelToView != null) is to see if modelToView             // is already allocated. If we don't do this check; sorting can become             // a performance bottleneck for applications where cells              // change rapidly in different parts of the table. If cells             // change alternately in the sorting column and then outside of                         // it this class can end up re-sorting on alternate cell updates -             // which can be a performance problem for large tables. The last             // clause avoids this problem.             int column = e.getColumn();             if (e.getFirstRow() == e.getLastRow()                     && column != TableModelEvent.ALL_COLUMNS                     && getSortingStatus(column) == NOT_SORTED                     && modelToView != null) {                 int viewIndex = getModelToView()[e.getFirstRow()];                 fireTableChanged(new TableModelEvent(TableSorter.this,                                                      viewIndex, viewIndex,                                                      column, e.getType()));                 return;             }             // Something has happened to the data that may have invalidated the row order.             clearSortingState();             fireTableDataChanged();             return;         }     }     private class MouseHandler extends MouseAdapter {         public void mouseClicked(MouseEvent e) {             JTableHeader h = (JTableHeader) e.getSource();             TableColumnModel columnModel = h.getColumnModel();             int viewColumn = columnModel.getColumnIndexAtX(e.getX());             int column = columnModel.getColumn(viewColumn).getModelIndex();             if (column != -1) {                 int status = getSortingStatus(column);                 if (!e.isControlDown()) {                     cancelSorting();                 }                 // Cycle the sorting states through {NOT_SORTED, ASCENDING, DESCENDING} or                 // {NOT_SORTED, DESCENDING, ASCENDING} depending on whether shift is pressed.                 status = status + (e.isShiftDown() ? -1 : 1);                 status = (status + 4) % 3 - 1; // signed mod, returning {-1, 0, 1}                 setSortingStatus(column, status);             }         }     }     private static class Arrow implements Icon {         private boolean descending;         private int size;         private int priority;         public Arrow(boolean descending, int size, int priority) {             this.descending = descending;             this.size = size;             this.priority = priority;         }         public void paintIcon(Component c, Graphics g, int x, int y) {             Color color = c == null ? Color.GRAY : c.getBackground();                         // In a compound sort, make each succesive triangle 20%             // smaller than the previous one.             int dx = (int)(size/2*Math.pow(0.8, priority));             int dy = descending ? dx : -dx;             // Align icon (roughly) with font baseline.             y = y + 5*size/6 + (descending ? -dy : 0);             int shift = descending ? 1 : -1;             g.translate(x, y);             // Right diagonal.             g.setColor(color.darker());             g.drawLine(dx / 2, dy, 0, 0);             g.drawLine(dx / 2, dy + shift, 0, shift);             // Left diagonal.             g.setColor(color.brighter());             g.drawLine(dx / 2, dy, dx, 0);             g.drawLine(dx / 2, dy + shift, dx, shift);             // Horizontal line.             if (descending) {                 g.setColor(color.darker().darker());             } else {                 g.setColor(color.brighter().brighter());             }             g.drawLine(dx, 0, 0, 0);             g.setColor(color);             g.translate(-x, -y);         }         public int getIconWidth() {             return size;         }         public int getIconHeight() {             return size;         }     }     private class SortableHeaderRenderer implements TableCellRenderer {         private TableCellRenderer tableCellRenderer;         public SortableHeaderRenderer(TableCellRenderer tableCellRenderer) {             this.tableCellRenderer = tableCellRenderer;         }         public Component getTableCellRendererComponent(JTable table,                                                        Object value,                                                        boolean isSelected,                                                        boolean hasFocus,                                                        int row,                                                        int column) {             Component c = tableCellRenderer.getTableCellRendererComponent(table,                     value, isSelected, hasFocus, row, column);             if (c instanceof JLabel) {                 JLabel l = (JLabel) c;                 l.setHorizontalTextPosition(JLabel.LEFT);                 int modelColumn = table.convertColumnIndexToModel(column);                 l.setIcon(getHeaderRendererIcon(modelColumn, l.getFont().getSize()));             }             return c;         }     }     private static class Directive {         private int column;         private int direction;         public Directive(int column, int direction) {             this.column = column;             this.direction = direction;         }     } }
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