java - 当我单击按钮时 JTable 颜色单元格永久

Question

我想创建一个 JTable 并通过单击按钮永久为其单元格着色(非常像 excel 中的单元格着色)。到目前为止，我选择的每个单元格都会进入 ArrayList<Cell>。 .

首先，我希望在单击按钮时列表中的每个单元格都永久着色(这与我找到的代码不同)。我是否必须使用这样的语句 table.getColumnModel().getColumn(column).setCellRenderer(this); ？

这是一个可编译的代码，如果你调试它，你会看到当点击按钮时，我无法访问 getTableCellRendererComponent() 方法。为什么会这样？如果您能告诉我您的意见，我将不胜感激。

(注意:这是一个庞大程序的复制品，所以它有点乱，并且在某些地方进行了硬编码。无法针对我要解决的问题缩小它)。

类 ColorSelectedTableCells.java

public class ColorSelectedTableCells extends JPanel {
   private JButton btn = new JButton("color cells");
   private MyCellRenderer myCellRenderer = new MyCellRenderer();
   public static final Object[][] DATA = new Object[3][3];
   public static final String[] COLS = {"A", "B", "C"};
   private static final int PREF_WIDTH = 400;
   private static final int PREF_HEIGHT = 300;
   private static CellSelectionSet cellSelectionSet = new CellSelectionSet();

   private JTable table = new JTable(DATA,COLS){
       @Override
       public boolean isCellEditable(int row, int column) {return false;}

       @Override
       public boolean isCellSelected(int row, int column) {
          if (cellSelectionSet.containsOneOrLess()) {
            return super.isCellSelected(row, column);
          }
            return cellSelectionSet.contains(row, column);
        }

        @Override
        public void changeSelection(int rowIndex, int columnIndex, boolean toggle, boolean extend) {
          super.changeSelection(rowIndex, columnIndex, toggle, extend);
          if (toggle) {
            cellSelectionSet.add(rowIndex, columnIndex);
          } 
          else {
            if (extend) {
              cellSelectionSet.add(rowIndex, columnIndex);
            } 
            else {
              cellSelectionSet.clear();
              cellSelectionSet.add(rowIndex, columnIndex);
            }
          }
        }   
      };

 public ColorSelectedTableCells() {
  table.setDefaultRenderer(Integer.class, myCellRenderer);
  table.setCellSelectionEnabled(true);
  table.setColumnSelectionAllowed(false);
  table.setRowSelectionAllowed(false);

  JScrollPane scrollPane = new JScrollPane(table, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
  JPanel btnPanel = new JPanel();
  btnPanel.add(btn);

  setLayout(new BorderLayout());
  add(scrollPane, BorderLayout.CENTER);
  add(btnPanel, BorderLayout.SOUTH);

  btn.addActionListener(new ActionListener() {
     @Override
     public void actionPerformed(ActionEvent e) {
        myCellRenderer.setShowSelected(true);
        table.repaint();
     }
  });
}

@Override
public Dimension getPreferredSize() {
   return new Dimension(PREF_WIDTH, PREF_HEIGHT);
}

private static void createAndShowUI() {
  JFrame frame = new JFrame();
  frame.getContentPane().add(new ColorSelectedTableCells());
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.pack();
  frame.setLocationRelativeTo(null);
  frame.setVisible(true);
}

public static void main(String[] args) {
  java.awt.EventQueue.invokeLater(new Runnable() {
     public void run() {
        createAndShowUI();
     }
  });
}

MyCellRenderer.java 类

private static class MyCellRenderer extends DefaultTableCellRenderer {
  private boolean showSelected = false;
  private byte colorSwitcher;

  public void setShowSelected(boolean showSelected) {
     this.showSelected = showSelected;
  }

  public void setColorSwitcher(byte colorSwitcher){
      this.colorSwitcher = colorSwitcher;
  }

  @Override
  public Component getTableCellRendererComponent(JTable table,Object value, boolean isSelected, boolean hasFocus, int row,int column) {
    Component superComponent = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

      if(showSelected && table.isCellSelected(row, column)){
        superComponent.setBackground(Color.GREEN);
      }
      else if (table.isCellSelected(row, column)){
        superComponent.setBackground(table.getSelectionBackground());
      }
      else {
        superComponent.setBackground(table.getBackground());
      }
       return superComponent;
    }
  }
}

类 cellSelectionSet.java

  public class CellSelectionSet {
  private List<Cell> cells = new ArrayList<>();

  public void add(int r, int c) {
    if (!contains(r, c)) {
        cells.add(new Cell(r, c));
    }
  }

  public boolean containsOneOrLess() {
    return cells.size() <= 1;
  }

  public boolean contains(int r, int c) {
    for (Cell cell : cells) {
        if (cell.is(r, c)) {
            return true;
        }
    }
    return false;
  }

  public Cell getElementAt(int i){
    return cells.get(i);
  }

  public int getSize(){
    return this.cells.size();
  }

  public void clear() {
    cells.clear();
    System.out.println("CellSelectionSet cleared.");
  }  
}

类 Cell.java

public class Cell {
  private int row, column;

  public Cell(int row, int column){
    this.row = row;
    this.column = column;
  }

  public boolean is(int r, int c) {
    return row == r && column == c;
  }
}

Answer 1

主要问题:

table.setDefaultRenderer(Integer.class, myCellRenderer);

应该是

table.setDefaultRenderer(Object.class, myCellRenderer);

这将使您的细胞改变颜色。但是你会遇到一个问题，在你按下按钮之后，你选择的每个单元格都会自动改变颜色，因为 showSelected 属性设置为 true。谁知道呢，也许这就是你想要的。

另一个问题是单元格保持选择颜色。如果你的检查语句有问题

if(showSelected && table.isCellSelected(row, column)){

一旦您进行了更多选择，原来的选择将被清除。一个修复方法是检查 CellSelectionSet 以查看它是否包含单元格，同时检查它是否是新选择的。有点像

if (cellSelectionSet.contains(row, column)
                  && !cellSelectionSet.getCellAt(row, column).isNewlySelected())

我添加了一个方法 getCellAt 到你的 CellSelectionSet

public Cell getCellAt(int row, int column) {
    Cell c = null;
    for (Cell cell : cells) {
        if (cell.is(row, column)) {
            c = cell;
        }
    }
    return c;
}

还有 Cell 类中的一个标志，用于检查它是否是 newlySelected。默认为真

class Cell {

    private boolean newlySelected = true;

    public boolean isNewlySelected() {
        return newlySelected;
    }

    public void setNewlySelected(boolean newlySelected) {
        this.newlySelected = newlySelected;
    }
}

当你第一次添加单元格时，它会被重新选中并且不会呈现不同的颜色，因为它没有通过检查

!cellSelectionSet.getCellAt(row, column).isNewlySelected()

但是当您按下按钮时，您将遍历列表并将所有单元格 newlySelected 设置为 false。

public void actionPerformed(ActionEvent e) {
    //myCellRenderer.setShowSelected(true);
    for (int i = 0; i < cellSelectionSet.getSize(); i++) {
        cellSelectionSet.getElementAt(i).setNewlySelected(false);
    }
    table.repaint();
}