更改JTable的选择行为以仅选择行或列中可变数量的单元格

问题描述

我有一个JTable，可以在其中启用行或列选择之间进行更改。此功能效果很好，但我希望能够确定在当前所选单元格旁边突出显示的单元格数量。当前，选择整个行或整个列。我试图添加一个ListSelectionModel来实现此功能，但它只允许选择整个行或整个列。以下是示例图片：

和

ADJACENTSELECTION默认情况下设置为2，因此我想在启用rowSelection时突出显示所选单元格左右两侧的2个单元格，或者当rowSelection为false时突出显示所选单元格上下的2个单元格。任何帮助将不胜感激。这是我的代码：

package selectionTest;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.ActionMap;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTable;
import javax.swing.Keystroke;
import javax.swing.border.Border;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.table.DefaultTableModel;

public class App {

    private void display() {
        JFrame f = new JFrame("Demo");
        JPanel gui = new JPanel(new BorderLayout());
        GridTable gridTable = new GridTable(25,25);
        gui.add(gridTable,BorderLayout.CENTER);
        f.add(gui);
        f.setBackground(Color.BLUE);
        gui.setBackground(Color.WHITE);
        f.setLocationByPlatform(true);
        f.pack();
        f.setSize(500,600);
        f.setVisible(true);

    }

    public static void main(String[] args) {
        EventQueue.invokelater(new Runnable() {
            @Override
            public void run() {
                new App().display();
            }
        });
    }

}

class GridTable extends JTable {

    static int ADJACENTSELECTION = 2;
    boolean rowSelection = false;
    int rows,cols;

    public GridTable(int rows,int cols) {
        this.rows = rows;
        this.cols = cols;
        this.setModel(new DefaultTableModel(rows,cols));
        this.setShowGrid(true);
        Border blackline = BorderFactory.createLineBorder(Color.black);
        this.setBorder(blackline);
        this.setGridColor(Color.black);
        ActionMap map = this.getActionMap();
        Action action = switchOrientation();
        String keystrokeAndKey = "control O";
        Keystroke keystroke = Keystroke.getKeystroke(keystrokeAndKey);
        this.getInputMap().put(keystroke,keystrokeAndKey);
        this.getActionMap().put(keystrokeAndKey,action);
        this.getSelectionModel().addListSelectionListener(new ListSelectionListener() {
            public void valueChanged(ListSelectionEvent event) {
                int row = getSelectedRow();
                int column = getSelectedColumn();
                if (rowSelection) {
                    setRowSelectionInterval(Math.max(0,row - ADJACENTSELECTION),Math.min(row,row + ADJACENTSELECTION));
                } else {
                    setColumnSelectionInterval(Math.max(0,column - ADJACENTSELECTION),Math.min(column,column + ADJACENTSELECTION));
                }
            }
        });
    }

    private AbstractAction switchOrientation() {
        AbstractAction switchOrientation = new AbstractAction() {
            @Override
            public void actionPerformed(ActionEvent e) {
                rowSelection = !rowSelection;
                setColumnSelectionAllowed(rowSelection);
                setRowSelectionAllowed(!rowSelection);
            }
        };
        return switchOrientation;
    }

}

解决方法

您快到了，只需执行几个额外的步骤，就可以更新选择侦听器以仅突出显示特定的单元格：

通过向this.setCellSelectionEnabled(true);方法中添加GridTable来选择特定的单元格：
```
public GridTable(int rows,int cols) {
    this.setCellSelectionEnabled(true);
    //...
```

确保SelectionInterval范围/值正确：

if (rowSelection == true){
    //Correct using `getRowCount()` for selection range
    setRowSelectionInterval(Math.max(0,row - ADJACENTSELECTION),Math.min(getRowCount()-1,row + ADJACENTSELECTION));
}
else{
    //Correct using `getColumnCount()` for selection range
    setColumnSelectionInterval(Math.max(0,column - ADJACENTSELECTION),Math.min(getColumnCount()-1,column + ADJACENTSELECTION));
}

确保在更新选择时不会触发选择事件再次发生。您可以通过使用布尔值来跟踪选择事件来做到这一点：

this.getSelectionModel().addListSelectionListener(new ListSelectionListener(){
    //Use this to track changes
    boolean initial = true;
    //...
    public void valueChanged(ListSelectionEvent e){
        if (initial){
            int column = getSelectedColumn();
            int row = getSelectedRow();
            //...

最后，将它们放在一起，这是完整的选择侦听器（并且不要忘记将this.setCellSelectionEnabled(true);添加到GridTable中）：

this.getSelectionModel().addListSelectionListener(new ListSelectionListener(){
    //Use this to track changes
    boolean initial = true;

    public void valueChanged(ListSelectionEvent e){
        //Only change value on first select (This prevents the below from triggering itself)
        if (initial){
            int column = getSelectedColumn();
            int row = getSelectedRow();
            initial = false;
            if (rowSelection == true){
                setRowSelectionInterval(Math.max(0,row + ADJACENTSELECTION));
            }
            else{
                setColumnSelectionInterval(Math.max(0,column + ADJACENTSELECTION));
            }
        }
        //Set the value back once a selection is complete
        else{
            initial = true;
        }
    }
});

这将突出显示选定的单元格，并在选择的两侧显示两个单元格

java java jtable swing