跨越JTable中两个单元格的图形内容

Question

我有一个使用DefaultTableModel的JTable，它产生如下表格：

但是我很好奇是否有一种很好的方法可以在下面的例子中跨越细胞创建箭头...

这对我来说似乎很难。有没有办法可能使用DefaultTableCellRenderer，或者也许使用awt.Paint包将是要走的路？想法？

Answer 1

使用单元格渲染器并不容易，因为这会涉及很多匹配的事情。

您最简单的方法可能是覆盖整个paintComponent的{​​{1}}方法，然后在完成绘图的其余部分后（JTable）绘制你的箭头手动。

Answer 2

我通过覆盖JTable的paintComponent（）得到了这个：

/**For drawing arrows between cells to clarify workflow.
             */
            @Override
            protected void paintComponent(Graphics g){

                super.paintComponent(g);

                Graphics2D g2 = (Graphics2D) g;
                g2.setStroke(new BasicStroke(2));

                //draw arrows
                for (int i = 0; i < getRowCount() - 1; i++)
                {
                    // -- draw arrow between A,B columns --
                    // stem
                    Rectangle cell = getCellRect(i, 0, false); // cell.x , y = top left corner coords. of rectangle
                    int outReach = 5; //length to go from paint starting point
                    Point center = new Point(cell.x + cell.width, cell.y + cell.height); //bottom right corner of cell
                    Point sw = new Point(center.x - outReach, center.y + outReach); //go southwest. remember x++ is right, y++ is down
                    Point ne = new Point(center.x + outReach, center.y - outReach); //go northeast
                    g2.setColor( Color.BLACK);
                    g2.drawLine(sw.x, sw.y, ne.x, ne.y);

                    //now the arrow tip starting from (sw.x, sw.y) - upper part here
                    outReach = 6;
                    center = new Point(sw.x, sw.y);
                    Point north = new Point(center.x, center.y - outReach); 
                    g2.drawLine(center.x, center.y, north.x, north.y);

                    //lower part of arrow tip
                    Point e = new Point(center.x + outReach, center.y); //east
                    g2.drawLine(center.x, center.y, e.x, e.y);


                    // -- X,Y columns --
                    cell = getCellRect(i, 2, false);
                    outReach = 5; 
                    center = new Point(cell.x + cell.width, cell.y + cell.height); //bottom right corner of cell
                    Point nw = new Point(center.x - outReach, center.y - outReach); 
                    Point se = new Point(center.x + outReach, center.y + outReach); 
                    g2.drawLine(nw.x, nw.y, se.x, se.y);

                    //horizontal tip (above other part)
                    outReach = 6;
                    center = new Point(nw.x, nw.y);
                    e = new Point(center.x + outReach, center.y ); 
                    g2.drawLine(center.x, center.y, e.x, e.y);

                    //vertical tip (lower)
                    Point south = new Point(center.x, center.y + outReach);
                    g2.drawLine(center.x, center.y, south.x, south.y);

                }
            }// end paintComponent()