重繪方法不起作用？

Question

我在按下按鈕后無法在面板上重新繪制矩形。 我更改顏色並調用repaint方法，所以我不確定為什么按下按鈕后就不重繪。 “畫布面板”是帶有我要重繪的矩形的面板。“整個面板”是帶有應該響應的按鈕的面板。

我的代碼：

public WholePanel()
{
//white is the default color
 currentColor = Color.WHITE;

 //default x-y cooridnate, width, and height of a rectangle
 currentWidth = currentHeight = 100;
 x1 = 100; y1 = 100;

//Creating buttons
 fillCheck = new JCheckBox("Filled");
 white=new JRadioButton("white");
 red=new JRadioButton("red");

 //Adds listeners to each button
 white.addItemListener(new ColorListener());
 red.addItemListener(new ColorListener());



 //Adding buttons to buttonGroup so only one can be pressed at a time
 group.add(white);
 group.add(red);


 menuPanel = new JPanel();
 menuPanel.add(fillCheck);
 menuPanel.add(white);
 menuPanel.add(red);



 canvas = new CanvasPanel();

 JSplitPane sPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, menuPanel, canvas);

 setLayout(new BorderLayout());
 add(sPane, BorderLayout.CENTER);

}


 //insert ColorListener and FillListener classes

public class ColorListener implements ItemListener {


        @Override

        public void itemStateChanged(ItemEvent e) {
            Object source=e.getSource();

              if(source==red) {
                currentColor=Color.white;
                repaint();
                }

            else if (source==white) {
                currentColor=Color.white;
                repaint();
                }

        }


 }

 //This method is in a seperate CanvasPanel class where pressed keys will be 
drawn

 //this method draws all characters pressed by a user so far
 public void paintComponent(Graphics page)
  {
   super.paintComponent(page);

   //set color, then draw a rectangle
   page.setColor(currentColor);

   page.drawRect(x1, y1, currentWidth, currentHeight);
  }



  } // end of Canvas Panel Class

   } // end of Whole Pane

Answer 1

我認為缺陷在於您編寫的itemStateChanged方法內：

if (source==red) { 
    currentColor=Color.white; 
    ... 
}

在red收音機和white收音機中，您都將顏色設置為white ，這就是矩形顏色不變的原因。