java - 当用户检查 JCheckBox 时，尝试让 Jframe 类和 JComponent 类进行交互

Question

到目前为止，代码创建了两个框架:一个放置 DrawingComponent 的框架和一个带有交互式按钮的框架。目前，用户可以选择绘制直线、矩形或椭圆形。我为 DrawingComponent 设置了 MouseActionListener，因此可以单独绘制每个形状。

<小时/>

public class DrawingViewer extends JFrame {

private JFrame controlFrame;
private JButton drawButton, fillButton, undoButton; 
private JCheckBox lineBox, recBox, ellipseBox;
private JLabel drawLabel, fillLabel;
private DrawingComponent component;

public DrawingViewer () {
    setupThisFrame();       
    setupControlFrame();
    setupButtons();
    showFrames();   
}

....

 fillLabel = new JLabel();
    fillLabel.setOpaque(true);
    fillLabel.setFont(new Font("Consolas", Font.PLAIN,12));
    fillLabel.setForeground(Color.BLACK);
    fillLabel.setBackground(null);
    if(fillLabel.getBackground() != null){
        fillLabel.setText("         ");
    }
    else{
        fillLabel.setText(" nothing ");
    }

....

class shapeCheckListener implements ActionListener{

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == lineBox){
            System.out.println("Line Chosen");
            component.setLine();
        }
        else if (e.getSource() == recBox){
            System.out.println("Rectangle Chosen");
            component.setRec();
        }
        else if (e.getSource() == ellipseBox){
            System.out.println("Ellipse Chosen");
            component.setEllipse();
        }
      }
   }    
}

----------------------------------------------------------
public class DrawingComponent extends JComponent {

private int mouseX;
private int mouseY;
private int mouseX2;
private int mouseY2;
public Shape shape; 
public Color borderColor;
public Color fillColor;

public DrawingComponent() {
    setupMouse();
}

@Override
public void paintComponent(Graphics g){

    Graphics2D g2 = (Graphics2D) g;

    if(shape != null){
        g2.draw(shape);
    }
    else{
        shape = null;
    }

}

public void setLine(){
    shape = new Line2D.Double(mouseX, mouseY, mouseX2, mouseY2);
}
public void setRec(){
    shape = new Rectangle(Math.min(mouseX, mouseX2), Math.min(mouseY, mouseY2) , Math.abs(mouseX - mouseX2), Math.abs(mouseY - mouseY2));
}
public void setEllipse(){
    shape = new Ellipse2D.Double(Math.min(mouseX, mouseX2), Math.min(mouseY, mouseY2), Math.abs(mouseX - mouseX2), Math.abs(mouseY - mouseY2));
}

Answer 1

框架只是一个外壳。它不应包含与应用程序相关的任何数据。事实上，您甚至根本不需要扩展 JFrame。

您的绘图区域应该具有更改类属性的方法。然后您可以创建一个可以访问绘图区域类的按钮面板。每当您想要更改形状时，只需将更改通知绘图区域即可。

查看Custom Painting Approaches有关此方法的示例。此示例只有一个可以更改的“颜色”属性。因此，根据您的情况，您需要添加“形状”属性。