JComponent setSize() 和 setLocation() 不工作

Question

我正在尝试设置一个容器 JComponent，它绘制一个带有虚线边框的矩形。问题是 setLocation() 和 setSize() 不起作用。我已经尝试了一些东西，例如 super.setSize() 和 super.setPrefferedSize().

对于任何上下文，我都将其添加到带有 FlowLayout 的 JPanel。 JFrame 的宽度为 500，高度为 300。这是 Linux 上的运行，以防 OS 重要。

public class RectangleContainer extends JComponent{
int x = 0;
int y = 0;
int length = 50;
int dashLength = 10;

RectangleContainer(){
    super();
    setSize(60, 60);
    setPreferredSize(new Dimension(60, 60)); //length+dashLength
}

// @Override
// public void setSize(int width, int height){
//     this.length = (width > height) ? height:width;
//     super.setSize(length+dashLength, length+dashLength);
//     super.setPreferredSize(new Dimension(length+dashLength, length+dashLength));
//     revalidate();
// }

//TODO: add dashLength or not?
@Override
public Dimension getSize(){
    return new Dimension(length+dashLength, length+dashLength);
}

@Override
public void setLocation(int x, int y){
    super.setLocation(x, y);
    // System.out.println(String.format("X: %d", x));
    // System.out.println(String.format("Y: %d", y));

    // this.x = x;
    // this.y = y;
    // //super.setSize(length+dashLength+x, length+dashLength+y);
    // //super.setPreferredSize(new Dimension(length+dashLength+x, length+dashLength+y));
    // //repaint();
    // revalidate();
}

@Override
public Point getLocation(){
    return new Point(this.x, this.y);
}

//Code altered, but mainly from http://www.java2s.com/Code/Java/2D-Graphics-GUI/Dashedstroke.htm
@Override
public void paintComponent(Graphics g){
    super.paintComponent(g);
    setBackground(Color.white);

    Graphics2D g2 = (Graphics2D) g;

    g2.setStroke(new BasicStroke(3.0f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER, dashLength, new float[]{dashLength}, 0.0f));
    g2.setPaint(Color.black);
    Rectangle r = new Rectangle(x, y, length, length);

    g2.draw(r);
}
}

Answer 1

如果您想要完成的只是在特定位置创建一个带有虚线边框的组件，那么我希望这个示例能帮助您入门

    public class DashTest
    {
     public static void main(String args[])
     {
      JFrame frame=new JFrame("Dash Test");
    
      frame.setContentPane(new JPanel(null)); /*A panel with no layout as the main container*/
    
      JButton button=new JButton("Dashed Button");
    
      button.setBorder(BorderFactory.createDashedBorder(Color.red));
    /*swing comes inbuilt with custom borders*/
    
  
     button.setBounds(100,100,150,30);/*set the x,y,width,height of the button works only if you have no layout set as shown above*/
    
     frame.add(button);
    
     frame.setSize(500,500);
    
     frame.setVisible(true);
     }
    }

为了您的目的，不需要仅仅为了使用边框而将您的组件子类化为 JComponent，但是如果您试图在您的组件内做更多花哨的东西而不仅仅是边框，那么您必须覆盖该组件绘制组件方法

class MyComponent extends JComponent
{  
 MyComponent ()
 {
  super();
    
  setBorder(BorderFactory.createDashedBorder(Color.red));/*keep the red border*/
  }

 @Override
 public void paintComponent(Graphics g)
{
 super.paintComponent(g);/*NEVER FORGET THIS*/

 Graphics2D g2d=(Graphics2D)g;

 /*do more creative stuff now with graphics*/
 }
}

JComponent setSize() 和 setLocation() 不工作

JComponent setSize() and setLocation() not working

java

swing

awt

jcomponent