在JPanel上绘图 [英] Drawing on a JPanel

问题描述

我首先从NetbeanIDE的JPanel扩展创建create RubicPanel类，将其设置为黑色背景，将其放置在JFrame上，然后开始使用类似这样的其他类来绘制它.

I'm start with create RubicPanel class extended from JPanel from NetbeanIDE set it to black background, put it on a JFrame and I start to draw on it by using another class like this.

public class Drow {
  private final int SquareSize = 99;

  public void DrowRubic(RubicEntity GameRubic, RubicPanel rPanel) {

    Graphics g = rPanel.getGraphics();

          g.setColor(Color.pink);
          g.fillRect(0, 0, 301, 301);
          int CurrentFace = GameRubic.getDirection(1);

          for(int i=0; i<3; i++) {
              for(int j=0; j<3; j++) {
                DrowSquare(g, (99*i)+1 , (j*99)+1, GameRubic.getSpecificCell(i, j, CurrentFace));
              }
          }

       Toolkit.getDefaultToolkit().sync();
       g.dispose();
   }

   public void DrowSquare(Graphics g, int x, int y, Color c) {
       g.setColor(c);
       g.fillRect(x, y, this.SquareSize-1, this.SquareSize-1);
   }
}

结果出现的时间很短，似乎立即被黑色背景所取代.

and result is appear very short time and seem to be replace with black background immediately.

我该如何解决?为什么会发生此问题?

how can i fix it and why this problem happened?

最后一件事，对不起我的英语不好. :)

and the last thing sorry for my bad English. :)

推荐答案

要执行自定义绘制，请覆盖paintComponent.而且，由于您不想破坏传递的Graphics对象，因此最好制作一个副本，以备日后使用.例如，

To perform custom painting, override paintComponent. And since you don't want to clobber the passed Graphics object, it's best that you make a copy that will you later dispose of. For instance,

@Override
protected void paintComponent(Graphics g){
    // Get copy
    Graphics gCopy = g.create();
    // Draw on copy
    ...
    // Dispose of copy
    gCopy.dispose();
}

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