Question

我不清楚如何在现有代码中重新绘制JPanel。我也不明白如何调用paintComponent。首先，我只想清除JPanel，但我甚至不能这样做。

我希望能够按下“下一步移动”按钮并重新绘制JPanel，因为我正在读取颜色的网格。我无法通过调用，revalidate（），removeAll（）和repaint（）更改JPanel到我的tile JPanel。

我打电话给这些，没有任何事情发生在俄罗斯方块网格（图片）下面的现有JPanel上。（

在下面的代码中，我有一个扩展JPanel的嵌套类，而setup函数创建了一个窗口，它采用了2d arraylist网格并构建了原始网格。

我如何至少清除JPanel或更好地重新绘制新网格......我在考虑一种方法：

    public void redraw(Grid g) {
        removeAll();
                    getColor(); //gets new grid of tiles
                    repaint();
        revalidate();
    }

在嵌套的JPanel类中，但这似乎根本没有改变JPanel，甚至没有清除当前的绘图。

Tetris Board reading in original grid

 public class BoardGraphics {

    public ArrayList<ArrayList<Color>> colours;

    private final int width;

    private int height;

    private JFrame display;

    private TetrisSquares tiles;

    private Container c;

    public BoardGraphics(int width, int height,
        ArrayList<ArrayList<Integer>> grid) {
        this.width = width;
        this.height = height;
        colours = new ArrayList<ArrayList<Color>>(width);
        setColor(grid);
        setup();
    }

    public void setup() {
        System.out.println("Let the Tetris Begin");
        display = new JFrame("Tetris Agent");



        final TextArea welcome = new TextArea("Welcome to Tetris", 2, 10,
                TextArea.SCROLLBARS_NONE);

        welcome.setBackground(Color.black);
        welcome.setForeground(Color.red);
        welcome.setFont(new Font("monospaced", 0, 11));
        welcome.setEditable(false);

        Button btnStart = new Button("Next Move");
        btnStart.setFocusable(false);



        tiles = new TetrisSquares(TetrisBoard.BOARD_WIDTH, height);

        c = new Container();
        c.setLayout(new BorderLayout());
        c.add(welcome, BorderLayout.NORTH);
        c.add(tiles);
        c.add(btnStart,BorderLayout.SOUTH);

        btnStart.addActionListener(new ActionListener()
        {
           public void actionPerformed(ActionEvent e)
           {
             tiles.removeAll();
             tiles.revalidate();
           }
        });


        final Container main = new Container();

        main.setLayout(new GridLayout(1, 2));
        display.add(c);



        display.pack();

        display.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });

        display.setVisible(true);
    }

    public ArrayList<ArrayList<Color>> getBoard() {
        return colours;
    }

    public void setColor(ArrayList<ArrayList<Integer>> grid) {
        ListIterator<Integer> li;

        for (int i = 0; i < width; i++) {
            colours.add(new ArrayList<Color>());
            li = grid.get(i).listIterator();
            for (int j = 0; j <= height; j++) {
                int n = 0;
                if(li.hasNext()) {
                    n = li.next();

                }
                switch (n) {
                case 1:
                    colours.get(i).add(Color.red);
                    break;
                case 2:
                    colours.get(i).add(Color.pink);
                    break;
                case 3:
                    colours.get(i).add(Color.orange);
                    break;
                case 4:
                    colours.get(i).add(Color.yellow);
                    break;
                case 5:
                    colours.get(i).add(Color.green);
                    break;
                case 6:
                    colours.get(i).add(Color.cyan);
                    break;
                case 7:
                    colours.get(i).add(Color.blue);
                    break;
                default:
                    colours.get(i).add(Color.gray);
                    break;
                }
            }
        }
    }



    public class TetrisSquares extends JPanel {

        public int width;
        public int height;

        public TetrisSquares(int width, int height) {
            this.width = width;
            this.height = width;
            this.setPreferredSize(new Dimension(width * 20, height * 20));
        }

        public void redraw() {
            removeAll();
            //add your elements
            //revalidate();
            //repaint();
        }


        public void paintComponent(Graphics g) {

            super.paintComponent(g);

            Graphics2D graphics = (Graphics2D) g;
            graphics.setColor(Color.BLACK);
            /*
             * tiles.width = getSize().width / width; tiles.height =
             * getSize().height / 800;
             * 
             * insets.left = (getSize().width - width * tiles.width) / 2;
             * insets.right = insets.left; insets.top = 0; insets.bottom =
             * getSize().height - height * tiles.height;
             */
            Dimension size = getSize();
            Insets insets = getInsets();

            int w = size.width - insets.left - insets.right;
            int h = size.height - insets.top - insets.bottom;

            int tileWidth = w / width;
            int tileHeight = w / width;

            ListIterator<Color> li;

            for (int i = 0; i < width; i++) {
                li = colours.get(i).listIterator();
                int n = 20;

                while(li.hasNext()) {
                    --n;
                    int x = (int) (i * tileWidth);
                    int y = (int) (n * tileHeight);
                    graphics.setColor(li.next());
                    graphics.fillRect(x, y, tileWidth, tileHeight);
                    graphics.setColor(Color.black);
                    graphics.drawRect(x, y, tileWidth, tileHeight);
                }
            }

        }

    }

}

Answer 1

首先阅读Painting in AWT and Swing以更好地了解绘画系统。

removeAll从容器中删除所有子组件，在这种情况下这实际上无法帮助您...

revalidate处理布局子系统并更新容器层次结构以响应容器内容的变化，同样，并没有真正帮助......

在paintComponent方法中，您引用的是名为ArrayList的{{1}}，用于绘制正方形。您需要重置此列表以阻止colours方法填充颜色

您的paintComponent方法应该更像......

redaw

重绘/重新验证JPanel不会工作

1 个答案: