Question

我正在为简单的battlships克隆设计一个简单的GUI。我曾经使用彩绘方块做过类似的事情，但决定尝试使用JPanels。除了顶部的标签（1-14）之外，这里的所有内容都按照我的意图运行。它已显示在1到4之间的任何地方，但从未全部显示为14，并且似乎有些随机显示了多少。应运行此代码，以便轻松查看问题。打印语句只是为了确认值是正确的。谢谢你的帮助！

import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Rectangle;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Foo {
    private JFrame frame;
    private JPanel[][] opponentBoard;
    private JLabel[] coordLabels;
    private final int FRAME_HEIGHT = 800;
    private final int FRAME_WIDTH = 600;
    private final int SQ_SIZE = 30;
    public Foo() {
        frame = new JFrame();
        frame.setBounds(new Rectangle(FRAME_WIDTH, FRAME_HEIGHT));
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setBackground(Color.RED); // for debugging porpoises
        frame.setLayout(null);

        Container container = frame.getContentPane();
        container.setBackground(Color.BLACK);
        container.setVisible(true);

        opponentBoard = new JPanel[15][11];

        coordLabels = new JLabel[24];

        for (int i = 0; i < 15; i++) {
            for (int j = 0; j < 11; j++) {
                opponentBoard[i][j] = new JPanel();
                container.add(opponentBoard[i][j]);
                opponentBoard[i][j].setLocation(i + i * SQ_SIZE, j + j * SQ_SIZE);
                opponentBoard[i][j].setSize(new Dimension(SQ_SIZE, SQ_SIZE));
                opponentBoard[i][j].setVisible(true);
                if ((i == 0) ^ (j == 0)) {
                    opponentBoard[i][j].setBackground(Color.GRAY);
                    if (i == 0) {
                        coordLabels[j - 1] = new JLabel((char) (j + 64) + "");
                        opponentBoard[i][j].add(coordLabels[j - 1]);
                        System.out.println(j-1);
                    }
                    if (j == 0) {
                        coordLabels[i + 9] = new JLabel(i + "");
                        System.out.println(i + 9 + "    " + i + " " + coordLabels[i + 9].getText());
                        opponentBoard[i][j].add(coordLabels[i + 9]);
                    }
                    opponentBoard[i][j].repaint();
                } else {
                    opponentBoard[i][j].setBackground(Color.DARK_GRAY);
                }
            }
        }
        opponentBoard[0][0].setBackground(Color.BLACK);
    }

    public static void main(String[] args){
        new Foo();
    }
}

Answer 1

在将所有面板添加到容器后，您需要调用container.validate()。另外，我会删除内部for循环中对repaint()的调用。

或者，在添加面板之前，您无法将框架设置为可见;这表现得更好。

您可以在此处找到代码的工作版本：

import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Rectangle;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Foo {
    private JFrame frame;
    private JPanel[][] opponentBoard;
    private JLabel[] coordLabels;
    private final int FRAME_HEIGHT = 800;
    private final int FRAME_WIDTH = 600;
    private final int SQ_SIZE = 30;
    public Foo() {
        frame = new JFrame();
        frame.setBounds(new Rectangle(FRAME_WIDTH, FRAME_HEIGHT));
        //frame.setVisible(true); Build the UI before making it visible
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setBackground(Color.RED); // for debugging porpoises
        frame.setLayout(null);

        Container container = frame.getContentPane();
        container.setBackground(Color.BLACK);
        container.setVisible(true);

        opponentBoard = new JPanel[15][11];

        coordLabels = new JLabel[24];

        for (int i = 0; i < 15; i++) {
            for (int j = 0; j < 11; j++) {
                opponentBoard[i][j] = new JPanel();
                container.add(opponentBoard[i][j]);
                opponentBoard[i][j].setLocation(i + i * SQ_SIZE, j + j * SQ_SIZE);
                opponentBoard[i][j].setSize(new Dimension(SQ_SIZE, SQ_SIZE));
                opponentBoard[i][j].setVisible(true);
                if ((i == 0) ^ (j == 0)) {
                    opponentBoard[i][j].setBackground(Color.GRAY);
                    if (i == 0) {
                        coordLabels[j - 1] = new JLabel((char) (j + 64) + "");
                        opponentBoard[i][j].add(coordLabels[j - 1]);
                        System.out.println(j-1);
                    }
                    if (j == 0) {
                        coordLabels[i + 9] = new JLabel(i + "");
                        System.out.println(i + 9 + "    " + i + " " + coordLabels[i + 9].getText());
                        opponentBoard[i][j].add(coordLabels[i + 9]);
                    }
                    //opponentBoard[i][j].repaint();
                } else {
                    opponentBoard[i][j].setBackground(Color.DARK_GRAY);
                }
            }
        }
        opponentBoard[0][0].setBackground(Color.BLACK);

        // If the UI is already visible call validate
        // I've chose to not make the frame visible until all of the children
        // have been added so the call to validate isn't really needed.
        //container.validate();
        frame.setVisible(true);
    }

    public static void main(String[] args){
        new Foo();
    }
}

Swing显示一些JLabel但不显示其他JLabel

1 个答案: