将按钮数组分配给Gridlayout时

Question

因此，我从头开始启动了一个计算器，以练习Java知识。 我有一个小问题，当我使用jlabel使用gridlayout将按钮分配给 返回异常java.lang.illegalgumentException。 我知道我正在做一些愚蠢的事情，我最好重新组织数组，并为循环做一个分配按钮，但是我太懒了，无法做到这一点，想了解我做错了什么。

这是代码：

buttonDisplay.setBounds(30, 30, 400, 320); //buttonDisplay is a JLabel
buttonDisplay.setLayout(new GridLayout(5,4,5,5));
        
operator = new JButton[20];
operator[0] = new JButton("0");
operator[1] = new JButton("1");
operator[2] = new JButton("2");
operator[3] = new JButton("3");
operator[4] = new JButton("4");
operator[5] = new JButton("5");
operator[6] = new JButton("6");
operator[7] = new JButton("7");
operator[8] = new JButton("8");
operator[9] = new JButton("9");
operator[10] = new JButton("+");
operator[11] = new JButton("-");
operator[12] = new JButton("*");
operator[13] = new JButton("/");
operator[14] = new JButton(".");
operator[15] = new JButton("=");
operator[16] = new JButton("AC");
operator[17] = new JButton("C");
operator[18] = new JButton("TAX+");
operator[19] = new JButton("TAX-");

buttonDisplay.add(operator[0],4,2); //exception starts on this line
buttonDisplay.add(operator[1],3,3);
buttonDisplay.add(operator[2],3,2);
buttonDisplay.add(operator[3],3,1);
buttonDisplay.add(operator[4],2,3);
buttonDisplay.add(operator[5],2,2);
buttonDisplay.add(operator[6],2,1);
buttonDisplay.add(operator[7],1,3);
buttonDisplay.add(operator[8],1,2);
buttonDisplay.add(operator[9],1,1);
buttonDisplay.add(operator[10],1,4);
buttonDisplay.add(operator[11],2,4);
buttonDisplay.add(operator[12],3,4);
buttonDisplay.add(operator[13],4,4);
buttonDisplay.add(operator[14],4,1);
buttonDisplay.add(operator[15],4,3);
buttonDisplay.add(operator[16],5,1);
buttonDisplay.add(operator[17],5,2);
buttonDisplay.add(operator[18],5,3);
buttonDisplay.add(operator[19],5,4);

Answer 1

当我运行您的代码的一部分时，以下行抛出了一个例外：

buttonDisplay.add(operator[0],4,2);

这是我得到的堆栈跟踪的[一部分]：

Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: illegal component position
    at java.desktop/java.awt.Container.addImpl(Container.java:1115)
    at java.desktop/java.awt.Container.add(Container.java:1033)

您要调用的方法是：

​ - 但不是。 gridlayout在添加组件时没有提供指示行和列的能力。我认为 gridbagaglayout 可能是更合适的布局经理您正在尝试做什么。

另外，即使类javax.swing.jlabel从class java.awt.container继承，它也不打算包含jbutton s。还有其他用于此目的的 swing 组件，例如 javax.swing.jpanel 。

因此，我建议用jpanel和使用gridbaglayout替换jlabel。

也许以下内容更符合您要实现的目标。

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class Calculat {
    private JTextField  display;

    private void createAndDisplayGui() {
        JFrame frame = new JFrame("Testing JTextField and JPasswordField");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(createDisplay(), BorderLayout.PAGE_START);
        frame.add(createButtons(), BorderLayout.CENTER);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private JPanel createButtons() {
        JPanel buttonDisplay = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.fill = GridBagConstraints.BOTH;

        JButton[] operator = new JButton[20];
        operator[0] = new JButton("0");
        operator[1] = new JButton("1");
        operator[2] = new JButton("2");
        operator[3] = new JButton("3");
        operator[4] = new JButton("4");
        operator[5] = new JButton("5");
        operator[6] = new JButton("6");
        operator[7] = new JButton("7");
        operator[8] = new JButton("8");
        operator[9] = new JButton("9");
        operator[10] = new JButton("+");
        operator[11] = new JButton("-");
        operator[12] = new JButton("*");
        operator[13] = new JButton("/");
        operator[14] = new JButton(".");
        operator[15] = new JButton("=");
        operator[16] = new JButton("AC");
        operator[17] = new JButton("C");
        operator[18] = new JButton("TAX+");
        operator[19] = new JButton("TAX-");

        gbc.gridx = 2;
        gbc.gridy = 4;
        buttonDisplay.add(operator[0], gbc); //exception starts on this line
        gbc.gridx = 3;
        gbc.gridy = 3;
        buttonDisplay.add(operator[1], gbc);
        gbc.gridx = 2;
        buttonDisplay.add(operator[2], gbc);
        gbc.gridx = 1;
        buttonDisplay.add(operator[3], gbc);
        gbc.gridx = 3;
        gbc.gridy = 2;
        buttonDisplay.add(operator[4], gbc);
        gbc.gridx = 2;
        buttonDisplay.add(operator[5], gbc);
        gbc.gridx = 1;
        buttonDisplay.add(operator[6], gbc);
        gbc.gridx = 3;
        gbc.gridy = 1;
        buttonDisplay.add(operator[7], gbc);
        gbc.gridx = 2;
        buttonDisplay.add(operator[8], gbc);
        gbc.gridx = 1;
        buttonDisplay.add(operator[9], gbc);
        gbc.gridx = 4;
        buttonDisplay.add(operator[10], gbc);
        gbc.gridy = 2;
        buttonDisplay.add(operator[11], gbc);
        gbc.gridy = 3;
        buttonDisplay.add(operator[12], gbc);
        gbc.gridy = 4;
        buttonDisplay.add(operator[13], gbc);
        gbc.gridx = 1;
        buttonDisplay.add(operator[14], gbc);
        gbc.gridx = 3;
        buttonDisplay.add(operator[15], gbc);
        gbc.gridx = 1;
        gbc.gridy = 5;
        buttonDisplay.add(operator[16], gbc);
        gbc.gridx = 2;
        buttonDisplay.add(operator[17], gbc);
        gbc.gridx = 3;
        buttonDisplay.add(operator[18], gbc);
        gbc.gridx = 4;
        buttonDisplay.add(operator[19], gbc);
        return buttonDisplay;
    }

    private JPanel createDisplay() {
        JPanel displayPanel = new JPanel();
        display = new JTextField(16);
        display.setFocusable(false);
        displayPanel.add(display);
        return displayPanel;
    }

    public static void main(String[] args) {
        Calculat calc = new Calculat();
        EventQueue.invokeLater(() -> calc.createAndDisplayGui());
    }
}

这是运行上述代码时显示的内容。

Answer 2

Jlabel不是容器，它用于放置纯文本或图像。但是我知道您需要一个可以容纳所有按钮的容器。因此，您应该使用jpanel。
这是对您有很大帮助的代码。

import java.awt.Color;
import javax.swing.JPanel;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import static javax.swing.JFrame.EXIT_ON_CLOSE;

public class Calculator extends javax.swing.JFrame {

    JFrame frame = new JFrame();
    JPanel buttonContainer = new JPanel();
    JButton operator[] = new JButton[20];
    public static void main(String args[]) {
        new Calculator();
    }

    public Calculator() {

        operator[0] = new JButton("0");
        operator[1] = new JButton("1");
        operator[2] = new JButton("2");
        operator[3] = new JButton("3");
        operator[4] = new JButton("4");
        operator[5] = new JButton("5");
        operator[6] = new JButton("6");
        operator[7] = new JButton("7");
        operator[8] = new JButton("8");
        operator[9] = new JButton("9");
        operator[10] = new JButton("+");
        operator[11] = new JButton("-");
        operator[12] = new JButton("*");
        operator[13] = new JButton("/");
        operator[14] = new JButton(".");
        operator[15] = new JButton("=");
        operator[16] = new JButton("AC");
        operator[17] = new JButton("C");
        operator[18] = new JButton("TAX+");
        operator[19] = new JButton("TAX-");

        setSize(500, 500);
        setResizable(false);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        buttonContainer.setLayout(new GridLayout(5, 4,5,5));
        buttonContainer.setBackground(Color.red);
        for (int i = 0; i < 20; i++) {
            buttonContainer.add(operator[i]);
        }
        add(buttonContainer);
        setVisible(true);
    }
}