当我使用按钮调用任何操作时，ActionListener将无法接收代码时出现问题。我以前做过这个，但这是我第一次尝试GridBagLayout并且它似乎没有正常工作。 GUI功能齐全。我该怎么做让ActionListener起作用？这是整个班级。
package body;
import java.awt.ComponentOrientation;
import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class mainFrame extends JFrame implements ActionListener{
final static boolean shouldFill = true;
final static boolean shouldWeightX = true;
final static boolean RIGHT_TO_LEFT = false;
static String string = "default";
static JButton one, two, three, four, five, six, seven, eight, nine, zero;
static JButton plus, minus, multiply, divide, equals;
public void init() {
one.setActionCommand("one");
one.addActionListener(this);
two.setActionCommand("two");
two.addActionListener(this);
three.setActionCommand("three");
three.addActionListener(this);
four.setActionCommand("four");
four.addActionListener(this);
five.setActionCommand("five");
five.addActionListener(this);
six.setActionCommand("six");
six.addActionListener(this);
seven.setActionCommand("seven");
seven.addActionListener(this);
eight.setActionCommand("eight");
eight.addActionListener(this);
nine.setActionCommand("nine");
nine.addActionListener(this);
zero.setActionCommand("zero");
zero.addActionListener(this);
plus.setActionCommand("plus");
plus.addActionListener(this);
minus.setActionCommand("minus");
minus.addActionListener(this);
multiply.setActionCommand("multiply");
multiply.addActionListener(this);
divide.setActionCommand("divide");
divide.addActionListener(this);
equals.setActionCommand("equals");
equals.addActionListener(this);
}
public static void addComponentsToPane(Container pane) {
if (RIGHT_TO_LEFT) {
pane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
}
pane.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
if (shouldFill) {
c.fill = GridBagConstraints.HORIZONTAL;
}
if (shouldWeightX) {
c.weightx = 0.5;
}
JLabel display = new JLabel(string);
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 0;
c.gridy = 0;
pane.add(display, c);
one = new JButton("1");
c.weightx = 0.5;
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 1;
pane.add(one, c);
two = new JButton("2");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 1;
c.gridy = 1;
pane.add(two, c);
three = new JButton("3");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 2;
c.gridy = 1;
pane.add(three, c);
plus = new JButton("+");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 3;
c.gridy = 1;
pane.add(plus, c);
four = new JButton("4");
c.weightx = 0.5;
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 2;
pane.add(four, c);
five = new JButton("5");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 1;
c.gridy = 2;
pane.add(five, c);
six = new JButton("6");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 2;
c.gridy = 2;
pane.add(six, c);
minus = new JButton("-");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 3;
c.gridy = 2;
pane.add(minus, c);
seven = new JButton("7");
c.weightx = 0.5;
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 3;
pane.add(seven, c);
eight = new JButton("8");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 1;
c.gridy = 3;
pane.add(eight, c);
nine = new JButton("9");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 2;
c.gridy = 3;
pane.add(nine, c);
multiply = new JButton("*");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 3;
c.gridy = 3;
pane.add(multiply, c);
zero = new JButton("0");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 0;
c.gridy = 4;
pane.add(zero, c);
equals = new JButton("Equals");
c.fill = GridBagConstraints.HORIZONTAL;
c.weighty = 1.0;
c.gridx = 1;
c.gridwidth = 2;
c.gridy = 4;
pane.add(equals, c);
divide = new JButton("/");
c.fill = GridBagConstraints.HORIZONTAL;
c.anchor = GridBagConstraints.PAGE_END;
c.weightx = 0.5;
c.gridx = 3;
c.gridy = 4;
pane.add(divide, c);
}
private static void createAndShowGUI() {
JFrame frame = new JFrame("Calculator");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
addComponentsToPane(frame.getContentPane());
frame.pack();
frame.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand() == "one") {
System.out.println("hello");
}
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
答案 0 :(得分：1)
除了我指出的==和equals之外，您永远不会调用init()来初始化您的操作命令。
另请注意，您的课程已经是JFrame。使用类JFrame或使用实例JFrame。
您应该解决上述问题，以便正确调用init()方法。
试试这个
private static void createAndShowGUI() {
mainFrame frame = new mainFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
addComponentsToPane(frame.getContentPane());
frame.init(); <<<<<================== Don't forget about meeeee!
frame.pack();
frame.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent e) {
if ("one".equals(e.getActionCommand())) {
System.out.println("hello");
}
}
此外，您应该遵循Java命名约定。班级名称以大写字母开头。所以mainFrame→MainFrame