我已经花了几天时间搜索答案,但始终找不到错误所在。我的目的是让顶部JLabel(称为 display
)右对齐,底部JLabel(称为 notice
)左对齐。然而,两者都无法实现。根据我的阅读,我的代码应该可以实现,但事实并非如此。请帮忙解决一下?
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import javax.swing.border.Border;
public class Calculator {
private static JButton clear, add, subtract, multiply, divide, equals, point, zero, one, two, three, four, five, six, seven, eight, nine;
private static JLabel display, notice, blank1, blank2, blank3;
private static JPanel mainPanel, buttonPanel, topLabel, bottomLabel;
public static void goGUI() {
JFrame frame = new JFrame("Calculator");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setPreferredSize(new Dimension(600,300));
mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
frame.setContentPane(mainPanel);
Border empty = BorderFactory.createEmptyBorder(10,10,10,10);
mainPanel.setBorder(empty);
buttonPanel = new JPanel(new GridLayout(5,4, 5,5));
Border buttonBorder = BorderFactory.createEmptyBorder(10,0,10,0);
buttonPanel.setBorder(buttonBorder);
topLabel = new JPanel();
bottomLabel = new JPanel();
clear = new JButton("C");
add = new JButton("+");
subtract = new JButton("-");
multiply = new JButton("*");
divide = new JButton("/");
equals = new JButton("=");
point = new JButton(".");
zero = new JButton("0");
one = new JButton("1");
two = new JButton("2");
three = new JButton("3");
four = new JButton("4");
five = new JButton("5");
six = new JButton("6");
seven = new JButton("7");
eight = new JButton("8");
nine = new JButton("9");
// Here I added ActionListeners to all the buttons...
display = new JLabel("0");
display.setAlignmentX(Component.RIGHT_ALIGNMENT);
notice = new JLabel("*Maximum 19 digits - Order of operations not taken into account*");
notice.setAlignmentX(Component.LEFT_ALIGNMENT);
blank1 = new JLabel();
blank2 = new JLabel();
blank3 = new JLabel();
buttonPanel.add(clear);
buttonPanel.add(blank1);
buttonPanel.add(blank2);
buttonPanel.add(blank3);
buttonPanel.add(seven);
buttonPanel.add(eight);
buttonPanel.add(nine);
buttonPanel.add(divide);
buttonPanel.add(four);
buttonPanel.add(five);
buttonPanel.add(six);
buttonPanel.add(multiply);
buttonPanel.add(one);
buttonPanel.add(two);
buttonPanel.add(three);
buttonPanel.add(subtract);
buttonPanel.add(zero);
buttonPanel.add(point);
buttonPanel.add(equals);
buttonPanel.add(add);
topLabel.add(display);
bottomLabel.add(notice);
mainPanel.add(topLabel);
mainPanel.add(buttonPanel);
mainPanel.add(bottomLabel);
frame.pack();
frame.setVisible(true);
} //end goGUI
//ActionListener classes went here...
public static void main(String[] args) {
try {
// Set cross-platform Java L&F (also called "Metal")
UIManager.setLookAndFeel(
UIManager.getCrossPlatformLookAndFeelClassName());
}
catch (Exception e) {}
goGUI();
} //end main
} //end Calculator
为了更清晰地表达,我删除了所有ActionListener相关的内容。但是这是我无法解决的布局问题。
topLabel.add(display, BorderLayout.EAST);
和display.setHorizontalAlignment(SwingConstants.RIGHT);
之间有什么区别吗?在这种情况下,它们得到的结果是相同的。+1 如果解决方案有效! - alain.janinm