展开全部
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Main extends JFrame implements ActionListener{
LabledText upperBase = new LabledText("上底："),
62616964757a686964616fe59b9ee7ad9431333337373561lowerBase = new LabledText("下底："),
height = new LabledText("高：");
JButton getArea = new JButton("求梯形面积");
JTextArearesult = new JTextArea();
public Main() {
super("梯形");
JPanel main = new JPanel();
main.setLayout(new BorderLayout(10, 10));
JPanel top = new JPanel(),
base = new JPanel();
top.setLayout(new GridLayout(2, 2));
top.add(upperBase);
top.add(lowerBase);
top.add(height);
getArea.addActionListener(this);
top.add(getArea);
main.add(top, BorderLayout.NORTH);
result.setBorder(BorderFactory.createLoweredBevelBorder());
JScrollPane scroll = new JScrollPane(result);
scroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
scroll.setPreferredSize(new Dimension(200, 100));
base.add(scroll);
main.add(base, BorderLayout.CENTER);
main.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
this.add(main);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setResizable(false);
this.pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
}
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
try {
Trapezoid trapezoid = new Trapezoid(upperBase.getValue(), lowerBase.getValue(), height.getValue());
result.setText("梯形面积为： " + String.valueOf(trapezoid.getArea()));
} catch (Exception e) {
result.setText(e.toString());
}
}
class LabledText extends JPanel {
JTextField text = new JTextField();
JLabellabel;
public LabledText(String nm) {
this.setLayout(new BorderLayout());
label = new JLabel(nm);
label.setPreferredSize(new Dimension(40, 30));
label.setHorizontalAlignment(JLabel.RIGHT);
this.add(label, BorderLayout.WEST);
text.setPreferredSize(new Dimension(60, 30));
this.add(text, BorderLayout.EAST);
this.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
}
public double getValue() throws Exception{
double retval = Double.parseDouble(text.getText());
if(retval
throw new Exception("长度不能为负数");
return retval;
}
}
public static void main(String[] args) {
new Main();
}
}
class Trapezoid {
private double upperBase, lowerBase, height;
public Trapezoid() {}
public Trapezoid(double upperBase, double lowerBase, double height) {
this.setUpperBase(upperBase);
this.setLowerBase(lowerBase);
this.setHeight(height);
}
public double getUpperBase() {
return upperBase;
}
public void setUpperBase(double upperBase) {
this.upperBase = upperBase;
}
public double getLowerBase() {
return lowerBase;
}
public void setLowerBase(double lowerBase) {
this.lowerBase = lowerBase;
}
public double getHeight() {
return height;
}
public void setHeight(double height) {
this.height = height;
}
public double getArea() {
return (upperBase + lowerBase) * height / 2;
}
}
