做了好久都没做出来，请求帮忙！
编写一个将华氏温度转换为摄氏温度的程序，通过一个文本框输入华氏温度，能过一个标签输出相应的摄氏温度，公式是：摄氏温度=5/9( 华氏温度-32)
[解决办法]
提取文本框的内容，转换成数字，然后计算，呵呵。。。
[解决办法]
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Temperature extends JFrame implements ActionListener
{
JTextField text;
JLabel label;
public Temperature(String s)
{
super(s);
setBounds(100, 100, 160, 100);
Container con = getContentPane();
con.setLayout(new FlowLayout());
text = new JTextField(8);
label = new JLabel("摄氏温度: ");
text.addActionListener(this);
con.add(text);
con.add(label);
con.validate();
}
public void actionPerformed(ActionEvent e)
{
String ss = text.getText();
try
{
int a = (Integer.valueOf(ss) - 32) * 5 / 9;
label.setText("摄氏温度: " + a);
}
catch(Exception ee){label.setText("请输入整数");}
}
public static void main(String[] args)
{
Temperature t = new Temperature("温度");
t.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
t.setVisible(true);
}
}
[解决办法]
在计算公式处 楼主可以修改！
- Java code
import java.awt.FlowLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.JTextField;/** * @author bzwm * */public class ConvFahrenheit { public static void main(String[] args) { new FahrenToCentigrade(); }}class FahrenToCentigrade { private JFrame f = null; private JPanel p = null; private JLabel fl = null; private JTextField ft = null; private JLabel cl = null; private JTextField ct = null; private JButton b = null; public FahrenToCentigrade() { f = new JFrame("ConvFahrenheit"); p = new JPanel(new FlowLayout(FlowLayout.LEFT)); fl = new JLabel("ConvFahrenheit"); ft = new JTextField(5); cl = new JLabel("centigrade"); ct = new JTextField(15); ct.setEditable(false); b = new JButton("Conv"); b.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent ae) { String fahren = ft.getText(); if (fahren.matches("[+-]?\\d+(.\\d+)?")) { if (Float.parseFloat(fahren) - 32 == 0) try { throw new java.lang.ArithmeticException("/ by zero"); } catch (Exception e) { javax.swing.JOptionPane.showMessageDialog(null, "input value is illegal[/ by zero]"); e.printStackTrace(); } //计算公式 ct.setText(String.valueOf((5.0 / 9.0 * (Float.parseFloat(fahren) - 32.0)))); } else{ javax.swing.JOptionPane.showMessageDialog(null, "input value is illegal"); } } }); p.add(fl); p.add(ft); p.add(cl); p.add(ct); p.add(b); f.getContentPane().add(p, java.awt.BorderLayout.CENTER); f.setSize(300, 300); f.setLocation(100, 100); f.pack(); f.setVisible(true); }}
[解决办法]
- Java code
import java.awt.*;import java.awt.event.*;import javax.swing.*;import java.math.BigDecimal; public class Demo extends JFrame implements ActionListener{ private JLabel lab1=new JLabel("华氏温度"); private JLabel lab2=new JLabel("摄氏温度"); private JTextField t1=new JTextField(10); //用来输入并显示华氏温度 private JTextField t2=new JTextField(10); //用来显示摄氏温度 private JButton sure=new JButton("转换"); private JButton reset=new JButton("重置"); private String temStr1=null; //用来存储华氏温度的字符串 public Demo(){ t2.setEditable(false); //设为不可编辑状态 sure.addActionListener(this); //注册给本类监听器 reset.addActionListener(this); Container c = this.getContentPane(); c.setLayout(new FlowLayout(FlowLayout.CENTER,20,30)); //采用流式布局 //添加所有组件 c.add(lab1); c.add(t1); c.add(sure); c.add(lab2); c.add(t2); c.add(reset); this.setTitle("温度转换"); this.setBounds(450,100,300,200); //设置主窗口显示的位置以及大小 this.setResizable(false); //主窗口大小固定，不可改变 this.setVisible(true); //设为可见 this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //退出处理 } public void actionPerformed(ActionEvent e){ //处理事件 if(e.getSource()==sure){ //当点击“转换”按钮时 double tem1,tem2; try{ temStr1=t1.getText().trim(); //获取华氏温度的字符串 if(temStr1==null||temStr1.equals("")) throw new NumberFormatException(); //获取华氏温度的值 tem1=Double.parseDouble(temStr1); tem2=5*(tem1-32)/9; //转换为摄氏温度 //四舍五入并保留小数后的前两位 t2.setText(String.valueOf((new BigDecimal(tem2)).setScale(2,BigDecimal.ROUND_HALF_UP))); }catch(NumberFormatException nfc){ //捕捉数据转换异常 JOptionPane.showMessageDialog(this,"请输入正确的华氏温度!","转换错误",JOptionPane.WARNING_MESSAGE); t1.setText(""); return ; }catch(Exception exc){ System.exit(0); } } else if(e.getSource()==reset){ //当点击“重置”按钮时 //全部设为初始状态 temStr1=null; t1.setText(""); t2.setText(""); } } public static void main(String args[]){ Demo mainFrame = new Demo(); }}