关于JTextField 小弟想做一个计算器,但不知道如何获取JTextField里输入的数。比如说,一个加法,当输入完毕按确定后点确定,在编程时的问题在于如何编写事件处理,我怎么才能得到JTextField中的数呢?谢过! 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 Float.parseFloat(jTextField.getText())//取到浮点型其它类似 计算器完整代码:import java.awt.*;import java.awt.event.*;import javax.swing.*;class CalculatorPanel extends JPanel implements ActionListener{ public CalculatorPanel() { setLayout(new BorderLayout()); display = new JTextField("0"); display.setEditable(false); add(display, "North"); JPanel p = new JPanel(); p.setLayout(new GridLayout(4, 4)); String buttons = "789/456*123-0.=+"; for (int i = 0; i < buttons.length(); i++) addButton(p, buttons.substring(i, i + 1)); add(p, "Center"); } private void addButton(Container c, String s) { JButton b = new JButton(s); c.add(b); b.addActionListener(this); } public void actionPerformed(ActionEvent evt) { String s = evt.getActionCommand(); if ('0' <= s.charAt(0) && s.charAt(0) <= '9' || s.equals(".")) { if (start) display.setText(s); else display.setText(display.getText() + s); start = false; } else { if (start) { if (s.equals("-")) { display.setText(s); start = false; } else op = s; } else { double x = Double.parseDouble(display.getText()); calculate(x); op = s; start = true; } } } public void calculate(double n) { if (op.equals("+")) arg += n; else if (op.equals("-")) arg -= n; else if (op.equals("*")) arg *= n; else if (op.equals("/")) arg /= n; else if (op.equals("=")) arg = n; display.setText("" + arg); } private JTextField display; private double arg = 0; private String op = "="; private boolean start = true;}class CalculatorFrame extends JFrame{ public CalculatorFrame() { setTitle("Calculator"); setSize(200, 200); addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } } ); Container contentPane = getContentPane(); contentPane.add(new CalculatorPanel()); }}public class Calculator{ public static void main(String[] args) { JFrame frame = new CalculatorFrame(); frame.show(); }} 在java里写了个往oracle里插值的代码,但是执行不成功? 文字编码问题 SCJP 6.0認證教戰手冊考題.97--finalize() 有去传智播客的7月11号基础班加我,团报三人省500块钱。516247613 十进制的数转换为十六进制 初学者救助 没分了,大家帮帮忙,谢谢了! 什么是事务传播行为 本人的小程序,在刷新上有些问题,请各位大虾帮忙看一下,谢谢! 参数传递的问题!(大家讨论讨论) 如何替换字符串abc"abf1"feet"123"中“”内的内容? 为什么这样会字符串不匹配??
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;class CalculatorPanel extends JPanel implements ActionListener
{ public CalculatorPanel()
{ setLayout(new BorderLayout());
display = new JTextField("0");
display.setEditable(false);
add(display, "North");
JPanel p = new JPanel();
p.setLayout(new GridLayout(4, 4));
String buttons = "789/456*123-0.=+";
for (int i = 0; i < buttons.length(); i++)
addButton(p, buttons.substring(i, i + 1));
add(p, "Center");
} private void addButton(Container c, String s)
{ JButton b = new JButton(s);
c.add(b);
b.addActionListener(this);
}
public void actionPerformed(ActionEvent evt)
{ String s = evt.getActionCommand();
if ('0' <= s.charAt(0) && s.charAt(0) <= '9'
|| s.equals("."))
{ if (start) display.setText(s);
else display.setText(display.getText() + s);
start = false;
}
else
{ if (start)
{ if (s.equals("-"))
{ display.setText(s); start = false; }
else op = s;
}
else
{ double x =
Double.parseDouble(display.getText());
calculate(x);
op = s;
start = true;
}
}
}
public void calculate(double n)
{ if (op.equals("+")) arg += n;
else if (op.equals("-")) arg -= n;
else if (op.equals("*")) arg *= n;
else if (op.equals("/")) arg /= n;
else if (op.equals("=")) arg = n;
display.setText("" + arg);
}
private JTextField display;
private double arg = 0;
private String op = "=";
private boolean start = true;
}class CalculatorFrame extends JFrame
{ public CalculatorFrame()
{ setTitle("Calculator");
setSize(200, 200);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
} ); Container contentPane = getContentPane();
contentPane.add(new CalculatorPanel());
}
}public class Calculator
{ public static void main(String[] args)
{ JFrame frame = new CalculatorFrame();
frame.show();
}
}