import java.awt.*;
import java.awt.event.*;
public class Test {
public static void main(String[] args) {
new TM("简易计算器");
}
}
class TM extends Frame {
public TM(String s) {
super(s);
TextField tf1 =new TextField(10);
Panel p1 = new Panel();
Panel p11 = new Panel(new BorderLayout());
Panel p2 = new Panel();
TextField tf2 = new TextField(10);
TextField tf3 = new TextField(20);
Button b = new Button("=");
Button a1 = new Button("+");
Button a2 = new Button("-");
Button a3 = new Button("*");
Button a4 = new Button("/");
setLayout(new GridLayout(2,1));
TextField tf4 = new TextField(15);
p11.add(a1,BorderLayout.NORTH);
p11.add(a2,BorderLayout.SOUTH);
p11.add(a3,BorderLayout.WEST);
p11.add(a4,BorderLayout.EAST);
p1.add(tf1);
p1.add(p11);
p1.add(tf2);
p1.add(b);
p1.add(tf3);
p2.add(tf4);
add(p1);
add(p2);
setVisible(true);
b.addActionListener(new Monitor(tf1,tf2,tf3,tf4));
a1.addActionListener(new Monitor1(tf4));
a2.addActionListener(new Monitor1(tf4));
a3.addActionListener(new Monitor1(tf4));
a4.addActionListener(new Monitor1(tf4));
tf4.setVisible(false);
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
setVisible(false);
System.exit(0);
}
});
}
}
class Monitor implements ActionListener {
TextField tf1,tf2,tf3,tf4;
public Monitor(TextField tf1,TextField tf2,TextField tf3,TextField tf4) {
this.tf1 = tf1;
this.tf2 = tf2;
this.tf3 = tf3;
this.tf4 = tf4;
}
public void actionPerformed(ActionEvent e) {
double n1 = Double.parseDouble(tf1.getText());
double n2 = Double.parseDouble(tf2.getText());
String s = tf1.getText();
for(int i = 0; i<s.length; i++) {
char c = s.charAt(i);
if(c>='a' && c<='z') {
tf3.setText("" +"输入出错");
}
else if(c>='A' && C<='Z') {
tf3.setText("" +"输入出错");
}
}
if(tf4.getText().equals("+")) {
tf3.setText("" +(n1+n2));
}
if(tf4.getText().equals("-")) {
tf3.setText("" +(n1-n2));
}
if(tf4.getText().equals("*")) {
tf3.setText("" +(n1*n2));
}
if(tf4.getText().equals("/")) {
tf3.setText("" +(n1/n2));
}
}
}
class Monitor1 implements ActionListener {
TextField tf4;
public Monitor1(TextField tf4) {
this.tf4 = tf4;
}
public void actionPerformed(ActionEvent e) {
tf4.setText(e.getActionCommand());
}
}
import java.awt.event.*;
public class Test {
public static void main(String[] args) {
new TM("简易计算器");
}
}
class TM extends Frame {
public TM(String s) {
super(s);
TextField tf1 =new TextField(10);
Panel p1 = new Panel();
Panel p11 = new Panel(new BorderLayout());
Panel p2 = new Panel();
TextField tf2 = new TextField(10);
TextField tf3 = new TextField(20);
Button b = new Button("=");
Button a1 = new Button("+");
Button a2 = new Button("-");
Button a3 = new Button("*");
Button a4 = new Button("/");
setLayout(new GridLayout(2,1));
TextField tf4 = new TextField(15);
p11.add(a1,BorderLayout.NORTH);
p11.add(a2,BorderLayout.SOUTH);
p11.add(a3,BorderLayout.WEST);
p11.add(a4,BorderLayout.EAST);
p1.add(tf1);
p1.add(p11);
p1.add(tf2);
p1.add(b);
p1.add(tf3);
p2.add(tf4);
add(p1);
add(p2);
setVisible(true);
b.addActionListener(new Monitor(tf1,tf2,tf3,tf4));
a1.addActionListener(new Monitor1(tf4));
a2.addActionListener(new Monitor1(tf4));
a3.addActionListener(new Monitor1(tf4));
a4.addActionListener(new Monitor1(tf4));
tf4.setVisible(false);
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
setVisible(false);
System.exit(0);
}
});
}
}
class Monitor implements ActionListener {
TextField tf1,tf2,tf3,tf4;
public Monitor(TextField tf1,TextField tf2,TextField tf3,TextField tf4) {
this.tf1 = tf1;
this.tf2 = tf2;
this.tf3 = tf3;
this.tf4 = tf4;
}
public void actionPerformed(ActionEvent e) {
double n1 = Double.parseDouble(tf1.getText());
double n2 = Double.parseDouble(tf2.getText());
String s = tf1.getText();
for(int i = 0; i<s.length; i++) {
char c = s.charAt(i);
if(c>='a' && c<='z') {
tf3.setText("" +"输入出错");
}
else if(c>='A' && C<='Z') {
tf3.setText("" +"输入出错");
}
}
if(tf4.getText().equals("+")) {
tf3.setText("" +(n1+n2));
}
if(tf4.getText().equals("-")) {
tf3.setText("" +(n1-n2));
}
if(tf4.getText().equals("*")) {
tf3.setText("" +(n1*n2));
}
if(tf4.getText().equals("/")) {
tf3.setText("" +(n1/n2));
}
}
}
class Monitor1 implements ActionListener {
TextField tf4;
public Monitor1(TextField tf4) {
this.tf4 = tf4;
}
public void actionPerformed(ActionEvent e) {
tf4.setText(e.getActionCommand());
}
}
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public void actionPerformed(ActionEvent e) {
double n1 = Double.parseDouble(tf1.getText());//在这里已经出现异常,不会继续下面的判断
double n2 = Double.parseDouble(tf2.getText());
String s = tf1.getText();
for(int i = 0; i<s.length; i++) {
char c = s.charAt(i);
if(c>='a' && c<='z') {
tf3.setText("" +"输入出错");
}
else if(c>='A' && C<='Z') {
tf3.setText("" +"输入出错");
}改为double n1 = 0;
double n2 = 0;
try{
n1 = Double.parseDouble(tf1.getText());
}
catch(Exception e1){
}
try{
n2 = Double.parseDouble(tf2.getText());
}
catch(Exception e1){
}
但还是不行啊,不信你改成你的运行试下
我用你的代码运行结果:如果前面框输入了含有字母,后面第三个输入框结果就不是预期的“输入出错”,而是其他不可预期的结果。
还望大哥帮人帮到底,小弟在此先只有诚挚的谢意了。
import java.awt.*;
import java.awt.event.*;public class Test {
public static void main(String[] args) {
new TM("简易计算器");
}
}class TM extends Frame {
public TM(String s) {
super(s);
TextField tf1 = new TextField(10);
Panel p1 = new Panel();
Panel p11 = new Panel(new BorderLayout());
Panel p2 = new Panel();
TextField tf2 = new TextField(10);
TextField tf3 = new TextField(20);
Button b = new Button("=");
Button a1 = new Button("+");
Button a2 = new Button("-");
Button a3 = new Button("*");
Button a4 = new Button("/");
setLayout(new GridLayout(2, 1));
TextField tf4 = new TextField(15);
p11.add(a1, BorderLayout.NORTH);
p11.add(a2, BorderLayout.SOUTH);
p11.add(a3, BorderLayout.WEST);
p11.add(a4, BorderLayout.EAST);
p1.add(tf1);
p1.add(p11);
p1.add(tf2);
p1.add(b);
p1.add(tf3);
p2.add(tf4);
add(p1);
add(p2);
setVisible(true);
b.addActionListener(new Monitor(tf1, tf2, tf3, tf4));
a1.addActionListener(new Monitor1(tf4));
a2.addActionListener(new Monitor1(tf4));
a3.addActionListener(new Monitor1(tf4));
a4.addActionListener(new Monitor1(tf4));
tf4.setVisible(false);
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
setVisible(false);
System.exit(0);
}
}); }
}class Monitor implements ActionListener {
TextField tf1, tf2, tf3, tf4; public Monitor(TextField tf1, TextField tf2, TextField tf3, TextField tf4) {
this.tf1 = tf1;
this.tf2 = tf2;
this.tf3 = tf3;
this.tf4 = tf4; } public void actionPerformed(ActionEvent e) {
double n1 = 0;
try {
n1 = Double.parseDouble(tf1.getText());
} catch (Exception e1) { }
double n2 = 0;
try {
n2 = Double.parseDouble(tf2.getText());
} catch (Exception e1) { }
String s = tf1.getText();
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if (c >= 'a' && c <= 'z') {
tf3.setText("" + "输入出错");
return;
} else if (c >= 'A' && c <= 'Z') {
tf3.setText("" + "输入出错");
return;
}
} if (tf4.getText().equals("+")) {
tf3.setText("" + (n1 + n2));
}
if (tf4.getText().equals("-")) {
tf3.setText("" + (n1 - n2));
}
if (tf4.getText().equals("*")) {
tf3.setText("" + (n1 * n2));
}
if (tf4.getText().equals("/")) {
tf3.setText("" + (n1 / n2));
} }
}class Monitor1 implements ActionListener {
TextField tf4; public Monitor1(TextField tf4) {
this.tf4 = tf4;
} public void actionPerformed(ActionEvent e) {
tf4.setText(e.getActionCommand()); }
}
你真是一个好人,我没有什么可以回报的,只有奉上分数和我诚挚的谢意,希望你能听见