我刚用Java制作GUI计算器并且我一直在使用eclipse，事情是我没有得到任何语法错误但是当我编译时我得到了一些编译错误，我无法和＃39;弄清楚原因。这些是我收到的错误。
Exception in thread "main" java.lang.IllegalArgumentException: cannot add to layout: constraints must be a GridBagConstraint
at java.awt.GridBagLayout.addLayoutComponent(Unknown Source)
at java.awt.Container.addImpl(Unknown Source)
at java.awt.Container.add(Unknown Source)
at javax.swing.JFrame.addImpl(Unknown Source)
at java.awt.Container.add(Unknown Source)
at Calculator1.<init>(Calculator1.java:81)
at Calculator1.main(Calculator1.java:178)
这是我的源代码：
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Calculator1 extends JFrame{
JButton add, subtract, multiply, division; //These are going to be all the buttons
JTextField num1, num2; //All the fields I need
JLabel result, enter1, enter2; //The labels
public Calculator1(){ //Starting of constructor class
setLayout(new GridBagLayout()); //Declaring I'm going to be using the GridBagLayout
GridBagConstraints c = new GridBagConstraints(); //Making a GridBagLayout Object
enter1 = new JLabel("1st :"); //New JLabel with 1st being put into enter1
c.fill = GridBagConstraints.HORIZONTAL; //Will set the size
c.gridx = 0; //Position x
c.gridy = 0; //Position y
add(enter1, c); //Add options to our object c
num1 = new JTextField(10); //How big can user enter a value upto
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 1;
c.gridy = 0;
c.gridwidth = 3;
add(num1, c);
enter2 = new JLabel("2nd :");
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 1;
c.gridheight = 1;
add(enter2, c);
num2 = new JTextField(10);
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 1;
c.gridy = 1;
c.gridwidth = 3;
add(num2, c);
add = new JButton("+");
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 2;
c.gridwidth = 1;
add(add, c);
subtract = new JButton("-");
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 1;
c.gridy = 2;
c.gridwidth = 1;
add(subtract, c);
multiply = new JButton("*");
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 2;
c.gridy = 2;
c.gridwidth = 1;
add(multiply, c);
division = new JButton("/");
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 3;
c.gridy = 2;
c.gridwidth = 1;
add(division, c);
result = new JLabel("");
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 4;
c.gridwidth = 4;
add(result, add);
event a = new event();
add.addActionListener(a); //If user clicks add on the button, it should load the adding function from event class
subtract.addActionListener(a);
multiply.addActionListener(a);
division.addActionListener(a);
}
public class event implements ActionListener{
public void actionPerformed(ActionEvent a) { //This will be used to do what the user wants
double number1, number2;
try{
number1 = Double.parseDouble(num1.getText()); //This will convert num1 into a double
} catch(NumberFormatException e){ //If user enters a value that's not a double such as a String, it will display this message
result.setText("Illegal Data for first field");
result.setForeground(Color.red);
return;
}
try{
number2 = Double.parseDouble(num2.getText());
} catch(NumberFormatException e){
result.setText("Illegal Data for second field");
result.setForeground(Color.red);
return;
}
String op = a.getActionCommand(); //Put whatever the user clicks into op, op is just a name
if(op.equals("+")){
double sum = number1 + number2;
result.setText(number1 + "+" + number2 + "=" + sum);
result.setForeground(Color.red);
}
else if(op.equals("-")){
double diff = number1-number2;
result.setText(number1 + "-" + number2 + "=" + diff);
result.setForeground(Color.red);
}
else if(op.equals("*")){
double times = number1*number2;
result.setText(number1 + "*" + number2 + "=" + times);
result.setForeground(Color.red);
}
else if(op.equals("/")){
if(number2 == 0){
result.setText("Cannot divide by 0 you dumb shit");
result.setForeground(Color.red);
}
else{
double divide = number1/number2;
result.setText(number1 + "/" + number2 + "=" + divide);
result.setForeground(Color.red);
}
}
}
}
public static void main(String args[]){
Calculator1 Gui = new Calculator1(); //Creating our calculator Object
Gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Gui.setVisible(true);
Gui.setSize(250, 175);
Gui.setTitle("My Java calculator");
}
}
答案 0 :(得分：1)
错误是运行时而不是编译错误 - 变量add是Swing组件而不是预期的布局管理器约束。添加result组件
add(result, c);