1.首先思考壹下制作計算器需要哪些Swing組件，下面列出壹些制作計算器的壹些常用組件：
JFrame Jpanel JButton JTextField
2.選用布局管理器：
這裏采用的是GridBagLayout，即網格包布局管理器。
3.如何處理按鈕事件：
這裏可以分兩種情況來考慮，壹：處理0~9的數字按鈕和"."按鈕，這種按鈕的單擊事件很簡單，只需要獲取監聽的對象，並在文本框中顯示對象的數據即可。
二：處理操作按鈕即文本為+，-，*，/，C（清除），D（刪除）和=的按鈕，這些按鈕的事件處理稍微復雜。
4.具體實現代碼如下：
1.創建Calculator類，該類繼承自JFrame類
[java]?view plain?copy
import?java.awt.BorderLayout;?
import?java.awt.GridBagConstraints;?
import?java.awt.GridBagLayout;?
import?java.awt.event.ActionEvent;?
import?java.awt.event.ActionListener;?
import?javax.swing.JButton;?
import?javax.swing.JFrame;?
import?javax.swing.JOptionPane;?
import?javax.swing.JPanel;?
import?javax.swing.JTextField;?
public?class?Calculator?extends?JFrame?{?
private?static?final?long?serialVersionUID?=?1L;?
private?JTextField?jtf=new?JTextField();?
private?JPanel?panel=new?JPanel();?
private?GridBagLayout?gridbaglayout=new?GridBagLayout();?
private?GridBagConstraints?constraints=new?GridBagConstraints();?
private?int?select=0;?
//private?String?command="";?
private?double?temp=0.0;?
private?double?number;?
public?Calculator(){//創建Calculator類的構造方法?
this.setTitle("計算器");?
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);?
this.add(jtf,BorderLayout.NORTH);?
this.add(panel,?BorderLayout.CENTER);?
panel.setLayout(gridbaglayout);//將panel面板設置成網格包布局管理器?
this.add(panel);?
jtf.setHorizontalAlignment(JTextField.RIGHT);?//文本靠右
ActionListener?nums=new?CalculatorAction1();?
ActionListener?opin=new?CalculatorAction2();?
constraints.fill=GridBagConstraints.BOTH;?
//?constraints.weightx=0.1;?
//?constraints.weighty=0.1;?
constraints.gridheight=GridBagConstraints.REMAINDER;?
addButton("",nums);?
constraints.gridheight=1;?
addButton("C",opin);?
addButton("7",nums);?
addButton("4",nums);?
addButton("1",nums);?
constraints.gridheight=GridBagConstraints.REMAINDER;?
addButton("%",nums);?
constraints.gridheight=1;?
addButton("D",opin);?
addButton("8",nums);?
addButton("5",nums);?
addButton("2",nums);?
constraints.gridheight=GridBagConstraints.REMAINDER;?
addButton("0",nums);?
constraints.gridheight=1;?
addButton("/",opin);?
addButton("9",nums);?
addButton("6",nums);?
addButton("3",nums);?
constraints.gridheight=GridBagConstraints.REMAINDER;?
addButton(".",nums);?
constraints.gridheight=1;?
addButton("*",opin);?
addButton("-",opin);?
addButton("+",opin);?
constraints.gridheight=GridBagConstraints.REMAINDER;?
addButton("=",opin);?
}?
private?void?addButton(String?str,ActionListener?list){?//添加按鈕方法?
JButton?button=new?JButton(str);?
if(str.equals("")||str.equals("%")){?
button.setEnabled(false);?
}?
button.addActionListener(list);?//向按鈕添加事件?
gridbaglayout.setConstraints(button,?constraints);?
panel.add(button);//將按鈕添加到JPanel容器中
}?
class?CalculatorAction1?implements?ActionListener{//創建內部類並實現ActionListener接口，實現數字按鈕的監聽事件?
public?void?actionPerformed(ActionEvent?e){?
String?input?=?e.getActionCommand();?
//?System.out.println(input);?
jtf.setText(jtf.getText()+input);//在文本中顯示用戶單擊的按鈕文本內容?
}?
}?
class?CalculatorAction2?implements?ActionListener{?//創建內部類並實現ActionListener接口，實現操作按鈕的監聽事件?
public?void?actionPerformed(ActionEvent?e){?
String?command=e.getActionCommand();?
if(command.equals("+")){?
temp=Double.parseDouble(jtf.getText());?
jtf.setText("");?
select=1;?
}?
if(command.equals("-")){?
temp=Double.parseDouble(jtf.getText());?
jtf.setText("");?
select=2;?
}?
if(command.equals("*")){?
temp=Double.parseDouble(jtf.getText());?
jtf.setText("");?
select=3;?
}?
if(command.equals("/")){?
temp=Double.parseDouble(jtf.getText());?
jtf.setText("");?
select=4;?
}?
if(command.equals("C")){?
jtf.setText("");?
}?
if(command.equals("D")){?
jtf.setText(jtf.getText().substring(0,?jtf.getText().length()-1));?
}?
if(command.equals("=")){?
if(select==1){?
number=Double.parseDouble(jtf.getText());?
jtf.setText((temp+number)+"");?
}?
else?if(select==2){?
number=Double.parseDouble(jtf.getText());?
jtf.setText((temp-number)+"");?
}?
else?if(select==3){?
number=Double.parseDouble(jtf.getText());?
jtf.setText((temp*number)+"");?
}?
else?if(select==4){?
number=Double.parseDouble(jtf.getText());?
if(number==0){?
JOptionPane.showMessageDialog(panel,?"除數不能為0");?
}?
else?
jtf.setText((temp/number)+"");?
}?
}?
}?
}?
}?
2.創建CalculatorTest類
[java]?view plain?copy
public?class?CalculatorTest?{?
public?static?void?main(String[]?args)?{?
Calculator?mainFrame=new?Calculator();?
mainFrame.setBounds(300,?200,?200,?200);?
mainFrame.setVisible(true);?
mainFrame.setResizable(false);?
}?
}?
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