Java Swing实现计算器功能

爱被打了一巴掌 2023-06-30 15:57 21阅读 0赞

***学习Java Swing实现计算器功能，本文实现该系统的功能截图，和核心代码大家参考***

## Java Swing实现计算器功能 ##

**计算器支持混合四则运算**  
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## 核心代码 ##

/* 监听运算符包括点 */
    	private class CalculatorListener implements ActionListener { 
    
    		JTextField display;
    		JButton str;
    
    		CalculatorListener(JTextField display, JButton str) { 
    
    			this.display = display;
    			this.str = str;
    		}
    
    		public void actionPerformed(ActionEvent e) { 
    
    			StringBuffer s = new StringBuffer(display.getText());
    			if (flag) { 
    				display.setText("0");
    				flag = false;
    			} else if (!(s.length() == 0)) { 
    
    				if (!((display.getText().endsWith("+")) || (display.getText().endsWith("-"))
    						|| (display.getText().endsWith("X")) || (display.getText().endsWith("/")))) { 
    					// 当为无穷和非数字型，清空
    					if (display.getText().indexOf("Infinity") != -1 || display.getText().indexOf("NaN") != -1) { 
    
    						display.setText("0");
    						// 判断前面的数是不是小数，以决定要不要在它后面加小数点
    					} else if (str.getText() == "." && Character.isDigit(s.charAt(s.length() - 1))) { 
    						int lastIndex = -1;
    						Stack<String> stack = new Stack<String>();
    						for (int i = 0; i < s.length(); i++) { 
    							lastIndex = new CalculatorImpl().readDouble(display.getText(), i);
    							stack.push(display.getText().substring(i, lastIndex));
    							i = lastIndex;
    						}
    						String last = stack.pop();
    
    						if (last.indexOf(".") == -1) { 
    							s.append(str.getText());
    							display.setText(s.toString());
    						}
    						// 普通情况
    					} else if (!display.getText().endsWith(".")) { 
    						s.append(str.getText());
    						display.setText(s.toString());
    					}
    					// 当前面是符号时，自动填零
    				} else if (str.getText() == "." && (s.charAt(s.length() - 1) == '+' || s.charAt(s.length() - 1) == '-'
    						|| s.charAt(s.length() - 1) == 'X' || s.charAt(s.length() - 1) == '/')) { 
    					s.append("0.");
    					display.setText(s.toString());
    
    				}
    				// 为空时，按点填零
    			} else if (s.length() == 0 && str.getText() == ".") { 
    				s.append("0.");
    				display.setText(s.toString());
    			}
    		}
    
    	}

/* 转换逆波兰式 */
    	public double toReversePolishNotation(String s) throws NumberFormatException { 
    
    		Stack<Character> s1 = new Stack<Character>();//
    		Stack<Double> s2 = new Stack<Double>();
    		int lastIndex = -1;
    		char temp;
    		String num;
    
    		for (int i = 0; i < s.length(); i++) { 
    			System.out.println("第" + i + "趟");
    			temp = s.charAt(i);
    			// 判断是否为操作数，如果是，就截取操作数
    			if (Character.isDigit(temp) || temp == '.' || temp == '-') { 
    				// 对出现的前面的负号进行处理
    				if (temp == '-') { 
    					lastIndex = readDouble(s, i + 1);
    					num = s.substring(i, lastIndex);
    					System.out.println("截取字符串" + num);
    					s2.push(Double.parseDouble(num));
    					System.out.println("s2 入栈" + s2.peek());
    					System.out.println("s1 入栈 --> +");
    					s1.push('+');
    				} else { 
    					lastIndex = readDouble(s, i);
    					num = s.substring(i, lastIndex);
    					System.out.println("截取字符串" + num);
    					s2.push(Double.parseDouble(num));
    					System.out.println("s2 入栈" + s2.peek());
    				}
    				i = lastIndex - 1;
    				System.out.println("当前i" + i);
    			} else { 
    				// 乘除时，直接做运算
    				if (temp == 'X' || temp == '/') { 
    					System.out.println("s2出栈:-->" + s2.peek());
    					double num1 = s2.pop();
    					lastIndex = readDouble(s, i + 1);
    					double num2 = Double.parseDouble(s.substring(i + 1, lastIndex));
    					System.out.println("操作数:" + num2);
    
    					i = lastIndex - 1;
    					System.out.println("当前i" + i);
    					double result = calculate(num1, temp, num2);
    					System.out.println("num1" + temp + " num2 =" + result);
    					System.out.println("result 入栈 s2" + result);
    					s2.push(result);
    					// 当为加减时，让他直接入栈，等待操作
    				} else if (temp == '+' || temp == '-') { 
    					System.out.println("s1 入栈" + temp);
    					s1.push(temp);
    				}
    			}
    
    		}
    		// 对剩下的加减运算，得出最终结果
    		while (!s1.isEmpty() && !s2.isEmpty() && s2.size() >= 2) { 
    
    			System.out.println("s2 出栈:" + s2.peek());
    			double num2 = s2.pop();
    			System.out.println("s2 出栈:" + s2.peek());
    			double num1 = s2.pop();
    			System.out.println("s1 出栈:" + s1.peek());
    			double result = calculate(num1, s1.pop(), num2);
    			System.out.println("计算结果为: " + result);
    			s2.push(result);
    		}
    
    		return s2.pop();
    	}

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