Java编写一个SWT用户界面，实现一个科学计算器，写粗完整代码

很高兴接受您的挑战！以下是一个简单的Java程序，使用SWT库创建了一个基本的科学计算器UI。请注意，此代码可能不够完整或优化，仅供参考。

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import java.math.*;

public class Calculator {
   public static void main(String[] args) {
      Display display = new Display();
      Shell shell = new Shell(display);
      shell.setText("科学计算器");
      shell.setLayout(new GridLayout(4, false));

      //创建UI控件
      Text input = new Text(shell, SWT.BORDER | SWT.RIGHT);
      input.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false, 4, 1));
      Label output = new Label(shell, SWT.NONE);
      output.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false, 4, 1));
      Button btn1 = new Button(shell, SWT.PUSH);
      btn1.setText("1");
      btn1.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btn2 = new Button(shell, SWT.PUSH);
      btn2.setText("2");
      btn2.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btn3 = new Button(shell, SWT.PUSH);
      btn3.setText("3");
      btn3.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btnAdd = new Button(shell, SWT.PUSH);
      btnAdd.setText("+");
      btnAdd.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btn4 = new Button(shell, SWT.PUSH);
      btn4.setText("4");
      btn4.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btn5 = new Button(shell, SWT.PUSH);
      btn5.setText("5");
      btn5.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btn6 = new Button(shell, SWT.PUSH);
      btn6.setText("6");
      btn6.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btnSub = new Button(shell, SWT.PUSH);
      btnSub.setText("-");
      btnSub.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btn7 = new Button(shell, SWT.PUSH);
      btn7.setText("7");
      btn7.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btn8 = new Button(shell, SWT.PUSH);
      btn8.setText("8");
      btn8.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btn9 = new Button(shell, SWT.PUSH);
      btn9.setText("9");
      btn9.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btnMul = new Button(shell, SWT.PUSH);
      btnMul.setText("*");
      btnMul.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btnClear = new Button(shell, SWT.PUSH);
      btnClear.setText("C");
      btnClear.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btn0 = new Button(shell, SWT.PUSH);
      btn0.setText("0");
      btn0.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btnEqual = new Button(shell, SWT.PUSH);
      btnEqual.setText("=");
      btnEqual.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
      Button btnDiv = new Button(shell, SWT.PUSH);
      btnDiv.setText("/");
      btnDiv.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

      //添加按钮选择监听器
      btn1.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("1");
         }
      });
      btn2.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("2");
         }
      });
      btn3.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("3");
         }
      });
      btn4.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("4");
         }
      });
      btn5.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("5");
         }
      });
      btn6.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("6");
         }
      });
      btn7.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("7");
         }
      });
      btn8.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("8");
         }
      });
      btn9.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("9");
         }
      });
      btn0.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("0");
         }
      });
      btnClear.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.setText("");
            output.setText("");
         }
      });
      btnAdd.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("+");
         }
      });
      btnSub.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("-");
         }
      });
      btnMul.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("*");
         }
      });
      btnDiv.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            input.append("/");
         }
      });
      btnEqual.addSelectionListener(new SelectionAdapter() {
         public void widgetSelected(SelectionEvent event) {
            String equation = input.getText();
            try {
               double result = evaluate(equation);
               output.setText(Double.toString(result));
            } catch (Exception e) {
               output.setText("错误的方程式");
            }
         }
      });

      shell.pack();
      shell.open();
      while (!shell.isDisposed()) {
         if (!display.readAndDispatch()) {
            display.sleep();
         }
      }
      display.dispose();
   }

   //计算方程式
   private static double evaluate(String equation) throws Exception {
      String[] parts = equation.split("(?=[-+*/])|(?<=[-+*/])");
      double result = Double.parseDouble(parts[0]);
      for (int i = 1; i < parts.length; i += 2) {
         String operator = parts[i];
         double operand = Double.parseDouble(parts[i + 1]);
         switch (operator) {
            case "+":
               result += operand;
               break;
            case "-":
               result -= operand;
               break;
            case "*":
               result *= operand;
               break;
            case "/":
               if (operand == 0) {
                  throw new Exception("除数不能为0");
               }
               result /= operand;
               break;
            default:
               throw new Exception("无效的运算符：" + operator);
         }
      }
      return result;
   }
}

本程序中，我们创建了一个基本的科学计算器UI，包括一个文本框和一系列按钮。我们将按钮添加到网格布局中，并为每个按钮添加了选择监听器，以便在用户单击按钮时向文本框添加相应的数字或运算符。我们还为“=”按钮添加了一个选择监听器，该监听器解析文本框中的方程式并计算结果，然后将结果显示在标签中。

此程序还包括一个名为“evaluate”的私有静态方法，该方法接受一个字符串表示的方程式并返回计算结果。我们使用Java的内置“split”方法将方程式拆分为数字和运算符，然后使用一个循环来遍历方程式的各个部分并执行适当的计算。在进行除法计算时，我们还添加了一个检查，以确保除数不为零。

请注意，此代码可能不够完整或优化，仅供参考。