Question

我的最终目标是让用户输入三个跑步者的名字以及他们完成跑步的时间。它将根据流动时间组织跑步者，我想将结果打印到桌子上，但是当我最后编译得到以下错误;

error: variable declaration not allowed here
       JFrame frame = new JFrame();

当我单独运行JFrame代码时它工作得很好，但是当我将所有代码编译在一起时，我得到了上述错误。

import java.awt.BorderLayout;
import javax.swing.*;

public class JTableCreatingDemo {
  public static void main(String args[]) {

    String runner1, runner2, runner3;
    double runTime1, runTime2, runTime3;

    //Get the names and run time of each runner 
    runner1 = JOptionPane.showInputDialog("Enter name of runner 1"); //runner1
    runTime1 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 1 in minutes")); //runTime1
    while (runTime1<0)
        {
            JOptionPane.showMessageDialog(null, "Invalid Entry");
            runtTime1 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 1 in minutes \nEntery format should be MM.SS"));
        }

    runner2 = JOptionPane.showInputDialog("Enter name of runner 2"); //runner2
    runTime2 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 2 in minutes")); //runTime2
    while (runTime2<0)
        {
            JOptionPane.showMessageDialog(null, "Invalid Entry");
            runtTime2 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 2 in minutes \nEntery format should be MM.SS"));
        }

    runner3 = JOptionPane.showInputDialog("Enter name of runner 3"); //runner3
    runtime3 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 3 in minutes")); //runTime3
    while (runTime3<0)
        {
            JOptionPane.showMessageDialog(null, "Invalid Entry");
            runtTime3 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 3 in minutes \nEntery format should be MM.SS"));
        }

    //Sort the runners by their respective run times
    if(runtime1<=runtime2 && runtime1<=runtime3) //runner1 is the fastest
    {
        if(runtime2<=runtime3)
            JFrame frame = new JFrame();
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            Object rowData[][] = { { runner1, runtime1 + " minutes", "-" },
                { runner2, runtime2 + " minutes", (runtime2-runtime1) },
                {runner3, runtime3 + " minutes", (runtime3-runTime1)} };
            Object columnNames[] = { "Runners Name", "Finish Time", "Differnce" };
            JTable table = new JTable(rowData, columnNames);

            JScrollPane scrollPane = new JScrollPane(table);
            frame.add(scrollPane, BorderLayout.CENTER);
            frame.setSize(300, 150);
            frame.setVisible(true);
    }

  }
}

Answer 1

尝试此代码，它应该工作。我刚刚修正了括号错误：）

import java.awt.BorderLayout;
import javax.swing.*;

public class JTableCreatingDemo {
  public static void main(String args[]) {

    String runner1, runner2, runner3;
    double runTime1, runTime2, runTime3;

    //Get the names and run time of each runner 
    runner1 = JOptionPane.showInputDialog("Enter name of runner 1"); //runner1
    runTime1 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 1 in minutes")); //runTime1
    while (runTime1<0)
        {
            JOptionPane.showMessageDialog(null, "Invalid Entry");
            runtTime1 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 1 in minutes \nEntery format should be MM.SS"));
        }

    runner2 = JOptionPane.showInputDialog("Enter name of runner 2"); //runner2
    runTime2 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 2 in minutes")); //runTime2
    while (runTime2<0)
        {
            JOptionPane.showMessageDialog(null, "Invalid Entry");
            runtTime2 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 2 in minutes \nEntery format should be MM.SS"));
        }

    runner3 = JOptionPane.showInputDialog("Enter name of runner 3"); //runner3
    runtime3 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 3 in minutes")); //runTime3
    while (runTime3<0)
        {
            JOptionPane.showMessageDialog(null, "Invalid Entry");
            runtTime3 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 3 in minutes \nEntery format should be MM.SS"));
        }

    //Sort the runners by their respective run times
    if(runtime1<=runtime2 && runtime1<=runtime3) //runner1 is the fastest
    {
        if(runtime2<=runtime3) 
           {
            JFrame frame = new JFrame();
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            Object rowData[][] = { { runner1, runtime1 + " minutes", "-" },
                { runner2, runtime2 + " minutes", (runtime2-runtime1) },
                {runner3, runtime3 + " minutes", (runtime3-runTime1)} };
            Object columnNames[] = { "Runners Name", "Finish Time", "Differnce"
           }
 };
            JTable table = new JTable(rowData, columnNames);

            JScrollPane scrollPane = new JScrollPane(table);
            frame.add(scrollPane, BorderLayout.CENTER);
            frame.setSize(300, 150);
            frame.setVisible(true);
    }

    }
    }

为什么我在JFrame中收到Variable Declaration错误？

1 个答案: