使用JOptionPane要求用戶輸入時間

Question

我的老師要求我們通過使用JOptionPane輸入時間（HH，mm，ss）來要求用戶提供賽車手的開始時間和停止時間。 我不確定該怎么做。 我曾嘗試做integer.parseint（joptionpane ....），但輸入時間后仍會收到錯誤消息。 另外，我知道問題在於，由於我要用戶為我的Time類輸入一個時間，因此該時間應該有所不同。 從這一點開始，我需要一些幫助。 這是我的代碼（我還在其中包含了時間類：

package Racers.java;

import javax.swing.JOptionPane;

public class Racers
{   

public static void main(String[] args)
{

    //racer1
    String racer1;
    Time startTime1;
    Time stopTime1;
    double elapsedTime1;

    //assigning racer1
    racer1 = JOptionPane.showInputDialog("Please enter the name of the first racer: ");
    startTime1 = new Time();
    stopTime1 = new Time();
    elapsedTime1 = stopTime1.minus(startTime1).getTime();

    JOptionPane.showMessageDialog(null, 
            "Here is the racer's name, start time, stop time, and elapsed time:\n"
            + racer1 + (" - ") + ("Start time: ") + startTime1 + ("; ") + ("Stop time: ") + stopTime1 + ("; ") + ("Elapsed time: ") + elapsedTime1 + "\n"

}//End main
}//End Racers


class Time 
{
//Variable to hold seconds
double seconds;

//Constructors for class Time
public Time()
{
    seconds = 0.0;
}

public Time(double newSeconds)
{
    seconds = newSeconds;
}

public Time(int hours, int minutes, double newSeconds)
{
    seconds = (double)(hours * 3600 + minutes * 60) + newSeconds;
}

//Observers for class Time
public double getTime()
{
    //Return elapsed time
    return seconds;
}

public int getHours()
{
    //Compute whole hours from seconds
    return (int)seconds / 3600;
}

public int getMinutes()
{
    //Seconds after hours taken out
    int remainingSeconds = (int)seconds % 3600;
    //Compute minutes from remainder
    return remainingSeconds / 60;
}

public double getSeconds()
{
    //Seconds after minutes taken out
    return seconds % 60.0;
}

//Returns HH:MM:SS.FFF
public String toString()
{
    int hours = (int)seconds / 3600;
    int minutes = (int)seconds % 3600 / 60;
    return hours + ":" + minutes + ":" + seconds % 60.0;
}

//Operations for class Time
public Time plus(Time otherTime)
{
    return new Time(seconds + otherTime.seconds);
}

public Time minus(Time otherTime)
{
    return new Time(seconds - otherTime.seconds);
}

}//End Time

Answer 1

這是問題

startTime1 = new Time();
stopTime1 = new Time();

您正在使用默認構造函數初始化開始和停止時間，其中默認構造函數將開始和停止時間返回為零，因此輸出也為零。

因此，您需要使用參數化構造函數來區分時間。

即

startTime1 = new Time(10,10,10d); // 10hr 10 min 10 sec
stopTime1 = new Time(10,20,10d);  //10hr 20 min 10 sec

那么您發現10分鍾的時間差就是600秒。

也使用下面的行

JOptionPane.showMessageDialog(null, "Here is the racer's name, start time, stop time, and elapsed time:\n" + racer1 + (" - ") + ("Start time: ") + startTime1 + ("; ") + ("Stop time: ") + stopTime1 + ("; ") + ("Elapsed time: ") + elapsedTime1 + "\n");

希望你能理解。