I used the C# Stopwatch Class in Unity, but it returns only 00:00:00

Question

I want to measure and return the time that passes between the time a user presses the Tab & the Space Button. Unfortunately my Code only returns 00:00:00. This is my code so far.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Threading;
using System;
using System.Diagnostics;
using Debug=UnityEngine.Debug;
public class timer : MonoBehaviour {
    public Stopwatch zeit;
    void Update () {
        zeit = new Stopwatch();
        if (Input.GetKeyDown ("tab")) {
            zeit.Start();
        }

        if (Input.GetKeyDown ("space")){
            TimeSpan ts = zeit.Elapsed;
            zeit.Stop ();
            print(ts);
            zeit.Reset ();
        }
    }
}
    

Solution 1

You are re-creating the stopwatch when calling update. You can initialize the stopwatch on forehand in the "constructor".

public Stopwatch zeit = new StopWatch();
void Update () {
    if (Input.GetKeyDown ("tab")) {
        zeit.Start();
    }

    if (Input.GetKeyDown ("space")){
        TimeSpan ts = zeit.Elapsed;
        zeit.Stop ();
        print(ts);
        zeit.Reset ();
    }
}

Solution 2

I think the problem is you always create a new object and set it into zeit variable each Update function is raised.

So, you must create that object only one time.

public Stopwatch zeit = new Stopwatch();
    void Update () {
        if (Input.GetKeyDown ("tab")) {
            zeit.Start();
        }

        if (Input.GetKeyDown ("space")){
            TimeSpan ts = zeit.Elapsed;
            zeit.Stop ();
            print(ts);
            zeit.Reset ();
        }
    }

Solution 3

You have to move your instantiation of Stopwatch outside of Update. Currently you are recreating your stopwatch every frame.

So move zeit = new Stopwatch(); outside of Update

private readonly Stopwatch zeit;

void Start() 
{
    zeit = new Stopwatch();
}

void Update()
{
  //...
}

Solution 4

You create new Stopwatch each Update method:

void Update () {
    zeit = new Stopwatch();

Don't do that, instead, try this approach:

private readonly Stopwatch _zeit = new Stopwatch();

void Update ()
{
    if (Input.GetKeyDown ("tab"))
    {
        _zeit.Restart();
    }

    if (Input.GetKeyDown ("space")
    {
        print(_zeit.Elapsed);
    }
}

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Comments

[UnholySheep]

You are creating a new Stopwatch every single frame. You want to move zeit = new Stopwatch(); outside of the Update (e.g. in Start?)

[Izukani]

It is not necessary to Stop to get the Elapsed time.