Question How to stop Threading?

I have a following code:

Code (CSharp):

1. Thread thread;
2.  
3.     void Start()
4.     {
5.         thread = new Thread (() => Test ());
6.         thread.Start ();
7.     }
8.     public void Test()
9.     {
10.         int test_ID = 0;
11.         for (long i = 0; i < 1000000000; i++) {
12.             test_ID++;
13.         }
14.         Debug.Log (test_ID);
15.     }

When I pressed Play and quickly pressed Play again (that means I was out of the Play window), this code continued to run. How to stop it?

 

Press stop! Simples!

Also, when you're displaying code, please use CODE tags.

 

Thank but I don't understand. What do you mean?

 

English isn't your first language?

There's a simple tag in the post, when you're displaying code, click the CODE button, and then write out your code.

 

Threads don't stop automatically when you exit play mode in Unity, you have to do it manually.
There is no stop button for stopping threads after exiting play mode.
Also the Unity API doesn't work in threads because it is not thread safe.

That being said I don't recommend using threads in Unity for asynchronous code, try Tasks that can have the same problems, even better Unitask or if you are in the 2023 version the new awaitable https://docs.unity3d.com/2023.1/Documentation/ScriptReference/Awaitable.html
you can also look at the job system:
https://docs.unity3d.com/Manual/JobSystem.html

In any case, for your example something like this works:

Code (CSharp):

1.  
2. Thread thread;
3.     CancellationTokenSource cts = new();
4.  
5.     void Start()
6.     {
7.         thread = new Thread (() => Test(cts.Token));
8.         thread.Start ();
9.     }
10.  
11.     public void Test(CancellationToken token)
12.     {
13.         int test_ID = 0;
14.         for (long i = 0; i < 1_000_000_000; i++)
15.         {
16.             if (token.IsCancellationRequested)
17.                 break;
18.          
19.             test_ID++;
20.         }
21.         Debug.Log(test_ID);
22.     }
23.  
24.     private void OnDestroy()
25.     {
26.         cts?.Cancel();
27.         cts?.Dispose();
28.     }

this stops the thread manually in the OnDestroy method