When two co-routines are running, how do you stop the first co-routine?
GLOBALS.stableTime = 5;
IEnumerator StableWaittingTime ()
{
yield return new WaitForSeconds (1f);
if (GLOBALS.stableTime == 0) {
GameManager.instance.LevelFaildMethod ();
} else {
GameManager.instance.stableWaittingTime.text = GLOBALS.stableTime.ToString ();
GLOBALS.stableTime--;
StartCoroutine ("StableWaittingTime");
}
}
There are three ways to stop coroutines.
The first is to call StopAllCoroutines(), which will obviously stop all running coroutines.
The second is to call StopCoroutine(coroutine), where coroutine is a variable name given to your IEnumerator.
And the third is to do a yield break from within the coroutine.
Worth noting is that both StopAllCoroutines and StopCoroutine can only stop a coroutine when the coroutine reaches a yield return *.
So if you have two coroutines with the same name and you want to stop the one you are executing in you do yield break.
Interestingly, if you want to stop every other coroutine besides the one you are executing in, you call StopCoroutines() from within that coroutine.
#Imapler answer is almost all you need. I would just add that StopCoroutine method of MonoBehaviour is overloaded and has 3 types of parameters, so it is possible to stop many coroutines of same name.
For your need here, just use yield break; like this:
void Start ()
{
StartCoroutine (StableWaittingTime ());
}
IEnumerator StableWaittingTime ()
{
yield return new WaitForSeconds (1f);
if (false)
{
// do something
}
else
{
// do something
StartCoroutine (StableWaittingTime ());
yield break;
}
}
Related
I have a coroutine which takes in some variable running in the update function and I need the code to be something like this:
void Update(){
if(/*coroutine is not running*/){
StartCoroutine(coroutine(some variable));
}
}
Is there a way to know if the coroutine is still running before I run it with some other variable. I know that there is a way of doing it where I put that coroutine into another coroutine and use yield return coroutine(some variable) and that should work. But in my case the variable that the coroutine takes in depends on an event that my script is subscribed to, so the above implementation won't work. So is a way to know if my coroutine is still running or not?
bool isCouroutineRunning = false;
void Update()
{
if(isCouroutineRunning == false)
{
StopCoroutine("MyCourutine");
StartCoroutine("MyCourutine",variable);
}
}
IEnumerator MyCourutine()
{
isCouroutineRunning = true;
yield return new WaitForSeconds(1.0f);
isCouroutineRunning = false;
}
i'm writing some c# code within Unity game i'm developing.
and there's a problem i can't fix.
i'm using StartCoroutine in my code and inside i'm calling another StartCoroutine. i know that when doing that, there's two threads executing the code in those parts.
but not if i'm calling yield return to that StartCorotuine;
IEnumerator StartLoop()
{
yield return StartCorotuine(GetInputFromUser()); // 1
// some variables
yield return StartCorotuine(GetInputFromUser()); // 2
}
IEnumerator GetInputFromUser()
{
if (Input.GetKeyDown(KeyCode.Space))
{
print("IN");
}
else
{
yield return null;
}
}
the problem is, it prints twice.
the buffer isn't empty from the first time calling "GetInputFromUser()" and it keeps it until the second time and enters immediately to the if even when i'm not pressing Space.
things i've tried:
Console.Clear();
Console.ReadKey();
Console.ReadLine();
UnityEngine.Rendering.CommandBuffer.Clear();
while(Console.KeyAvailable)
Console.ReadKey();
and some more i can't even remember.
either the whole idea is wrong and somehow it worked till now. or i'm missing something.
any advise? i've googled everything i could think of.
[[[SOLVED]]]
I don't know how it works here, and if you're closing the post or something. but I've solved it.
The problem was, as someone suggested, that the calls happened in the same frame, so i've added another null in between to force skipping to the next frame:
IEnumerator StartLoop()
{
yield return StartCorotuine(GetInputFromUser()); // 1
// some variables
yield return null; // skipping frame
yield return StartCorotuine(GetInputFromUser()); // 2
}
IEnumerator GetInputFromUser()
{
if (Input.GetKeyDown(KeyCode.Space))
{
print("IN");
}
else
{
yield return null;
}
}
Thanks for the helpers!
First of all: Coroutines have nothing to do with threads! Every Coroutine is executed in the Unity main thread and get their MoveNext executed right after Update has finished for that behaviour.
Your problem should be that in
IEnumerator GetInputFromUser()
{
if (Input.GetKeyDown(KeyCode.Space))
{
print("IN");
}
else
{
yield return null;
}
}
in the case there was no input you do yield return null; which causes the Coroutine to wait at least one frame!
So the second one is executed in the next frame.
But in case there was an input you do not wait so the next Coroutine is directly started where again you don't wait!
Result: You get your print twice without waiting at all.
It's not fully clear what you are trying here but I assume you want to wait until Space is pressed so you should rather use e.g.
bool GetInputFromUser()
{
if (Input.GetKeyDown(KeyCode.Space))
{
print("IN");
return true
}
return false;
}
And use it like
// This now waits until the user presses Space
yield return new WaitUntil (GetInputFromUser);
or simply also yield for one frame in case there was the input like
IEnumerator GetInputFromUser()
{
if (Input.GetKeyDown(KeyCode.Space))
{
print("IN");
}
yield return null;
}
though
the goal is to check if the user presses the SpaceBar more than once.
It is very very unlikely that a user manages to press the key down twice in two consecutive frames.
StartLoop starts inside Start()
but at this moment the user can't provide any input yet anyway. So you check only once if the user presses a key within the first frames..
In Start()
I'm waiting for the first Space stroke.
once he has, I'm starting the StartCorotuine(StartLoop()); sorry for the mixup.
I'm using it like that, maybe it'll be more clear, once the user Starting the loop, I'm waiting for him to press Space. once he has a timer is set on and once the timer has timed the IEnumerator return without Input from the User and I'm getting to the next iteration, the only thing I want to do is to check if the user pressed twice on that Space.
{
while (timer < timeSetInStart)
{
If(Input.GetKeyDown(KeyCode.Space))
{
print("IN";
yield break;
}
else
{
yield return null;
}
}
}
I'm not sure if there's a specific reason why this needs to be in a coroutine but it might be easier to handle this all in Update():
bool spacePressed = false;
void Update()
{
if (Input.GetKeyDown(KeyCode.Space))
{
if (spacePressed)
{
print("Space pressed twice");
spacePressed = false;
}
else
{
print("Space pressed once");
spacePressed = true;
}
}
}
i'm very new to programming and i have a feeling that there is a very stupid mistake here. But can anyone explain me, why instead of 4 messages with a delay of 2 seconds between, i instantaniously get the last message shown only.
using UnityEngine;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using UnityEngine.UI;
public class Wait : MonoBehaviour {
private int i = 0;
public string[] message;
[SerializeField]
private Text toText;
public IEnumerator Message(float waitTime)
{
toText.text = message[i];
i++;
yield return new WaitForSeconds(waitTime = 2f);
}
void Start()
{
StartCoroutine(Message(i));
StartCoroutine(Message(i));
StartCoroutine(Message(i));
StartCoroutine(Message(i));
}
}
void Start()
{
StartCoroutine(Message(i));
StartCoroutine(Message(i));
StartCoroutine(Message(i));
StartCoroutine(Message(i));
}
I don't think that is doing what you think it should. This will not wait for each StartCoroutine to finish and will call the next StartCoroutine.
This is what happens:
The first StartCoroutine(Message(i)); call will start the Message function.
Once it meets the yield return new WaitForSeconds(waitTime = 2f); line of code, it will then jump back into the Start() function.
The next StartCoroutine(Message(i)); will be called then the-same thing will happen again.
When calling a coroutine function from a non coroutine function, as long as you have yield return new WaitForSeconds, yield return null;, or yield return what-ever YieldInstruction is implemented, the execution will return to that non coroutine function in-which the StartCoroutine function was called from and continue to execute other code.
To make coroutine wait for another one to finish, make the StartCoroutine(Message(i)); function call from another coroutine function. This will allow you to yield each coroutine function call. This is called chaining coroutine.
To chain or yield a coroutine function call, simply put yield return in front of the StartCoroutine function. yield return StartCoroutine(Message(i));
public class Wait : MonoBehaviour {
private int i = 0;
public string[] message;
[SerializeField]
private Text toText;
public IEnumerator Message(float waitTime)
{
// toText.text = message[i];
i++;
yield return new WaitForSeconds(waitTime = 2f);
}
void Start()
{
StartCoroutine(startMessage());
}
IEnumerator startMessage()
{
yield return StartCoroutine(Message(i));//Wait until this coroutine function retuns
yield return StartCoroutine(Message(i));//Wait until this coroutine function retuns
yield return StartCoroutine(Message(i));//Wait until this coroutine function retuns
yield return StartCoroutine(Message(i));//Wait until this coroutine function retuns
}
}
Now, each StartCoroutine(Message(i)); call will wait until the first one finishes. You can always use a boolean variable to do this but it is much better to yield the StartCoroutine call.
The reason the text is set instantly is because StartCoroutine will execute the enumerator from Message.
The first two things that happen is setting the text and incrementing i. Only after that is done, you will yield the WaitForSeconds. It is at that point StartCoroutine will pause further execution of Message.
If you had had a line after the yield return you would have seen the effects of that after the 2 seconds.
in the example in the docs you can also see the behavior after the yield return Wait
https://docs.unity3d.com/ScriptReference/MonoBehaviour.StartCoroutine.html
I would suggest running the next test to become more familiar with how yield return works:
IEnumerator MessageOuter() {
Console.WriteLine("outer 1");
var inner = MessageInner();
Console.WriteLine("outer 2");
return inner;
}
IEnumerator MessageInner() {
Console.WriteLine("inner 1");
yield return new WaitForSeconds(1);
Console.WriteLine("inner 2");
yield return new WaitForSeconds(1);
Console.WriteLine("inner 3");
}
void Start() {
Console.WriteLine("start 1");
var outer = MessageOuter();
Console.WriteLine("start 2");
StartCoroutine(outer);
Console.WriteLine("start 3");
}
I want my character to stop when I press a button on my gamepad or keyboard. The character must do a specific animation when I press the button and nothing else, so no movement at all, just the animation.
I'm trying to figure out how WaitForSeconds works, but when I try to use it, it doesn't work. Here the code of the function that calls WaitForSeconds
public IEnumerator Wait()
{
yield return new WaitForSeconds (6);
}
When the bool variable animationTest is true I want the program to wait for 6 seconds
if (animationTest)
{
UnityEngine.Debug.Log ("check1");
StartCoroutine (Wait ());
UnityEngine.Debug.Log ("check2");
animationTest = false;
}
but this doesn't work! check1 and check2 are printed at the same time. I'm missing something. This runs in FixedUpdate().
The Coroutine does not work like this. It starts a new (parallel) execution.
In order to achieve the wait you'd have to do it in the IEnumerator.
public IEnumerator SomethingElse() {
animationTest = false;
Debug.Log("check1");
yield return new WaidForSeconds(6f);
Debug.Log("check2");
yield return true;
}
void FixedUpdate() {
if (animationTest) {
StartCoroutine(SomethingElse());
}
}
Now when you set the animationTest at some point, you should see the two logs with a time gap of 6 seconds in between.
I know that Unity3D StartCoroutine calls a function which runs on the same thread as StartCoroutine, but when does the called function return back to the original caller?
I looked around the internet for a good Unity3D Coroutine example and couldn't find a complete one. There is a great explanation by UnityGems, but even their example is incomplete. So I wrote my own example.
This:
using UnityEngine;
using System.Collections;
public class MainCamera: MonoBehaviour {
void Start () {
Debug.Log ("About to StartCoroutine");
StartCoroutine(TestCoroutine());
Debug.Log ("Back from StartCoroutine");
}
IEnumerator TestCoroutine(){
Debug.Log ("about to yield return WaitForSeconds(1)");
yield return new WaitForSeconds(1);
Debug.Log ("Just waited 1 second");
yield return new WaitForSeconds(1);
Debug.Log ("Just waited another second");
yield break;
Debug.Log ("You'll never see this"); // produces a dead code warning
}
}
Produces this output:
About to StartCoroutine
about to yield return WaitForSeconds(1)
Back from StartCoroutine
Just waited 1 second
Just waited another second