Touch Input on GUI interfering with gameplay in the background (Android)

Hi guys. I'm new to Unity and the forum so I don't know whether this thread should be somewhere else, feel free to move it.

So I'm making this game where the player object is moving to the position were the player pressed on the screen (android device). It's working great. The player is moving to the x-axis coordinate just as wanted. But, there's a little problem.

I've implemented a button, a raw image in the Canvas and added a Button Script component to it (I've also tried just to add a normal button). Problem is, when pressed, the player is moving towards the x coordinate of that button. And I dont want that. I want the player to stay at the x-coordinate and only move if the touch is outside of the button.

My question is: How can you make the player object ignore touch input on a GUI Object? Is it possible? Can I make some checks to see what kind of objects the player are touching on the screen? Any hints would be appreciated.

Here is some code, don't know if that could help.
Input Class:

Code (CSharp):

1.    
2.  
3. void Update () {  
4.         if (player.playerIsAlive)
5.         {
6.             if (Input.touchCount == 1)
7.             {
8.                     if (gameModePressAndWait)
9.                     {
10.                        Touch touchen = Input.GetTouch(0);
11.  
12.                         float distanceFromCamera = 10.0f;
13.  
14.                         Vector3 PressedByPlayer = new Vector3(touchen.position.x, touchen.position.y, distanceFromCamera);
15.                         Vector3 PressedByPlayerWorldPosition = Camera.main.ScreenToWorldPoint(PressedByPlayer);
16.  
17.                         if (touchen.phase == TouchPhase.Began)
18.                         {
19.                             player.pressedlocation = PressedByPlayerWorldPosition;
20.                         }                  
21.                    }                              
22.                 }                    
23.             }
24.         }
25.  

And some code of my Player Object class:

Code (CSharp):

1.      
2. if (playerIsAlive)
3.         {
4.             //player is moving up
5.             GetComponent<Rigidbody2D>().velocity = new Vector2(0, shipSpeedVertical);
6.  
7.  
8.             if (Application.platform == RuntimePlatform.Android)
9.             {
10.                 pressedlocation.y = transform.position.y;
11.                 transform.position = Vector3.MoveTowards(transform.position, pressedlocation, shipSpeedHorizontal * Time.deltaTime);
12.          
13.             }
14.         }
15.  

Anything else you need to know?

Thanks in advance.

 

You can use EventSystem.current.IsPointerOverGameObject() to check if mouse is over UI element:

https://docs.unity3d.com/ScriptReference/EventSystems.EventSystem.IsPointerOverGameObject.html

 

Yeah I've tried it, but it's not working. Here's what I did in my Input class:

Code (CSharp):

1.  
2. if (EventSystem.current.IsPointerOverGameObject(Input.GetTouch(0).fingerId))
3. {
4.        Debug.Log("Clicked on the UI");
5. }
6. else
7. {
8.        if (touchen.phase == TouchPhase.Began)
9.         {
10.                  player.pressedlocation = PressedByPlayerWorldPosition;
11.         }
12. }
13.  

Right now the player object is not responding at all. The button is working though, but the player keeps the same x-axis position. What does IsPointerOverGameObject even do? I made some google searches but I still don't think I understand.

Does it check if the touch is over any GameObject in the scene or only UI/GUI elements in the scene? If it checks all kinds of GameObjects I think I can imagine why it's not working, because right now my backgrounds, which are randomly generated, are also GameObjects. And then he enters the first if block since we are pressing an GameObject.

Gah, I'm confused

 

It checks if pointer is over UI elements from new UI system (UnityEngine.UI). It's not working for old GUI system (OnGUI function), but you shouldn't use it anyway (except for editor tools).

 

I'm using UnityEngine.UI.

So wierd.. Even if I press outside the button i get "Clicked on the UI" printed out (see code above). So the method IsPointerOverGameObject thinks my backgrounds GameObjects are UI elements? Maybe something to do with the canvas, that all objects are inside the canvas and therefore it register them as UI elements? (in the hierarchy they are not, there are only four UI elements there). I've no idea..

 

No. It checks with raytracing if it collides with UI element graphics. If it doesn't have renderer it shouldn't detect that object.

 

Much appreciated that you are taking your time trying to help me. I'm still not sure though.

Could you elaborate, what do you mean with "If it doesn't have renderer it shouldn't detect that object.". Both my buttons and my generated backgrounds have Sprite Renderers. Do you need more info?

 

You mean both are using Unity UI (backgrounds and button)? So that would explain why IsPointerOverGameObject always returns true. You can disable UI raycasting for background images by disabling RaycastTarget in background UI Sprite (and all other images you don't want UI to know about)..

 

I double checked. My buttons inside the canvas has Canvas Renderer, not Sprite Renderer. The backgrounds though, they have Sprite Renderer. Only my buttons are using Unity UI. The backgrounds are not part of the UI. And it's keep returning true when pressed. So wierd.

 

You can check with which UI object eventsystem is colliding. It can only raycast on UI elements, so there must be UI element:

Code (csharp):

1.  
2. //usage example
3. Debug.Log("Clicked on the UI");
4. CheckUIObjectsInPosition(Input.GetTouch(0).position);
5.  
6. void CheckUIObjectsInPosition(Vector2 position)
7. {
8.   UnityEngine.EventSystems.PointerEventData pointer = new UnityEngine.EventSystems.PointerEventData(UnityEngine.EventSystems.EventSystem.current);
9.   pointer.position = position;
10.   List<UnityEngine.EventSystems.RaycastResult> raycastResults = new List<UnityEngine.EventSystems.RaycastResult>();
11.   UnityEngine.EventSystems.EventSystem.current.RaycastAll(pointer, raycastResults);
12.  
13.   if (raycastResults.Count > 0)
14.   {
15.   foreach (var go in raycastResults)
16.   {
17.   Debug.Log(go.gameObject.name, go.gameObject);
18.   }
19.   }
20. }
21.  

 

Oh, I'm dumb. It was the canvas itself not the backgrounds. Explains why it was always true..

This

Code (CSharp):

1.  
2. if (results.Count > 0)
3. {
4.             foreach(var go in results)
5.             {
6.                 Debug.Log("game object name: " + go.gameObject.name + " , go.gameObject: " + go.gameObject);
7.             }
8. }

made this output:
game object name: weakLazerButton , go.gameObject: weakLazerButton (UnityEngine.GameObject)
game object name: Canvas , go.gameObject: Canvas (UnityEngine.GameObject)

It will work if I do it like this in the method (and change to bool return type ofc):
return results.Count > 1;

Everything is now working fine. Thank you!

Now.. Wonder how I could exclude the canvas itself in the raycasts, or in IsPointerOverGameObject.

 

Canvas shouldn't be there. I've tested code and it never returned canvas object. Are you sure you don't have some UI Image or other raycast target as component of canvas GameObject?

 

Yes, I found it. It was both a Button and a Text Component attached to the canvas object, for some reason.. Explains it all. Well now I have a better understanding. Thanks man!

 

I made this solution:

Code (CSharp):

1.  
2.  
3.     using UnityEngine.EventSystems;
4.     ...
5.  
6.     if (EventSystem.current.currentSelectedGameObject == null) {
7.                //not toch UI
8.     }
9.  

if you have a panel or something to block only add button component, and changue color tint to none

 

This is the only solution which worked for me! You are a life saver...

 

Worked! Thanks a lot.

 

I found a solution which I think should work for mostly every use-case:

Code (CSharp):

1.  
2. using UnityEngine.EventSystems;
3.  
4. /// <summary>
5. /// Checks if the pointer, or any touch is over (Raycastable) UI.
6. /// WARNING: ONLY WORKS RELIABLY IF IN LateUpdate/LateTickable!
7. /// </summary>
8. private bool IsPointerOverUIObject()
9. {
10.     if (EventSystem.current.IsPointerOverGameObject())
11.         return true;
12.  
13.     for (int touchIndex = 0; touchIndex < Input.touchCount; touchIndex++)
14.     {
15.         Touch touch = Input.GetTouch(touchIndex);
16.         if (EventSystem.current.IsPointerOverGameObject(touch.fingerId))
17.             return true;
18.     }
19.  
20.     return false;
21. }
22.  

The important part here is to run this check in LateUpdate (AND/OR) Verify that the Script Execution Order has EventSystem before mostly everything else.


I spent too many hours debugging this, so thought I could dump this here for someone else to use.

 

Thanks,worked for me

 

worked for me

 

I adapted what NHals posted into this and I had to add some extra code to get it to work because the end phase of touch was giving false always. Posting it here in case anyone gets the same issue as me.

Code (CSharp):

1. private void LateUpdate()
2.     {
3.         if (Input.touchCount > 0)
4.         {
5.             Touch touch = Input.GetTouch(0);
6.             if (!EventSystem.current.IsPointerOverGameObject(touch.fingerId) && touch.phase != TouchPhase.Ended)
7.             {
8.                 OnGridTouch?.Invoke(PixelPointToTile(touch.position));
9.             }
10.         }
11.     }