Buttons within scroll rect are difficult to press on mobile

it's working for me. Thank you!

 

I had the same issue. It appears that when pressing a button on a mobile device your finger might move a tiny tiny bit which starts the drag and interrupts the on click.

I only noticed the issue when I tried to implement the functionality of holding a button down for 1 second and then triggering an event.

To fix it I went to the EventSystem in my scene which gets created when you make a canvas. Inside the EventSystem there is an option called "Drag Threshold". Change the value to about 32 and see if it improves.

 

That's not a good solution. Every device has a different pixel density and you don't want to change the Drag threshold for every single one. That's why the optimal solution is taking the devices dpi into account, define the threshold per inch(cm) and it works for all
devices.

 

Thanks ALot For This Solutions. Its 100% working

 

Hello, just wanted to say thanks for this post and for the code Johannski. I'm very surprised Unity after 3 years of this being reported has not addressed it on their own.

 

just encounter this gimmick today, on 2017.4.4f1, nice work Unity

 

Version 2018.1.7f1 and the issue continues here.
This solutions was good for me!
Thanks!

 

Is there any way to use a different drag threshold for touch input as compared to mouse input?

 

@Johannski solution works perfectly for me. Unity 2017. Thanks a lot!

 

Same thing on Unity 2019.1.4f1. Used Johannski script and that helped.

 

Hi, i thought i would come back here and post my solution, as this thread helped me.
Just pop this onto your Canvas Parent, no need to set variables, it uses canvas scaling and not DPI.

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.EventSystems;
3.  
4. public class DragThreshold : MonoBehaviour
5. {
6.     private Canvas myCanvas;
7.     private int defaultDrag = 0;
8.     void Start()
9.     {
10.         defaultDrag = EventSystem.current.pixelDragThreshold;
11.         myCanvas = this.GetComponent<Canvas>();
12.         EventSystem.current.pixelDragThreshold = (int)(defaultDrag * myCanvas.scaleFactor);
13.        // Above way recommend by poster below.
14.        // EventSystem.current.pixelDragThreshold = defaultDrag * (int)myCanvas.scaleFactor;
15.     }
16. }

 

You should really replace this line:

Code (CSharp):

1. EventSystem.current.pixelDragThreshold = defaultDrag * (int)myCanvas.scaleFactor;

with this:

Code (CSharp):

1. EventSystem.current.pixelDragThreshold = (int)(defaultDrag * myCanvas.scaleFactor);

Otherwise you are only allowing the threshold to change in integer multiples of the original threshold. For example, if the original threshold was 5 pixels, then you are only allowing values of 10, 15, 20, ... and not, for example, 6. If you have to change the threshold downward, it can only snap between 5 and 0.

 

Good catch, i did not notice that.
*Editing original post for those copy n pasters out there.

 

This problem is occurring when I'm using a VR pointer with the UI. Setting the drag threshold to max int (or 0) does not seem to resolve the issue (buttons are being selected, but onClick is not firing).

 

This issue is still there in 2020.3.19f1 , cant scroll the ScrolView when the content has children that are selectable/clickable/interactable when implementing IPointerClickHandler for the content elements they cant be clicked but scrollview works ,if using the EventTrigger component on the content items they are clickable but the scrollView cant be moved. Why you do this Unity Technologies?

Edit: Instead of only IPointerClickHandler also Up and Down MUST be implemented even if the method body stays empty, docs dont tell this.

 

EventTrigger captures all the listed events (thereby preventing them from reaching parent objects).

This is probably the only way EventTrigger could work, given that Unity relies on interfaces to determine which events a component should capture, and interfaces cannot be changed at runtime.

I would not expect this to change.

 

2022 and this post is from 2014, please can someone from Unity team @phil-Unity, or anyone, share their thoughts on this topic ? This issue seems to be fixed by the community but

would you say I should go with the (Johannski's) answer that many are supporting or is the (jesusluvsyooh) a better approach ?

Johannski:

Code (CSharp):

1. public class AdaptingEventSystemDragThreshold : MonoBehaviour
2.     {
3.         [SerializeField] private EventSystem eventSystem;
4.         [SerializeField] private int referenceDPI = 100;
5.         [SerializeField] private float referencePixelDrag = 8f;
6.         [SerializeField] private bool runOnAwake = true;
7.         void Awake()
8.         {
9.             if (runOnAwake)
10.             {
11.                 UpdatePixelDrag(Screen.dpi);
12.             }
13.         }
14.         public void UpdatePixelDrag(float screenDpi)
15.         {
16.             if (eventSystem == null)
17.             {
18.                 Debug.LogWarning("Trying to set pixel drag for adapting to screen dpi, " +
19.                                "but there is no event system assigned to the script", this);
20.             }
21.             eventSystem.pixelDragThreshold = Mathf.RoundToInt(screenDpi/ referenceDPI*referencePixelDrag);
22.         }
23.         void Reset()
24.         {
25.             if (eventSystem == null)
26.             {
27.                 eventSystem = GetComponent<EventSystem>();
28.             }
29.         }
30.     }

OR

jesusluvsyooh:

"Hi, i thought i would come back here and post my solution, as this thread helped me.
Just pop this onto your Canvas Parent, no need to set variables, it uses canvas scaling and not DPI."

Code (CSharp):

1. public class DragThreshold : MonoBehaviour
2. {
3.     private Canvas myCanvas;
4.     private int defaultDrag = 0;
5.     void Start()
6.     {
7.         defaultDrag = EventSystem.current.pixelDragThreshold;
8.         myCanvas = this.GetComponent<Canvas>();
9.         EventSystem.current.pixelDragThreshold = (int)(defaultDrag * myCanvas.scaleFactor);
10.     }
11. }