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How to detect click/touch events on UI and GameObjects

Posted by: admin November 1, 2017 Leave a comment

Questions:

How to detect UI object on Canvas on Touch in android?

For example, I have a canvas that have 5 objects such as

Image, RawImage, Buttons, InputField and so on.

When I touch on Button UI object Then do something.

Each button do different process when clicked depending.

The code will be look like :

void Update()
{
    if (Input.touches.Length > 0)
    {
        for (int i = 0; i < Input.touchCount; i++)
        {
            if (Button1.touch)
            {
                if (Input.GetTouch(i).phase == TouchPhase.Began)
                {
                    // Call a Function
                    login();
                }
            }
            else if (Button2.touch)
            {
                if (Input.GetTouch(i).phase == TouchPhase.Began)
                {
                    // Call a Function
                    LogOut();
                }
            }
        }
    }
}

So how to do it?

Second:
How to detect Gameobject get touch? Is it same with that above or not?

Answers:

You don’t use the Input API for the new UI. You subscribe to UI events or implement interface depending on the event.

These are the proper ways to detect events on the new UI components:

1.Image, RawImage and Text Components:

Implement the needed interface and override its function. The example below implements the most used events.

using UnityEngine.EventSystems;

public class ClickDetector : MonoBehaviour, IPointerDownHandler, IPointerClickHandler,
    IPointerUpHandler, IPointerExitHandler, IPointerEnterHandler,
    IBeginDragHandler, IDragHandler, IEndDragHandler
{
    public void OnBeginDrag(PointerEventData eventData)
    {
        Debug.Log("Drag Begin");
    }

    public void OnDrag(PointerEventData eventData)
    {
        Debug.Log("Dragging");
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        Debug.Log("Drag Ended");
    }

    public void OnPointerClick(PointerEventData eventData)
    {
        Debug.Log("Clicked: " + eventData.pointerCurrentRaycast.gameObject.name);
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        Debug.Log("Mouse Down: " + eventData.pointerCurrentRaycast.gameObject.name);
    }

    public void OnPointerEnter(PointerEventData eventData)
    {
        Debug.Log("Mouse Enter");
    }

    public void OnPointerExit(PointerEventData eventData)
    {
        Debug.Log("Mouse Exit");
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        Debug.Log("Mouse Up");
    }
}

2.Button Component:

You use events to register to Button clicks:

public class ButtonClickDetector : MonoBehaviour
{
    public Button button1;
    public Button button2;
    public Button button3;

    void OnEnable()
    {
        //Register Button Events
        button1.onClick.AddListener(() => buttonCallBack(button1));
        button2.onClick.AddListener(() => buttonCallBack(button2));
        button3.onClick.AddListener(() => buttonCallBack(button3));

    }

    private void buttonCallBack(Button buttonPressed)
    {
        if (buttonPressed == button1)
        {
            //Your code for button 1
            Debug.Log("Clicked: " + button1.name);
        }

        if (buttonPressed == button2)
        {
            //Your code for button 2
            Debug.Log("Clicked: " + button2.name);
        }

        if (buttonPressed == button3)
        {
            //Your code for button 3
            Debug.Log("Clicked: " + button3.name);
        }
    }

    void OnDisable()
    {
        //Un-Register Button Events
        button1.onClick.RemoveAllListeners();
        button2.onClick.RemoveAllListeners();
        button3.onClick.RemoveAllListeners();
    }
}

If you are detecting something other than Button Click on the Button then use method 1. For example, Button down and not Button Click, use IPointerDownHandler and its OnPointerDown function from method 1.

3.InputField Component:

You use events to register to register for InputField submit:

public InputField inputField;

void OnEnable()
{
    //Register InputField Events
    inputField.onEndEdit.AddListener(delegate { inputEndEdit(); });
    inputField.onValueChanged.AddListener(delegate { inputValueChanged(); });
}

//Called when Input is submitted
private void inputEndEdit()
{
    Debug.Log("Input Submitted");
}

//Called when Input changes
private void inputValueChanged()
{
    Debug.Log("Input Changed");
}

void OnDisable()
{
    //Un-Register InputField Events
    inputField.onEndEdit.RemoveAllListeners();
    inputField.onValueChanged.RemoveAllListeners();
}

4.Slider Component:

To detect when slider value changes during drag:

public Slider slider;

void OnEnable()
{
    //Subscribe to the Slider Click event
    slider.onValueChanged.AddListener(delegate { sliderCallBack(slider.value); });
}

//Will be called when Slider changes
void sliderCallBack(float value)
{
    Debug.Log("Slider Changed: " + value);
}

void OnDisable()
{
    //Un-Subscribe To Slider Event
    slider.onValueChanged.RemoveListener(delegate { sliderCallBack(slider.value); });
}

For other events, use Method 1.

5.Dropdown Component

public Dropdown dropdown;
void OnEnable()
{
    //Register to onValueChanged Events

    //Callback with parameter
    dropdown.onValueChanged.AddListener(delegate { callBack(); });

    //Callback without parameter
    dropdown.onValueChanged.AddListener(callBackWithParameter);
}

void OnDisable()
{
    //Un-Register from onValueChanged Events
    dropdown.onValueChanged.RemoveAllListeners();
}

void callBack()
{

}

void callBackWithParameter(int value)
{

}

NONE UI OBJECTS:

6.For 3D Object (Mesh Renderer/any 3D Collider)

Add PhysicsRaycaster to the Camera then use any of the events from Method 1.

The code below will automatically add PhysicsRaycaster to the main Camera.

public class MeshDetector : MonoBehaviour, IPointerDownHandler
{
    void Start()
    {
        addPhysicsRaycaster();
    }

    void addPhysicsRaycaster()
    {
        PhysicsRaycaster physicsRaycaster = GameObject.FindObjectOfType<PhysicsRaycaster>();
        if (physicsRaycaster == null)
        {
            Camera.main.gameObject.AddComponent<PhysicsRaycaster>();
        }
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        Debug.Log("Clicked: " + eventData.pointerCurrentRaycast.gameObject.name);
    }

    //Implement Other Events from Method 1
}

7.For 2D Object (Sprite Renderer/any 2D Collider)

Add Physics2DRaycaster to the Camera then use any of the events from Method 1.

The code below will automatically add Physics2DRaycaster to the main Camera.

public class SpriteDetector : MonoBehaviour, IPointerDownHandler
{
    void Start()
    {
        addPhysics2DRaycaster();
    }

    void addPhysics2DRaycaster()
    {
        Physics2DRaycaster physicsRaycaster = GameObject.FindObjectOfType<Physics2DRaycaster>();
        if (physicsRaycaster == null)
        {
            Camera.main.gameObject.AddComponent<Physics2DRaycaster>();
        }
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        Debug.Log("Clicked: " + eventData.pointerCurrentRaycast.gameObject.name);
    }

    //Implement Other Events from Method 1
}

Questions:
Answers:

You can add an EventTrigger Componenet to Your UI elements that already have these Events you just have to pass method/Function on specific event.