Why does Update() call itself more than once?

Questions & Answers
1

I’m new in unity and developing a cricket game. I have a screen that shows squad selection. It shows images of 15 players, out of which I have to select any 11. I keep on adding the clicked(selected) player in a List. But the problem is that when I click the player once, the size of my list becomes 4 or 5 or even more sometimes.
My script is as follows:

using UnityEngine;
using System.Collections;

public class clickbull : MonoBehaviour {

	// Use this for initialization
	void Start () {
	
	}
	
	
	void Update () {
		
		if (Input.touchCount == 1)
		{
			Vector3 wp = Camera.main.ScreenToWorldPoint(Input.GetTouch(0).position);
			Vector2 touchPos = new Vector2(wp.x, wp.y);
			if (collider2D == Physics2D.OverlapPoint(touchPos))
			{
				//if(countausplayer.countteam<=11){
				Material newMat = Resources.Load("New Material", typeof(Material)) as Material;
				gameObject.renderer.material = newMat;
				PlayersManager.objPlayerList.Add(PlayersManager.setPlayerObject("Bull"));
				countausplayer.countteam++;
				//}
				
			}
			
		}
	}
	}
	
Please guide me where am I going wrong?? why is the List size increasing on its own?? How to use this..Please help, its really urgent.
2

Update calls itself once per frame, a frame last a fraction of a second, so even the quickest touch will last several frames.

Therefore you need to add some safeguard that only permits the action once per touch. Then unlock it once the touch ends.

3

Update is called every frame, so that script is called a bunch of times every second as long as you have a finger on the screen.

The solution is to replace

if (Input.touchCount == 1)

with

if(Input.GetTouch(0).phase == TouchPhase.Began)

which checks if the Input started this frame, which is what you’re looking for.

The 0 means to check the phase of the first (index 0) touch input - ie. the first finger that’s on the screen at the moment.