error CS0501: `CharacterDetection.IsTouching(Collider2D)` Error (Help Needed)

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class CharacterDetection : MonoBehaviour {
6.     //change to negative for enemy
7.     public float CharSpeed = 1f;
8.     public Rigidbody2D rb;
9.     public Collider2D coll;
10.     public bool IsTouching(Collider2D collider);
11.     void Start () {
12.         rb = GetComponent <Rigidbody2D> ();
13.         coll = GetComponent <Collider2D> ();
14.     }
15.    
16.     // Update is called once per frame
17.     void FixedUpdate () {
18.         IsTouching(Collider2D);
19.         if (coll.IsTouching) {
20.         }
21.         else {
22.             rb.AddForce (Vector2.right * CharSpeed * Time.deltaTime);
23.         }
24.     }
25. }

 

I think you meant to use one of Unity's callback functions for collision detection:

Code (CSharp):

1.  
2. //If your Collider2D component IS NOT set to "is trigger"
3. void OnCollisionEnter2D(Collision2D coll) {
4.  
5. }
6.  
7. //If your Collider2D component IS set to "is trigger"
8. void OnTriggerEnter2D(Collider2D coll) {
9.  
10. }
11.  

Because "public bool IsTouching(Collider2D collider);" is not a valid variable declaration, nor a valid method.