Game Object not moving in Canvas

Hello Everyone, I just started with unity game development for android and I was following Udemy tutorial. I created a game GoHippoGo in which a Hippo sprite moves around the screen wherever touched.

When I tried to make the game UI responsive by using canvas object, the Hippo started rotating but was did not move at all except for the movement due to gravity.

Please Help.

Here is my MoveHippo Script :

 using UnityEngine;
 using System.Collections;
 
 public class MoveHippo : MonoBehaviour {
 
     private float lastTouchTime, currentTouchTime;
 
     public float velocityVal;
     public float torqueVal;
     public float thresholdTime;
 
        void Awake() {
         velocityVal = 8.0f;
         torqueVal = 200.0f;
         thresholdTime = 0.3f;
     }   
 
     void Update () {
     
     #if UNITY_ANDROID
         moveHippoAndroid ();
     #endif
     
     #if UNITY_EDITOR
         moveHippo();
     #endif    
     }
 
       void moveHippo() { //For testing only in your COMPUTER
         Vector3 currentPos, touchedPos, distanceVec;
         if (Input.GetMouseButtonDown(0)) {
             startRotatingHippoAndStopIt();
         }
 
         else if (Input.GetMouseButtonUp(0)) {
             currentPos = Camera.main.WorldToScreenPoint (transform.position);
             touchedPos = Input.mousePosition;
             distanceVec = (touchedPos - currentPos).normalized;
             stopRotatingHippoAndMoveIt(distanceVec, velocityVal);
         }
     }
 
     void moveHippoAndroid() { 
         Vector3 currentPos, touchedPos, distanceVec;        
         for (int i = 0; i < Input.touches.Length; i++) {
             Touch touch = Input.GetTouch(i);
             currentPos = Camera.main.WorldToScreenPoint(transform.position);
             touchedPos = touch.position;
             distanceVec = (touchedPos - currentPos).normalized;
             if (Input.GetTouch(0).phase == TouchPhase.Began) {
                 startRotatingHippoAndStopIt();
             } else if (Input.GetTouch(0).phase == TouchPhase.Ended){
                 currentTouchTime = Time.time;
                 if (currentTouchTime - lastTouchTime > thresholdTime) { //No Double Touch detected ...
                     lastTouchTime = Time.time;
                     stopRotatingHippoAndMoveIt(distanceVec, velocityVal);
                 } else if (currentTouchTime - lastTouchTime < thresholdTime){ //Double Touch detected!
                     lastTouchTime = Time.time;
                     stopRotatingHippoAndMoveIt(distanceVec, velocityVal*2.0f);
                 }
             }
         }
     }

    void startRotatingHippoAndStopIt() {
         // We rorate the hippo...
         GetComponent<Rigidbody2D>().fixedAngle = false;
         GetComponent<Rigidbody2D>().AddTorque(torqueVal);
 
         // ... and stop it
         GetComponent<Rigidbody2D>().velocity=Vector2.zero;
     }
   
     void stopRotatingHippoAndMoveIt(Vector3 distanceVec, float velocity) {
         // We stop rotating the hippo...
         Quaternion hippoQuatern = new Quaternion();
         hippoQuatern.eulerAngles = new Vector3(0,0,0);
         GetComponent<Rigidbody2D>().fixedAngle = true;
         GetComponent<Rigidbody2D>().transform.rotation = hippoQuatern;
        // ... and move it.
         GetComponent<Rigidbody2D>().velocity = distanceVec*velocity;
     }
   
 }