How to detect Double Tap in Android

I know this post i dead. But for the people still looking for an awnser, this is my shot at it. Im am still a beginner so gime me some feedback.

 public class JumpTowardsTap : MonoBehaviour {
 
     int TapCount;
     public float MaxDubbleTapTime;
     float NewTime;
 
     void Start () {
         TapCount = 0;
     }
 
     void Update () {
 if (Input.touchCount == 1) {
             Touch touch = Input.GetTouch (0);
             
             if (touch.phase == TouchPhase.Ended) {
                 TapCount += 1;
             }
 
             if (TapCount == 1) {
                 
                 NewTime = Time.time + MaxDubbleTapTime;
             }else if(TapCount == 2 && Time.time <= NewTime){
                 
                 //Whatever you want after a dubble tap    
                 print ("Dubble tap");
 
                     
                 TapCount = 0;
             }
 
         }
         if (Time.time > NewTime) {
             TapCount = 0;
         }
     }
 }
 

bellow function works well:

 public static bool IsDoubleTap(){
         bool result = false;
         float MaxTimeWait = 1;
         float VariancePosition = 1;
 
         if( Input.touchCount == 1  && Input.GetTouch(0).phase == TouchPhase.Began)
         {
             float DeltaTime = Input.GetTouch (0).deltaTime;
             float DeltaPositionLenght=Input.GetTouch (0).deltaPosition.magnitude;
 
             if ( DeltaTime> 0 && DeltaTime < MaxTimeWait && DeltaPositionLenght < VariancePosition)
                 result = true;                
         }
         return result;
     }

For whoever is reading this in 2020, since this is still the top ranking search result...

One of the first answers suggests that using tapCount is not supported in Android. This was way back in 2012 when Unity 3.x was in use and is no longer correct.

It's perfectly supported now and has been since Unity 5.x (tested and using it on Android): https://docs.unity3d.com/520/Documentation/ScriptReference/Touch-tapCount.html

so doing something like this should be just fine:

 void Update() {
     if (Input.touchCount <= 0)
     {
         return;
     }
     for(touch in Input.touches) {
         if (touch.tapCount == 2) {
              // your handler here
         }    
     }      
 }

If you are looking for simple double tap, this might do the trick. I used this to simply set bool to true or false

 if(Input.GetTouch(0).tapCount == 2){
      //Double tap
  }
         
 if(Input.GetTouch(0).tapCount == 1){
      //Single tap
 }

Not my code but this works on GameObject in Android and Windows:

 float lastTimeClick;
 
 public void OnPointerClick(PointerEventData eventData)
 {
     float currentTimeClick = eventData.clickTime;
             
     if (Mathf.Abs(currentTimeClick - lastTimeClick) < 0.75f)
     {
             //double-click happened
     }
 
     lastTimeClick = currentTimeClick;
 }