35.3 Implementing the Listener Class

As previously outlined, it is necessary to create a class that implements the GestureDetector.OnGestureListener interface and, if double tap detection is required, the GestureDetector.OnDoubleTapListener interface. While this can be an entirely new class, it is also perfectly valid to implement this within the current activity class. For the purposes of this example, therefore, we will modify the MainActivity class to implement these listener interfaces. Edit the MainActivity.kt file so that it reads as follows:

package com.ebookfrenzy.commongestures

 

import androidx.appcompat.app.AppCompatActivity

import android.os.Bundle

import android.view.GestureDetector

import android.view.MotionEvent

 

class MainActivity : AppCompatActivity(),

   GestureDetector.OnGestureListener, GestureDetector.OnDoubleTapListener

{

.

.

Declaring that the class implements the listener interfaces mandates...