Recognizing tap and other common gestures

Unlike the Event Listeners described in the previous recipe, gestures require a two-step process:

• Gather the movement data

• Analyze the data to determine whether it matches a known gesture

Step 1 begins when the user touches the screen, which fires the onTouchEvent() callback with the movement data sent in a MotionEvent object. Fortunately, Android makes Step 2, analyzing the data, easier with the GestureDetector class, which detects the following gestures:

• onTouchEvent()

• onDown()

• onFling()

• onLongPress()

• onScroll()

• onShowPress()

• onDoubleTap()

• onDoubleTapEvent()

• onSingleTapConfirmed()

This recipe will demonstrate using the GestureDetector.SimpleOnGestureListener to recognize the touch and double tap gestures.

Getting ready

Create a new project in Android Studio and call it: CommonGestureDetector. Use the default Phone & Tablet options and select Empty Activity when prompted for the Activity Type.

How to do it...

We will be using the activity itself...