Android Training (Touch)
Download as PPTX, PDF1 like594 views
This document provides an overview of touch support and gestures in Android. It discusses how to handle touch events via the MotionEvent class and onTouchEvent method. It also covers using the GestureDetector class to detect gestures like taps, swipes, pinches. Specific tasks demonstrated include drawing lines as the user touches, connecting drawn dots, and implementing swipe to delete in a ListView.
Android Training (Touch)
- 1. Android Touch Android Training By Khaled Anaqwa
- 2. Android touch basics The Android standard View class support touch events. You can react to touch events in your custom views and your activities. Android supports multiple pointers, e.g. fingers which are interacting with the screen.
- 3. The base class for touch support is the MotionEvent class which is passed to Views via the onTouchEvent() method. To react to touch events you override the onTouchEvent() method.
- 4. Single touch If single input is used you can use the getX() and getY() methods to get the current position of the first finger. Via the getAction() method you receive the action which was performed
- 5. The MotionEvent class provides the following constants to determine the action which was performed.
- 6. Demo Using One Touch Create custom View Draw in it Track touches points Draw lines while move
- 7. Task Draw dot’s and connects these dot’s on screen
- 8. Gestures Android provides special types of touch screen events such as pinch , double tap, scrolls , long presses and flinch. These are all known as gestures. Android provides GestureDetector class to receive motion events and tell us that these events correspond to gestures or not.
- 9. Using you need to create an object of GestureDetector and then extend another class with GestureDetector.SimpleOnGestureListener to act as a listener.
- 10. Gestures Type Touch Long press Swipe or drag Long press drag Double touch (Tap) Pinch open / close
- 11. Where I can use onTouch Listener onTouchEvent (Activity Override) onTouchEvent (CustomView Override) onTouch(view.setOnTouchListener)
- 13. Task Create Listview and implement Swipe to delete