Android Training - Pull to Refresh
18
Pull To Refresh Training 2014/03/11 John
Transcript of Android Training - Pull to Refresh
Pull To Refresh Training2014/03/11 John
Outline
● Introduction● Design● How to implement
○ Touch Event○ Adding view○ On Touching○ Smooth Scrolling○ Window Manager
● Summary● Homework
Introduction
Introduction
There is a patent application for the “pull-to-refresh” feature that Loren Brichter pioneered in Tweetie and is now an extremely popular UI gesture used in a lot of iOS, Mac and Android apps.
ref: http://goo.gl/PjTjMA
Design1. The user pulls down a list.2. A message appears, telling the user
who can pull down the list to refresh.3. The user pulls the list further down.4. A new message appears, telling the
user that the list will refresh when he releases it.
5. A refreshing or loading message appears.
6. The refreshing message disappears and a new list is shown, with the new items at the top of the list.
Design
i.e. LinearLayout
How to implement
Touch event Touch Event
How to implement
Touch eventThe onInterceptTouchEvent() method is called whenever a touch event is detected on the surface of a ViewGroup, including on the surface of its children.The onInterceptTouchEvent() method gives a parent the chance to see any touch event before its children do.
How to implement
Managing Touch events Use ViewConfigurationConstants
ref: http://goo.gl/JJN80z
How to implement
Managing Touch events Extend a Child View's Touchable Area
ref: http://goo.gl/JJN80z
How to implementAdding View
How to implementOn Touching
● Touch event filter.● Setting variable up.
How to implementOn Touching
● Doing actions.
How to implementSmooth scrolling
Ref: http://goo.gl/eb3DQH
SmoothScrollRunnable:● Get next position from
Interpolator.● Set scroll to position.● Post(this).
How to implementWindow Manager● Every display has a
WindowManager.● WindowManager is a
System Manager.
Summary
● “Make it a little simpler”● How dose Touch event transit.● How to implement smooth scrolling.
HomeworkSample source code: (You can also fInd it at the video record nearby if this link is invalid.)https://www.dropbox.com/s/9zqt60tf7drppyi/TrainingPullToRefresh.zip
Basic:● Let it be pulled from left.
Advance:● Let it be pulled from both top and bottom.
