[TIMOB-27879] Android: ListView should only fire "scrolling" event when moving a min distance

GitHub Issue	n/a
Type	New Feature
Priority	Medium
Status	Closed
Resolution	Fixed
Resolution Date	2020-08-07T10:39:23.000+0000
Affected Version/s	n/a
Fix Version/s	Release 9.1.0
Components	Android
Labels	ScrollView, android, scroll
Reporter	Michael Gangolf
Assignee	Joshua Quick
Created	2020-05-03T13:35:42.000+0000
Updated	2020-08-07T10:39:23.000+0000

Description

Android's ListView can spam a "scrolling" event even when your finger is held at a single position. This is because there is currently no touch tolerance applied and 1 pixel scroll movement will fire the event. It should only fire a "scrolling" event when the scroll direction changes and for a minimum pixel distance specified by Google's [ViewConfiguration.getScaledTouchSlop()](https://developer.android.com/reference/android/view/ViewConfiguration#getScaledTouchSlop()) API.

var win = Ti.UI.createWindow({backgroundColor: 'gray'});
var listView = Ti.UI.createListView();
var sections = [];

var fruitSection = Ti.UI.createListSection({ headerTitle: 'Fruits'});
var fruitDataSet = [
    {properties: { height: 100,title: 'Apple'}},
    {properties: { height: 100,title: 'Apple'}},
    {properties: { height: 100,title: 'Apple'}},
    {properties: { height: 100,title: 'Apple'}},
    {properties: { height: 100,title: 'Apple'}},
    {properties: { height: 100,title: 'Apple'}},
    {properties: { height: 100,title: 'Apple'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
    {properties: { height: 100,title: 'Banana'}},
];
fruitSection.setItems(fruitDataSet);
sections.push(fruitSection);

listView.appendSection(sections);
listView.addEventListener("scrolling",function(e){
	console.log(e.direction);
})
win.add(listView);
win.open();

Comments

Michael Gangolf 2020-05-03

PR: https://github.com/appcelerator/titanium_mobile/pull/11680
Samir Mohammed 2020-07-02

FR Passed, waiting on Jenkins build.
Christopher Williams 2020-07-06

merged to master for 9.1.0 target
Sohail Saddique 2020-08-07

Fix verified on build 9.1.0.v20200804082025. Ticket closed.

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