[TIMOB-24963] iOS/Android: Added new ScrollView.scrollToTop() method

[jquick-axway]

Note:
This is a modified version of @m1ga's PR #9221. (Thanks Michael!)

JIRA:
Main Ticket
https://jira.appcelerator.org/browse/TIMOB-24963

Also Fixes
https://jira.appcelerator.org/browse/TIMOB-25514
https://jira.appcelerator.org/browse/TIMOB-25515

Summary:

• Added new ScrollView.scrollToTop() method.
• [TIMOB-25514] Fixes Android bug where vertical ScrollView.scrollTo() goes to wrong position when animated. (Introduced in Titanium 6.2.2.)
• [TIMOB-25515] Fixes Android bug where vertical ScrollView.scrollTo() ignores "ti.ui.defaultunit" when animated.
• Animated vertical scrolling bugs mentioned above were solved by disabling the smooth scrolling animation. It now immediately jumps to the given position. This appears to be a Google bug in their Java NestedScrollView class.

Test:

Run the below test on both Android and iOS...

1. Build and run the below code on an Android or iOS device.
2. An alert dialog will be displayed. Tap the "Vertical" scroll view button.
3. Tap the scroll-to "End" button.
4. Verify that the scroll view scrolls to the bottom.
5. Tap the scroll-to "Middle" button.
6. Verify that the top of the middle view is now displayed at the top of the scroll view.
7. Tap the scroll-to "Beginning" button.
8. Verify that the scroll view scrolls to the top.
9. Restart the app.
10. An alert dialog will be displayed. Tap the "Horizontal" scroll view button.
11. Tap the scroll-to "End" button.
12. Verify that the scroll view scrolls all the way to the right side.
13. Tap the scroll-to "Middle" button.
14. Verify that the left side of the middle view is now displayed at the left edge of the scroll view.
15. Tap the scroll-to "Beginning" button.
16. Verify that the scroll view scrolls all the way to the left side.

function showScrollView(isVertical) {
	var window = Ti.UI.createWindow();
	var scrollView = Ti.UI.createScrollView(
	{
		layout: isVertical ? "vertical" : "horizontal",
		scrollType: isVertical ? "vertical" : "horizontal",
		showHorizontalScrollIndicator: !isVertical,
		shorVerticalScrollIndicator: isVertical,
		width: Ti.UI.FILL,
		height: Ti.UI.FILL,
	});
	var firstView = Ti.UI.createLabel(
	{
		text: "First View",
		textAlign: Ti.UI.TEXT_ALIGNMENT_CENTER,
		color: "white",
		backgroundColor: "blue",
		borderColor: "white",
		borderWidth: "1dp",
		width: isVertical ? "100%" : "75%",
		height: isVertical ? "75%" : "100%",
	});
	scrollView.add(firstView);
	var middleView = Ti.UI.createLabel(
	{
		text: "Middle View",
		textAlign: Ti.UI.TEXT_ALIGNMENT_CENTER,
		color: "white",
		backgroundColor: "#008800",
		borderColor: "white",
		borderWidth: "1dp",
		width: isVertical ? "100%" : "75%",
		height: isVertical ? "75%" : "100%",
	});
	scrollView.add(middleView);
	var lastView = Ti.UI.createLabel(
	{
		text: "Last View",
		textAlign: Ti.UI.TEXT_ALIGNMENT_CENTER,
		color: "white",
		backgroundColor: "purple",
		borderColor: "white",
		borderWidth: "1dp",
		width: isVertical ? "100%" : "75%",
		height: isVertical ? "75%" : "100%",
	});
	scrollView.add(lastView);
	window.add(scrollView);
	var floatingView = Ti.UI.createView(
	{
		layout: "vertical",
		backgroundColor: "white",
		borderColor: "black",
		borderWidth: "1dp",
		bottom: "10dp",
		width: Ti.UI.SIZE,
		height: Ti.UI.SIZE,
	});
	floatingView.add(Ti.UI.createLabel(
	{
		text: "Scroll to:",
		color: "black",
		top: "5dp",
		bottom: "5dp",
		left: "10dp",
		width: Ti.UI.SIZE,
		height: Ti.UI.SIZE,
	}));
	var buttonContainer = Ti.UI.createView(
	{
		layout: "horizontal",
		bottom: "5dp",
		width: Ti.UI.SIZE,
		height: Ti.UI.SIZE,
	});
	var scrollUpButton = Ti.UI.createButton(
	{
		title: "Beginning",
		left: "5dp",
		right: "5dp",
		width: Ti.UI.SIZE,
		height: Ti.UI.SIZE,
	});
	scrollUpButton.addEventListener("click", function(e) {
		scrollView.scrollToTop();
	});
	buttonContainer.add(scrollUpButton);
	var scrollMiddleButton = Ti.UI.createButton(
	{
		title: "Middle",
		left: "5dp",
		right: "5dp",
		width: Ti.UI.SIZE,
		height: Ti.UI.SIZE,
	});
	scrollMiddleButton.addEventListener("click", function(e) {
		var x = isVertical ? 0 : firstView.size.width;
		var y = isVertical ? firstView.size.height : 0;
		scrollView.scrollTo(x, y, { animated: true });
	});
	buttonContainer.add(scrollMiddleButton);
	var scrollDownButton = Ti.UI.createButton(
	{
		title: "End",
		left: "5dp",
		right: "5dp",
		width: Ti.UI.SIZE,
		height: Ti.UI.SIZE,
	});
	scrollDownButton.addEventListener("click", function(e) {
		scrollView.scrollToBottom();
	});
	buttonContainer.add(scrollDownButton);
	floatingView.add(buttonContainer);
	window.add(floatingView);
	window.add(buttonContainer);
	window.open();
}

var dialog = Ti.UI.createAlertDialog(
{
	message: "Select ScrollView Type",
	buttonNames: ["Vertical", "Horizontal"],
});
dialog.addEventListener("click", function(e) {
	if (e.index == 0) {
		showScrollView(true);
	} else if (e.index == 1) {
		showScrollView(false);
	}
});
if ((Ti.Platform.osname === "iphone") || (Ti.Platform.osname === "ipad")) {
	var rootWindow = Ti.UI.createWindow();
	rootWindow.addEventListener("open", function(e) {
		dialog.show();
	});
	rootWindow.open();
} else {
	dialog.show();
}

[hansemannn]

iOS approved. Waiting for Android-approval before QE can merge.

[mukherjee2]

Tested with this environment:
Node Version: 8.9.1
NPM Version: 5.5.1
Mac OS: 10.13
Appc CLI: 7.0.0-master.13
Appc CLI NPM: 4.2.11-2
Titanium SDK version: 7.0.0.v20171114213729
Appcelerator Studio vers 4.10.0
Xcode 9.1/iOS 11.1 iPhone 7 Plus
Android 7.1.2 (Pixel), 4.1.2 (Galaxy S2)

Passed FR. I followed the steps per Josh's test case with iOS 11, and Android 7.1.2, and 4.1.2. Tests passed.

[mukherjee2]

@garymathews can you please CR? If there are code changes, I'll redo the FR. Otherwise, I'll merge it.

[garymathews]

CR: PASS