[AC-6646] [Android] Scrollable View `currentPage` Property Not Updated After Being Assigned

GitHub Issue	n/a
Type	Bug
Priority	n/a
Status	Open
Resolution	Unresolved
Affected Version/s	n/a
Fix Version/s	n/a
Components	Titanium SDK & CLI
Labels	android, parity
Reporter	Ma Wenli
Assignee	Abir Mukherjee
Created	2020-12-15T08:43:17.000+0000
Updated	2020-12-15T10:23:56.000+0000

Description

If currentPage property of scrollable view is assigned in the code, the value doesn't seem to get updated immediately on Android. This issue can be reproduced by creating a new project with the following sample code, building the project with Titanium SDK 9.3.0.GA, and running the app on an *_Android_* device:

var win = Ti.UI.createWindow();

var v0 = Ti.UI.createView({
    backgroundColor: 'red'
});
v0.add(Ti.UI.createLabel({
    color: 'white',
    text: 'Page index = 0'
}));

var v1 = Ti.UI.createView({
    backgroundColor: 'blue'
});
v1.add(Ti.UI.createLabel({
    color: 'white',
    text: 'Page index = 1'
}));

var v2 = Ti.UI.createView({
    backgroundColor: 'green'
});
v2.add(Ti.UI.createLabel({
    color: 'white',
    text: 'Page index = 2'
}));

var scrollableView = Ti.UI.createScrollableView({
    views: [v0, v1, v2],
    height: Ti.UI.FILL,
    width: Ti.UI.FILL
});
win.add(scrollableView);

// Note that currentPage property of scrollable view is assigned here
scrollableView.currentPage = 1;

Ti.API.info('currentPage property of scrollable view is: ' + scrollableView.currentPage);

win.open();

What I observed in the console was a message saying "[INFO] currentPage property of scrollable view is: 0", but currentPage should have been updated to 1 already. FYI, when I run the above sample code on an iOS device, the console output would be "[INFO] currentPage property of scrollable view is: 1" instead, which was the expected behaviour.

Comments

Ewan Harris 2020-12-15

I can reproduce this issue back to 8.3.1.GA, it's possible this might be some form of timing issue on Android as adding even a small timeout to the log like below will log the correct value setTimeout(() => { Ti.API.info('currentPage property of scrollable view is after timeout: ' + scrollableView.currentPage); }, 50)

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