[BUG] Quick sliding to the top and bottom, do not adjust this method "onPageChanged"

[JingChen1]

Quick sliding, do not adjust this method "onPageChanged"

[geraldvoit]

I can confirm that there is an issue with the 'onPageChanged' handler.

Describe the bug

The 'onPageChanged' callback (PagerContent.swift:232) is not called in the event of gestures followed quickly by each other. Therefore, the app is not able to react on index change updates.

To Reproduce

• Quick Drag Gesture from right to left followed instantly by a second one.

Expected behavior

'onPageChanged' handler will be called on every page index change.

Environment:

OS: iOS 16
SwiftUIPager 2.5.0

Additional context

The SwiftUIPager detects both Drag Gestures and finishes both with 'onDragGestureEnded' (PagerContent.swift:373). The 'onAnimationCompleted' (PagerContent.swift:227) observer triggers only once, which is totally fine. But the second 'onDragGestureEnded' call sets self.pagerModel.pageIncrement = 0. Therefore, the following 'onAnimationCompleted' observation won't trigger the 'onPageChanged' callback.

[PatrickGaissert]

We really need this fix. For now we're pointing to the forked commit (thank you @geraldvoit !!!) but we would really like to have the fix in an official release of the library. Is there any chance this will happen?

[ghost]

Hello, @fermoya. Can you create a new release of the library with this fix, please🙏

[alexshekhovtsov]

Hello, guys, if somebody needs to fix this issue quickly, so just instead of using
.onPageChanged on Pager

use this:

.onDraggingEnded {
    viewModel.onDraggingEnded()
}

and this workaround in your ViewModel:

private var pageWorkItem: DispatchWorkItem?
private var workItemPageIndex: Int = 0

func onDraggingEnded() {
    pageWorkItem?.cancel()
    
    pageWorkItem = DispatchWorkItem {
        self.handleOnDraggingEnded()
    }
    DispatchQueue.main.asyncAfter(deadline: .now() + 0.3,
                                  execute: pageWorkItem!)
}

private func handleOnDraggingEnded() {
    guard workItemPageIndex != currentPage.index else { return }
    updatePage()
    workItemPageIndex = currentPage.index
}