Xamarin.forms: [Enhancement] Add Scrolled event to CollectionView

Created on 27 Mar 2019 · 7Comments · Source: xamarin/Xamarin.Forms

Description

CollectionView aims to be more flexible by provide us the ability to know when CollectionView has been scrolled.

Many people have been asking for such an event, and a quick web search for 'xamarin forms listview scroll event' shows it. to make parallax headers, make some views dis/appearing when scroll up/down or other stuff using the scroll event.

API Event

| API | Description |
| ------------- | ------------- |
| Scrolled | Occurs when user interact with the CollectionView|

Implementation

this is exact same signature of ScrollView.Scrolled event .

public event EventHandler<Xamarin.Forms.ScrolledEventArgs> Scrolled;

Backward Compatibility

New feature, so it does not have any impact.

Difficulty

Hmmm...
CollectionView inherit from ScrollView, it should not be a big deal.

collectionview enhancement ➕

Source

Phenek

👍12 🚀1

Most helpful comment

It would be awesome if the ScrolledEventArgs could provide us some ScrollStatus,
similar to PanUpdatedEventArgs.StatusType Property

public enum ScrollStatus

| Enum | Int |Description|
| ------------- | ------------- |------------- |
|Canceled | 3 | The scroll was canceled|
|Completed | 2 | The scroll completed|
|Running | 1 | The scroll is still being recognized|
|Started | 0 | The scroll started|

Phenek on 26 Apr 2019

👍2

All 7 comments

5754 adds a `RecyclerViewScrollListener` to Android's `ItemsViewRenderer` and can be used to send scroll events.

adrianknight89 on 30 Mar 2019

4654

adrianknight89 on 30 Mar 2019

It would be awesome if the ScrolledEventArgs could provide us some ScrollStatus,
similar to PanUpdatedEventArgs.StatusType Property

public enum ScrollStatus

Phenek on 26 Apr 2019

👍2

@Phenek We might need to create a different event for this. ScrolledEventArgs is getting crowded with multiple properties already and provides numerical data. State data can be provided by another event, in my opinion.

adrianknight89 on 30 Apr 2019

👍1

With merging #5754 I’m going to close this for now. The basic Scrolled event is there, if there is anything you are still missing please open a new issue with the specific information for that. And let us know what you think of the current implementation when it’s released, thanks!