I like the rich features of CollectionView but I find it a bit sluggish, for example, on Android (Maui). I use the Grouped listing feature to categorize list items with Group Key and that is when I start to notice performance issues. I have gone through the documentation. Are there tips and tricks outwith the documentation that I can consider to make CollectionView more responsive?

Hello, Here are some tips that you can refer. We should avoid a nested view and try to create a flat view wherever possible. Nested view reduces CollectionView performance. For example, add vertical CollectionView in horizontal CollectionView . CollectionView is rendererd by AndroidX.RecyclerView.Widget.RecyclerView in Native Android. If the height of all the items is equal. Set recycleView.HasFixedSize = true; in CollectionViewHandler. Here are tips from Xamarin offical document Improve Xamarin.Forms App Performance . But some tips are working in MAUI. Such as following topics: Reduce unnecessary , Choose the correct layout bindings , Optimize layout performance , Use asynchronous programming and Reduce the visual tree size . Best Regards, Leon Lu If the answer is the right solution, please click " Accept Answer " and kindly upvote it. If you have extra questions about this answer, please click "Comment". Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Are there tips and tricks that will make the CollectionView control more responsive on mobile devices?

Accepted answer

Leon Lu (Shanghai Wicresoft Co,.Ltd.) 68,571 Reputation points Microsoft Vendor

2022-11-22T05:56:23.587+00:00

Hello,

Here are some tips that you can refer.

We should avoid a nested view and try to create a flat view wherever possible. Nested view reduces CollectionView performance. For example, add vertical CollectionViewin horizontal CollectionView.

CollectionView is rendererd by AndroidX.RecyclerView.Widget.RecyclerView in Native Android. If the height of all the items is equal. Set recycleView.HasFixedSize = true; in CollectionViewHandler.

Here are tips from Xamarin offical document Improve Xamarin.Forms App Performance. But some tips are working in MAUI. Such as following topics: Reduce unnecessary, Choose the correct layout bindings, Optimize layout performance, Use asynchronous programming and Reduce the visual tree size.

Best Regards,

Leon Lu

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

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dg2k 1,386 Reputation points

2022-11-22T07:38:14.827+00:00

As always thank you @Leon Lu (Shanghai Wicresoft Co,.Ltd.)

How might I get to the recycleView instance with the Platform handler?
Sorry, still on the learning curve with the nuances of getting to Platform objects with .Net Maui.

#if ANDROID CollectionViewHandler.Mapper.AppendToMapping(nameof(IView.Background), (handler, view) => { if (view is CollectionView) { ??? } } #endif

Leon Lu (Shanghai Wicresoft Co,.Ltd.) 68,571 Reputation points Microsoft Vendor

2022-11-22T08:08:30.317+00:00

Please refer to following link. Here is document about using handler.

Microsoft.Maui.Controls.Handlers.Items.CollectionViewHandler.Mapper.AppendToMapping("ChatStackFromEnd", (h, v) => { #if ANDROID AndroidX.RecyclerView.Widget.RecyclerView recycleView = h.PlatformView; // recycleView.SetItemViewCacheSize(size); recycleView.HasFixedSize = true; #endif });

dg2k 1,386 Reputation points

2022-11-22T08:23:20.837+00:00

Thank you a lot @Leon Lu (Shanghai Wicresoft Co,.Ltd.) .
Just one final query on this question:

I am using the IsGrouped="True" for CollectionView in order to use grouping of list items based on a Grouping Key criteria. Therefore, I end up creating two distinct list items:

CollectionView.GroupHeaderTemplate for groups, and

CollectionView.ItemTemplate for the grouped items.

Now, each of the Groups are the same group height, and each of the grouped items are also of the same item height.

However, the group height and item height are different. Does this mean that what you said:

If the height of all the items is equal...

is no more valid?

Leon Lu (Shanghai Wicresoft Co,.Ltd.) 68,571 Reputation points Microsoft Vendor

2022-11-22T09:21:40.27+00:00

I think it is not valid, Please check the source code of grouping Collectionview. When you have header or footer, it will retrun a new BindTemplatedItemViewHolder in OnBindViewHolder, this will make height of all the items not equal.

By the way, if we want to improve performance for RecycleView in native android, onBindViewHolder method should do very less work.

dg2k 1,386 Reputation points

2022-11-22T09:34:11.547+00:00

Can you please elaborate on your last statement? You're making an important point and don't want to miss out.

Leon Lu (Shanghai Wicresoft Co,.Ltd.) 68,571 Reputation points Microsoft Vendor

2022-11-22T09:57:24.623+00:00

onBindViewHolder(): RecyclerView calls this method to associate a ViewHolder with data. The method fetches the appropriate data and uses the data to fill in the view holder's layout.

From Google RecycleView's adapter

onBindViewHolder is executed before each item is displayed, so less work(such as judge item type, then load the different item layout) will improve performance in the onBindViewHolder
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Are there tips and tricks that will make the CollectionView control more responsive on mobile devices?

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