1. Home
  2. Forum
  3. Xamarin.Forms
  4. About sflistView .The data will jump when sflistview slides thank you

About sflistView .The data will jump when sflistview slides thank you

About sflistView .The data will jump when sflistview slides thank you

Here is a screenshot of the test phone


微信图片_20210705004005.jpg

微信图片_20210705130535.jpg


Attachment: demo_and_video_ea4ce3f3.rar


66 Replies
? ? July 5, 2021 08:32 AM UTC

Several models have been tested, only this vivo X50 origin OS

There is a problem thank you 


LN Lakshmi Natarajan Syncfusion Team July 5, 2021 10:36 AM UTC

Hi,  
   
Thank you for using Syncfusion products.  
   
We have checked the reported query “The data will jump when sflistview slides” from our side. We would like to inform you that we have checked the reported sample in Pixel 3XL Pie 9.0 (Android 9.0 – API 28) emulator but we are unable to reproduce the scenario at our side.   
   
Due to Covid 19, we are working on remote, and the android device is not available. So, we are unable to check the issue in the android device mentioned.  
   
Meanwhile, could you please share the LoadMoreKnowlsCommand code snippets to analyze the scenario further from our side. Since, the SfListView will scroll to top if we clear the collection bound to the ItemsSource and replace a new collection at run time.   
   
Regards,  
Lakshmi Natarajan  


? ? July 5, 2021 12:18 PM UTC

I tested a lot of models,only this vivo X50 origin OS ，There are the above problems

It's normal on the simulator 

android7，android8，android9，android10,android11 

Also tested, no problem


only this vivo X50 origin OS ，There are the above problems

Origin OS is an OS of Android deeply customized by vivo

If the loadmoreknowlscommand binding is not used, the same problem will occur

I used an official example. As long as I use vivo X50 origin OS, I have the same problem



Attachment: 两个实列_7d4799de.rar

? ? July 5, 2021 12:23 PM UTC

A test video


Attachment: 9fc347c32d8dd901da6cc03fd9568490_115dac73.rar

? ? July 5, 2021 01:32 PM UTC

That is, the data doesn't slide to the end at all, and the scroll bar jumps up.


? ? July 6, 2021 10:31 AM UTC

Vivo mobile phone is the second largest mobile phone manufacturer in China, so our app must adapt to it.

We are very anxious to solve this problem, thank you very much!


? ? July 6, 2021 01:06 PM UTC

The feeling is that it's bouncing back before it slides to the end


LN Lakshmi Natarajan Syncfusion Team July 6, 2021 02:25 PM UTC

Hi, 
 
We deeply regret for the inconvenience caused. 
 
We have checked the availability for the mentioned device (Vivo X50 origin OS) with other teams. Unfortunately, the reported device is not available. We will request the device to our management and update you further details as soon as possible. We appreciate your patience until then. 
 
Regards, 
Lakshmi Natarajan 


? ? July 6, 2021 02:38 PM UTC

Thank you very much for your reply. I'd like to ask when we can solve this problem

We urgently need to solve this problem. Thank you very much


? ? July 6, 2021 03:21 PM UTC

We are very eager and urgently to solve this problem.

I really very much hope that we can solve this problem as soon as possible

Thank you very much， Thank you very much


LN Lakshmi Natarajan Syncfusion Team July 7, 2021 12:42 PM UTC

Hi, 
 
We regret for the inconvenience caused. 
 
We can understand your emergency, we will update once we got the device as soon as possible. We appreciate your patience until then. 
 
Lakshmi Natarajan 
 


? ? July 8, 2021 02:39 AM UTC

I would like to ask if we have started to fix this problem now。

thank you very mach


? ? July 10, 2021 01:33 AM UTC

hi,

I would like to ask how long this problem can be solved. Is it on the way to solve it? Thank you very much.



? ? July 11, 2021 04:26 AM UTC

hi,

I would like to ask how long this problem can be solved. Is it on the way to solve it? Thank you very much.


? ? July 12, 2021 07:15 AM UTC

hi,

I would like to ask how long this problem can be solved. Is it on the way to solve it? Thank you very much.


LN Lakshmi Natarajan Syncfusion Team July 12, 2021 09:22 AM UTC

Hi, 
 
We regret for the inconvenience caused. 
 
We would like to inform you that we have tested the reported scenario in Vivo V7+ device. Unfortunately, the reported issue cannot be reproduced and the SfListView scrolling works fine as expected. Please find the tested device configurations below, 
  
Model number: Vivo 1716 
Model name: V7+ 
Android OS: Funtouch OS 
Android version: API 8.1.0 
 
Due to non- availability of the particular device, we checked in another similar device and we are unable to reproduce the issue.  
 
Meanwhile, could you please set SfListView.IsScrollingEnabled to False and check whether the reported issue resolved or not? 
 
Please try the following suggestions mentioned in the documentations, 
 
If not, please check with Xamarin.Forms ListView and CollectionView or Xamarin.Forms ScrollView controls and try to replicate the same issue. If the same issue reproduced in the framework controls also, please log issue report to Xamarin team.  
 
Regards, 
Lakshmi Natarajan 


? ? July 12, 2021 09:57 AM UTC

The device that doesn't work is vivox50 origin OS 

Not the device you're testing

There is no problem with funtouch OS system

未标题-2fff11.jpg


? ? July 12, 2021 10:00 AM UTC

I've tried collectionview, no problem


? ? July 12, 2021 10:06 AM UTC

The operating system that doesn't work is origin OS 。thank you


? ? July 12, 2021 10:09 AM UTC

Device configuration that does not work

Model number: Vivo

Model name: x50

Android OS: Origin OS

Android version: API 10

12313.jpg


? ? July 12, 2021 10:17 AM UTC

This property sflistview. Isscrollingenabled = false，still can't work

There is no problem with funtouch OS system

The operating system that doesn't work is origin OS 。thank you

I've tried collectionview and listview, no problem


Device configuration that does not work

Model number: Vivo

Model name: x50

Android OS: Origin OS

Android version: API 10


thank you very much


? ? July 12, 2021 10:28 AM UTC

I really hope we can use vivo X50 origin OS to reproduce the problem

thank you very much


Attachment: 两个实列_7d4799de_d5dceb23.rar

? ? replied to ? July 12, 2021 12:02 PM UTC

I really hope we can use vivo X50 origin OS to reproduce the problem

thank you very much

Model number: Vivo

Model name: x50

Android OS: Origin OS

Android version: API 10



? ? July 12, 2021 01:24 PM UTC

Funtouch OS has been tested,It can work well.

Only origin OS cannot working

I really hope we can use vivo X50 origin OS to reproduce the problem

thank you very much


LN Lakshmi Natarajan Syncfusion Team July 13, 2021 01:43 PM UTC

Hi, 
 
Thank you for the update. 
 
We are currently analyzing the reported scenario at our side. We will check and update you further details on or before July 16, 2021. We appreciate your patience until then. 
 
Lakshmi Natarajan 
 


? ? July 13, 2021 03:37 PM UTC

Today, I tested many more mobile phones

The following devices do not work

vivo x50         originos   v2001A

vivo x50pro+ originos   v2011A


LN Lakshmi Natarajan Syncfusion Team July 14, 2021 12:01 PM UTC

Hi, 
 
Thank you for the update. 
 
As promised, we will share further details on July 16, 2021. We appreciate your patience until then. 
 
Lakshmi Natarajan 
 


? ? July 17, 2021 10:40 AM UTC

hi,

I am very eager to get your reply about this issue.

Has it been solved or is it on the way  now

thank you very much.


? ? July 17, 2021 12:36 PM UTC

Today, I upgrade the latest version of xamarin. Forms and the latest version of sflistview. Problems still exist!

I very much hope that this problem can be solved as soon as possible。

thank you very much


? ? July 18, 2021 04:46 AM UTC

hi,

I am very eager to get your reply about this issue.

Has it been solved or is it on the way now

thank you very much.


? ? July 19, 2021 09:25 AM UTC

hi,

I am very eager to get your reply about this issue.

Has it been solved or is it on the way now

thank you very much.


LN Lakshmi Natarajan Syncfusion Team July 20, 2021 09:32 AM UTC

Hi, 
 
Sorry for the inconvenience caused. 
 
We have checked with our management, and we could not find an environment to replicate the issue on our side. Also, since the reported issue occurs in a particular device with customized OS, we could not find emulator for the same. If you have any emulator setup to replicate the issue, please share the emulator with us which would help us to check on it and provide you with the solution as soon as possible. 
 
Regards, 
Lakshmi Natarajan 


? ? July 20, 2021 10:43 AM UTC

hi,

Thank you for actively fix this isuue

You can visit the following website:

https://vcl.vivo.com.cn/

This is the vivo cloud test platform, which has many types of vivo devices。

You can choose vivo X50 and vivo X50 pro+  to test this problem

thank you very much.


? ? July 20, 2021 10:52 AM UTC

https://vcl.vivo.com.cn/

Select after login：

未标题-11.jpg

未标题-22.jpg


LN Lakshmi Natarajan Syncfusion Team July 22, 2021 03:19 AM UTC

Hi, 
 
Thank you for the update. 
 
We have checked the mentioned website as suggested. Unfortunately, we could not login properly to check the applications at our side. We will check other possibilities for test platforms and update you further details on July 23, 2021. We appreciate your patience until then. 
 
Regards, 
Lakshmi Natarajan 


? ? July 25, 2021 03:51 AM UTC

Hi,
Thank you for the update.

At first, didn't you say that you tested this issue with other teams? This issue is also confirmed.

Can you tell me the details of this issue.thank you very much.

123.jpg


LN Lakshmi Natarajan Syncfusion Team July 26, 2021 04:10 AM UTC

Hi, 
 
Sorry for the inconvenience caused. 
 
We have checked with other teams and management regarding the device. Unfortunately, the device mentioned is not available and we are unable to test the issue. We have also checked for the test platforms, but we could not find the same. We will let you know if we got the chance to test the issue. We appreciate your patience until then. 
 
Lakshmi Natarajan 
  
 


? ? July 26, 2021 04:51 AM UTC

HI,

Thank you for update.

Have you seen the test issue video I sent?

Can you guess the cause of the issue？



LN Lakshmi Natarajan Syncfusion Team July 27, 2021 08:56 AM UTC

Hi, 
 
We have checked the reported scenario based on the information provided.  
 
Meanwhile, we would like to suggest that you can disable the default scrolling of the ListView and use Xamarin.Forms ScrollView for scrolling. You can achieve this requirement by setting the NestedScrollingEnabled as False in sample level. If you are still facing the same issue, then we can assume that the jump issue occurs from the framework level and you can raise the issue ticket for framework team. 
 
Please refer to the following code snippets for more reference,  
  
Write dependency interface in the PCL project  
public interface IDependencyListView 
{ 
    void DisableListViewScrolling(SfListView ListView); 
} 
  
Implement the interface and set the NestedScrollingEnabled for the renderer in the native android project.  
[assembly: Dependency(typeof(ListViewDependencyService))] 
namespace ListViewScrollToEnd.Droid 
{ 
    public class ListViewDependencyService : IDependencyListView 
    { 
        ExtendedScrollView ExtendedScrollView; 
 
        public void DisableListViewScrolling(SfListView ListView) 
        { 
            ExtendedScrollView = ListView.GetScrollView();  
            var extendedScrollViewRenderer = Platform.GetRenderer(ExtendedScrollView);  
            extendedScrollViewRenderer.View.NestedScrollingEnabled = false;  
        } 
    } 
} 
  
In the Loaded event, call the dependency method for the ListView to update the API.  
ListView.Loaded += ListView_Loaded; 
 
private void ListView_Loaded(object sender, ListViewLoadedEventArgs e) 
{ 
    if (Device.RuntimePlatform == Device.Android) 
    { 
        DependencyService.Get<IDependencyListView>().DisableListViewScrolling(ListView); 
    } 
} 
  
Also, set the IsScrollingEnabled as False for the ListView to load the ListView with full height. And load the SfListView inside the ScrollView.  
<ScrollView> 
    <sync:SfListView x:Name="listView" ItemsSource="{Binding BookInfo}" ItemSize="100" IsScrollingEnabled="False"> 
 
        <sync:SfListView.Behaviors> 
            <local:Behavior/> 
        </sync:SfListView.Behaviors> 
        ... 
    </sync:SfListView> 
</ScrollView> 
  
We have attached the sample for your requirement and updated in the following link,  
 
Also, you can refer to the following documentation to load the SfListView inside ScrollView, 
  
Please let us know if you need further assistance.  
 
Regards, 
Lakshmi Natarajan 


? ? July 27, 2021 04:18 PM UTC

Hi,

Thank you for update

This can solve this issue but after this is solved, loadmorecommand cannot be working, syncfusion: dragindicatorview is also affected, and the performance is degraded


? ? July 28, 2021 02:07 AM UTC

This method can really solve the issue, but there are many disadvantages. loadmorecommand cannot be working,Page switching will be slow.Can this issue be completely solved in the next version?


LN Lakshmi Natarajan Syncfusion Team July 28, 2021 03:59 PM UTC

Hi, 
 
Sorry for the inconvenience caused. 
 
#Regarding This can solve this issue but after this is solved, loadmorecommand cannot be working, syncfusion: dragindicatorview is also affected, and the performance is degraded 
 
We would like to inform you that the above mentioned features will be affected if we disabled the default scrolling of the ListView.  
 
#Regarding testing on vivo cloud test platform 
 
We are unable to login to the mentioned website and getting invalid mobile number error while navigating to the Remote real machine -> Application page. Please refer to the following screenshot for the same, 
 
Could you please share your vivo cloud test platform credentials with us so that we can access the above-mentioned site? If yes, we can open a support incident under your email address in which you can share your credentials. The incident's shared details will not be made public, and only you and the support engineer working on the issue will have access to it. 
 
Meanwhile, please share us the procedures to connect the Visual Studio and the vivo cloud test platform to deploy the Xamarin.Forms application and debug on the issue. It will be really helpful for us to check on the reported scenario at the earliest. 
 
Lakshmi Natarajan 
 


? ? July 29, 2021 04:26 AM UTC

Hi,

thandk you for update

The Vivo cloud test platform cannot be deployed together with visual studio for remote debugging. It can only package APK and upload it to test platform to test the effect.

We'd better have a vivox50 or vivox50 pro+ machine to test.


LN Lakshmi Natarajan Syncfusion Team July 29, 2021 02:08 PM UTC

Hi, 
 
Thank you for the update. 
 
We would like to inform you that we need some details to check at our side. We have attached the sample with the ExtendScrollView.Scrolled event. Could you please run the attached sample in vivox50 or vivox50 pro+ device share us the stack trace when the listview scrolls back to top automatically. 
 
Please refer to the event below, 
 
 
Please add the break point as mentioned in the above screenshot and share the entire stack trace. It will be helpful for us to analyze the root cause of the issue in our source level. 
 
Please find the sample in the following link, 
 
Lakshmi Natarajan 
 


? ? July 29, 2021 03:17 PM UTC

Hi, 
Thank you for the update. 

I set a breakpoint on line 36. When I debug the app, the code at the breakpoint will not be executed


Attachment: testvideo_5cd9ea08.rar

LN Lakshmi Natarajan Syncfusion Team July 30, 2021 11:34 AM UTC

Hi, 
 
Sorry for the inconvenience. 
 
Could you please confirm whether or not the Scrolled event was triggered by inserting a break point at Line 33? If so, please do only one down scroll and allow the device to automatically return to the top and retrieve the call stack for this case. 
 
Also, we suspect that the break point does not hit since the scrollview does not jumps all the way to the top to reach ScrollY 0. Could you please get the ScrollY position when scrolling back and put break point for that particular position and the call stack from the Scrolled event. 
 
Please refer to the following code snippets for more reference, 
 
 
 
Regards, 
Lakshmi Natarajan 


? ? July 30, 2021 03:51 PM UTC

Hi, 
Thank you for the update. 

I set a breakpoint on line 33, and it can run to the breakpoint. I'll send you the running output log and effect video. thank you very much.


Attachment: out_log_and_vedio_56b7c3cf.rar

LN Lakshmi Natarajan Syncfusion Team August 2, 2021 10:06 AM UTC

Hi, 
 
Thank you for the update. 
 
We have checked the output log included in the attachment. We would like to inform you that the ScrollY value in the mentioned device suddenly reaches an abnormal value (715827882.333333) and then becomes 0, as shown in the log below.  
 
 
Based on the output log, we need more information to check the reported scenario further. Please add the condition as shown in the code snippets below, 
Behavior.cs 
public class Behavior: Behavior<SfListView> 
{ 
    #region Fields 
    SfListView ListView; 
    ExtendedScrollView ScrollView; 
 
    #endregion 
 
    #region Overrides 
    protected override void OnAttachedTo(SfListView bindable) 
    { 
        ListView = bindable; 
 
        ScrollView = ListView.GetScrollView(); 
        ScrollView.Scrolled += Scrollview_Scrolled; 
 
        base.OnAttachedTo(bindable); 
    } 
 
    private void Scrollview_Scrolled(object sender, ScrolledEventArgs e) 
    { 
        //Get ScrollY position from the output window without breakpoint. 
        System.Diagnostics.Debug.WriteLine("ScrollY value is " + e.ScrollY); 
 
        if(e.ScrollY == 715827882.333333) 
        { 
            System.Diagnostics.Debug.WriteLine("ScrollY 715827882.333333"); 
        } 
 
        if (e.ScrollY == 0) 
        { 
            System.Diagnostics.Debug.WriteLine("ScrollY 0"); 
        } 
    } 
 
    protected override void OnDetachingFrom(SfListView bindable) 
    { 
        ListView = null; 
        base.OnDetachingFrom(bindable); 
    } 
 
    #endregion 
} 
 
 
Also, add a breakpoint in each of the if conditions and share the call stack for each separately. For reference, please see the call stack screenshot below, 
 
 
Lakshmi Natarajan 
  
 


? ? August 2, 2021 05:50 PM UTC

hi,

thank you for update

The first place, the breakpoint, can't reach that place.

        if(e.ScrollY == 715827882.333333) 
        { 

Here is a picture of the second breakpoint

未标题-4.jpg


Attachment: 输出log_679d450a.rar

LN Lakshmi Natarajan Syncfusion Team August 3, 2021 03:16 PM UTC

Hi, 
 
Thank you for the update. 
 
We would like to inform you that we need the call stack of the Scrolled event call to analyze the reported scenario in our source level. Please enable External code to check the entire call stack. When the break point is reached, select all lines in the call stack window for each condition and send the stack trace. 
 
Please refer to the following code snippets to enable external code, 
 
Right click on the call stack window -> Click Show External Code 
 
 
 
#Regarding first condition’s break point not executed 
Please add the following condition to check whether the condition executed or not. 
 
private void Scrollview_Scrolled(object sender, ScrolledEventArgs e) 
{ 
    //Get ScrollY position from the output window without breakpoint. 
    System.Diagnostics.Debug.WriteLine("ScrollY value is " + e.ScrollY); 
 
    if(e.ScrollY > 3000) 
    { 
        System.Diagnostics.Debug.WriteLine("ScrollY 715827882.333333"); 
    } 
 
    if (e.ScrollY == 0) 
    { 
        System.Diagnostics.Debug.WriteLine("ScrollY 0"); 
    } 
} 
 
 
 
Lakshmi Natarajan 
  
 


? ? August 4, 2021 03:09 AM UTC

Hi,

Thank you for the update.

1.jpg

2.jpg


LN Lakshmi Natarajan Syncfusion Team August 4, 2021 01:47 PM UTC

Hi, 
 
Please find the following video to get the call stack and share us in the text file. 
 
 
Note: You need to set breakpoint inside the if conditions and share us the call stack for both conditions. 
 
Also, we have prepared a sample using framework elements based on the SfListView architecture. please check the following sample in the Vivo X50 device and let us know the reported issue reproduced or not? 
 
Regards, 
Lakshmi Natarajan 


? ? August 5, 2021 02:12 AM UTC

Hi,

Thank you for the update.

As for the example you sent, I tested the issue and did not reproduce it. It is working well.



Attachment: Callstack20210805_71ac096c.rar


LN Lakshmi Natarajan Syncfusion Team August 6, 2021 03:40 AM UTC

Hi, 
 
Thank you for the update. 
 
We have checked the shared call stack from our end. Could you please confirm whether or not the call stack shared was for an automatic scroll jump case (issue scenario)? Since the Scrolled event is called from the OnTouchEvent, which is triggered when a touch scroll is performed. If not, please provide us with the call stack when the scrolling automatically resets (e.ScrollY == 0). Also, please share the call stack for the first condition, which is the abnormal value (e.ScrollY > 3000) for line 38. 
 
Lakshmi Natarajan 
 


? ? August 6, 2021 08:42 AM UTC

Hi,

Thank you for the update.

I'm not sure, but I took a video. You can have a look and the call stack .

However, it should be the call stack when the scroll bar reaches the top


Attachment: Callstack20210806_905cdd95.rar

LN Lakshmi Natarajan Syncfusion Team August 9, 2021 01:55 PM UTC

Hi, 
 
Thank you for the update. 
 
Currently, we are analyzing the call stacks shared at our side. We will check completely based on the call stack and output logs and update you further details on or before August 12, 2021. We appreciate your patience until then. 
 
Lakshmi Natarajan 
 


? ? August 9, 2021 04:20 PM UTC

Thank you very much


LN Lakshmi Natarajan Syncfusion Team August 12, 2021 03:08 PM UTC

Hi, 
 
Thank you for your patience. 
 
We have checked the reported scenario using the call stack provided. On further analysis, both if conditions were called from the ComputeScroll method. In addition, we have added debug lines to the methods mentioned in the stack trace to check the values and prepared a sample using our custom assemblies. 
 
Please find the sample with custom assemblies below,  
 
Please run the sample in the Vivo X50 device and share us the output log to analyze the reported at our side. It will be really helpful for us to find out the cause of the issue at our side. 
 
Lakshmi Natarajan 
 


? ? August 12, 2021 03:33 PM UTC

Hi,

Thank you for your update.

There is no reference to this custom assembly。

Do you want to provide a download of this custom assembly? thank you.

123123.jpg


LN Lakshmi Natarajan Syncfusion Team August 13, 2021 12:38 PM UTC

Hi, 
 
Sorry for the inconvenience caused. 
 
Please find the sample with assemblies in the following link, 
 
Lakshmi Natarajan 
 


? ? August 13, 2021 03:41 PM UTC

Hi,

Thank you for your update.



Attachment: outlog08132338_19c267ef.rar

LN Lakshmi Natarajan Syncfusion Team August 16, 2021 01:04 PM UTC

Hi, 
 
Thank you for the update. 
 
We have checked the shared log. On further analysis, the native scroller’s FinalY value is larger while running in the Vivo device. Please refer to the following screenshot, 
 
Vivo device log 
 
 
We have taken output log in our testing device. As you can see in the following screenshot, the scroller value is significantly lower than the vivo device. 
 
 
We suspect that the issue occurs from the native scroller. So, we have prepared a simple sample with custom scrollView and renderer based on our architecture and attached in the following link, 
 
Please run the sample in the Vivo X50 device and share us the output log. It will be really helpful for us to identify the exact cause of the issue as soon as possible. 
 
Lakshmi Natarajan 
 


? ? August 16, 2021 02:05 PM UTC

Hi,

Thank you for the update.

The simple is working well.


Attachment: ListViewScrollToEnd87814103_outlog_6fb8aba7.rar

LN Lakshmi Natarajan Syncfusion Team August 17, 2021 02:29 PM UTC

Hi, 
 
Thank you for the update. 
 
We have analyzed the reported scenario based on the shared output log. We would like to inform you that, as we have mentioned in our previous update, we suspect that the reported scenario occurs from the framework level. Hence, we have created a thread in the Xamarin.Forms discussion. 
 
Please find the following discussion regarding the same, 
 
Kindly follow up with the above discussion for further updates. We will notify you if there are any updates from our end. 
 
Lakshmi Natarajan 
 


? ? August 17, 2021 04:30 PM UTC

Hi, 
Thank you for the update. 

 I see，thank you very much.

However, I have a question why collectionview does not have the above issue.


LN Lakshmi Natarajan Syncfusion Team August 18, 2021 12:06 PM UTC

Hi, 
 
We would like to inform you that the implementation of the CollectionView and SfListView is different and hence the issue does not occur in the CollectionView. 
 
Lakshmi Natarajan 
 


Loader.
Up arrow icon