Scroll Speed/Duration For ScrollView/HorizontalScrollView

Question

Scroll Speed/Duration For ScrollView/HorizontalScrollView

Nathan Sokalski 4,111

I have a HorizontalScrollView for which I would like to control the duration when calling methods to scroll to different positions (such as SmoothScrollTo or ScrollTo, I don't care whether I use Smooth Scrolling or not). For my RecyclerView(s) I created a custom LinearSmoothScroller & did an override of CalculateSpeedPerPixel. I would prefer to not need to do this, so is there another way to specify the time/duration, or do I need to create a custom LinearSmoothScroller for my HorizontalScrollView as well?

1 answer

Your answer

Answer 1

Wenyan Zhang (Shanghai Wicresoft Co,.Ltd.) 36,436 Microsoft External Staff

Hello,

is there another way to specify the time/duration

Yes, you could customize a ScrollView, and override the Fling method, if it is a HorizontalScrollView, the parameter is velocityX. Refer to the following code:

public class MyScrollView : ScrollView  
{  
    ......  
    public override void Fling(int velocityY)  
    {  
        base.Fling(velocityY / 5);// one-fifth the speed, you can set other values  
    }  
}

Best Regards,
Wenyan Zhang

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.

Nathan Sokalski 4,111 Reputation points

2022-06-09T20:19:42.05+00:00
I tried that, but it doesn't seem to be making any difference. I created a custom HorizontalScrollView that overrides Fling as follows:

public override void Fling(int velocityX) { base.Fling(velocityX / 5); }

I tried adding a breakpoint in the Fling overload, but it was never hit, so I am wondering if Fling is actually being used. It still scrolls, but it does it instantly rather than slowly (which is what I want to change). Is there something I need to do to make it use Fling?
Wenyan Zhang (Shanghai Wicresoft Co,.Ltd.) 36,436 Reputation points Microsoft External Staff

2022-06-10T09:05:13.4+00:00

May I ask will other methods be triggered? I mean only this Fling method was never hit?
Nathan Sokalski 4,111 Reputation points

2022-06-10T15:17:18.007+00:00
Which other methods are you referring to? Fling is the only method I override. When I do the scrolling, I use the following line of code:

this.scrPuzzle.SmoothScrollTo((int)(x * 55 * Resources.DisplayMetrics.Density), 0);

this.scrPuzzle is the class that inherits from HorizontalScrollView & overrides Fling, and x is an int that I have defined. The child of my custom HorizontalScrollView is a RecyclerView, on which I call the following immediately after the line above:

this.rvPuzzle.SmoothScrollToPosition(index);

Is it possible that calling this immediately afterwards is causing my custom HorizontalScrollView to scroll instantly rather than take the time specified?

Anonymous

I create MyScroolView with following code, add this breakpoint in the Fling method, when you scroll MyScroolView, Fling will be hitted.

   public class MyScroolView : HorizontalScrollView  
       {  
           public MyScroolView(Context context) : base(context)  
           {  
           }  
     
           public MyScroolView(Context context, IAttributeSet attrs) : base(context, attrs)  
           {  
           }  
     
           protected MyScroolView(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)  
           {  
           }  
           public override void Fling(int velocityX)  
           {  
               base.Fling(velocityX/5);  
           }  
     
       }

Share via

Scroll Speed/Duration For ScrollView/HorizontalScrollView

1 answer

Your answer