ContentButton in Xamarin Forms sends command after scrolling

[kanadaj]

As said in the title, embedding the ContentButton in a ScrollView and then scrolling the view causes the button to move with the user's finger, so the command is sent on release.

[nickrandolph]

@kanadaj for clarification can you break your explanation into expected behaviour and actual behaviour, just so I'm clear on what the issue is.

[kanadaj]

Sure! The expected behaviour would be that if you drag the scroll view containing the Content Button control while holding the button, the button shouldn't detect a tap event since the scroll view should take priority.

Actual behaviour is that the Content Button detects a tap (possibly a long tap) and fires the bound Command while trying to scroll. I must also add that this happens even if I don't release the button, it executes the Command after a second or so even if I never release it.

[kanadaj]

After some testing, it seems to me that the TouchEffect's TouchAction is never called with TouchActionType.Exited nor with TouchActionType.Entered

[kanadaj]

Note, in the end I ended up replacing the ContentButton with a custom control using https://github.com/mrxten/XamEffects and a fairly simple:

<ContentView.ControlTemplate>
  <ControlTemplate>
      <Grid xamEffects:TouchEffect.Color="#66000000" xamEffects:Commands.Tap="{TemplateBinding InternalCommand}" xamEffects:Commands.TapParameter="{TemplateBinding CommandParameter}">
          <ContentPresenter Content="{TemplateBinding Content}"/>
          <BoxView Color="Transparent"/>
          <!--<Button BackgroundColor="Transparent" Command="{TemplateBinding Command}" CommandParameter="{TemplateBinding CommandParameter}" Clicked="Button_OnClicked" Padding="0" Margin="0" WidthRequest="0" HorizontalOptions="Fill" VerticalOptions="Fill"/>-->
      </Grid>
  </ControlTemplate>
</ContentView.ControlTemplate>

with InternalCommand being a simple command calling

private void ExecuteInternalCommand()
{
    if (Command != null && Command.CanExecute(CommandParameter))
    {
        Command.Execute(CommandParameter);
    }
    else
    {
        Pressed?.SafeRaise(this, null);
    }
}

The press effect is much better (it uses the native "wave" effect) and the behaviour is far more consistent than the original ContentButton here. Maybe it'd be worth considering to replace the implementation here with it?

[nickrandolph]

Yeh we'd considered removing the ContentButton for exactly this reason - good find and thanks for posting feedback here.