How to trigger touch start (not when the finger released) in the xamarin forms?

Question

The problem is that TapGestureRecognizer triggers only when I release my finger, but I want to trigger when I just started the touch

Here is the way how I use it at the moment:

<Image.GestureRecognizers>
    <TapGestureRecognizer
         Tapped="TapGestureRecognizer_Tapped"
         NumberOfTapsRequired="1" />
</Image.GestureRecognizers>

Answer 1

You can try to use a custom render to do something you want when the user touches the image.

1. Declare the custom image in the share project:

   public class MyImage : Image
   {
   }
   

2. In the android part:

   [assembly: ExportRenderer(typeof(MyImage), typeof(MyImageRenderer))]
   namespace AppTest.Droid
   {
   
       public class MyImageRenderer : ImageRenderer
       {
           public MyImageRenderer(Context context) : base(context) { }
           public override bool OnTouchEvent(MotionEvent e)
           {
               if(e.Action == MotionEventActions.Down)
               {
                   //do something
               }
   
               return base.OnTouchEvent(e);
   
           }
       }
   }
   

3. In the ios part:

   [assembly: ExportRenderer(typeof(MyImage), typeof(MyImageRenderer))]
   namespace AppTest.iOS
   {
       public class MyImageRenderer : ImageRenderer
       {
           protected override void OnElementChanged(ElementChangedEventArgs<Image> e)
           {
               base.OnElementChanged(e);
               if (Control != null)
               {
                   Control.UserInteractionEnabled = true;
               }
           }
           public override void TouchesBegan(NSSet touches, UIEvent evt)
           {
               //do something
               base.TouchesBegan(touches, evt);
           }
   
       }
   }
   

4. Use it in the xaml:

   <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
        xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
        xmlns:local="clr-namespace:AppTest"
        x:Class="AppTest.MainPage">
       <StackLayout>
         <local:MyImage Source="your image" BackgroundColor="Blue"/>
       </StackLayout>
   
   </ContentPage>