Bug 57515 - PinchGestureRecognizer not getting called on Android
Summary: PinchGestureRecognizer not getting called on Android
Alias: None
Product: Forms
Classification: Xamarin
Component: Android ()
Version: 2.3.5
Hardware: PC Windows
: High critical
Target Milestone: 2.4.0
Assignee: Rui Marinho
Depends on:
Reported: 2017-06-15 08:20 UTC by Gordon Brown
Modified: 2017-09-18 14:40 UTC (History)
8 users (show)

Tags: ac android pinchgesture gesturerecognizer
Is this bug a regression?: Yes
Last known good build:

repro project (1.98 MB, application/x-zip-compressed)
2017-08-18 16:47 UTC, Jimmy [MSFT]

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Description Gordon Brown 2017-06-15 08:20:12 UTC
The PinchGestureRecognizer is not being called when running on Android in a MasterDetailPage environment.

To reproduce, take the Hanselman.Forms sample and add the basics from the PinchGesture sample as a page from the Hanselman menu. A project that demonstrates this issue is available at https://1drv.ms/f/s!AmeCKE6dgpGln8Zy0avc8Vh94OOe2Q 

The picture is displayed but not zoomable.

It functions correctly on UWP desktop but the gesture code is not being called on Android on a Google Pixel device running 7.1.

This is based on the latest pre3 build.

Other notables.  
The PinchGesture sample functions correctly as a standalone app.
I believe the issue also affects the iOS build but was only able to test it on a simulator. 
Adding a TapGesture to the container (in addition to the PinchGesture) results in the TapGesture code being invoked.
Comment 1 Jimmy [MSFT] 2017-06-20 18:40:13 UTC
I was able to reproduce the issue using the attached project. As mentioned, this seems to only be affecting Android.

This appears to _not_ be specific to using a MasterDetailPage. I removed the MasterDetailPage from the sample and still saw the issue. I also ran the PinchGesture sample from our site[1] and experienced the issue after updating it to the 2.3.5 pre-release. So this looks like a regression between 2.3.4 and 2.3.5.

### Version Tests   BAD
2.3.5-pre3          BAD
2.3.5-pre1          BAD           GOOD

[1] https://developer.xamarin.com/samples/xamarin-forms/WorkingWithGestures/PinchGesture/
Comment 2 Jimmy [MSFT] 2017-08-18 16:47:03 UTC
Created attachment 24309 [details]
repro project

This issue is still happening with 2.4.0-pre1.

### Platforms Affected

### Steps to Reproduce
1. Run the attached Android project
2. Do a pinch gesture on the image

### Expected Results
The image will be zoomed in.

### Actual Results
The image does not zoom.

### Possible Workaround
Use a Frame for the zoom container instead or add the PinchGestureRecognizer directly to the image. The issue seems to occur when the container is a ContentView or a layout (StackLayout, Grid, etc).

### Version Tests
2.4.0-pre1  BAD
2.3.5-pre6  BAD   GOOD
Comment 4 Samantha Houts [MSFT] 2017-09-11 23:07:44 UTC
Comment 5 Nicholas Bauer 2017-09-17 13:36:56 UTC
May be relevant - I had a problem getting the pinch gesture to work on the emulator, but it did work on a physical device (API level 23).