It has been tested with the ScummVM core on:
- NVIDIA Shield TV running Android Nougat 7.0
- NVIDIA Shield Tablet running Android Nougat 7.0
- NVIDIA Shield Tablet running Android Lollipop 5.1
- Huawei Honor 7 running Android Marshmallow 6.0
- HTC Desire 500 running Android Jelly Bean 4.1
It's been tested using the touch screen, a USB mouse/keyboard combo, and a bluetooth mouse.
The Android version running on the device limits the functionality and user experience of the external mouse support.
Android Nougat and/or an NVIDIA SHIELD device with NVIDIA extensions provides the best user experience:
Android API < 14:
- Only left mouse button supported
- The Android mouse cursor will be visible along with the in game mouse cursor
- When the Android mouse cursor hits the edge of the screen it will not be possible to move the in-game mouse cursor further in that direction
Android API < 24 and no NVIDIA extensions available:
- Both left and right mouse buttons supported
- The Android mouse cursor will be visible along with the in game mouse cursor
- When the Android mouse cursor hits the edge of the screen it will not be possible to move the in-game mouse cursor further in that direction
Android API > 23 and/or NVIDIA extensions available (SHIELD devices):
- Both left and right mouse buttons supported
- The Android mouse cursor will be hidden
- The mouse is not limited by the (hidden) Android mouse cursor hitting the edge of the screen
Description of how the the touchscreen mouse support works:
- You can move the in-game mouse cursor using the touch screen. The in-game mouse cursor will move relative to your movements on the touch screen, it will not be centered on where you press the screen.
- One quick tap on the touch screen results in the left mouse button being clicked
- Two taps on the screen and keeping the second tap pressed down results in a left mouse being held down until you release
- Two fingers on the touch screen results in the right mouse button being clicked
The touch screen mouse functionality is active at the same time as overlay support. This might cause some confusion when using cores that are designed for mouse support but where you have also enabled overlay controls. At the top of android_input.c there's a define that can be used to turn off this functionality if it causes more problems than it solves.
QUITFOCUS
If enabled this will cause Retroarch to quit completely when it loses focus (eg. when the home button is pressed). This is useful when you are using an alternative launcher such as Kodi because it will make the home button function as an alternative quit key, return to the alternative launcher, and then allow for a different game to start instead of returning to the current session.
HIDEMOUSE
Normally it is not possible to hide the mouse cursor if you have attached an external mouse to your Android unit. This makes it difficult to implement mouse support in the Android version of Retroarch because you will end up having two mouse cursors on the screen. NVIDIA has implemented extensions on the SHIELD that allows for hiding the mouse cursor. If this parameter is provided when starting Retroarch it will check for these extensions and if available it will hide the mouse cursor.
(I am almost done with adding mouse support to the Android input driver and will be submitting a suggestion for this very soon)
