Godot: KEY_BACK is confusing on mobile devices

[alexzheng]

Godot version:

Godot 3.0.2

OS/device including version:

Android device with soft navigation keys.

Issue description:

When press the back key, no InputEventKey is triggered.

Steps to reproduce:

Minimal reproduction project:

[bojidar-bg]

Shouldn't it trigger a NOTIFICATION_WM_GO_BACK_REQUEST instead? Docs about handling it.

[alexzheng]

Yes, it triggered a NOTIFICATION_WM_GO_BACK_REQUEST, the document need update.
However, there is a KEY_BACK definition, I thought there must some way to catch it, or else this constant is useless.

[bojidar-bg]

Looking at the code, KEY_BACK is emitted when pressing:

• AKEYCODE_MEDIA_REWIND on android,
• VK_BROWSER_BACK on windows,
• XF86XK_Back on x11/linux (with a comment about it being a media key).

Maybe it would be better to rename it as KEY_MEDIA_BACK (similar for KEY_MEDIA_FORWARD)?

[alexzheng]

Yes, the KEY_BACK will be mistaken as pressed the back key of the device in Android.
Then is the only correct way to catch the press back key in Android is the NOTIFICATION_WM_GO_BACK_REQUEST? If that's true, the issue can be closed.