Handle all mouse events in Android

Question

Well, the question is rather simple - how can i handle left/right/middle click, wheel and (!)hover move in android 2/3/4.

I've been digging on this topic and found the following

• in api 14 we can handle almost anything with fancy new MotionEvent
• we also have Open Accessory that seems to be ok with USB mouse since api 12 (still missing bluetooth) (UPD OA backported to 2.3.4)
• mouse actually works well on tablets with ICS and Honeycomb and cyanogen 2.3.7, but act like just single touch on every button.I wonder is there a way to intercept mouse messages.

Help me please to understand how i can handle bluetooth and usb mouse in most simple and right way in each version of android. Or say its impossible.

UPD2: seems like USB Host only in 3.1+, while USB Accessory useless for this task

• Pankaj Kumar: Read zdnet.com/blog/burnette/… and developer.android.com/reference/android/view/MotionEvent.html
• mjollneer: I looked at those articles, but a haven't found anything new. What are you hinting at?

Answer 1

These are my findings:

For Api Level < 9:

• External mouse primary button is handled just as a normal finger touch. There seems to be no way to detect the mouse.
• Secondary button is dispatched trough a KeyEvent with KeyEvent.KEYCODE_BACK. No way to distinguish between actual "Back" presses and secondary button presses.

For Api Level 9+:

• A new method has been added MotionEvent.getSource(). I use this one to detect if input is from mouse.
• Secondary button is still dispatched through a KeyEvent with KeyEvent.KEYCODE_BACK. On some devices the KeyEvent.getSource() returns InputDevice.SOURCE_MOUSE, so secondary button detection works in some cases.

For Api Level 12+:

• OnGenericMotionListener has been added. I use this one to detect mouse moves with ACTION_HOVER_MOVE and wheel changes with ACTION_SCROLL.

For Api Level 14+:

• New method MotionEvent.getButtonState(). I track this one to distinguish if a primary, secondary, tertiary mouse button is pressed when the MotionEvent.getActionMasked() is ACTION_MOVE, ACTION_DOWN or ACTION_UP.

I haven't looked into Api Level 15/16 or the tool type, because I'm able to track all mouse events with what I described above. Would be interesting if anybody has additional information or if I' missing out with 15/16/tooltypes.

• mjollneer: Clear presentation and some new hints))
• Roel: On Samsung devices with API level 23 I still only get an KeyEvent and not a MotionEvent and there is no way to detect a MousUp event with OnGenericMotionListener on vanilla Android devices it works with the OnGenericMotionListener.
• Robin: @Maik, This works somewhat, but I noticed a problem. When I hold down the left mouse button and drag the mouse, it only fires ACTION_BUTTON_PRESS once. It does not fire ACTION_HOVER_MOVE or any other actions anymore until I release the left mouse button, so it can't track for moving the mouse while holding down mouse buttons.
• Maik: ACTION_HOVER_MOVE will only happen as long as you don't press any buttons. If I remember correctly you should receive ACTION_MOVE while a mouse button is pressed. It has been a long time since the last time I looked at this, but there was definitely a way to track it.
• Robin: I just log and return false in OnGenericMotion. Nothing is fired while moving with mouse button held down

Answer 2

OK. I think i got a clue. I've read highlights about android 3.x/4.x and realized that...

1. we can use mouse in android 3+, in older versions mouse is device-specific

2. we can intercept recognized mouse events from any source (BT or USB)...

2.1. ... scroll or hover_move in 3.1+ in onGenericMotionEvent

2.2. ... primary, secondary, and tertiary buttons and hover enter/leave in android 4.0+ (and finally TOOL_TYPE_MOUSE constant)

The other option is to parse pretty lowlevel data from bluetooth socket or usb in host mode.

Am i right? Still wonder if anybody have better solution.

Answer 3

Please, consult the Android SDK documentation, exactly on your own SDK directory: android-sdk/docs/reference/android/view/MotionEvent.html

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