How to capture key events from bluetooth headset with android

Question

My app can be controlled by normal headset. It simply overrides \"onKeyDown\". But key events from bluetooth headset are not captured - why? Or how to capture bluetooth key

Answer 1

Add a broadcast listener to MEDIA_BUTTON:

<intent-filter android:priority="<some number>"> 
   <action android:name="android.intent.action.MEDIA_BUTTON" /> 
</intent-filter> 

You should register your broadcast receiver inside your application (not in manifest file). Otherwise Google Music player will catch your broadcast and aboard it.

Your IntentFilter priority should be higher that other media players priorities in your phone)

Add android.permission.BLUETOOTH permission in manifest to support Bluetooth headset

After received you key you have to manually abort the broadcast using abortBroadcast().

However priorities and abortBroadcast() work fine as long as each app only responds while e.g. something is played. But several users also expect a "default player" to be launched (or start playing) upon button press, like the default player, so it might happen some app with a higher priority number won't let the intent come through to your app

In the onReceive, you can get the button event with

KeyEvent key = (KeyEvent) 
intent.getParcelableExtra(Intent.EXTRA_KEY_EVENT); 

key.getKeyAction() tells you whether the button was released or pressed, key.getKeyCode() tells which button is pressed.

If you want to handle single button cable headsets as well, also regard the key code KEYCODE_HEADSETHOOK

Override the onKeyDown method in any activity and check for the KeyEvent.KEYCODE_MEDIA_KEYCODE_pressed_key

e.g.

 boolean onKeyDown(int keyCode, KeyEvent event) { 
            AudibleReadyPlayer abc; 
            switch (keyCode) { 
            case KeyEvent.KEYCODE_MEDIA_FAST_FORWARD: 
                    // code for fast forward 
                    return true; 
            case KeyEvent.KEYCODE_MEDIA_NEXT: 
                    // code for next 
                    return true; 
            case KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE: 
                    // code for play/pause 
                    return true; 
            case KeyEvent.KEYCODE_MEDIA_PREVIOUS: 
                    // code for previous 
                    return true; 
            case KeyEvent.KEYCODE_MEDIA_REWIND: 
                    // code for rewind 
                    return true; 
            case KeyEvent.KEYCODE_MEDIA_STOP: 
                    // code for stop 
                    return true; 
            } 
            return false; 
    } 

Volume key integration example Android - Volume Buttons used in my application
This one may need permission

<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

Or you can try slimier implementations over the following link

Android Developer Blog : Handling remote control buttons
Android Tales : Add Headset button support to your Android application

Answer 2

Check out this article. It explains how to implement something similar using media button actions.

I know you've mentioned that you walked this way without success, still give it a try. Point your attention to gotchas related to registering broadcast receiver, setting intent filter priorities and adding permissions (all explained in the article).

Hope this will help.

Answer 3

If you are trying to listen for this from an activity, use onKeyDown() and catch the KEYCODE_MEDIA_PLAY_PAUSE (KEYCODE_MEDIA_PLAY and KEYCODE_MEDIA_PAUSE post ICS) key events.

Also for the broadcast receiver solution to work make sure there arent other apps installed and running in the background that catch these events which might take priority over yours.

Also look at this: Android - registering a headset button click with BroadcastReceiver