如何使用Android2.2在应用程序启动时获得蓝牙耳机连接状态？

Question

How to get Bluetooth Headset connection state (connected/disconnected) using android api level 8 on application start-up? Is there any sticky broadcast intent available in android2.2? Is there any API to fetch initial Bluetooth Headset state? Is there any workaround available?

Answer 1

I figured out the solution:

private static final String ACTION_BT_HEADSET_STATE_CHANGED  = "android.bluetooth.headset.action.STATE_CHANGED";
private static final int STATE_CONNECTED = 0x00000002; 
private static final int STATE_DISCONNECTED  = 0x00000000;  
private static final String EXTRA_STATE = "android.bluetooth.headset.extra.STATE";

private BroadcastReceiver mBlueToothHeadSetEventReceiver = new BroadcastReceiver() {

@Override
public void onReceive(Context context, Intent intent) {
    try {
        String action = intent.getAction();

        if(action == null)
            return;

        if(action.equals(ACTION_BT_HEADSET_STATE_CHANGED)){
            int extraData = intent.getIntExtra(EXTRA_STATE  , STATE_DISCONNECTED);
            if(extraData == STATE_CONNECTED ){

                //TODO :

            }else if(extraData == STATE_DISCONNECTED){

                //TODO:
            }
        }
        } catch (Exception e) {

        //TODO:

        }
}
};

Answer 2

This won't really work on application startup, but as intent-filters are registered automatically, you might have a valid value, once your app gets started up:

Declare the following intent-filter

        <intent-filter >
            <action android:name="android.bluetooth.headset.action.AUDIO_STATE_CHANGED" />
        </intent-filter>

and in your Receiver in onReceive check for:

if ("android.bluetooth.headset.action.AUDIO_STATE_CHANGED".equals(intent.getAction())) {
  headsetAudioState = intent.getIntExtra("android.bluetooth.headset.extra.AUDIO_STATE", -2);
}

and save the int as a static variable. Access it anytime you want to know if BT audio is connected(1) / disconnected(0). Not pretty, but gets the job done.

Also check out: https://github.com/android/platform_frameworks_base/blob/gingerbread/core/java/android/bluetooth/BluetoothHeadset.java

Answer 3

from packages/apps/Phone/src/com/android/phone/PhoneGlobals.java:1449

        } else if (action.equals(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED)) {
            mBluetoothHeadsetState = intent.getIntExtra(BluetoothHeadset.EXTRA_STATE,
                                                      BluetoothHeadset.STATE_DISCONNECTED);
            if (VDBG) Log.d(LOG_TAG, "mReceiver: HEADSET_STATE_CHANGED_ACTION");
            if (VDBG) Log.d(LOG_TAG, "==> new state: " + mBluetoothHeadsetState);
            updateBluetoothIndication(true);  // Also update any visible UI if necessary