android speakerphone/

http://www.cnblogs.com/innost/archive/2011/01/22/1942149.html

http://blog.sina.com.cn/s/blog_5418969101012yde.html 

Android中文API（129） —— AudioManager(http://www.cnblogs.com/over140/archive/2011/08/07/2130393.html)

http://www.cnblogs.com/over140/archive/2011/08/07/2130393.html

Something like this might work on some devices (I've only tested in on an XPeria P):

Class audioSystemClass = Class.forName("android.media.AudioSystem");
Method setForceUse = audioSystemClass.getMethod("setForceUse", int.class, int.class);
// First 1 == FOR_MEDIA, second 1 == FORCE_SPEAKER. To go back to the default
// behavior, use FORCE_NONE (0).
setForceUse.invoke(null, 1, 1);

The combination FOR_MEDIA, FORCE_SPEAKER is typically only used internally to route the FM-radio audio to the loudspeaker (since the FM-radio requires you to have a wired headset / headphone plugged in to act as an antenna). Devices that don't have FM-radio functionality (or uses an alternative implementation) might ignore this combination of parameters, so this method would not work on such a device.

You can acquire either a rear speaker or a front earpiece at time.

If no accessory connected;

Use audioManager.setMode(AudioManager.MODE_IN_CALL); & audioManager.setSpeakerphoneOn(false); to use front speaker/earpiece. But this would play audio in earpiece not on speaker. To use rear speaker, use audioManager.setMode(AudioManager.MODE_NORMAL); & audioManager.setSpeakerphoneOn(true);

If accessory connected; Use audioManager.setMode(AudioManager.MODE_IN_CALL); & audioManager.setSpeakerphoneOn(false); to use front speaker/earpiece. But this would play audio in earpiece not on speaker. To use rear speaker, use audioManager.setMode(AudioManager.MODE_IN_CALL); & audioManager.setSpeakerphoneOn(true);

Note: Make sure audioManager.setWiredHeadsetOn(boolean on) and audioManager.setBluetoothScoOn(boolean on) set to false to route audio via earpiece . And set either to true to route audio accordingly.

if u just want to open your speakerphone on u just write this line in oncreate() of your activity.

static AudioManager audioManager =  (AudioManager)getSystemService(Context.AUDIO_SERVICE);
audioManager.setMode(AudioManager.MODE_IN_CALL);
audioManager.setSpeakerphoneOn(true);