安卓的Earpiece和扬声器speaker切换要怎么用代码实现，用如下的代码切换会报错，求解
AudioManager audioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
private void setSpeakerphoneOn(boolean on) {
if(on) {
audioManager.setSpeakerphoneOn(true);
} else {
audioManager.setSpeakerphoneOn(false);//关闭扬声器
audioManager.setRouting(AudioManager.MODE_NORMAL, AudioManager.ROUTE_EARPIECE, AudioManager.ROUTE_ALL);
setVolumeControlStream(AudioManager.STREAM_VOICE_CALL);
//把声音设定成Earpiece（听筒）出来，设定为正在通话中
audioManager.setMode(AudioManager.MODE_IN_CALL);
}
}