Android CALL关于电话音频和紧急电话设置和获取

获取音频服务，设置音源类型：电话类型和获取最大电话音量，响铃模式

private AudioManager mAudioManager;

mAudioManager = (AudioManager) getSystemService(AUDIO_SERVICE);
        mAudioManager.setStreamVolume(AudioManager.STREAM_VOICE_CALL,
                mAudioManager.getStreamMaxVolume(AudioManager.STREAM_VOICE_CALL),
                AudioManager.FLAG_ALLOW_RINGER_MODES);

发送广播：打开紧急电话，拨打112

        startActivity(new Intent(Intent.ACTION_CALL_EMERGENCY)
                .setData(Uri.fromParts(PhoneAccount.SCHEME_TEL, "112", null))
                .setFlags(Intent.FLAG_ACTIVITY_NEW_TASK));