title: (Android) Get audio signal from the audio line-in instead of phone microphone
body: <p>I'm working on an Android program whose purpose is to record a sound signal and then to analyse it.
  To record this sound signal, I am using a special microphone I want to plug to my Android device directly via the audio line-in, so I won't use the mobile phone microphone.</p>
  
  <p>Here is what I found on Android website :</p>
  
  <p>" Defines the audio source. These constants are used with setAudioSource(int).
  Summary
  Constants
  int CAMCORDER Microphone audio source with same orientation as camera if available, the main device microphone otherwise
  int DEFAULT Default audio source
  int MIC Microphone audio source
  int VOICE_CALL Voice call uplink + downlink audio source
  int VOICE_COMMUNICATION Microphone audio source tuned for voice communications such as VoIP.
  int VOICE_DOWNLINK Voice call downlink (Rx) audio source
  int VOICE_RECOGNITION Microphone audio source tuned for voice recognition if available, behaves like DEFAULT otherwise.
  int VOICE_UPLINK Voice call uplink (Tx) audio source  "</p>
  
  <p>It seems that there is no way to define the line in as an audio source. I have tried to plug my own microphone to my mobile and then to record the sound, hoping that it will recognize my own microphone (as a handfree kit) but it keeps recording on the mobile phone microphone.</p>
  
  <p>Does anyone know what to set as an audio source so I can use the line-in ?</p>
  
  <p>Many thanks in advance !</p>