title: Android, How to use microphone in order to calculate sound frequencies?
body: <p>I'm working on Audio tuner application in order to tune musical instruments.
  User should play a note, then in my application I should show which frequency it has.</p>
  
  <p>The first, I should access to microphone?</p>
  
  <pre><code>AudioRecord recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
  sampleRate, AudioFormat.CHANNEL_IN_STEREO,
  AudioFormat.ENCODING_PCM_16BIT, bufferSize);
  </code></pre>
  
  <p>Then I need to calculate frequency of sound. How can I do this? </p>