getKeyHash.java

try {
  PackageInfo info = getPackageManager().getPackageInfo("com.yjw.android.busanbus", PackageManager.GET_SIGNATURES);
  for (Signature signature : info.signatures) {
    MessageDigest md = MessageDigest.getInstance("SHA");
    md.update(signature.toByteArray());
    String str = Base64.encodeToString(md.digest(), Base64.DEFAULT);
    Log.d("KeyHash:", str);
    Toast.makeText(this, str, Toast.LENGTH_LONG).show();
  }
}catch(NoSuchAlgorithmException e){
  e.printStackTrace();
}catch (PackageManager.NameNotFoundException e){
  e.printStackTrace();
}