Android开发之获取Facebook应用的key hash

 public void printKeyHash(AppActivity ap){      try {              PackageInfo info = ap.getPackageManager().getPackageInfo(ap.getPackageName(),                      PackageManager.GET_SIGNATURES);              for (Signature signature : info.signatures) {                  MessageDigest md = MessageDigest.getInstance("SHA");                  md.update(signature.toByteArray());                  ap.print(Base64.encodeToString(md.digest(), Base64.DEFAULT));              }          } catch (NameNotFoundException e) {          ap.print("NameNotFoundException:" + e.getMessage());          } catch (NoSuchAlgorithmException e) {          ap.print("NoSuchAlgorithmException:" + e.getMessage());          }    }