Generate key hash for Facebook - Android

generate_key_fb.java

/**generate key hash facebook**/
EditText txt_key_fb = (EditText) findViewById(R.id.txt_fb);
try {
	PackageInfo info = getPackageManager().getPackageInfo(
		getPackageName(), PackageManager.GET_SIGNATURES);
		for (android.content.pm.Signature signature : info.signatures) {
			MessageDigest md;

                md = MessageDigest.getInstance("SHA");
                md.update(signature.toByteArray());
                String something = new String(Base64.encode(md.digest(), 0));
                txt_key_fb.setText(something);
		}
        } catch (PackageManager.NameNotFoundException e1) {
            Log.e("name not found", e1.toString());
        } catch (NoSuchAlgorithmException e) {
            Log.e("no such an algorithm", e.toString());
        } catch (Exception e) {
            Log.e("exception", e.toString());
        }