ziglee

PackageInfo info = getPackageManager().getPackageInfo("<your_package_name>", PackageManager.GET_SIGNATURES);
for (Signature signature : info.signatures) {
   MessageDigest md = MessageDigest.getInstance("SHA");
   md.update(signature.toByteArray());
   Log.d("Hash Key:", Base64.encodeToString(md.digest(), Base64.DEFAULT));
}

ziglee

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;