ToByteArray () will not be allowed to enter facebook

Question

I am creating an application that requires facebook login and authentication.

I follow

https://developers.facebook.com/docs/android/getting-started#create-app

I got this error: when I clicked the facebook login button:

Several posts say this code should fix the error

Cache hash does not match when logging into facebook on android

:

try { PackageInfo info = getPackageManager().getPackageInfo( "com.hitup.hitup", PackageManager.GET_SIGNATURES); for (Signature signature : info.signatures) { MessageDigest md = MessageDigest.getInstance("SHA"); md.update(signature.toByteArray()); Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT)); } } catch (NameNotFoundException e) { } catch (NoSuchAlgorithmException e) { } 

however, the toByteArray () method cannot be resolved!

How can I resolve this error and achieve a simple facebook login for my application?

Answer 1

You should import android.content.pm.Signature , not java.security.Signature .

Answer 2

 from Logcat you can get hash key of facebook please do copy from logcat which having Logcat tag "KeyHash" and put it in your project on developer.facebook site 

 import android.content.pm.Signature; try { PackageInfo info = getPackageManager().getPackageInfo( **"do not forgot to your package name"**, PackageManager.GET_SIGNATURES); for (Signature signature : info.signatures) { MessageDigest md = MessageDigest.getInstance("SHA"); md.update(signature.toByteArray()); Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT)); } } catch (NameNotFoundException e) { } catch (NoSuchAlgorithmException e) { } OR 1. for Android default keystore : add this to in your terminal keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore | openssl sha1 -binary | openssl base64 2. for signed keystore keytool -exportcert -alias aliasname -keystore keystorename | openssl sha1 -binary | openssl base64