improves coding style

app/src/main/java/chat/rocket/android/authentication/login/ui/LoginFragment.kt

@@ -9,6 +9,7 @@ import android.graphics.PorterDuff
 import android.os.Build
 import android.os.Bundle
 import android.support.v4.app.Fragment
+import android.support.v4.app.FragmentActivity
 import android.text.style.ClickableSpan
 import android.view.LayoutInflater
 import android.view.View
@@ -117,13 +118,14 @@ class LoginFragment : Fragment(), LoginView, GoogleApiClient.ConnectionCallbacks
 
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
         if (resultCode == Activity.RESULT_OK) {
+            if (data != null) {
                 when (requestCode) {
-                REQUEST_CODE_FOR_CAS -> data?.apply {
+                    REQUEST_CODE_FOR_CAS -> data.apply {
                         presenter.authenticateWithCas(getStringExtra(INTENT_CAS_TOKEN))
                     }
                     REQUEST_CODE_FOR_OAUTH -> {
                         isOauthSuccessful = true
-                    data?.apply {
+                        data.apply {
                             presenter.authenticateWithOauth(
                                 getStringExtra(INTENT_OAUTH_CREDENTIAL_TOKEN),
                                 getStringExtra(INTENT_OAUTH_CREDENTIAL_SECRET)
@@ -132,13 +134,13 @@ class LoginFragment : Fragment(), LoginView, GoogleApiClient.ConnectionCallbacks
                     }
                     MULTIPLE_CREDENTIALS_READ -> {
                         val loginCredentials: Credential =
-                        data!!.getParcelableExtra(Credential.EXTRA_KEY)
+                            data.getParcelableExtra(Credential.EXTRA_KEY)
                         handleCredential(loginCredentials)
                     }
                     NO_CREDENTIALS_EXIST -> {
                         //use the hints to autofill sign in forms to reduce the info to be filled
                         val loginCredentials: Credential =
-                        data!!.getParcelableExtra(Credential.EXTRA_KEY)
+                            data.getParcelableExtra(Credential.EXTRA_KEY)
                         val email = loginCredentials.id
                         val password = loginCredentials.password
 
@@ -151,31 +153,25 @@ class LoginFragment : Fragment(), LoginView, GoogleApiClient.ConnectionCallbacks
                         Toast.LENGTH_SHORT
                     ).show()
                 }
-        } else if (requestCode == SAVE_CREDENTIALS) {
-            Timber.e("ERROR: Cancelled by user")
-        } else if (requestCode == MULTIPLE_CREDENTIALS_READ) {
-            Timber.e("ERROR: Failed reading credentials")
+            }
         }
         //cancel button pressed by the user in case of reading from smart lock
         else if (resultCode == Activity.RESULT_CANCELED && requestCode == REQUEST_CODE_FOR_OAUTH) {
             Timber.d("Returned from oauth")
         }
-        //no hints for user id's exist
-        else if (resultCode == CredentialsApi.ACTIVITY_RESULT_NO_HINTS_AVAILABLE) {
-        }
     }
 
     override fun onDestroy() {
         super.onDestroy()
         googleApiClient.let {
-            it.stopAutoManage(activity!!)
+            activity?.let { it1 -> it.stopAutoManage(it1) }
             it.disconnect()
         }
     }
 
     private fun buildGoogleApiClient() {
         googleApiClient = GoogleApiClient.Builder(context!!)
-            .enableAutoManage(activity!!, {
+            .enableAutoManage(activity as FragmentActivity, {
                 Timber.e("ERROR: Connection to client failed")
             })
             .addConnectionCallbacks(this)
@@ -198,14 +194,13 @@ class LoginFragment : Fragment(), LoginView, GoogleApiClient.ConnectionCallbacks
         Auth.CredentialsApi.request(googleApiClient, request)
             .setResultCallback { credentialRequestResult ->
                 val status = credentialRequestResult.status
-                if (status.isSuccess) {
-                    // Auto sign-in success
-                    handleCredential(credentialRequestResult.credential)
-                } else if (status.statusCode == CommonStatusCodes.RESOLUTION_REQUIRED) {
-                    resolveResult(status, MULTIPLE_CREDENTIALS_READ)
-                } else if (status.statusCode == CommonStatusCodes.SIGN_IN_REQUIRED) {
-
-                    //build a dialog for possible account hints
+                when {
+                    status.isSuccess -> handleCredential(credentialRequestResult.credential)
+                    (status.statusCode == CommonStatusCodes.RESOLUTION_REQUIRED) -> resolveResult(
+                        status,
+                        MULTIPLE_CREDENTIALS_READ
+                    )
+                    (status.statusCode == CommonStatusCodes.SIGN_IN_REQUIRED) -> {
                         val hintRequest: HintRequest = HintRequest.Builder()
                             .setHintPickerConfig(
                                 CredentialPickerConfig.Builder()
@@ -230,8 +225,8 @@ class LoginFragment : Fragment(), LoginView, GoogleApiClient.ConnectionCallbacks
                         } catch (e: IntentSender.SendIntentException) {
                             Timber.e("ERROR: Could not start hint picker Intent")
                         }
-                } else {
-                    Timber.d("ERROR: nothing happening")
+                    }
+                    else -> Timber.d("ERROR: nothing happening")
                 }
             }
     }
@@ -240,7 +235,7 @@ class LoginFragment : Fragment(), LoginView, GoogleApiClient.ConnectionCallbacks
         if (loginCredentials.accountType == null) {
             presenter.authenticateWithUserAndPassword(
                 loginCredentials.id,
-                loginCredentials.password!!
+                loginCredentials.password.toString()
             )
         }
     }
@@ -259,8 +254,9 @@ class LoginFragment : Fragment(), LoginView, GoogleApiClient.ConnectionCallbacks
             return
         }
 
+        activity?.let {
             Auth.CredentialsApi.save(googleApiClient, credentialsToBeSaved).setResultCallback(
-            object : ResolvingResultCallbacks<Status>(activity!!, SAVE_CREDENTIALS) {
+                object : ResolvingResultCallbacks<Status>(it, SAVE_CREDENTIALS) {
                     override fun onSuccess(status: Status) {
                         Timber.d("credentials save:SUCCESS:$status")
                         credentialsToBeSaved = null
@@ -272,6 +268,7 @@ class LoginFragment : Fragment(), LoginView, GoogleApiClient.ConnectionCallbacks
                     }
                 })
         }
+    }
 
     private fun tintEditTextDrawableStart() {
         ui {

app/src/main/java/chat/rocket/android/authentication/signup/ui/SignupFragment.kt

@@ -144,8 +144,9 @@ class SignupFragment : Fragment(), SignupView {
     }
 
     private fun saveCredentials() {
+        activity?.let {
             Auth.CredentialsApi.save(googleApiClient, credentialsToBeSaved).setResultCallback(
-            object : ResolvingResultCallbacks<Status>(activity!!, SAVE_CREDENTIALS) {
+                object : ResolvingResultCallbacks<Status>(it, SAVE_CREDENTIALS) {
                     override fun onSuccess(status: Status) {
                         Timber.d("save:SUCCESS:$status")
                     }
@@ -155,6 +156,7 @@ class SignupFragment : Fragment(), SignupView {
                     }
                 })
         }
+    }
 
     override fun showLoading() {
         ui {