Resolve deprecated API warnings

* fetchProvidersForEmail => fetchSignInMethodsForEmail
* ```(Map<String, String>) call.arguments``` => ```call.arguments()```
* Fix warnings with `unchecked` & `unuse`

Author: ko2ic

packages/firebase_auth/android/src/main/java/io/flutter/plugins/firebaseauth/FirebaseAuthPlugin.java

@@ -145,8 +145,7 @@ public void onMethodCall(MethodCall call, Result result) {
   }
 
   private void handleSignInWithPhoneNumber(MethodCall call, Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String verificationId = arguments.get("verificationId");
     String smsCode = arguments.get("smsCode");
 
@@ -158,7 +157,6 @@ private void handleSignInWithPhoneNumber(MethodCall call, Result result) {
   }
 
   private void handleVerifyPhoneNumber(MethodCall call, Result result) {
-    @SuppressWarnings("unchecked")
     final int handle = call.argument("handle");
     String phoneNumber = call.argument("phoneNumber");
     int timeout = call.argument("timeout");
@@ -230,6 +228,7 @@ public void onCodeAutoRetrievalTimeOut(String verificationId) {
               registrar.activity(),
               verificationCallbacks);
     }
+    result.success(null);
   }
 
   private Map<String, Object> getVerifyPhoneNumberExceptionMap(FirebaseException e) {
@@ -251,8 +250,7 @@ private Map<String, Object> getVerifyPhoneNumberExceptionMap(FirebaseException e
   }
 
   private void handleLinkWithEmailAndPassword(MethodCall call, Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String email = arguments.get("email");
     String password = arguments.get("password");
 
@@ -263,7 +261,7 @@ private void handleLinkWithEmailAndPassword(MethodCall call, Result result) {
         .addOnCompleteListener(new SignInCompleteListener(result));
   }
 
-  private void handleCurrentUser(MethodCall call, final Result result) {
+  private void handleCurrentUser(@SuppressWarnings("unused") MethodCall call, final Result result) {
     final FirebaseAuth.AuthStateListener listener =
         new FirebaseAuth.AuthStateListener() {
           @Override
@@ -278,13 +276,13 @@ public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
     firebaseAuth.addAuthStateListener(listener);
   }
 
-  private void handleSignInAnonymously(MethodCall call, final Result result) {
+  private void handleSignInAnonymously(
+      @SuppressWarnings("unused") MethodCall call, final Result result) {
     firebaseAuth.signInAnonymously().addOnCompleteListener(new SignInCompleteListener(result));
   }
 
   private void handleCreateUserWithEmailAndPassword(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String email = arguments.get("email");
     String password = arguments.get("password");
 
@@ -294,49 +292,47 @@ private void handleCreateUserWithEmailAndPassword(MethodCall call, final Result
   }
 
   private void handleFetchProvidersForEmail(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String email = arguments.get("email");
 
     firebaseAuth
-        .fetchProvidersForEmail(email)
-        .addOnCompleteListener(new ProvidersCompleteListener(result));
+        .fetchSignInMethodsForEmail(email)
+        .addOnCompleteListener(new SignInMethodCompleteListener(result));
   }
 
   private void handleSendPasswordResetEmail(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String email = arguments.get("email");
 
     firebaseAuth
         .sendPasswordResetEmail(email)
         .addOnCompleteListener(new TaskVoidCompleteListener(result));
   }
 
-  private void handleSendEmailVerification(MethodCall call, final Result result) {
+  private void handleSendEmailVerification(
+      @SuppressWarnings("unused") MethodCall call, final Result result) {
     firebaseAuth
         .getCurrentUser()
         .sendEmailVerification()
         .addOnCompleteListener(new TaskVoidCompleteListener(result));
   }
 
-  private void handleReload(MethodCall call, final Result result) {
+  private void handleReload(@SuppressWarnings("unused") MethodCall call, final Result result) {
     firebaseAuth
         .getCurrentUser()
         .reload()
         .addOnCompleteListener(new TaskVoidCompleteListener(result));
   }
 
-  private void handleDelete(MethodCall call, final Result result) {
+  private void handleDelete(@SuppressWarnings("unused") MethodCall call, final Result result) {
     firebaseAuth
         .getCurrentUser()
         .delete()
         .addOnCompleteListener(new TaskVoidCompleteListener(result));
   }
 
   private void handleSignInWithEmailAndPassword(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String email = arguments.get("email");
     String password = arguments.get("password");
 
@@ -346,8 +342,7 @@ private void handleSignInWithEmailAndPassword(MethodCall call, final Result resu
   }
 
   private void handleSignInWithGoogle(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String idToken = arguments.get("idToken");
     String accessToken = arguments.get("accessToken");
     AuthCredential credential = GoogleAuthProvider.getCredential(idToken, accessToken);
@@ -357,8 +352,7 @@ private void handleSignInWithGoogle(MethodCall call, final Result result) {
   }
 
   private void handleLinkWithGoogleCredential(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String idToken = arguments.get("idToken");
     String accessToken = arguments.get("accessToken");
     AuthCredential credential = GoogleAuthProvider.getCredential(idToken, accessToken);
@@ -369,8 +363,7 @@ private void handleLinkWithGoogleCredential(MethodCall call, final Result result
   }
 
   private void handleLinkWithFacebookCredential(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String accessToken = arguments.get("accessToken");
     AuthCredential credential = FacebookAuthProvider.getCredential(accessToken);
     firebaseAuth
@@ -380,8 +373,7 @@ private void handleLinkWithFacebookCredential(MethodCall call, final Result resu
   }
 
   private void handleLinkWithTwitterCredential(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String authToken = arguments.get("authToken");
     String authTokenSecret = arguments.get("authTokenSecret");
     AuthCredential credential = TwitterAuthProvider.getCredential(authToken, authTokenSecret);
@@ -392,8 +384,7 @@ private void handleLinkWithTwitterCredential(MethodCall call, final Result resul
   }
 
   private void handleSignInWithFacebook(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String accessToken = arguments.get("accessToken");
     AuthCredential credential = FacebookAuthProvider.getCredential(accessToken);
     firebaseAuth
@@ -418,14 +409,13 @@ private void handleSignInWithCustomToken(MethodCall call, final Result result) {
         .addOnCompleteListener(new SignInCompleteListener(result));
   }
 
-  private void handleSignOut(MethodCall call, final Result result) {
+  private void handleSignOut(@SuppressWarnings("unused") MethodCall call, final Result result) {
     firebaseAuth.signOut();
     result.success(null);
   }
 
   private void handleGetToken(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, Boolean> arguments = (Map<String, Boolean>) call.arguments;
+    Map<String, Boolean> arguments = call.arguments();
     boolean refresh = arguments.get("refresh");
     firebaseAuth
         .getCurrentUser()
@@ -444,26 +434,23 @@ public void onComplete(@NonNull Task<GetTokenResult> task) {
   }
 
   private void handleUpdateEmail(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     firebaseAuth
         .getCurrentUser()
         .updateEmail(arguments.get("email"))
         .addOnCompleteListener(new TaskVoidCompleteListener(result));
   }
 
   private void handleUpdatePassword(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     firebaseAuth
         .getCurrentUser()
         .updatePassword(arguments.get("password"))
         .addOnCompleteListener(new TaskVoidCompleteListener(result));
   }
 
   private void handleUpdateProfile(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
 
     UserProfileChangeRequest.Builder builder = new UserProfileChangeRequest.Builder();
     if (arguments.containsKey("displayName")) {
@@ -479,7 +466,8 @@ private void handleUpdateProfile(MethodCall call, final Result result) {
         .addOnCompleteListener(new TaskVoidCompleteListener(result));
   }
 
-  private void handleStartListeningAuthState(MethodCall call, final Result result) {
+  private void handleStartListeningAuthState(
+      @SuppressWarnings("unused") MethodCall call, final Result result) {
     final int handle = nextHandle++;
     FirebaseAuth.AuthStateListener listener =
         new FirebaseAuth.AuthStateListener() {
@@ -519,8 +507,7 @@ private void handleStopListeningAuthState(MethodCall call, final Result result)
   }
 
   private void handleSetLanguageCode(MethodCall call, final Result result) {
-    @SuppressWarnings("unchecked")
-    Map<String, String> arguments = (Map<String, String>) call.arguments;
+    Map<String, String> arguments = call.arguments();
     String language = arguments.get("language");
 
     firebaseAuth.setLanguageCode(language);
@@ -565,20 +552,21 @@ public void onComplete(@NonNull Task<Void> task) {
     }
   }
 
-  private class ProvidersCompleteListener implements OnCompleteListener<ProviderQueryResult> {
+  private class SignInMethodCompleteListener
+      implements OnCompleteListener<SignInMethodQueryResult> {
     private final Result result;
 
-    ProvidersCompleteListener(Result result) {
+    SignInMethodCompleteListener(Result result) {
       this.result = result;
     }
 
     @Override
-    public void onComplete(@NonNull Task<ProviderQueryResult> task) {
+    public void onComplete(@NonNull Task<SignInMethodQueryResult> task) {
       if (!task.isSuccessful()) {
         Exception e = task.getException();
         result.error(ERROR_REASON_EXCEPTION, e.getMessage(), null);
       } else {
-        List<String> providers = task.getResult().getProviders();
+        List<String> providers = task.getResult().getSignInMethods();
         result.success(providers);
       }
     }