[dynamic_links]: fix initialization process

packages/firebase_dynamic_links/README.md

@@ -95,8 +95,7 @@ Receiving dynamic links on *iOS* requires a couple more steps than *Android*. If
 applinks:YOUR_SUBDOMAIN.page.link
 ```
 
-4. To receive a dynamic link, call the `getInitialLink()` method from `FirebaseDynamicLinks` which gets the link that opened the app (or null if it was not opened via a dynamic link)
-and configure listeners for link callbacks when the application is active or in background calling `onLink`.
+4. To receive a dynamic link, configure listeners for link callbacks when the application is active or in background calling `onLink` and call the `getInitialLink()` method from `FirebaseDynamicLinks` which gets the link that opened the app (or null if it was not opened via a dynamic link).
 
 ```dart
 void main() {
@@ -120,13 +119,6 @@ class MyHomeWidgetState extends State<MyHomeWidget> {
   }
 
   void initDynamicLinks() async {
-    final PendingDynamicLinkData data = await FirebaseDynamicLinks.instance.getInitialLink();
-    final Uri deepLink = data?.link;
-
-    if (deepLink != null) {
-      Navigator.pushNamed(context, deepLink.path);
-    }
-
     FirebaseDynamicLinks.instance.onLink(
       onSuccess: (PendingDynamicLinkData dynamicLink) async {
         final Uri deepLink = dynamicLink?.link;
@@ -140,6 +132,13 @@ class MyHomeWidgetState extends State<MyHomeWidget> {
         print(e.message);
       }
     );
+    
+    final PendingDynamicLinkData data = await FirebaseDynamicLinks.instance.getInitialLink();
+    final Uri deepLink = data?.link;
+
+    if (deepLink != null) {
+      Navigator.pushNamed(context, deepLink.path);
+    }
   }
   .
   .

packages/firebase_dynamic_links/example/lib/main.dart

@@ -4,8 +4,8 @@
 
 import 'dart:async';
 
-import 'package:flutter/material.dart';
 import 'package:firebase_dynamic_links/firebase_dynamic_links.dart';
+import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:url_launcher/url_launcher.dart';
 
@@ -40,14 +40,6 @@ class _MainScreenState extends State<_MainScreen> {
   }
 
   void initDynamicLinks() async {
-    final PendingDynamicLinkData data =
-        await FirebaseDynamicLinks.instance.getInitialLink();
-    final Uri deepLink = data?.link;
-
-    if (deepLink != null) {
-      Navigator.pushNamed(context, deepLink.path);
-    }
-
     FirebaseDynamicLinks.instance.onLink(
         onSuccess: (PendingDynamicLinkData dynamicLink) async {
       final Uri deepLink = dynamicLink?.link;
@@ -59,6 +51,14 @@ class _MainScreenState extends State<_MainScreen> {
       print('onLinkError');
       print(e.message);
     });
+
+    final PendingDynamicLinkData data =
+        await FirebaseDynamicLinks.instance.getInitialLink();
+    final Uri deepLink = data?.link;
+
+    if (deepLink != null) {
+      Navigator.pushNamed(context, deepLink.path);
+    }
   }
 
   Future<void> _createDynamicLink(bool short) async {

packages/firebase_dynamic_links/ios/Classes/FLTFirebaseDynamicLinksPlugin.m

@@ -118,6 +118,33 @@ - (NSMutableDictionary *)getInitialLink {
   return getDictionaryFromDynamicLink(_initialLink);
 }
 
+- (void)onDeepLinkResult:(FIRDynamicLink *_Nullable)dynamicLink error:(NSError *_Nullable)error {
+  if (_initiated) {
+    if (error) {
+      FlutterError *flutterError = getFlutterError(error);
+      [_channel invokeMethod:@"onLinkError" arguments:getDictionaryFromFlutterError(flutterError)];
+    } else {
+      NSMutableDictionary *dictionary = getDictionaryFromDynamicLink(dynamicLink);
+      [_channel invokeMethod:@"onLinkSuccess" arguments:dictionary];
+    }
+  } else {
+    if (error) {
+      _flutterError = getFlutterError(error);
+    } else {
+      _initialLink = dynamicLink;
+    }
+  }
+}
+
+- (BOOL)checkForDynamicLink:(NSURL *)url {
+  FIRDynamicLink *dynamicLink = [[FIRDynamicLinks dynamicLinks] dynamicLinkFromCustomSchemeURL:url];
+  if (dynamicLink) {
+    [self onDeepLinkResult:dynamicLink error:nil];
+    return YES;
+  }
+  return NO;
+}
+
 - (BOOL)application:(UIApplication *)application
             openURL:(NSURL *)url
             options:(NSDictionary<UIApplicationOpenURLOptionsKey, id> *)options {
@@ -131,52 +158,17 @@ - (BOOL)application:(UIApplication *)application
   return [self checkForDynamicLink:url];
 }
 
-- (BOOL)checkForDynamicLink:(NSURL *)url {
-  FIRDynamicLink *dynamicLink = [[FIRDynamicLinks dynamicLinks] dynamicLinkFromCustomSchemeURL:url];
-  if (dynamicLink) {
-    if (dynamicLink.url) _initialLink = dynamicLink;
-    return YES;
-  }
-  return NO;
-}
-
-- (BOOL)onLink:(NSUserActivity *)userActivity {
-  BOOL handled = [[FIRDynamicLinks dynamicLinks]
-      handleUniversalLink:userActivity.webpageURL
-               completion:^(FIRDynamicLink *_Nullable dynamicLink, NSError *_Nullable error) {
-                 if (error) {
-                   FlutterError *flutterError = getFlutterError(error);
-                   [self.channel invokeMethod:@"onLinkError"
-                                    arguments:getDictionaryFromFlutterError(flutterError)];
-                 } else {
-                   NSMutableDictionary *dictionary = getDictionaryFromDynamicLink(dynamicLink);
-                   [self.channel invokeMethod:@"onLinkSuccess" arguments:dictionary];
-                 }
-               }];
-  return handled;
-}
-
-- (BOOL)onInitialLink:(NSUserActivity *)userActivity {
+- (BOOL)application:(UIApplication *)application
+    continueUserActivity:(NSUserActivity *)userActivity
+      restorationHandler:(void (^)(NSArray *))restorationHandler {
   BOOL handled = [[FIRDynamicLinks dynamicLinks]
       handleUniversalLink:userActivity.webpageURL
                completion:^(FIRDynamicLink *_Nullable dynamicLink, NSError *_Nullable error) {
-                 if (error) {
-                   self.flutterError = getFlutterError(error);
-                 }
-                 self.initialLink = dynamicLink;
+                 [self onDeepLinkResult:dynamicLink error:error];
                }];
   return handled;
 }
 
-- (BOOL)application:(UIApplication *)application
-    continueUserActivity:(NSUserActivity *)userActivity
-      restorationHandler:(void (^)(NSArray *))restorationHandler {
-  if (_initiated) {
-    return [self onLink:userActivity];
-  }
-  return [self onInitialLink:userActivity];
-}
-
 - (FIRDynamicLinkShortenerCompletion)createShortLinkCompletion:(FlutterResult)result {
   return ^(NSURL *_Nullable shortURL, NSArray *_Nullable warnings, NSError *_Nullable error) {
     if (error) {