[url_launcher] Removed reference to rootViewController during initialization (#2038)

The current plugin implementation stores a reference to the rootViewController during the initialisation which breaks scenarios like app2app. This PR does not store any variable to rootViewController but search through the VC hierarchy to get the top most VC in order to present the new vc.

Author: vitor-gyant

packages/url_launcher/CHANGELOG.md

@@ -1,3 +1,8 @@
+
+## 5.1.3
+
+* Always launch url from the top most UIViewController in iOS.
+
 ## 5.1.2
 
 * Update AGP and gradle.

packages/url_launcher/ios/Classes/UrlLauncherPlugin.m

@@ -61,33 +61,16 @@ @interface FLTUrlLauncherPlugin ()
 
 @end
 
-@interface FLTUrlLauncherPlugin ()
-
-@property(strong, nonatomic) UIViewController *viewController;
-
-@end
-
 @implementation FLTUrlLauncherPlugin
 
 + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
   FlutterMethodChannel *channel =
       [FlutterMethodChannel methodChannelWithName:@"plugins.flutter.io/url_launcher"
                                   binaryMessenger:registrar.messenger];
-  UIViewController *viewController =
-      [UIApplication sharedApplication].delegate.window.rootViewController;
-  FLTUrlLauncherPlugin *plugin =
-      [[FLTUrlLauncherPlugin alloc] initWithViewController:viewController];
+  FLTUrlLauncherPlugin *plugin = [[FLTUrlLauncherPlugin alloc] init];
   [registrar addMethodCallDelegate:plugin channel:channel];
 }
 
-- (instancetype)initWithViewController:(UIViewController *)viewController {
-  self = [super init];
-  if (self) {
-    self.viewController = viewController;
-  }
-  return self;
-}
-
 - (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
   NSString *url = call.arguments[@"url"];
   if ([@"canLaunch" isEqualToString:call.method]) {
@@ -153,9 +136,9 @@ - (void)launchURLInVC:(NSString *)urlString result:(FlutterResult)result API_AVA
   self.currentSession.didFinish = ^(void) {
     weakSelf.currentSession = nil;
   };
-  [self.viewController presentViewController:self.currentSession.safari
-                                    animated:YES
-                                  completion:nil];
+  [self.topViewController presentViewController:self.currentSession.safari
+                                       animated:YES
+                                     completion:nil];
 }
 
 - (void)closeWebViewWithResult:(FlutterResult)result API_AVAILABLE(ios(9.0)) {
@@ -165,4 +148,36 @@ - (void)closeWebViewWithResult:(FlutterResult)result API_AVAILABLE(ios(9.0)) {
   result(nil);
 }
 
+- (UIViewController *)topViewController {
+  return [self topViewControllerFromViewController:[UIApplication sharedApplication]
+                                                       .keyWindow.rootViewController];
+}
+
+/**
+ * This method recursively iterate through the view hierarchy
+ * to return the top most view controller.
+ *
+ * It supports the following scenarios:
+ *
+ * - The view controller is presenting another view.
+ * - The view controller is a UINavigationController.
+ * - The view controller is a UITabBarController.
+ *
+ * @return The top most view controller.
+ */
+- (UIViewController *)topViewControllerFromViewController:(UIViewController *)viewController {
+  if ([viewController isKindOfClass:[UINavigationController class]]) {
+    UINavigationController *navigationController = (UINavigationController *)viewController;
+    return [self
+        topViewControllerFromViewController:[navigationController.viewControllers lastObject]];
+  }
+  if ([viewController isKindOfClass:[UITabBarController class]]) {
+    UITabBarController *tabController = (UITabBarController *)viewController;
+    return [self topViewControllerFromViewController:tabController.selectedViewController];
+  }
+  if (viewController.presentedViewController) {
+    return [self topViewControllerFromViewController:viewController.presentedViewController];
+  }
+  return viewController;
+}
 @end

packages/url_launcher/pubspec.yaml

@@ -3,7 +3,7 @@ description: Flutter plugin for launching a URL on Android and iOS. Supports
   web, phone, SMS, and email schemes.
 author: Flutter Team <[email protected]>
 homepage: https://github.com/flutter/plugins/tree/master/packages/url_launcher
-version: 5.1.2
+version: 5.1.3
 
 flutter:
   plugin: