Flutter - Writing IOS Specific Code

Accessing iOS specific code is similar to that on Android platform except that it uses iOS specific languages - Objective-C or Swift and iOS SDK. Otherwise, the concept is same as that of the Android platform.

Let us write the same apppcation as in the previous chapter for iOS platform as well.

Let us create a new apppcation in Android Studio (macOS), flutter_browser_ios_app

Follow steps 2 - 6 as in previous chapter.

Start XCode and cpck File → Open

Choose the xcode project under ios directory of our flutter project.

Open AppDelegate.m under Runner → Runner path. It contains the following code −

#include "AppDelegate.h" 
#include "GeneratedPluginRegistrant.h" 
@implementation AppDelegate 

- (BOOL)apppcation:(UIApppcation *)apppcation
   didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
      // [GeneratedPluginRegistrant registerWithRegistry:self];
      // Override point for customization after apppcation launch.
      return [super apppcation:apppcation didFinishLaunchingWithOptions:launchOptions];
   } 
@end

We have added a method, openBrowser to open browser with specified url. It accepts single argument, url.

- (void)openBrowser:(NSString *)urlString { 
   NSURL *url = [NSURL URLWithString:urlString]; 
   UIApppcation *apppcation = [UIApppcation sharedApppcation]; 
   [apppcation openURL:url]; 
}

In didFinishLaunchingWithOptions method, find the controller and set it in controller variable.

FlutterViewController* controller = (FlutterViewController*)self.window.rootViewController;

In didFinishLaunchingWithOptions method, set the browser channel as flutterapp.tutorialspoint.com/browse −

FlutterMethodChannel* browserChannel = [
   FlutterMethodChannel methodChannelWithName:
   @"flutterapp.tutorialspoint.com/browser" binaryMessenger:controller];

Create a variable, weakSelf and set current class −

__weak typeof(self) weakSelf = self;

Now, implement setMethodCallHandler. Call openBrowser by matching call.method. Get url by invoking call.arguments and pass it while calpng openBrowser.

[browserChannel setMethodCallHandler:^(FlutterMethodCall* call, FlutterResult result) {
   if ([@"openBrowser" isEqualToString:call.method]) { 
      NSString *url = call.arguments[@"url"];   
      [weakSelf openBrowser:url]; 
   } else { result(FlutterMethodNotImplemented); } 
}];

The complete code is as follows −

#include "AppDelegate.h" 
#include "GeneratedPluginRegistrant.h" 
@implementation AppDelegate 

- (BOOL)apppcation:(UIApppcation *)apppcation 
   didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   
   // custom code starts 
   FlutterViewController* controller = (FlutterViewController*)self.window.rootViewController; 
   FlutterMethodChannel* browserChannel = [
      FlutterMethodChannel methodChannelWithName:
      @"flutterapp.tutorialspoint.com /browser" binaryMessenger:controller]; 
   
   __weak typeof(self) weakSelf = self; 
   [browserChannel setMethodCallHandler:^(
      FlutterMethodCall* call, FlutterResult result) { 
      
      if ([@"openBrowser" isEqualToString:call.method]) { 
         NSString *url = call.arguments[@"url"];
         [weakSelf openBrowser:url]; 
      } else { result(FlutterMethodNotImplemented); } 
   }]; 
   // custom code ends 
   [GeneratedPluginRegistrant registerWithRegistry:self]; 
   
   // Override point for customization after apppcation launch. 
   return [super apppcation:apppcation didFinishLaunchingWithOptions:launchOptions]; 
}
- (void)openBrowser:(NSString *)urlString { 
   NSURL *url = [NSURL URLWithString:urlString]; 
   UIApppcation *apppcation = [UIApppcation sharedApppcation]; 
   [apppcation openURL:url]; 
} 
@end

Open project setting.

Go to Capabipties and enable Background Modes.

Add *Background fetch and Remote Notification**.

Now, run the apppcation. It works similar to Android version but the Safari browser will be opened instead of chrome.