kmpdfkit_demo/ios/Classes/CompdfkitFlutterPlugin.m

#import "CompdfkitFlutterPlugin.h"
#import "FLNativeView.h"

#import <ComPDFKit/ComPDFKit.h>
#import "CPDFViewController.h"

@implementation CompdfkitFlutterPlugin

+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
    
  FlutterMethodChannel* channel = [FlutterMethodChannel
      methodChannelWithName:@"com.compdfkit.flutter.plugin"
            binaryMessenger:[registrar messenger]];
  CompdfkitFlutterPlugin* instance = [[CompdfkitFlutterPlugin alloc] init];

  [registrar addMethodCallDelegate:instance channel:channel];
}

- (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
  if ([@"sdk_version_code" isEqualToString:call.method]) {
    result([CPDFKit sharedInstance].versionString);
  } else if ([@"init_sdk" isEqualToString:call.method]) {
      NSDictionary *initInfo = (NSDictionary *)call.arguments;
      NSString *key = initInfo[@"key"] ?: @"";
      NSString *secret = initInfo[@"secret"] ?: @"";
      [CPDFKit setLicenseKey:key secret:secret];
  } else if ([@"sdk_build_tag" isEqualToString:call.method]) {
      result([@"iOS build tag:" stringByAppendingFormat:@"%ld", [CPDFKit sharedInstance].buildNumber]);
  } else if ([@"openDocument" isEqualToString:call.method]){
      NSString *path = (NSString *)call.arguments;
      UIViewController *tRootViewControl = [UIApplication sharedApplication].keyWindow.rootViewController;
              if ([tRootViewControl presentedViewController]) {
                  tRootViewControl = [tRootViewControl presentedViewController];
              }
      CPDFViewController *pdfViewController = [[CPDFViewController alloc] initWithFilePath:path password:nil];

      UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:pdfViewController];
      navigationController.modalPresentationStyle = UIModalPresentationFullScreen;
      [tRootViewControl presentViewController:navigationController animated:YES completion:nil];

  } else if ([@"getTemporaryDirectory" isEqualToString:call.method]){
      result([self getTemporaryDirectory]);
  } else {
      result(FlutterMethodNotImplemented);
  }
}

- (NSString*)getTemporaryDirectory {
    NSArray* paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    return paths.firstObject;
}

@end