ViewController.h

// this is ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController


@end

// end of ViewController.h

ViewController.m

// this is ViewController.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
	[super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning {
	[super didReceiveMemoryWarning];
	// Dispose of any resources that can be recreated.
}

- (void)viewDidAppear:(BOOL)animated {
	[super viewDidAppear:animated];
	[self doTest];
}

- (void)doTest {
	
	// 1
	NSString *dataUrl = @"https://www.example.com";
	NSURL *url = [NSURL URLWithString:dataUrl];
	
	NSURLRequest *req = [[NSURLRequest alloc] initWithURL:url];
 
	// 2
	NSURLSessionDataTask *downloadTask = [[NSURLSession sharedSession]
			dataTaskWithRequest:req
			completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
											  
			// 4: Handle response here
											  
			NSString *s = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
			NSLog(@"Data: %@", s);
			}];
 
	// 3
	[downloadTask resume];

}

@end

// end of ViewController.m