RunLoopStudy.m

//
//  ViewController.m
//  RunLoop
//
//  Created by cj on 2017/4/26.
//  Copyright © 2017年 cj. All rights reserved.
//

#import "ViewController.h"
#import <AFNetworking/AFNetworking.h>

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.google1.com"]];
        NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
        
        if (connection == nil) {
            NSLog(@"Request failed");
            
        } else {
            NSLog(@"Request sent");
        }
        
        [[NSRunLoop currentRunLoop] run]; // make the delegate method to get called
        NSLog(@"first roonloop end");
    });
    
    dispatch_async ( dispatch_get_global_queue ( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0 ), ^ {
        NSMutableURLRequest * request = [ [ NSMutableURLRequest alloc ] initWithURL: [NSURL URLWithString:@"https://www.google1.com"] ];
        [ request setHTTPMethod: @"GET" ];
    
        AFHTTPRequestOperation * requestOperation = [ [ AFHTTPRequestOperation alloc ] initWithRequest: request ];
        [ requestOperation setCompletionBlockWithSuccess: ^ ( AFHTTPRequestOperation * operation, id responseObject ) {
            NSLog(@"%s success", __PRETTY_FUNCTION__);
        } failure: ^ ( AFHTTPRequestOperation * operation, NSError * error ) {
            NSLog(@"%s fail", __PRETTY_FUNCTION__);
        } ];
        [ requestOperation start ];
        
        
        // no need for this currentRunLoop run, the block will still get involved
//        [ [ NSRunLoop currentRunLoop ] run ];
    } );
    
    dispatch_async ( dispatch_get_global_queue ( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0 ), ^ {
        NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:3
                                                          target:self
                                                        selector:@selector(foo:)
                                                        userInfo:nil
                                                         repeats:NO];
        NSLog(@"%s %@", __PRETTY_FUNCTION__, timer);
        
        [[NSRunLoop currentRunLoop] run]; // needed to let foo run successfully
        /*
         Puts the receiver into a permanent loop, during which time it processes data from all attached input sources.
         If no input sources or timers are attached to the run loop, this method exits immediately; otherwise, it runs the receiver in the NSDefaultRunLoopMode by repeatedly invoking runMode:beforeDate:. In other words, this method effectively begins an infinite loop that processes data from the run loop’s input sources and timers.
         */
        
        NSLog(@"RunLoop End");
    });
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    NSLog(@"%s", __PRETTY_FUNCTION__);
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"%s", __PRETTY_FUNCTION__);
}

- (void)foo:(id)sender
{
    NSLog(@"%s", __PRETTY_FUNCTION__);
}

@end