NSURLConnection的代理方法调用问题

#import "ViewController.h"

@interface ViewController ()<NSURLConnectionDataDelegate>

@end

@implementation ViewController

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    [self newThreaddelegate2];
}

- (void)delegate1
{
    //
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"https://api.apiopen.top/recommendPoetry"]];
    //设置代理
    //代理方法默认在主线程调用
    
    NSURLConnection *connection = [NSURLConnection connectionWithRequest:request delegate:self];
    //设置代理方法在哪个线程中调用
    //开子线程：[[NSOperationQueue alloc] init]
    //不能设置在主线程中执行[NSOperationQueue mainQueue],没有任何反应，不能这样设置
    [connection setDelegateQueue:[[NSOperationQueue alloc] init]];
    
    NSLog(@"+++++++++");
    
}
- (void)delegate2
{
   
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"https://api.apiopen.top/recommendPoetry"]];
    //设置代理
    //代理方法默认在主线程调用
    //设置为立刻执行，跟delegate1没有区别
    NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
    //设置代理方法在哪个线程中调用
    [connection setDelegateQueue:[[NSOperationQueue alloc] init]];
    //开始发送请求
    [connection start];
    NSLog(@"+++++++++");
    
}
//开子线程来发送请求
- (void)newThreaddelegate
{
    //在子线程中发送请求代理方法可调用的条件是，开启runloop，模式为默认，缺一不可
    dispatch_async(dispatch_get_global_queue(0, 0), ^{
        NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"https://api.apiopen.top/recommendPoetry"]];
        //设置代理
        //代理方法默认在主线程调用
        //该方法内部会将connection对象作为一个source添加到runloop中，指定运行模式为默认
        //由于是子线程，runloop没有开启，所以设置代理失败，代理方法不执行
        NSURLConnection *connection = [NSURLConnection connectionWithRequest:request delegate:self];
        //设置代理方法在哪个线程中调用
        //开子线程：[[NSOperationQueue alloc] init]
        //不能设置在主线程中执行[NSOperationQueue mainQueue],没有任何反应，不能这样设置
        [connection setDelegateQueue:[[NSOperationQueue alloc] init]];
        //让runloop开启
        //设置了模式不是默认，也不行
//        [[NSRunLoop currentRunLoop] runMode:UITrackingRunLoopMode beforeDate:[NSDate dateWithTimeIntervalSinceNow:1000]];
        [[NSRunLoop currentRunLoop] run];
        NSLog(@"newThreaddelegate-----%@",[NSThread currentThread]);
    });
   
    
    NSLog(@"+++++++++");
    
}

- (void)newThreaddelegate2
{
    dispatch_async(dispatch_get_global_queue(0, 0), ^{
        NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"https://api.apiopen.top/recommendPoetry"]];
        //设置代理
        //代理方法默认在主线程调用
        //设置为立刻执行，跟delegate1没有区别
        NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
        //设置代理方法在哪个线程中调用
        [connection setDelegateQueue:[[NSOperationQueue alloc] init]];
        //开始发送请求
        //如果connection对象没有添加到runloop中，start会自动添加
        //如果runloop没有开启，那么该方法内部会自动获得当前线程对应的runloop并开启，指定模式为默认
        [connection start];
        NSLog(@"%@",[NSThread currentThread]);
    });
    
   
    NSLog(@"+++++++++");
    
}
#pragma mark---------------------
#pragma mark NSURLConnectionDataDelegate
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    NSLog(@"didReceiveResponse-------%@", [NSThread currentThread]);
}

@end