NSOperationqueue的一些感悟

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor=[UIColor redColor];
    
    NSOperationQueue *queue=[[NSOperationQueue alloc]init];
    
    NSOperationQueue *queue2=[[NSOperationQueue alloc]init];
    
    NSBlockOperation *operation1=[NSBlockOperation blockOperationWithBlock:^(){
        NSLog(@"执行第一次:%@",[NSThread currentThread]);
    }];

    
    NSBlockOperation *operation2=[NSBlockOperation blockOperationWithBlock:^(){
        NSLog(@"执行第二次:%@",[NSThread currentThread]);
    }];
    
    [operation1 addDependency:operation2];
    [queue addOperation:operation1];
    [queue addOperation:operation2 ];
    
    NSBlockOperation *operation3=[NSBlockOperation blockOperationWithBlock:^(){
        NSLog(@"执行第三次:%@",[NSThread currentThread]);
    }];
    NSBlockOperation *operation4=[NSBlockOperation blockOperationWithBlock:^(){
        NSLog(@"执行第四次:%@",[NSThread currentThread]);
    }];
    
    [queue2 addOperation:operation4];
    [queue2 addOperation:operation3];

　　

2016-05-10 17:00:00.552 testobjectc[2305:152414] 执行第四次:<NSThread: 0x78e89910>{number = 2, name = (null)}
2016-05-10 17:00:00.552 testobjectc[2305:152410] 执行第二次:<NSThread: 0x78e60090>{number = 3, name = (null)}
2016-05-10 17:00:00.553 testobjectc[2305:152415] 执行第三次:<NSThread: 0x78fa4280>{number = 4, name = (null)}
2016-05-10 17:00:00.559 testobjectc[2305:152414] 执行第一次:<NSThread: 0x78e89910>{number = 2, name = (null)}

　　

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor=[UIColor redColor];
    
    NSOperationQueue *queue=[[NSOperationQueue alloc]init];
    
    NSOperationQueue *queue2=[[NSOperationQueue alloc]init];
    
    NSBlockOperation *operation1=[NSBlockOperation blockOperationWithBlock:^(){
        NSLog(@"执行第一次:%@",[NSThread currentThread]);
    }];

    
    NSBlockOperation *operation2=[NSBlockOperation blockOperationWithBlock:^(){
        NSLog(@"执行第二次:%@",[NSThread currentThread]);
    }];
    
    [operation1 addDependency:operation2];
    [queue addOperation:operation1];
    [queue addOperation:operation2 ];
    
    NSBlockOperation *operation3=[NSBlockOperation blockOperationWithBlock:^(){
        NSLog(@"执行第三次:%@",[NSThread currentThread]);
    }];
    NSBlockOperation *operation4=[NSBlockOperation blockOperationWithBlock:^(){
        NSLog(@"执行第四次:%@",[NSThread currentThread]);
    }];
    
    [queue2 addOperation:operation4];
    [queue2 addOperation:operation3];
    [self downLoad];
    
    
    
    

    
    
    
    
    // Do any additional setup after loading the view, typically from a nib.
}


-(void)downLoad{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSURL *url=[NSURL URLWithString:@"www.baidu.com"];
        NSLog(@"%@",url);
        dispatch_async(dispatch_get_main_queue(), ^{
            self.view.backgroundColor=[UIColor blueColor];
        });
        
    });
}

　　

2016-05-10 19:52:57.269 testobjectc[2631:181847] www.baidu.com
2016-05-10 19:52:57.269 testobjectc[2631:181844] 执行第四次:<NSThread: 0x7d0ad9b0>{number = 3, name = (null)}
2016-05-10 19:52:57.274 testobjectc[2631:181861] 执行第三次:<NSThread: 0x7be3dde0>{number = 4, name = (null)}
2016-05-10 19:52:57.269 testobjectc[2631:181848] 执行第二次:<NSThread: 0x7d00b570>{number = 2, name = (null)}
2016-05-10 19:52:57.277 testobjectc[2631:181848] 执行第一次:<NSThread: 0x7d00b570>{number = 2, name = (null)}