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)}