NSOperationQueue 的整理

最新推荐文章于 2020-06-24 09:54:19 发布

转载最新推荐文章于 2020-06-24 09:54:19 发布 · 51 阅读

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原文链接：http://www.cnblogs.com/GnagWang/archive/2011/11/24/2261400.html

本文详细解析了NSOperationQueue的并发操作机制，通过多个实例展示了如何合理使用NSOperationQueue来优化多任务执行流程。从创建任务、设置最大并发数到任务间的依赖关系处理，每一步都配有实例代码及运行结果分析，帮助开发者深入理解并有效应用这一关键技术。

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@interface YkMainViewController : UIViewController <YkFlipsideViewControllerDelegate>
{
    NSOperationQueue *operationQueue; 
    BOOL b_init;
}

@interface MyTask : NSOperation
{
    int operationId;
}

@property int operationId;
@end

#import "MyTask.h"

@implementation MyTask
@synthesize operationId;

- (void)main{ 
    NSLog(@"task %i is begin run … ",operationId); 
    [NSThread sleepForTimeInterval:10]; 
    NSLog(@"task %i is run finished. ",operationId); 
}


@end

---------开始使用：场景1：

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
    
    if(!b_init)
    {
        operationQueue = [[NSOperationQueue alloc] init];
        [operationQueue setMaxConcurrentOperationCount:1];  
        
        int index = 1;
        MyTask * _task1 = [[[MyTask alloc] init] autorelease];
        _task1.operationId = index++;
        [operationQueue addOperation:_task1];
    }        
    b_init = YES;
}

结果：

2011-11-24 11:23:34.222 NSOperationQueueTest[2719:12d0b] task 1 is begin run …
2011-11-24 11:23:44.225 NSOperationQueueTest[2719:12d0b] task 1 is run finished.

场景2：

       operationQueue = [[NSOperationQueue alloc] init];
        [operationQueue setMaxConcurrentOperationCount:1];  
        
        int index = 1;
        MyTask * _task1 = [[[MyTask alloc] init] autorelease];
        _task1.operationId = index++;
        [operationQueue addOperation:_task1];
        
        MyTask * _task2 = [[[MyTask alloc] init] autorelease];
        _task2.operationId = index++; 
        
        [operationQueue addOperation:_task2];

结果：

2011-11-24 11:24:40.516 NSOperationQueueTest[2769:12e0b] task 1 is begin run …
2011-11-24 11:24:50.518 NSOperationQueueTest[2769:12e0b] task 1 is run finished.
2011-11-24 11:24:50.527 NSOperationQueueTest[2769:12e0b] task 2 is begin run …
2011-11-24 11:25:00.529 NSOperationQueueTest[2769:12e0b] task 2 is run finished.

场景3：

     operationQueue = [[NSOperationQueue alloc] init];
        [operationQueue setMaxConcurrentOperationCount:2];  
        
        int index = 1;
        MyTask * _task1 = [[[MyTask alloc] init] autorelease];
        _task1.operationId = index++;
        [operationQueue addOperation:_task1];
        
        MyTask * _task2 = [[[MyTask alloc] init] autorelease];
        _task2.operationId = index++;
        
        [operationQueue addOperation:_task2];

结果：

2011-11-24 11:25:41.663 NSOperationQueueTest[2815:11503] task 1 is begin run …
2011-11-24 11:25:41.663 NSOperationQueueTest[2815:12d0b] task 2 is begin run …
2011-11-24 11:25:51.667 NSOperationQueueTest[2815:11503] task 1 is run finished.
2011-11-24 11:25:51.669 NSOperationQueueTest[2815:12d0b] task 2 is run finished.

或者

2011-11-24 11:25:41.663 NSOperationQueueTest[2815:11503] task 1 is begin run …
2011-11-24 11:25:41.663 NSOperationQueueTest[2815:12d0b] task 2 is begin run …
2011-11-24 11:25:51.669 NSOperationQueueTest[2815:12d0b] task 2 is run finished.
2011-11-24 11:25:51.670 NSOperationQueueTest[2815:11503] task 1 is run finished.

。。。

场景4:

  operationQueue = [[NSOperationQueue alloc] init];
        [operationQueue setMaxConcurrentOperationCount:2];  
        
        int index = 1;
        MyTask * _task1 = [[[MyTask alloc] init] autorelease];
        _task1.operationId = index++;
        [operationQueue addOperation:_task1];
        
        MyTask * _task2 = [[[MyTask alloc] init] autorelease];
        _task2.operationId = index++;
        [_task2 addDependency:_task1]; 
        
        [operationQueue addOperation:_task2];

结果：

2011-11-24 11:27:00.820 NSOperationQueueTest[2859:11603] task 1 is begin run …
2011-11-24 11:27:10.823 NSOperationQueueTest[2859:11603] task 1 is run finished.
2011-11-24 11:27:10.830 NSOperationQueueTest[2859:13507] task 2 is begin run …
2011-11-24 11:27:20.832 NSOperationQueueTest[2859:13507] task 2 is run finished.

场景5:

      operationQueue = [[NSOperationQueue alloc] init];
        [operationQueue setMaxConcurrentOperationCount:2];  
        
        int index = 1;
        MyTask * _task1 = [[[MyTask alloc] init] autorelease];
        _task1.operationId = index++;
        
        
        MyTask * _task2 = [[[MyTask alloc] init] autorelease];
        _task2.operationId = index++;
        [_task2 addDependency:_task1]; 
        
        
        [operationQueue addOperation:_task2]; [operationQueue addOperation:_task1];

结果：

2011-11-24 11:29:19.807 NSOperationQueueTest[2945:11503] task 1 is begin run …
2011-11-24 11:29:29.809 NSOperationQueueTest[2945:11503] task 1 is run finished.
2011-11-24 11:29:29.817 NSOperationQueueTest[2945:12d0f] task 2 is begin run …
2011-11-24 11:29:39.818 NSOperationQueueTest[2945:12d0f] task 2 is run finished.

场景6:

 operationQueue = [[NSOperationQueue alloc] init];
        [operationQueue setMaxConcurrentOperationCount:2];  
        
        int index = 1;
        MyTask * _task1 = [[[MyTask alloc] init] autorelease];
        _task1.operationId = index++;
        
        
        MyTask * _task2 = [[[MyTask alloc] init] autorelease];
        _task2.operationId = index++;
        [_task2 addDependency:_task1]; 
        
        
        [operationQueue addOperation:_task2];
        [operationQueue addOperation:_task1];
        
        NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(doSomethingInBackground) object:nil];
        
        [operationQueue addOperation:operation];

- (void) doSomethingInBackground
{
    NSLog(@"doSomethingInBackground");
}

结果：

2011-11-24 11:32:15.211 NSOperationQueueTest[3038:11503] doSomethingInBackground
2011-11-24 11:32:15.211 NSOperationQueueTest[3038:12d0b] task 1 is begin run …
2011-11-24 11:32:25.215 NSOperationQueueTest[3038:12d0b] task 1 is run finished.
2011-11-24 11:32:25.225 NSOperationQueueTest[3038:12d0b] task 2 is begin run …
2011-11-24 11:32:35.226 NSOperationQueueTest[3038:12d0b] task 2 is run finished.

转载于:https://www.cnblogs.com/GnagWang/archive/2011/11/24/2261400.html